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We investigated the population growth of the khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae) on seven groups of commercially available non-grain commodities. Six powdered spices were used in the first group of experiments: black pepper, clove, nutmeg, allspice, cinnamon and turmeric. The second group of the tested commodities included seven animal products: powdered cow milk, powdered pork zelatin, sheeps’ wool, goat’s skin, ducks’ feathers, dry dog food and dry cat food. The third group of commodities was consisted of six herbs: oregano, spearmint, basil, coriander, laurel and marjoram. The fourth group of commodities contained ten pulses: chickpeas, lentil, split peas, black-eyed peas, beans, soybean flour and whole kernels, lima beans, mung bean, and broad beans. The fifth group comprised six dried fruits: Corinthian currants, sultanas, banana chips, melons, apricots and figs. The sixth group was consisted of five non-grain commodities: cottonseed cake, tobacco, black tea, Turk kahvesi and potato flour. The seventh group included seven nuts: sunflower seeds, pumpkin seeds, pistachios, roasted chickpeas (yellow), almonds, hazelnuts and walnuts. Finally, six cracked containment categories (0% cracked kernels, 5% cracked kernels and 95% intact kernels, 10% cracked kernels and 90% intact kernels, 25% cracked kernels and 75% intact kernels, 50% cracked kernels and 50% intact kernels and 100% cracked kernels) from five pulses were tested: chickpeas, black-eyed peas, mung bean, soybean and split peas. The highest progeny production (3.01 individuals per vial) was recorded on powdered cow milk. On pistachios, split peas, sunflower seeds, soybean flour, pumpkin seeds, walnuts, almonds and coriander, T. granarium built high population densities rapidly, while on roasted chickpeas, cottonseed cake, hazelnuts, chickpeas, dog food and lentils, its population growth was much less. Broad beans, melons, figs, lima beans, beans, Corinthian currants, pork zelatin and potato flour were less suitable diets for the development of this species. On black pepper, clove, nutmeg, allspice, cinnamon, turmeric, sheeps’ wool, goat’s skin, ducks’ feathers, cat food, sultanas, banana chips, apricots, tobacco, black tea, Turk kahvesi, oregano, spearmint, basil, laurel and marjoram, no progeny production was recorded. The proportion of 100% cracked black-eyed peas or mung beans was more suitable for the population growth of T. granarium. Also, the percentages of 50% cracked chickpeas or 10% cracked soybeans enhanced the development of the species, in comparison with the whole kernels of each pulse. Our study indicated that several non-grain commodities are beneficial for the population growth of T. granarium, a fact that should be seriously taken into account in international trade, as this pest may utilize them as “vehicles” of expansion.

The khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae) is a dangerous insect of stored products that has currently expanded in Africa, Asia and Europe. Control of this species encounters difficulties when synthetic insecticides are applied either as surface treatments or as grain protectants. Therefore, new insecticidal formulations should be assessed as additional tools towards an effective management of T. granarium. In the current study, we tested the new insecticidal formulation Dobol, that contains the pyrethroid insecticide d-tetramethrin and the neonicotinoid insecticide acetamiprid, as treatments on concrete. Their direct and delayed mortality against adults and larvae of T. granarium were estimated under two label doses (min and max) and two temperature levels (30 and 35 °C) after 1, 2, 3, 4 and 7 d of exposure interval. Results revealed that Dobol caused direct mortality to T. granarium adults that ranged between 87.8 and 96.7%. Concerning larvae, direct mortality was generally much lower, being at most 84.4% at the max dose after 7 d of exposure. Temperature had significant impact on the direct mortality of T. granarium adults and larvae within the vast majority of the tested exposure intervals at both doses. However, when the surviving adults and larvae were transferred on untreated concrete surfaces, despite higher mortality at 35 than 30 °C, there was no significant impact of temperature on their mortalities within any exposure interval and dose. Our study revealed that Dobol is a promising insecticidal formulation that can be effectively used against adults and larvae of T. granarium on concrete surfaces.

Insects damage grain during post-harvest storage. Grain loss during storage is a serious problem, especially in less-developed countries. In this study, a gaseous ClO2 treatment was applied to four different insect species known to damage stored grains: Sitophilus zeamais (Motschulsky), Trogoderma granarium (Everts), Callosobruchus chinensis (Linnaeus), and Tribolium castaneum (Herbst). Different insect species showed different sensitivities to the same ClO2 fumigation conditions. The 100 ppm treatment level with 24 h exposure is effective to controlling S. zeamais, T. granarium, and C. chinensis. However, to control T. castaneum, a higher concentration of the ClO2 gas or increased exposure time is needed. The 200 ppm treatment level with 48 h exposure is effective to controlling T. castaneum.

The khapra beetle, Trogoderma granarium Everts (Coloeptera: Dermestidae), is a globally serious pest of several agricultural stored-commodities. Among new methods that target to control this species is the insecticidal treatment of storage bags. In the present study, we tested the efficiency of alpha-cypermethrin (= α-cypermethrin), chlorfenapyr, deltamethrin and pirimiphos-methyl applied on woven polypropylene, biaxially oriented polypropylene and kraft paper storage bags against adults and larvae of T. granarium under three treatment scenarios: one surface of the storage bag was treated and individuals were exposed on treated or untreated surface or both surfaces were treated. We estimated the immediate mortality after 1, 3 and 5 days (d) of exposure. Then, we placed adults and larvae that were alive unto untreated surfaces of the same type of storage bags and evaluated the delayed mortality after 7 d of exposure. Regarding immediate mortality, the most effective insecticides were chlorfenapyr and pirimiphos-methyl against both life stages. All insecticidal combinations resulted in very high delayed mortality values that finally killed ≥91.1% of the initially exposed adult population of T. granarium while in several combinations all adults died due to the delayed mortality. The initial population of T. granarium larvae was further reduced through delayed mortality, but there were still alive individuals on the storage bags. In the majority of combinations with α-cypermethrin, deltamethrin and pirimiphos-methyl, there were no significant differences in the mortality levels of adults and larvae when they were exposed onto the treated surface of the storage bags having one or both surfaces treated. All insecticides performed equally on the three tested types of storage bags. The present study illustrates that the application of chlorfenapyr and pirimiphos-methyl on different types of storage bags could be considered as additional tools for the management and regulation of expansion of T. granarium.

The Khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), is an important insect pest of stored cereals, grains and other stored products in Iran and some countries of the world. Nutritional indices and digestive enzymatic activity of fifth instar T. granarium were investigated on nine maize hybrids (704, AR 89, AS 71, AS 77, BC 678, KSC 703, PL 472, SC 704, and Simax) at 33 ± 1 °C, relative humidity of 65 ± 5%, and a photoperiod of 14: 10 (L: D) h. The highest and lowest food consumption by larvae was on AR 89 and BC 678, respectively. Fifth instar larvae fed on 704 had the highest efficiency of conversion of ingested food, and those fed on BC 678 showed the lowest relative growth rate. The larval growth index, standardized insect-growth index and fitness index were the highest when larvae were reared on PL 472, and the lowest when they were reared on BC 678. The highest proteolytic and amylolytic activity was on KSC 703, and the lowest activity was on BC 678. The results of this study indicated that BC 678 was an unsuitable hybrid for feeding of fifth instar T. granarium. Studying the nutritional physiology of T. granarium on different maize hybrids can be useful in identifying the anti digestive compounds of host grains, which can be expressed in genetically engineered crops to confer resistance to this key pest.

Biology, some physiological processes and cold hardiness of Trogoderma granarium Everts (Coleoptera: Dermestidae) on ten diets (barley, corn, millet, rice, rye, sorghum, triticale, wheat groundnut, and walnut) were studied under laboratory conditions (33 ± 1 °C with 65 ± 5% RH, 14L: 10D). According to the results, the insects reared on triticale had shortest development time, and the highest fecundity and fertility. By contrast, the longest development time, and the lowest fecundity and fertility were on groundnut. The survival rates ranged from 40 to 87% with the lowest values observed on groundnut. T. granarium larvae fed on triticale and millet had the highest amylolytic activity. In contrast, groundnut-fed larvae possessed the lowest amylolytic activity. The highest and lowest proteolytic activity was on rice and millet, respectively. Different diets had a significant effect on larval energy reserves (total body sugars, glycogen, lipid, and protein), which were at the highest levels on triticale and rye, and lowest levels on sorghum. The highest level of trehalose was on triticale, groundnut and rye, and the lowest level was on barley and sorghum. The supercooling point (SCP) of larvae reared on triticale was −20.6, which was significantly lower than on the other diets. Exposures to −5 and −10 °C/24 h were somewhat endured by larvae fed on triticale, rye, walnut, and groundnut whilst exposure to −20 °C/24 h caused 100% mortality in these food groups. These results suggest that larval food quality can affect biological and physiological characteristics and influence the supercooling point and cold hardiness of T. granarium .

The development of resistance in stored-grain insect pests can be effectively reduced by using biological control methods. Entomopathogenic fungi have been under consideration as complementary and alternative agents to synthetic insecticides. The aim of this study is to identify the pathogenic potential of four different fungal isolates of Beauveria bassiana (Bals.-Criv.) Vuill. (Hypocreales: Cordycipitaceae) (WG-47, WG-48, WG-50, WG-51) and three isolates of Metarhizium anisopliae (Metchnikoff) Sorokin (Hypocreales: Clavicipitaceae) (WG-46, WG-49, WG-52) against the adult stages of the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae), the granary weevil, Sitophilus granarius (L.) (Coleoptera: Curculionidae), the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and the khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae) at 1 × 106, 1 × 107, 1 × 108 and 1 × 109 conidia/kg wheat. Mortality was found dose dependent among all the tested species. Rhyzopertha dominica was the most susceptible followed by S. granarius, T. castaneum and T. granarium. Among the different isolates B. bassiana caused higher mortality compared to M. anisopliae. The isolates WG-50 and WG-51 of B. bassiana provided maximum mortality among the different tested species and led to lower F1 individuals compared to the controls. Our study indicates that entomopathogenic fungi have an elevated potential to successfully manage the aforementioned coleopteran species on stored wheat.

The khapra beetle, Trogoderma granarium (Everts), is a highly destructive stored product insect that presents a significant threat to stored bagged grain. Hermetic packaging is designed to maintain the quality and safety of stored grain, while continually protecting the grain from insect infestations during storage. The objective of this research was to evaluate a prototype deltamethrin, all-in-one treated hermetic bag on contact efficacy, larval mobility, and the control of T. granarium in artificially infested wheat. The insecticidal activity of the deltamethrin-treated packaging was tested against larvae and adults of T. granarium through contact bioassays. There was a significant reduction in responsive adults after 5 day and >86% of larvae were unresponsive after 9 d of exposure on the treated bag. Trogoderma granarium movement toward a food bait was

The Khapra beetle, Trogoderma granarium Everts, is one of the most important pests of grains which rapidly infests durable stored products in hot and dry conditions. In the current study, effects of omit ten varieties of barley (Abidar, Bahman, Line20, Line22, Line30, Lisivi, Lokht11, Makuyi, Sahand and Sahraa) were determined on digestive enzymes and protein metabolsim of T. granarium larvae under laboratory conditions as 33 ± 1 °C, 65 ± 5% RH and photoperiod of 14:10 (L: D) h. The highest and the lowest activities of α-amylase were observed in T. granarium larvae fed on Line30 and Lisivi varieties, respectively but the glucosidases showed the highest activities followed by feeding on Lokht 11. Also, the latter variety caused the highest lipase activity in the larvae while Abidar, Line20, Lisuei and Sahand imposed the lowest lipase activity. The highest activities of serine proteases including trypsin, chymotrypsin and elastase were detected in the larvae fed on Line 30 but the two exopeptidases, amino- and carboxypeptidases, showed the highest activities when the larvae fed on Lisuei. All the three aminotransferses had the highest activities in the larvae fed on Lokht 11 as the related individuals contained the maximum amount of protein compared to other ones. Results of the current study highlighted Line30 as the most suitable variety to be digested by serine proteases and α-amylase but Lokht11 is appropriately digested by glucosidases and lipase which emboss their susceptibilities to T. granarium. Our findings on digestion and protein metabolism imply on susceptibility of varieties Line30 and Lokht11 to T. granarium larvae.

We evaluated the following six insecticides: cypermethrin, deltamethrin, pirimiphos-methyl, silicoSec, s-methoprene and spinosad, that are registered as grain protectants, against adults or larvae of the khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae) on wheat, barley, maize and rough rice. Three doses were tested: the half of the label dose, the label dose and the double label dose for each insecticide and mortality was assessed after 1, 3, 7 and 14 days (d) post exposure. For parental adults, progeny production was estimated after an additional period of 46 d of exposure. All tested insecticides were able to suppress T. granarium adults, even at the lowest dose. Pirimiphos-methyl and silicoSec were found to be most effective than the other insecticides, as these were the only ones that caused application resulted in 100% mortality at the 7-d exposure interval, at the half label or label dose. Conversely, the majority of the insecticides tested were found to be ineffective against T. granarium larvae. Pirimiphos-methyl was the only insecticide on which larval mortality reached 100% on all commodities tested and by far more effective than the other insecticides. For both adults and larvae, mortalities were generally higher on wheat and barley, than on rough rice and maize, for most of the combinations tested. Our findings indicate that the biological stage (i.e., adults or larvae) and the type of infected commodity should be seriously considered when insecticidal management strategies with cypermethrin, deltamethrin, pirimiphos-methyl, silicoSec, s-methoprene or spinosad are planned against T. granarium.

Trogoderma granarium is an important quarantine insect pest of economic importance worldwide. Insecticides are heavily used against this pest that can reduce its susceptibility levels, and if left unchecked, this could lead to misuse of insecticides. Here, the susceptibility of five field strains of T. granarium in comparison to a reference strain (Lab-TG) was determined against pirimiphos-methyl, permethrin and spinosad using dose-mortality bioassays. Based on lethal dose (LD50 and LD99) values, the Lab-TG strain was the most susceptible to all the insecticides in comparison to the field strains. In the case of field strains, LD50 values varied from: 17.68–31.97 mg/kg for pirimiphos-methyl, 20.50–42.47 mg/kg for permethrin, and 1.34–5.00 mg/kg for spinosad. Whereas LD99 values for pirimiphos-methyl, permethrin and spinosad of field strains varied from 409.07 to 730.24 mg/kg, 374.24–949.48 mg/kg, and 11.41–72.25 mg/kg, respectively. The resistance ratios (RR) at LD50 and LD99 levels were in the range of 13.71–24.78 and 39.33–70.21 fold for pirimiphos-methyl; 13.49–27.94 and 37.31–94.66 fold for permethrin; 2.35–8.77 and 3.37–21.31 fold for spinosad, respectively. Considering the overall results, spinosad proved to be the most toxic insecticide to the laboratory and field strains of T. granarium when compared with toxicity of pirimiphos-methyl or permethrin. Insecticidal bioassays implementing enzyme inhibitors revealed no effect on synergizing the toxicity of all the insecticides in the Lab-TG strain; however, enzyme inhibitors significantly synergized toxicity of pirimiphos-methyl in all the field strain suggesting the major involvement of metabolic mechanism associated with pirimiphos-methyl resistance. The study demonstrates variation in susceptibility to insecticides in T. granarium strains. The results might be helpful for monitoring future variation in susceptibility to insecticides in T. granarium and for setting field rates.

We evaluated the population growth of the khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae) on different grains, cracked wheat containment categories and amylaceous materials by conducting three series of laboratory bioassays. In the first series, peeled barley, whole (raw) barley, peeled oats, whole (raw) oats, peeled rice, rough rice, rye, triticale and hard wheat were tested. In the second series, six cracked wheat containment categories were tested: wheat containing intact kernels only (0% cracked kernels), wheat containing 5% cracked kernels and 95% intact kernels, wheat containing 10% cracked kernels and 90% intact kernels, wheat containing 25% cracked kernels and 75% intact kernels, wheat containing 50% cracked kernels and 50% intact kernels and wheat containing 100% cracked kernels. In the third series, the following amylaceous commodities were tested: hard wheat (intact kernels), whole oat flakes, maize flour, whole barley flour, pasta, white soft wheat flour, whole soft wheat flour, white hard wheat flour, whole hard wheat flour, whole rye flour and semolina. Significantly more dead adults were found on wheat than on peeled barley, maize, whole oats, rough rice and rye. Significantly more larvae alive were found on wheat and triticale, than on the other grains, with the exception of oats, both whole and peeled. The increase of the percentage of cracked wheat kernels increased population growth, except in the case of 10% cracked wheat kernels. In vials that contained 100% cracked wheat kernels, 584.1 individuals per vial were found, which was 3.7 times more than the respective number of larvae alive in vials with intact wheat kernels only. Significantly more dead adults were found on whole barley flour than on the other commodities. More than 1213 larvae per vial were recorded on whole barley flour, which was 1.3–15 times higher than the other commodities. The lowest number of larvae alive was found on pasta, followed by the white soft wheat flour. The findings of the present work show that some commodities are more prone to spread T. granarium than others, a fact which should be seriously taken into account in international trade of grains and related amylaceous products.

The Khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), is known as a serious pest of stored grains and stored products. Host plant is an effective ecological factor on performance of an insect pest. In this study, effects of ten wheat cultivars were evaluated on life table parameters and nutritional indices of T. granarium under laboratory conditions, 33 ± 1 °C, 60 ± 5% RH and a photoperiod of 14: 10 (L: D) h. Our research showed that various wheat cultivars have significant effects on life history, demographical parameters and nutritional indices of T. granarium . The highest immature survival rate was observed on cultivar Gaskojen. Significant differences on developmental time, adult fecundity and longevity of T. granarium were found across tested wheat cultivars. In addition, there were significant differences among the wheat cultivars for population growth parameters of T. granarium . The highest ( r m ) values were observed on Gaskojen (0.078 eggs/female/day) and its lower values were resulted from rearing of T. granarium on Kouhdasht and Bezostaya. The larvae fed on Gaskojen showed the higher value of food consumption as compared with others. In addition, the higher value of relative growth rate (RGR) was found on cultivar Gaskojen, while the relative lower value was observed on cultivar Kouhdasht. The results indicated that Gaskojen cultivar was a relatively susceptible wheat cultivar and Kouhdasht cultivar was relatively unsuitable host for feeding of T. granarium which could prove useful in the development of IPM programs for this pest.

Small and large larvae of the khapra beetle, Trogoderma granarium Everts were exposed for 1, 3, and 7 d on concrete that was treated with chlorfenapyr at 0.055 mg active ingredient (a.i.)/cm2 and 0.11 mg (a.i.)/cm2, deltamethrin at 0.0025 mg (a.i.)/cm2 and 0.005 mg (a.i.)/cm2, pirimiphos-methyl at 0.025 mg (a.i.)/cm2 and 0.05 mg (a.i.)/cm2, pyriproxyfen at 0.000115 mg (a.i.)/cm2 and 0.00023 mg (a.i.)/cm2, and spinosad at 0.05 mg (a.i.)/cm2 and 0.1 mg (a.i.)/cm2. Then, the survived individuals were transferred on untreated concrete for 7 more days and the delayed mortality of small or large larvae was evaluated. Concerning the immediate mortality of small larvae, chlorfenapyr was the most effective among the insecticides tested causing 70% immediate mortality after 7 d of exposure at the higher dose. The other insecticides provided similar mortality levels with the exception of pyriproxyfen which was not effective, for any of the combinations tested, as mortality did not exceed 4.4%. Delayed mortality for chlorfenapyr was also high reaching 76% at 7 d of exposure at the higher dose. Pirimiphos-methyl and deltamethrin gave similar results, indicating that for these two insecticides there is also a noticeable delayed effect. For pyriproxifen and spinosad, the delayed mortality was low. Large larvae were by far more tolerant than small ones in all dose-insecticide-exposure combinations examined for both immediate and delayed mortality counts. The results of the present study show that none of the insecticides were able to totally control T. granarium larvae, illustrating the difficulties in controlling this species, with dose rates that are usually effective for other major stored product beetle species.

Adults and larvae of the khapra beetle, Trogoderma granarium Everts were exposed to 3000 ppm of phosphine through the Phosphine Tolerance Test. In a first series of bioassays, observations were taken every 2 min and the exposed individuals were classified either as walking normally or as being immobilized (knocked down), i.e., not walking normally. In the second series of bioassays all individuals were exposed for 90 min to phosphine. For both bioassays delayed mortality was noted after a 7 and 14-day post exposure interval. Larvae were found to be more tolerant than adults, as the time required for the individuals to be immobilized was up to 20 min, which was almost twice as long as the time required for the immobilization of the adults. There were high levels of adult mortality 7 days later, and complete (100%) mortality 14 days after the exposure. In contrast, larval mortality was low, for both post-exposures. Adults were 100% immobilized after the termination of the 90-min exposure interval at 3000 ppm of phosphine, while the percentage of the active larvae was extremely low. Regarding the 7 days post exposure interval the percentage of larval immobilization was higher than that of adults, but this was reversed seven days later. Interestingly, development of the larvae was delayed compared to the control, after the 90 min exposure, in contrast to 20 min exposure which did not cause any delayed effect. Our work provides some first data for the evaluation of the influence of short exposures to phosphine on adults and larvae of T. granarium, which may be very useful in creating an effective initial quantification plan for the control of this species.

The distribution of Trogoderma granarium Everts has expanded steadily in recent years. This is a very destructive coleopteran species with many economic implications for the trade of grains in countries where it is present. Therefore, it is important to gather data that can confirm or reject the pest’s establishment in a particular country. Spain has been cited as a location where the species is established; however, the present study demonstrates that no actual data support its stablishment in Spain. We surveyed fifteen storage premises (mills and warehouses for animal feed, wheat, and rice) distributed along the Iberian Peninsula over two years. We used traps baited with Trogoderma spp. sex pheromone to conduct the survey. Collected samples were morphologically and molecularly identified, since the morphological identification of this species is difficult. Although we found populations of T. inclusum in most of the sampled premises, and even T. variabile in one of them, no T. granarium was found in any of them. Abundant samples of other coleopterans were captured in the traps, including Oryzaephilus surinamensis, Tribolium spp., Sitophilus spp., Cryptolestes ferrugineus, Lasioderma serricorne and Rhyzopertha dominica. In conclusion, no T. granarium was found in our samplings in Spain info:eu-repo/semantics/acceptedVersion

The current investigation was conducted to estimate the resistance level against deltamethrin in fourth and sixth instar larvae of Trogoderma granarium collected from wheat storage warehouses of Dera Ghazi Khan (DGK), Okara (OKR) and Gujranwala (GUW). Results showed that the fourth and sixth instar larvae of collected strains warehouses moderately resistant to deltamethrin compared with the same developmental stages of insecticide susceptible laboratory strain (LAB-S). Efficacies of bifenthrin, chlorpyrifos and their various combinations were analyzed against fourth and sixth instar larvae of different strains of pest populations to minimize the development of resistance against deltamethrin. LC50s of bifenthrin against fourth and sixth instar larvae of all the four populations were recorded at low concentrations compared to deltamethrin. The LC50 values of bifenthrin against fourth instar larvae of LAB-S, DGK, OKR and GUW populations were 359.32, 416.58, 524.01 and 598.91 ppm, respectively, while these values were 204.30, 262.98, 301.89 and 355.22 ppm against sixth instar larvae of those populations, respectively. Chlorpyrifos was found to be the most effective insecticide compared to bifenthrin and deltamethrin. The LC50 values of chlorpyrifos were 189.33, 305.37, 376.30 and 459.15 ppm against fourth instar larvae of LAB-S, DGK, OKR and GUW populations, respectively, whereas for sixth instar larvae those values were 98.24, 129.61, 163.43 and 230.74 ppm, respectively. Various combinations of bifenthrin and chlorpyrifos viz., 1:1, 2:1, 3:1, 1:2 and 1:3 were also tested. Based on the values of LC50 and relative toxic unit, 1:3 combination was observed as the most effective among all combinations. The LC50 values of fourth instar larvae of all the four populations against each insecticide and their combinations were recorded at high concentration compared to that of sixth instar larvae. Results of current investigation need to be considered in present stored grain insect pest control program of warehouses in Punjab1.

Grain commodities are subjected to multiple insect infestations during processing and storage. The kharpa beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae) is categorized as a destructive stored-product pest due to its elevated survival potential, preference for dry conditions and resistance to many insecticides. While public concern about pesticide related risks increases, the development of alternative, environmentally more benign disinfestation methods of stored commodities is pursued. The current study evaluated the effectiveness of three entomopathogenic nematodes, Heterorhabditis bacteriophora Poinar (Rhabditita: Heterorhabditidae), Steinernema carpocapsae (Weiser) (Rhabditita: Steinernematidae) and Steinernema feltiae (Filipjev) (Rhabditita: Steinernematidae) against small and large larvae of T. granarium. Suspensions of nematodes were applied at six doses: 100, 500, 1000, 5000, 10000 and 50000 infective juveniles (IJs)/ml of water on wheat at 30 °C. Mortality of larvae was estimated 4 and 8 days post-exposure to nematodes. All three entomopathogenic nematodes were able to cause mortality on the insect. High mortality rates were accomplished by the two Steinernema species. The most efficient entomopathogenic nematode against small larvae was S. feltiae which attained 98.9% mortality followed by S. carpocapsae which caused 91.1% mortality after 8 days of exposure. Similarly, S. feltiae and S. carpocapsae killed 87.8 and 63.3% of the exposed large larvae on wheat treated with 50000 IJs/ml after 8 days of exposure. In contrast, at the highest dose, H. bacteriophora was less effective than S. carpocapsae and S. feltiae since it caused 76.7 and 60.0% mortalities to exposed small and large larvae after 8 days of exposure. The effectiveness of all three entomopathogenic nematodes was increased at higher doses and longer exposures. The findings of the current study indicate that entomopathogenic nematodes are efficient biological control organisms of T. granarium larvae infesting stored-wheat.

The khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), is an important polyphagous pest of stored grains in the world. Nutritional performance and digestive amylase and protease activity of fifth instar larvae were studied on different commercial rice cultivars (Sadri, Tarom, Neda, Fajr, Nemat, Shafagh, Kadous, Gohar, Gilane, and Khazar) at 33 ± 1 °C, relative humidity of 65 ± 5%, and a photoperiod of 14:10 (L:D) h. Larvae fed with cultivar Gilane consumed more food and increased body weight higher than those fed with other cultivars. However, the lowest values of nutritional indices were found in larvae fed with cultivar Khazar. The lightest pupal weight was on cultivars Fajr, Nemat and Sadri. The larval growth index differed from 1.99 to 2.67 on cultivars Khazar and Tarom, respectively. Among various tested cultivars, the highest standardized insect-growth index was on cultivar Gilane, whereas the lowest index was on cultivars Fajr, Nemat and Sadri. Furthermore, the fitness index showed the highest value on cultivars Gilane and Neda, and the lowest on cultivar Sadri. The amylolytic activity was the highest in larvae fed with cultivar Gilane, and the lowest in larvae fed with cultivars Fajr and Khazar. The cultivar Gilane-fed larvae exhibited the highest proteolytic activity as compared with other cultivars. The cluster analysis showed that Nemat, Neda, Fajr and Khazar were the least suitable (partially resistant) cultivars to T. granarium, which could be further investigated to identify proteins that contribute to khapra beetle resistance.

In recent study, phosphine resistance was assessed in 14 populations of Trogoderma granarium collected from North India. These populations were resistant to phosphine as compared to susceptible laboratory population and the resistance ratios at LC50 ranged from 1.16 to 31.62-fold. In order to determine the trend and magnitude of evolution of phosphine resistance under laboratory conditions, phosphine resistant strain of T. granarium was developed in the laboratory by subjecting the parental strain to a selection pressure of 70% in each generation for ten successive generations. Resistant strain showed 12.74-fold resistance as compared to parental strain. Specific activity of antioxidant enzymes viz., catalase, peroxidase and superoxide dismutase was measured in both collected populations and successive generations, and correlated with phosphine resistance. Specific activity of peroxidase and superoxide dismutase was increased significantly with an increase in phosphine resistance (P

Residual film method was followed to analyze the toxicity of deltamethrin, essential oils (EOs) of Cymbopogon citratus and Cinnamonum camphora in separate and form of various combinations against LHR1 and LHR2 populations of fifth instar larvae of Trogoderma granarium. The cytotoxic potential of LC50s of both EOs, deltamethrin and their various combinations was as well investigated. The LHR2 population showed 23.73 fold deltamethrin resistance with respect to LHR1 population. Both EOs had high insecticidal activity than deltamethrin but C. citratus EO was less toxic than C. camphora EO against both populations. Based on strength of synergism and dose reduction index, the order of insecticidal activity of combinations in LHR1 population was: C. citratus EO: deltamethrin

We used the following new range of insect species as baits for trapping entomopathogenic fungi: Plodia interpunctella, Rhyzopertha dominica, Tribolium confusum, Trogoderma granarium, Ephestia kuehniella and Tenebrio molitor, which constitute important stored product pests. Soil samples were collected from random points in olive tree orchards in Western Greece using Geographical Information Systems (GIS) and sample point coordinates were located with the Global Positioning System (GPS). Entomopathogenic fungi were identified by sequencing the ITS4 and ITS5 regions of the genomic DNA. Among the isolated fungal species, Beauveria bassiana and Metarhizium anisopliae showed the highest frequency, at 33.8% and 25.4% respectively. They also caused the most infestations of R. dominica and T. confusum whose mortality reached 33–97% and 87–100% respectively. We have also isolated various other fungal taxa such as Aspergillus alliaceus, Aspergillus insuetus, Aspergillus sp., Apophysomyces ossiformis, Chaetomium acropullum, Chaetomium sp., Chaetomium globosum, Chaetomium truncatulum, Trichoderma gamsii and Purpureocillium lilacinum. Our study confirms that T. confusum and R. dominica may be further utilized as baits for entomopathogenic fungi.

In plant and animal kingdoms, isofuranodiene is a widespread, lipophilic and volatile furanosesquiterpene endowed with insecticidal properties. In the current study, we evaluated its toxicity against the larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae) adults and the khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae) adults and larvae at 500 and 1000 ppm. Results showed that the overall mortality of P. truncatus adults exposed to 500 ppm was low, while at the higher dose tested it increased to 56.7% after 7 days of exposure. Notably, isofuranodiene killed 95.6 and 96.7% of the exposed T. granarium adults 5 and 7 days post-exposure at 1000 ppm. On the other side, T. granarium larval mortality did not exceed 24.4 and 37.8% at 500 and 1000 ppm respectively, after 7 days of exposure. Isofuranodiene could be considered further to develop novel green tools against T. granarium adults, since there is a lack of effective grain protectants against this noxious species.

We surveyed 1293 farmers and traders in southern Niger to learn about their grain storage practices and their views on the storage pest problem. We identified the insect species found in samples obtained from 40 localities in three regions of the country. We stored 371 grain samples collected from respondents in the laboratory for seven months to allow populations of the insects present to develop and emerge and the resultant grain weight loss to be determined. The commodities most commonly stored in Niger were millet and sorghum, kept in storage on average for about 6 months by 53% and 80% of respondents respectively. When millet samples from respondents were kept in the laboratory for seven months, two pests were found, the rice moth Corcyra cephalonica Stainton, and Tribolium spp. This millet experienced a weight loss of 17.1% during seven months storage. Tribolium castaneum Herbst, Sitophilus granarius L., Cryptolestes spp, Sitotroga cerealella Oliver, Trogoderma granarium Everts, Rhyzopertha dominica F. and C. cephalonica were found in stored sorghum, which lost 10.1% weight after seven months. Eleven other grains or foods were stored by 2.9–24.4% of respondents. Recorded weight losses were 15.9% for groundnuts, 12.6% for paddy rice, 7.6% for sesame and 7.4% for maize. Seeds of Hibiscus sabdariffa L. and Bambara groundnut were essentially destroyed by bruchids during storage, mean weight losses being 83.9% and of 61.8% respectively. Most respondents took no measures to control insect pests in their stored grains. Food security and quality in Niger would be greatly improved if Africa-manufactured technology that is safe, low-cost, insecticide free, and widely available could be implemented for postharvest storage of food grains.

The Khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), is a serious pest of grain and other stored products through the world. In this research, effect of five host diets including barley, rice, rye, wheat and walnut was studied on some of biological traits, nutritional indices and digestive enzymatic activity of T. granarium at 33 ± 1 °C, 65 ± 5% RH and a photoperiod of 14:10 (L:D) h. The Khapra beetle larvae reared on walnut had the highest number of larval instar and longest duration of larval and pupal stages (91.30 ± 0.4 days). The heaviest pupal weight of T. granarium was on rye (4.22 ± 0.01 mg) and the lightest weight was on rice (3.99 ± 0.01 mg) and walnut (4.00 ± 0.01 mg). The highest realized fecundity and fertility were recorded for the females reared on rye (45.88 ± 1.08 eggs/female and 69.39 ± 0.68%, respectively) and wheat (49.02 ± 1.55 eggs/female and 67.54 ± 0.69%, respectively), and the lowest ones were observed for the females came from larvae fed walnut (15.45 ± 0.71 eggs/female and 34.55 ± 0.82%, respectively). Also, the results showed that T. granarium larvae reared on walnut had the lowest values of the efficiency of conversion of ingested food (7.67 ± 0.04%) and relative growth rate (0.044 ± 0.0002 mg/mg/day). The lowest midgut amylolytic (0.044 ± 0.0005 and 0.047 ± 0.0005 mU/individual, respectively) and proteolytic (0.015 ± 0.0004 and 0.016 ± 0.0001 mU/individual, respectively) activity of the sixth instar was detected on walnut and rice. The highest inhibition of amylase (53.37 ± 0.75%) and protease activity (48.54 ± 0.96%) was estimated by incubating midgut extracts from the last instars with wheat and barley proteinaceous extracts, respectively. The results indicated that walnut was the most unsuitable diet for feeding and development of T. granarium .

Laboratory bioassays were conducted to evaluate alpha-cypermethrin and thiamethoxam for the control of adults, small larvae and large larvae of the khapra beetle Trogoderma granarium, and the yellow mealworm beetle Tenebrio molitor, on concrete. Factors such as dose (0.025 and 0.1 mg alpha-cypermethrin or thiamethoxam/cm2), exposure interval (1, 3 and 7 d), and formulation (alpha-cypermethrin SC and thiamethoxam WG) were evaluated. Apart from immediate assessment at end of exposure, an assessment of delayed mortality was performed with the survivors of the 7-d exposure by removing them from the treated substrate and keeping them on untreated surfaces for 7 more days. After the 7-d exposure, more T. granarium adults were dead on dishes treated with alpha-cypermethrin than with thiamethoxam. Small larvae were generally less susceptible than adults. After 7 d, small larval mortality reached 64.4% for alpha-cypermethrin, while for thiamethoxam it was

Larvae of khapra beetle, Trogoderma granarium (Coleoptera: Dermestidae) have an unusual diapause during which they may sporadically feed for several years, but not complete development. Diapausing larvae have an enhanced tolerance to starvation, insecticides and extreme temperatures. Thus, knowledge of factors that terminate larval diapause may aid in the control of this pest. In the current study, we assessed the effect of diet quality (five mixtures of fresh and spent diet in a replacement series) on diapause termination for diapausing larvae from laboratory cultures aged 3, 10, or 14 months. Larvae (n = 10 replicates for each combination of diet quality and culture, 10 larvae/replicate) were held at 30 °C and observed at different intervals over the course of 188 days to record larval mortality and larval pupation (= diapause termination). Larvae were least able to survive on diets of lower quality; i.e., 88% mortality after 188 days on 0% fresh diet versus 8% mortality on 100% fresh diet (averaged across cultures). Larvae were most likely to terminate diapause on diets of higher quality; i.e., 87% termination after 188 days on 100% fresh diet versus 0% termination on 0% fresh diet (averaged across cultures). Diapausing larvae from older cultures were least likely to terminate diapause and least likely to survive. On 100% fresh diet, diapause termination of larvae from cultures aged 3, 10 and 14 months was 93, 91, and 78%, respectively. On 0% fresh diet, mortality of larvae from cultures aged 3, 10 and 14 months was 67, 97, and 100%, respectively. These results indicate that diapausing larvae can accumulate the nutrients required to terminate diapause and complete development when provided with an opportunity to do so. However, the window of opportunity continues to shrink the longer the larvae remain in diapause.

Trogoderma granarium Everts, khapra beetle, and Trogoderma inclusum LeConte, larger cabinet beetle, are highly destructive insect species that can infest a variety of food sources. Methoprene is an insect growth regulator, IGR, and recently has been incorporated into packaging materials as a treatment option for packaged grain, food, birdseed, and feed products, and labeled for this use by the US Environmental Protection Agency. The objective of this research was to investigate the effect of continual exposure to this novel packaging technology on the development of T. inclusum and T. granarium larvae, and its potential use as a packaging treatment to prevent the penetration or invasion of T. inclusum and T. granarium into food packages. The methoprene-treated packaging incorporated into Kraft paper, woven bag material, polyethylene-polyethylene (PE-PE) material, and a polyethylene terephthalate-polyethylene (PET-PE) material, reduced normal adult emergence of exposed larvae. No normal adult emergence was observed on the inside surface of the PET-PE material. The polymer-based materials were the most effective at preventing penetration or invasion by Trogoderma spp. Only 2% of packages were invaded among all packaging treatment combinations compared to 16.7% invasion of untreated packages. The materials were ranked in effectiveness as Kraft

The Khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), is one of the economic pests infesting many stored cereals in the world. The effects of six commercial rice, Oryza sativa L. cultivars including Hashemi, Shiroodi, Gilane, Khazar, Ali Kazemi and Domsiah were evaluated on nutritional indices and digestive enzymatic activity of fifth instar T. granarium at controlled conditions (33±1 °C, relative humidity of 65 ± 5%, and a photoperiod of 14:10 (L:D) h). Fifth instar larvae consumed more food when reared on Gilane, and less food when reared on Khazar and Ali Kazemi. The larvae fed with Khazar had the lowest weight gain, efficiency of conversion of ingested food and growth index. The relative growth rate was the highest when larvae were fed with Gilane and lowest when they were fed with Khazar. The highest midgut proteolytic and amylolytic activities of larvae were on Gilane. However, the lowest proteolytic activity was on Khazar and the lowest amylolytic activity was on Khazar and Ali Khazemi. According to the obtained results, Khazar is an unsuitable cultivar for feeding and growth of T. granarium.

The total glycoalkaloid fraction (TGA) and the two glycoalkaloids, α-chaconine and α-solanine of potato, Solanum tuberosum, were isolated. Their toxic and antifeedant activities against the Khapra beetle, Trogoderma granarium Everts were investigated. Results indicated considerable toxicity, especially when adults were topically treated with the glycoalkaloids. The TGA fraction was the most toxic with LC50’s of 16.7 and 11.9 μg/mg insect, 48 and 96 h post treatment, respectively. LC50’s of α-chaconine and α-solanine 96 h post treatment were 18.1 and 22.5 μg/mg insect, respectively. Moderate toxicities were recorded when insects were confined on dry-film residues of botanicals with LC50’s ranging between 26.1 and 56.6, and 19.4 and 45.7, μg/cm2 48 and 96 h post treatment, respectively. Nutritional studies using the flour disc bioassay revealed significant reduction in the growth rate (RGR), food consumption rate (RCR) and food utilization (ECI) by T. granarium at concentrations ranging between 20 and 30 mg g−1 food with feeding deterrent indices reaching 82.4% with the TGA fraction. When tested as binary or crude alkaloidal mixtures, toxic and antifeedant activities of glycoalkaloids were increased, indicating some additive interaction among these botanicals. There is potential for use of such compounds to protect stored grains from insect infestation.

Feeding deterrent activity of eight enantiomeric pairs and one optically inactive terpenoid lactone with a p -menthane system against three storage pests was determined. The lactones were tested on adults of Sitophilus granarius , adults and larvae of Tribolium confusum and larvae of Trogoderma granarium . The isomeric starting natural compounds, (+) and (−) pulegones and (+) and (−) isopulegols, were also tested. The results showed that the introduction of the lactone moiety into the p -menthane system produced antifeedant activity in the lactones obtained. The lactones with a spiro arrangement of lactone and cyclohexane rings were more active than those with condensed rings. The configuration of chiral centres present in the molecule significantly influenced the activity of the compounds studied. In most cases, lactones obtained from R -(+)-pulegone were more active antifeedants than those obtained from S -(−)-pulegone.

The lower temperature limit for breeding of the khapra beetle, Trogoderma granarium , was determined at constant temperatures in the laboratory. The length of female adult life, oviposition, egg incubation period and duration of larval plus pupal development were observed at 25, 22.5, 20 and 17.2 °C, respectively, at 70% r.h. The results show that breeding is slow at 25°, very slow at 22.5° and populations decline at 20 °C and below. Thus cooling of produce to 20 °C and retention at or below this temperature is a sound, safe, environmental friendly method for control of this pest. For newly dried malted barley, the results indicate that cooling to 25 °C would be sufficient to prevent T. granarium populations from reaching levels of economic importance.

Various instars of khapra beetle Trogoderma granarium were exposed to ultra-violet rays (UVC) to assess their effect on each instar and their potential in breaking the developmental cycle of the khapra beetle. Eggs aged zero (recently laid), 24 and 48 h were exposed to UVC at a radiation intensity of 31.4±0.02 W m −2 . Doses equivalent to 3 min (56.52 J cm −2 ), 8 min (150.72 J cm −2 ), and 12 min (226.08 J cm −2 ) resulted in death of all eggs, with a hatch of 96.6% in the control. Mortality of UVC-irradiated larvae increased proportionally with increase in UVC dose, while, for each dose, mortality was inversely related to age of larvae at irradiation. Thus, at a UVC dose of 56.52 J cm −2 , larval mortality was 98.3%, 93.3% and 83.3% and adult emergence was 1.7%, 6.7% and 11.7% for 1–9, 10–18 and 19–27 day-old larvae, respectively. Similar effects were observed for UVC doses 150.72 and 226.08 J cm −2 with an increase in the overall mortality of larvae and a decrease in adult emergence. Effect of irradiation of 0, 24 and 48 h-old pupae with doses of UVC, was inversely related to age of pupae at irradiation. Thus, at 56.52 J cm −2 , mortality as pupae was 91.7%, 71.7% and 73.3% and adult emergence was 0%, 3.3% and 1.7% for 0, 24 and 48 h-old pupae, respectively. Premature emergence of deformed adultoids was 25% when 24 and 48 h-old pupae were irradiated with the above dose. At a dose of 225.08 52 J cm −2 there was no adult emergence. Death as pupae was 98.3%, 96.7% and 78.3% and premature emergence was 1.7%, 3.3%, and 21.7% for pupae irradiated at 0, 24 and 48 h-old, respectively.

Samples of peanut seeds were collected from stores in eastern Uttar Pradesh, India and examined for their associated mycoflora and insects. Fifteen species of fungi and one insect, Trogoderma granarium, were isolated from the samples. Volatile constituents extracted in the form of essential oils from 32 plant species were evaluated against the dominant fungi, Aspergillus flavus and Aspergillus niger, as well as Trogoderma granarium. The oil of Putranjiva roxburghii exhibited the greatest toxicity. The oil was found to be fungicidal and thermostable at its minimum inhibitory concentration (MIC) of 400 ppm. The oil was characterized by the determination of its various physico-chemical properties. The oil protected the peanut seeds completely for 6 months at 0.25 and 0.38 mL in containers of 250 mL capacity holding 200 g seeds. It did not exhibit any adverse effect on seed germination, seedling growth and general health and morphology of plants. Thus, the oil of Putranjiva roxburghii showed potential as a preservative for peanut seeds against spoilage by fungi and insects during storage.

The effects of low pressure (50 mm Hg) and various exposure times were studied on the mortality of three important storage pest insects at 30 °C as part of an effort to eliminate the need for methyl bromide fumigation to control insects in stored commodities, through development of a novel “vacuum-hermetic” technology. Insects were exposed within test chambers containing cocoa beans with a moisture content in equilibrium with 55% relative humidity and at a constant temperature of 30 °C. Three insect species were used: Trogoderma granarium, Lasioderma serricorne and Oryzaephilus surinamensis. At 50±5 mm Hg and 30 °C, the egg was the most resistant stage in all three species at the LT99 level, times needed to obtain 99% mortality being 46, 91 and 32 h, respectively. Adults of T. granarium and L. serricorne, and pupae of O. surinamensis were most susceptible. These results widen the database established to kill insects at low pressure within the framework of practical exposure times and commercially available equipment, in order to provide an effective alternative to fumigation.

The efficacy of neem, citrus, garlic and podina powders and neem oil at 1 and 2% level (w/w) in sorghum grains was evaluated against larvae of Trogoderma granarium. Neem kernel powder and neem oil completely prevented damage by an introduced larval population. In other treatments, grain damage was noticeable after 3 months, although significantly less than in untreated grains. Thereafter, the percentage of damaged kernels increased progressively and reached as high as 29% (neem leaf), 44% (citrus), 56% (podina) and 71% (garlic) compared to 85% in the control after 6 months. Nutritional composition viz., moisture, ash, fibre, fat, protein and carbohydrates of treated grains remained unaffected after 1 month of storage. After 6 months, changes in nutritional composition were proportional to insect damage. Chapatis (unleavened bread) prepared from flour of treated grains after 1 and 6 months were of normal colour, appearance and texture, but in all cases, their taste, aroma and overall acceptability were adversely affected either by insect infestation or plant products or their combination.

Anisopteromalus calandrae How. was reared in the laboratory on full grown larvae of Rhyzopertha dominica (Fab.). The incubation period of the parasitoid's egg was 36 h at 26 °C and 27 h at 30 °C. The larval stage lasted 6.9 and 5.4 days, the prepupal stage lasted 23.6 and 17.8 h, and the pupa lasted 5.4 and 4.6 days at 26 and 30 °C, respectively. The total developmental time (from egg to adult) averaged 18.9 and 14.6 days at 26 and 30 °C, respectively. Sex ratio was 2.1♀:1♂ in the field and 2.3♀:1♂ in the laboratory. The daily and total numbers of eggs laid/female were 6.7, 150.4 and 8.3, 132.6 at 26 and 30 °C, respectively. The parasite female and male, fed on honey, lived for 32.6 and 25.5 days at 26 °C, respectively. Percentages of parasitism recorded in the laboratory were, respectively 69.5, 43.3, 30.1, 16.8 and 0 on R. domenica, Sitophilus granarius, Bruchus rufimanus, Trogoderma granarium and Oryzaephilus surinamensis . The parasitoid was active in the field from February to November, but reached its peak in July with a 59.3% parasitism on R. dominica .

A monoclonal antibody-based enzyme-linked immunosorbant assay specific for Trogoderma granarium Everts was developed. The assay could rapidly and accurately distinguish T. granarium adults, pupae and larvae from six other Trogoderma species found within the United States.

Insect infestation of wheat, maize and sorghum grains caused by Trogoderma granarium Everts and Rhyzopertha dominica Fabricius separately and in mixed populations resulted in substantial changes in the contents of calcium, phosphorus, zinc, iron, copper and manganese. At the highest infestation level (75%), R. dominica caused significant (P < 0.05) increases in the mineral matter of wheat and sorghum grains owing to loss of endosperm contents, but the increase due to T. granarium damage was not significant. On the other hand, R. dominica did not significantly change the mineral content of maize but a significant (P < 0.05) reduction was noticed at 75% infestation by T. granarium. Mixed populations of both species showed intermediate changes in the mineral contents of the three cereal grains. Storage of uninfested grains up to 4 months did not induce any appreciable changes in the levels of the six minerals. Variations in mineral content in relation to distribution in seed components and to feeding habits of insects have been discussed in the paper.

Pupae (1, 2 and 3 days old) of three stored grain beetles, Trogoderma granarium, Tribolium castaneum and Callosobruchus chinensis, were subjected to temperatures of 30, 40 and 45°C with an exposure period of 24, 48 and 72 h for each age-group. Observations of adult emergence and their progeny revealed that though all the temperatures were effective in causing sterility, exposure to 45°C was particularly effective in suppressing adult formation. With T. castaneum and C. chinensis, adult emergence was totally prevented by 48 and 72 h exposures to 45°C. With T. granarium, the inhibitory effect was greater with male pupae and the resultant adults were completely sterile.

Fifty stored wheat samples (25 each of insect pest free and infested) were collected from North Bihar (India). Of the four major pests recorded, Sitophilus oryzae was the dominant insect, followed by Tribolium castaneum, Rhizopertha dominica and Trogoderma granarium. Aspergillus flavus was recorded in all samples: infection in insect-damaged samples was 87% and in insect-free samples 25%. Aflatoxin contamination was found in 19 and 2 of the insect-damaged and insect-free lots respectively. The role of insect pests in making wheat grains vulnerable to A. flavus infection and subsequent aflatoxin production is discussed.

The history of Trogoderma granarium in South Africa, Zimbabwe and Zambia is reviewed. Particular attention is given to the occurrence of this species in South Africa and the climate at or near localities where the pest was previously found. The first South African records of other species of Trogoderma and Phradonoma are also reported. Climatic criteria considered by previous workers as indicative of a suitable climate for the establishment of T. granarium were used to predict the potential range of this species in southern Africa. Parts of the northern Cape Province, Namibia and Botswana have a climate well-suited for the establishment of T. granarium. An established infestation occurred within the delimited area in 1972, but has since disappeared from the region. Possible contributing factors for this outcome, which was a repetition of earlier events in Zambia and Zimbabwe are suggested. The southernmost boundary of possible distribution of T. granarium in South Africa is also drawn and it was found that the major grain production areas of the Republic lie outside the potential range of this pest.

The effects of photoperiod, insemination, and age on the calling and mating activities of Trogoderma granarium females were investigated. Among mature virgin females held on 10:14, 12:12, or 16:8 LD, some calling behaviour was observed throughout photophase but 75% or more females were active for a period lasting about 8 hr/day. Under all three light regimes, this period was centred around the middle of photophase when virtually 100% of females assumed the calling posture. Correlated with diurnal fluctuations in female calling, mating frequency was higher towards the middle as compared to the start of photophase. In contrast to virgins, only about 3% of recently mated females engaged in calling activity. Significant increases in both calling and female receptivity to mating occurred between the 1st and 3rd days of adult life, but the daily calling pattern of virgin females remained stable between the 4th and 10th days.

Several developmental stages of a laboratory strain of Trogoderma granarium Everts were subjected to an atmosphere of 60% carbon dioxide (CO2) in air at 20 or 30°C and 60% r.h. for varying lengths of time. The eggs, pupae and adults all died within 6 days, but some larvae survived for 16 days or more at both temperatures. Larvae were then exposed at 45, 60 and 75% r.h. to 45, 60 or 75% CO2 in air at 20 or 30°C and additionally to 30% CO2 in air at 30°C. Mortality increased with CO2 concentration and temperature. However, only when a CO2 concentration of 75% at 30°C was applied did all larvae die and, even then, a 15-day exposure was required. Some survival occurred after 18 days in all other conditions. Exposure times of 10 days or less, at temperatures of 20°C or above, have been recommended for use with high CO2 atmospheres for the control of stored products pests but this investigation shows that these may be inadequate if T. granarium is present.

The toxicity of phosphine to all stages of 13 species of stored product beetles was determined using large numbers of test insects which made possible more accurate assessments of mortality. Species tested were Acanthoscelides obtectus, Caryedon serratus, Cryptolestes ferrugineus, C. pusillus, Lasioderma serricorne, Oryzaephilus surinamensis, Ptinus tectus, Rhyzopertha dominica, Sitophilus granarius, S. oryzae, S. zeamais, Tribolium castaneum and Trogoderma granarium . Tests were conducted as appropriate at 10, 15, 25 and 30°C, all at 70% r.h., with concentrations ranging from 0.013 to 2.96 mg/l and exposure times from 1 to 16 days. Sitophilus spp. proved the most tolerant, and in all species other than T. granarium , in which diapausing larvae were the more tolerant in longer exposures, eggs and pupae were the most tolerant stages. Phosphine was most effective at the higher temperatures, whilst long exposures at low concentrations were far more effective than short exposures at high concentrations. The use of phosphine to control these species of stored-product insects will only be effective at 15°C or below if long exposures can be guaranteed.

The effectiveness of natural embelin isolated from berries of Embelia ribes is discussed as a grain protectant for wheat in storage. More than 50% mortality of Sitophilus oryzae (L.) adults was observed in wheat grains when treated at 0.025% concentration. The F1 progeny was reduced in treatments. However, productivity (progeny/21 adult-days) in treatments was not significantly different from controls. In the case of Rhyzopertha dominica (F.), there was 50% adult mortality at 0.025% concentration after 1 day and 3 months of storage, and both progeny and productivity were reduced significantly at all the concentrations. After 8 months of storage, only the highest concentration of 0.1% exhibited appreciable adult mortality, yet the F1 progeny and productivity were significantly low in all the concentrations of embelin. Against larvae of Corcyra cephalonica (Stainton) and Ephestia cautella (Walker) , 0.0125% concentration retained its effectiveness after 8 months, while higher concentrations of 0.05 and 0.1% offered good protection against Trogoderma granarium Everts larvae. Embelin in the present study did not show any contact toxicity to adults of S. oryzae or R. dominica . The treatment did not have any adverse effect on germination of wheat seeds. In general, the effectiveness of embelin tested against five insect species was C. cephalonica > E. cautella > R. dominica > T. granarium > S. oryzae .

Twenty-four species were tested on soya bean meal at 70% r.h. and at either 20°C, 25°C or 30°C. Those species that completed development at 25°C or 30°C were also tested at 20°C. Some species were also tested at 50 and 80% r.h. The following species were able to complete development from adult to adult at near optimum temperature and relative humidity conditions: Ahasverus advena, Cryptolestes ferrugineus, Ephestia cautella, Ephestia elutella, Lasioderma serricorne, Plodia interpunctella, Ptinus tectus, Stegobium paniceum, Tinea columbariella, Tineola bisselliella, Tribolium castaneum and Trogoderma granarium . A further five species were able to reach the adult stage when cultures were set up with half grown larvae, but failed to complete a second generation on soya bean meal: Attagenus pellio, Dermestes ater, Dermestes frischii, Dermestes lardarius, Tenebroides mauritanicus . Mould developed on all food at 80% r.h. and to a lesser extent at 70% r.h. This may have affected development of some species. Judging from the number of adult progeny and the development period, the species most likely to attack stored soya bean meal in temperate climates were Stegobium paniceum, Ptinus tectus, Tineola bisselliella, Ephestia cautella and Lasioderma serricorne . In heated premises and warmer climates Trogoderma granarium, Tribolium castaneum, Ahasverus advena, Lasioderma serricorne, Ephestia cautella and Plodia interpunctella might become a nuisance in this commodity. Ephestia elutella was able to develop at the relatively low moisture content of 8.8% wet weight, and so also might be troublesome in warmer conditions. The markedly different performances of congeneric species of Tribolium, Tenebrio , and Ephestia are discussed, and possible reasons for the failure of certain other species are suggested.

A modified commercially available Tullgren funnel was used to separate live, early or late instar larvae from 200 g (2·5 cm deep) and 400 g (5·0 cm deep) samples of wheat flour or kibbled maize. Larvae were extracted more readily from 200 g even though temperatures were lower after 24 hr than in the larger samples. Although only 26 per cent of early instar larvae of Tribolium castaneum were recovered from 400 g samples of wheat flour in 24 hr, all other trials with larvae of this insect yielded 85 per cent recovery or higher. With larvae of Lasioderma serricorne, Trogoderma granarium and Ephestia cautella the recoveries were highest for late instar larvae in 200 g of kibbled maize and lowest from 400 g of wheat flour. Oryzaephilus surinamensis larvae could not be adequately extracted from wheat flour but when non-infested kibbled maize was mixed with it, up to 58 per cent recovery was obtained. It is concluded that the modified Tullgren funnel would provide a useful method for extraction of live insect larvae from samples of finely divided food such as flours or meals.

The susceptibility to methyl chloroform of all developmental stages of Cryptolestes ferrugineus, Ephestia kuehniella, Oryzaephilus surinamensis, Rhyzopertha dominica, Sitotroga cerealella, Sitophilus granarius, S. oryzae and Tribolium confusum, diapausing larvae of Ephestia elutella, E. cautella, Plodia interpunctella and Trogoderma granarium and adults of Tribolium castaneum, was studied. Tests were conducted at 15, 20 and 25°C, 55–75% r.h. with concentrations ranging from 25 to 200 mg/l and exposure times from 8 h to 16 days. The toxicity of methyl chloroform was in general similar to that of carbon tetrachloride. Immature stages of R. dominica, S. cerealella and Sitophilus spp, and diapausing larvae of T. granarium, showed the highest levels of tolerance. Methyl chloroform was more effective at the higher temperatures but a concentration of 50 mg/l was below the threshold level for full toxicity against 5 species at 25°C. Depending on the species concerned, the concentration × time (CT) product required for control varied from 3,700 mgh/l at 25°C to 60,000 mgh/l or more at 20°C. At 15°C fewer species were tested but five out of nine survived CT products in the region of 30,000 mgh/l. There was no appreciable difference between the susceptibility of the immature stages of malathion-resistant and susceptible strains of O. surinamensis. Neither were any consistent differences observed between adults of normal susceptibility and those resistant to methyl bromide or phosphine.

Through selective screening and breeding, a population of the Trogoderma granarium Everts with reduced male response to the female sex pheromone was isolated. In the eighteenth generation of selection, male response was reduced by 74%, and there was a 5-fold increase in the pheromone concentration required for maximal attraction. Quantitative and qualitative changes in the pheromone secreted by females of the selected population were indicated also.