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In the past, the main management efforts with respect to the control of insects were focused on preharvest agriculture, and only lately has there also been emphasis on postharvest management. This chapter will provide a basic overview of the hygiene management of dry commodities where the moisture content of the products is less than 17%, such as grain, dry fruits, and vegetables, spices, flour products, and other sorts of dry food.

The effects of the chitin synthesis inhibitor (CSI) novaluron on egg hatch and on larval development ofTribolium castaneum (Herbst) concentrations of 1.0, 0.3, 0.2 or 0.1 ppm were tested. The effect of novaluron at low concentrations depended strongly on the exposure period. At 0.3 ppm, egg hatch ofT. castaneum was totally inhibited after 28 days; at 0.2 ppm the effect was much less but inhibition increased progressively to 66% in the 35-day experiment; at 0.1 ppm novaluron was ineffective. The viability of the larvae that hatched from the laid eggs and developed on untreated flour was also dependent on concentration of novaluron and exposure time: exposure ofT. castaneum adults to novaluron-treated flour at 0.3 ppm for 8 days, or at 0.2 ppm for 36 days, caused 100% or 97.5% mortality, respectively. At both 0.3 and 0.2 ppm, larval deaths were mainly in the first instar. Exposure ofT. castaneum adults to treated flour may serve as a good model for evaluating the effect of CSIs on internal feeders, especiallySitophilus oryzae (L.). The present study contributes to our understanding of CSI transovarial activity against internal stored product coleopterans whose larval stage develops inside the grain without contact with the toxicants.

The fumigant and repellent effects of Ocimum gratissimum L. oil and its constituents, β-(Z)-ocimene and eugenol, were evaluated against adults of Sitophilus oryzae (L.), Tribolium castaneum (Herbst), Oryzaephilus surinamensis (L.), Rhyzopertha dominica (F.) and Callosobruchus chinensis (L.). The fumigant toxicities of the oil and two of its constituents were assessed at four rates (0, 1, 5 and10 μL/L air) in space fumigation, whereas repellence of the oil and eugenol in acetone was evaluated in choice bioassays at five rates (0, 1.0, 2.0, 3.0 and 4.0 μL oil/2 g grain). Results showed that fumigant toxicity and repellence of the oil and its constituents were significantly (P

The insect growth regulator novaluron (Rimon 10 EC, Makhteshim-Agan Ltd, Israel) is used against many field pests on corn, vegetables, orchards, forests, and cotton plantations. Previously, we studied various effects of novaluron on stored grain pests. Termination in Tribolium castaneum (Herbst) eggs hatching after treating adults with novaluron and following restoration after adult transfer to untreated media was observed. The objective of this study was to investigate the restoration of T. castaneum egg hatch following transfer of adults from treated media to untreated favorable and unfavorable media. The time needed for hatching restoration of 50% of eggs laid by adults transferred from novaluron (1 ppm) treated flour to untreated flour (RT50) was 2.7 d. RT50 for those transferred to untreated wheat grain was 4.1 d. RT90 in flour was 3.6 d, in grain--6.1 d. Varieties of RTs in grain and in flour with nonoverlapping confidence intervals indicate that RTs were significantly different. Delay of eggs hatching restoration for adults transferred from treated flour to unfavorable media (Petri dishes with limited amount of flour, lying of eggs not detected) was observed. RT50 in flour was 2.1 d and RT90--3.1 d, while RT50 in the unfavorable media was 3.4 d and RT90 6.5 d. Delayed effect of egg hatching restoration after adult transfer to unfavorable media provides evidence of the significant role of insect physiological state in novaluron excretion and (or) degradation by T. castaneum females.

Novaluron, a novel chitin synthesis inhibitor (CSI), was tested against the various developmental stages of Tribolium castaneum (Herbst), at concentrations ranging from 0.1 to 100 ppm. It did not kill T. castaneum adults at these concentrations, but at 1.0 ppm it caused total mortality of third-instar larvae. Novaluron did not affect the number of eggs laid by T. castaneum adults that were exposed to treated wheat flour, but it totally inhibited their hatching after the third day of exposure at a concentration of 1 ppm. On the first day after infestation novaluron did not totally prevent hatching, even at the highest tested concentration of 100 ppm. The time needed to restore egg hatchability after adults were transferred to untreated flour depended on the concentration of novaluron used in the treatment. When the adults of T. castaneum were exposed to novaluron-treated whole wheat grains (at 1 ppm), similar effects to those of the treated flour at the same concentration were observed: egg hatching was drastically reduced. The effect of uptake via contact of adults with novaluron-treated surfaces was examined by exposing them to a mixture of untreated flour and 10% novaluron-treated sand at a concentration of 10 ppm, and only 1% of the eggs hatched after 18 days of exposure. When adults were removed from treated surfaces of Petri dishes to untreated flour, the hatching rate was again reduced by 100%. It was concluded that the contact penetration of novaluron into T. castaneum adults prevents the hatching of eggs subsequently laid.

The efficacy of two new microencapsulated formulations of chlorpyrifos against Sitophilus oryzae, Rhyzopertha dominica, Tribolium castaneum and Plodia interpunctella was studied under laboratory conditions. Master 25 and Master Quick at 10 and 20 ml/t were mixed with whole wheat grain as food. Master 25 resulted in the complete mortality of S. oryzae and T. castaneum adults at a concentration of 10 ml/t. A concentration of 20 ml/t was necessary to obtain 100% mortality in P. interpunctella larvae. Against R. dominica, Master 25 was not sufficiently effective at either rate. On the other hand, Master Quick resulted in 93 and 100% mortality of R. dominica adults at 10 and 20 ml/t, respectively, and 100% mortality of the other insects at 10 ml/t. Two months after treatment, the activity of Master 25 at 10 ml/t strongly decreased; at 20 ml/t, it was still highly active against S. oryzae, less active against T. castaneum and completely ineffective against R. dominica. On the other hand, Master Quick at 20 ml/t showed high activity against the insects, including R. dominica.

Novaluron is a novel chitin-synthesis inhibitor from the benzoyl phenyl ureas group of insect growth regulators. It has a broad-spectrum activity on various insects, but very low toxicity to mammals (LD50>5000 mg/kg). The objective of the study reported was to evaluate the efficacy of Novaluron against the main stored product insect pests, as a possible alternative to standard pesticides for stored-product pest control. The test insects were the beetles Sitophilus oryzae, Rhyzopertha dominica, and Tribolium castaneum, and the moth Plodia interpunctella. According to the differences in the life cycle and conditions for development of the test insects, adults of S. oryzae and R. dominica, and larvae of T. castaneum and P. interpunctella, were used. Concentrations ranging from 0.1 to 10 ppm of Novaluron were mixed with three kinds of food media: whole wheat grain for the internal pests S. oryzae and R. dominica, ground grain for the external feeder P. interpunctella and flour for T. castaneum. The results showed that Novaluron at 1 ppm reduced the number of new generation adults of S. oryzae and R. dominica by 95% compared with the control, and prevented the emergence of adults of P. interpunctella. At this concentration, Novaluron also yielded total mortality of T. castaneum third instar larvae. At 0.1 ppm, Novaluron had no effect on the insects tested.

Methyl bromide and phosphine are the most widely used fumigants for controlling pest infestation in grain, dry food products and quarantine insects in cut flowers. Some stored-product insects have developed resistance to phosphine and, with the proposed phase out of methyl bromide in the near future, there is an urgent need to search for suitable alternatives. This study reported here evaluated the potential of methyl iodide (CH3I), carbon disulfide (CS2), benzaldehyde (C7H6O), and several isothiocyanates against the main stored-product insects. The toxicity of the various fumigants was assessed against adults, pupae and larvae of six major stored-product insects. We report on the isolation and fumigant activity of several isothiocyanates from Cruciferae seeds. One of these, isolated from Eruca sativa, was partially identified as alkil-thio-alkil-isothiocyanate.