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The sugarcane, one of the most profitable crops, has been cultivated for many years under diverse ecological conditions in tropical and subtropical regions. It is one of the most strategic and economic crops in southern of Iran. The pink stem borers, Sesamia spp. (Lep.: Noctuidae), are key and important insect pests on sugarcane crop that lead to direct and indirect damage to sugarcane yield. In the current study, we were assessed effect of stem borers, Sesamia spp. infestation on qualitative traits such as Pol, Brix, juice purity, recoverable sugar, and sugar per hectare, and some chemical criteria of the three commercial varieties of sugarcane, CP69-1062, CP48-103, and IRC99-02. The outputs indicated that most qualitative factors (Brix, Pol, juice purity, and recoverable sugar) and sugar yield affected by internodes bored levels due to Sesamia infestation. Sugar yield in the control (without bored internodes) on CP69-1062, CP48-103, and IRC99-02 varieties was 98.08, 96.61, and 47.73 kg/ton, respectively, that was statistically significant differences with other groups of bored internodes. Overall, the highest bored internode levels by Sesamia spp. had the lowest value on every qualitative trait. Among chemical criteria, the invert is one of most key indices to evaluation of sugarcane quality. This process is the chemical conversion of sucrose into glucose and fructose. In addition, the findings revealed that there was no statistically significant difference between the invert values in different level on bored internodes by Sesamia infestation on CP69-1062, CP48-103, and IRC99-02 varieties. It is concluded that infestation internodes by Sesamia can be affected some qualitative and quantitative traits. Therefore, to control of Sesamia should be use integrated pest management such as apply of synthetic pheromone, utilize green traps, and use biological control and integrated field management including cultivate different commercial varieties, improvement of irrigation and drainage system, and timely harvest the crop. [ABSTRACT FROM AUTHOR]

Silicon (Si) is known for mitigating biotic stresses in various crops through diverse array of mechanisms. The present study was undertaken to decipher the mechanisms of Si in suppressing the impact of pink stem borer incidence and damage to wheat plants under field conditions. For this study, we have applied different Si sources like diatomaceous earth (a soil application source) and Orthosilicic acid (a foliar application source) along with two levels of potassium (soil application). The effect of these Si sources and potassium on total sugars, total phenols, anti-oxidant, and defense enzymes was monitored in wheat stem tissues along with their impact on pink stem borer damage and yield was recorded. All the Si sources and potassium levels significantly enhanced the activities of antioxidant and defense enzymes like peroxidase (300–450 change in absorbance/min/g), phenylalanine ammonia lyase (400 µ moles of trans-cinnamic acid/min/mg of protein), polyphenol oxidase (20–25 change in absorbance/min/g), and β- 1, 3- glucanase (15–25 µg of glucose released/min/g). Enhanced activities of defence enzymes, antioxidants and higher accumulation of total sugars (50–60%) and phenols (100–150 mg/g) in wheat stem tissues significantly reduced the impact of pink stem borer incidence. The percent Si content was positively correlated with all the defense enzymes and negatively with percent white ear at significant levels. Our current study convincingly proved Si induced defense reaction in wheat plants in suppressing pink stem borer impact. [ABSTRACT FROM AUTHOR]

Invasion of crops by stemborers previously known in natural vegetation only requires close monitoring for early detection of stemborer exchange between the habitats. This in turn demands up-to-date knowledge about the diversity of stemborers in natural habitats. The current list of known stemborers in South Africa includes 49 species associated with 65 wild host plant. The Eastern Cape and KwaZulu-Natal biogeographic regions received little coverage in earlier studies. This study sought to fill this knowledge gap. We conducted surveys from 14 November 2014 to 18March 2015 in the Eastern Cape and KwaZulu-Natal biogeographic regions. Potential host plants in families Poaceae, Cyperaceae, and Typhaceae were dissected in the field, stemborer life stages collected, reared on artificial diet, and identified to the lowest possible taxonomic level. Thirty-three species belonging to Crambidae, Noctuidae, Phycitidae, Pyralidae and Tortricidae were recovered from27 host plant species. Twenty-four species were recorded in Eastern Cape and 28 species in KwaZulu-Natal. The Chao 1 asymptotic species richness estimator predicted 3 and 5 more species for the biogeographic regions indicating an equitably complete species inventory of the study area. Fifteen species collected in this study are part of the existing inventory, and 19 are first records on the various host plants. The new records expand the list of stemborer species in South Africa from 49 to 68. The main factors influencing diversity were endemism, the number and disproportionate abundance of common and rare species. [ABSTRACT FROM AUTHOR]

The current study was conducted in the fields of the college of agriculture and forestry during the autumn season of 2013. The results were showed a significant effect of the varieties (Talar, Sara, Danya, Bohooth 106 and Rabia) and fertilization treatments (0, 60 and 90 kg/ha) and the times number of potassium addition (one time or twice) on reducing infestation percentage of corn stem borer within three periods of sampling (after 2, 4 and 6 weeks). The lowest average of infestation after six weeks from the potassium addition was on the Buhooth 106 (13.41%) and for the fertilizing treatment of 90 kg/ha which reached 4.78% and for the twice addition of fertilizer (14.34%). while the highest average of infestation was on the treatments of Rabia variety (19.9%), non-fertilizer addition (36,03%) and for one time of fertilizer addition (19.61%). [ABSTRACT FROM AUTHOR]

ساقه‌خوارها شایع‌ترین و مهم‌ترین آفاتی هستند که برنج را در طول دوران رشد مورد حمله قرار می‌دهند. در این پژوهش، پراکنش جغرافیایی شب‌پره‌های ساقه‌خوار برنج متعلق به خانواده‌های ‌Crambidae و Noctuidae در 16 استان برنج‌ کاری کشور در سال‌های 1394 و 1395 بررسی شد. جمع‌آوری حشرات کامل ساقه‌خوار به کمک تله‌ها‌ی نوری، مالایز و فرومونی انجام شد. در شالیزارهای کشور در مجموع شش گونه ساقه‌خوار شامل پنج گونه‌‌ی Chilo partellus، C. luteellus، C. suppressalis، C. phragmitella و Scirpophaga praelata از خانواده‌ی Crambidae و گونه‌ی Sesamia sp. از خانواده‌ی Noctuidae شناسایی شدند‌‌. در بین این گونه‌ها، ساقه‌خوار نواری برنج (C. suppressalis) و گونه‌ای از جنس سزامیا (Sesamia sp.) به عنوان مهم‌ترین آفات ساقه‌خوار برنج در کشور معرفی می‌شوند. طبق نتایج، حضور ساقه‌خوار نواری برنج از پنج استان خراسان رضوی، قزوین، زنجان، چهارمحال و بختیاری و آذربایجان شرقی و خسارت سزامیا روی برنج از چهار استان کهگیلویه و بویراحمد، اصفهان، ایلام و اردبیل برای اولین بار گزارش می‌شود. با توجه به نتایج این پژوهش و عدم دسترسی به نمونه‌ی تیپ، گزارش قبلی مبنی بر حضور ساقه‌خوار سفید برنج (Scirpophaga innotata) در ایران، مشکوک است. یافته‌های این پژوهش اطلاعات اولیه‌ و کلیدی درباره‌ی سطح پراکنش هر کدام از شش گونه ساقه‌خوار فعال در شالیزارهای ایران را فراهم می‌کند که می‌تواند ضرورت تجدید نظر در ارایه‌ی شیوه‌های مدیریت آن‌ها را متذکر شود. ساقه‌خوارها شایع‌ترین و مهم‌ترین آفاتی هستند که برنج را در طول دوران رشد مورد حمله قرار می‌دهند. در این پژوهش، پراکنش جغرافیایی شب‌پره‌های ساقه‌خوار برنج متعلق به خانواده‌های ‌Crambidae و Noctuidae در 16 استان برنج‌ کاری کشور در سال‌های 1394 و 1395 بررسی شد. جمع‌آوری حشرات کامل ساقه‌خوار به کمک تله‌ها‌ی نوری، مالایز و فرومونی انجام شد. در شالیزارهای کشور در مجموع شش گونه ساقه‌خوار شامل پنج گونه‌‌ی Chilo partellus، C. luteellus، C. suppressalis، C. phragmitella و Scirpophaga praelata از خانواده‌ی Crambidae و گونه‌ی Sesamia sp. از خانواده‌ی Noctuidae شناسایی شدند‌‌. در بین این گونه‌ها، ساقه‌خوار نواری برنج (C. suppressalis) و گونه‌ای از جنس سزامیا (Sesamia sp.) به عنوان مهم‌ترین آفات ساقه‌خوار برنج در کشور معرفی می‌شوند. طبق نتایج، حضور ساقه‌خوار نواری برنج از پنج استان خراسان رضوی، قزوین، زنجان، چهارمحال و بختیاری و آذربایجان شرقی و خسارت سزامیا روی برنج از چهار استان کهگیلویه و بویراحمد، اصفهان، ایلام و اردبیل برای اولین بار گزارش می‌شود. با توجه به نتایج این پژوهش و عدم دسترسی به نمونه‌ی تیپ، گزارش قبلی مبنی بر حضور ساقه‌خوار سفید برنج (Scirpophaga innotata) در ایران، مشکوک است. یافته‌های این پژوهش اطلاعات اولیه‌ و کلیدی درباره‌ی سطح پراکنش هر کدام از شش گونه ساقه‌خوار فعال در شالیزارهای ایران را فراهم می‌کند که می‌تواند ضرورت تجدید نظر در ارایه‌ی شیوه‌های مدیریت آن‌ها را متذکر شود.

The sugarcane stalk borers, Sesamia spp. (Lepidoptera: Noctuidae) are the most destructive sugarcane insect pests in Iran. The efficiency of Telenomus busseolae Gahan (Hymenoptera: Scelionidae) used alone or in combination with silicon fertilization was investigated for controlling the sugarcane stalk borers under field conditions. The treatments were: a combination of silicon plus multiple releases of 2,500 T. busseolae, and multiple releases of 5,000, 2,500 and 1,250 T. busseolae alone. Plots receiving no soil amendment or parasites were included as the controls. Three weeks after the first application of each treatment, 100 shoots were selected randomly from each plot and the percentage of dead heart was determined. Then, three months after the first application of parasites, the percentage of stalks damaged, the percentage of internodes bored, and the level of parasitism were determined. Finally, at harvest the percentage of stalks damaged, the percentage of internodes bored, and sugarcane quality characteristics were determined. Results indicated that the efficiency of parasitism increased when combined with an application of silicon fertilizer. The release of 2,500 T. busseolae followed by an application of silicon fertilizer decreased dead hearts to 4%, while 12% dead hearts was observed in the control plots. For the combination treatment, the percentages of stalk damage were 1.5% and 17.2%, at 3 weeks and 3 months after time release, respectively. However, the percentages of stalk damage were 35.2% and 51% when no treatment was applied. Cane quality was significantly higher with the application of silicon fertilizer plus the release of 2,500 T. busseolae, followed by releasing 5,000 Hymenoptera. The level of parasitism was also greater when parasites were released in combination with an application of silicon. We conclude that biological control by egg parasitoids can be enhanced with concurrent applications of silicon fertilizer as a soil amendment and thereby creating a more robust, Integrated Pest Management (IPM) program of stalk borers in Iranian sugarcane fields.

The susceptibilities of three field populations of pink stem borer (PSB), Sesamia inferens (walker) to diamide insecticides, chlorantraniliprole and flubendiamide, were evaluated in this study. The results showed that these PSB field populations were still sensitive to the two diamide insecticides after many years of exposure. To further understand PSB and diamide insecticide, the full-length ryanodine receptor (RyR) cDNA (named as SiRyR), the molecular target of diamide insecticides was cloned from PSB and characterized. The SiRyR gene contains an open reading frame of 15,420 nucleotides, encoding 5140 amino acid residues, which shares 77% to 98% sequence identity with RyR homologous of other insects. All hallmarks of RyR proteins are conserved in the SiRyR protein, including the conserved C-terminal domain with the consensus calcium-biding EF-hands (calcium-binding motif), the six transmembrane domains, as well as mannosyltransferase, IP3R and RyR (pfam02815) (MIR) domains. Real-time qPCR analysis revealed that the highest mRNA expression levels of SiRyR were observed in pupa and adults, especially in males. SiRyR was expressed at the highest level in thorax, and the lowest level in wing. The full genetic characterization of SiRyR could provide useful information for future functional expression studies and for discovery of new insecticides with selective insecticidal activity. [ABSTRACT FROM AUTHOR]

Biology of pink stem borer, Sesamia inferens (Walker) (Lepidoptera: Noctuidae) was conducted during 2015-16 in laboratories of CCS Haryana Agricultural University, Regional Research Station, Karnal on HQPM 1 (hybrid) and HKI 1128 (inbred) for two generations at room temperature. Results on biology of S. inferens in the first generation revealed that incubation period varied from 10-14 days on HQPM 1 and 11-15 days on HKI 1128. The larval duration lasted for 21-37 days on HQPM 1 and 24-39 days on HKI 1128. The adult longevity of male and female ranged from 6-7 days and 7-8 days on HQPM 1 and 5-7 days and 6-7 days on HKI 1128, respectively. The total life span ranged from 63-72 days for female and 45-58 days for male on HQPM 1 and 65-74 days for female and 49-62 days for male on HKI 1128, respectively in the first generation. The total life span in second generation ranged 94-107 days for female and 83-96 days for male on HQPM 1 and 98-112 days for female and 86-101 days for male on HKI 1128. The biology of an insect pest is a condition precedent to find out its management strategies. The biology of S. inferens on maize has not yet been studied in north western part of the country. Having regards to the fact that no systematic work on this aspect has been carried out, studies were conducted on biology of this pest for developing efficient pest management strategies. [ABSTRACT FROM AUTHOR]

A field study on population dynamics of pink stem borer, Sesamia inferens (Walker) on maize was carried out during rabi, 2015-2016 at the research farm of CCS Haryana Agricultural University, Regional Research Station, Karnal. Studies on population dynamics revealed that the maximum number of egg masses was observed during 46th SW (standard week), 2015. The larval population increased after 45th SW and reached the maximum during the 49th SW, 2015 and then declined till 7th SW, 2016. Maximum plant infestation by larvae was recorded 19.5 per cent in inbred HKI 1128 and 21.0 per cent in hybrid HQPM 1 during the 7th SW, 2016. No larval activity of S. inferens, plant infestation and dead hearts were observed during 2nd SW to 4th SW of 2016 (second week to last week of January). It could be due to the fact that insect might have entered the hibernation. Correlation of S. inferens population with various environmental factors revealed that larval population had a significant negative correlation with maximum temperature (Tmax.) and minimum temperature (Tmin.), rainfall (RF) (r= -0.4992, -0.5183 and -0.5698) on HKI 1128 and (r= -0.4872, -0.4717 and -0.5242) on HQPM 1, respectively. Multiple regression analysis of S. inferens population with weather parameters showed that there was 80 per cent (HQPM1) and 82 per cent (HKI 1128) variability in larval population due to various environmental factors. The population dynamics revealed by this study have far reaching significance in pest management strategy as integrated control measures may be focused only during the period wherein population exceeds economic threshold level (ETL). [ABSTRACT FROM AUTHOR]

Many parasitoid species are subjected to strong selective pressures from their host, and their adaptive response may result in the formation of genetically differentiated populations, called host races. When environmental factors and reproduction traits prevent gene flow, host races become distinct species. Such a process has recently been documented within the Cotesia flavipes species complex, all of which are larval parasitoids of moth species whose larvae are stem borers of Poales. A previous study on the African species C. sesamiae, incorporating molecular, ecological and biological data on various samples, showed that a particular population could be considered as a distinct species, because it was specialized at both host (Sesamia nonagrioides) and plant (Typha domingensis) levels, and reproductively isolated from other C. sesa-miae. Due to its potential for the biological control of S. nonagrioides, a serious corn pest in Mediterranean countries and even in Iran, we describe here Cotesia typhae Fernandez-Triana sp. n. The new species is characterized on the basis of morphological, molecular, ecological and geographical data, which proved to be useful for future collection and rapid identification of the species within the species complex. Fecundity traits and parasitism success on African and European S. nonagrioides populations, estimated by laboratory studies, are also included. [ABSTRACT FROM AUTHOR]

The sugarcane stalk borers, Sesamia spp. (Lepidoptera: Noctuidae) are the most destructive sugarcane insect pests in Iran. The efficiency of Telenomus busseolae Gahan (Hymenoptera: Scelionidae) used alone or in combination with silicon fertilization was investigated for controlling the sugarcane stalk borers under field conditions. The treatments were: a combination of silicon plus multiple releases of 2,500 T. busseolae, and multiple releases of 5,000, 2,500 and 1,250 T. busseolae alone. Plots receiving no soil amendment or parasites were included as the controls. Three weeks after the first application of each treatment, 100 shoots were selected randomly from each plot and the percentage of dead heart was determined. Then, three months after the first application of parasites, the percentage of stalks damaged, the percentage of internodes bored, and the level of parasitism were determined. Finally, at harvest the percentage of stalks damaged, the percentage of internodes bored, and sugarcane quality characteristics were determined. Results indicated that the efficiency of parasitism increased when combined with an application of silicon fertilizer. The release of 2,500 T. busseolae followed by an application of silicon fertilizer decreased dead hearts to 4%, while 12% dead hearts was observed in the control plots. For the combination treatment, the percentages of stalk damage were 1.5% and 17.2%, at 3 weeks and 3 months after time release, respectively. However, the percentages of stalk damage were 35.2% and 51% when no treatment was applied. Cane quality was significantly higher with the application of silicon fertilizer plus the release of 2,500 T. busseolae, followed by releasing 5,000 Hymenoptera. The level of parasitism was also greater when parasites were released in combination with an application of silicon. We conclude that biological control by egg parasitoids can be enhanced with concurrent applications of silicon fertilizer as a soil amendment and thereby creating a more robust, Integrated Pest Management (IPM) program of stalk borers in Iranian sugarcane fields. [ABSTRACT FROM AUTHOR]

Sesamia inferens (Walker) is the most important Rabi pest of maize causing serious losses in India. The objective of the study was to identify maize landraces with high levels of resistance to S. inferens by screening 427 maize land races sourced from different agro-ecological regions, along with CM 500 and CML 451 as resistant and susceptible checks, respectively under natural conditions during Rabi, 2012-13. The range of average per cent dead hearts observed in land races was 0.0 to 57.14%. The most resistant land races were IC258225, IC319533, IC321053, IC321110, IC321111, IC321119, IC326886, IC331795, IC 338827 and IC350198 which showed no dead hearts infestation while the susceptible were IC331939, IC340368, IC369174, IC369184, IC406420, IC549985, IC549989, IC549990, IC569669 and IC547811 suffered to the extent of 46.15 to 57.14 % dead hearts. There was no dead hearts infestation on resistant check CM 500 while susceptible check CML 451 showed 50 - 100 % dead hearts. These resistant land races identified are recommended for use in the development of S. inferens resistant maize. [ABSTRACT FROM AUTHOR]

BACKGROUND Chilo suppressalis and Sesamia inferens are important lepidopteran rice pests that occur concurrently in rice-growing areas of China. The development of transgenic rice expressing Cry1A insecticidal proteins has provided a useful strategy for controlling these pests. RESULTS This study evaluated the baseline susceptibilities of C. suppressalis and S. inferens to Cry1A, as well as their responses to selection with Cry1A. Wide geographic variation in susceptibility was observed across all field populations. Within a given population, the LC50 of both Cry1Ab and Cry1Ac against S. inferens was drastically higher than that of C. suppressalis. Large LC50 differences (74.6-fold) were detected between the two species for Cry1Ab in the Poyang population, while small differences (3.6-fold) were detected for Cry1Ac in the Changsha population. The Cry1Ac LC50 of C. suppressalis and S. inferens increased 8.4- and 4.4-fold after 21 and eight selection generations respectively. Additionally, the estimated realised heritabilities ( h2) of Cry1Ac tolerance were 0.11 in C. suppressalis and 0.292 in S. inferens. CONCLUSIONS S. inferens exhibited a significantly lower susceptibility and more rapidly evolved resistance to Cry1A compared with C. suppressalis. Therefore, S. inferens is more likely to evolve increased resistance, which threatens the sustainability of rice expressing Cry1A protein. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Sesamia inferens (Walker) causes 25.7-78.9% losses in maize production in South and South-East Asia. The genetic basis of host plant resistance is the prerequisite for resistance breeding. Twenty-four populations derived from S. inferens resistant × susceptible inbreds were used to study the genetic regulation of resistance to S. inferens in maize, to determine the importance of genetic effects through generation mean analysis ( GMA) and to understand correlation between resistance and yield. Resistant and susceptible inbreds differed significantly in leaf and stem injury ratings ( LSIR), a measure of host plant resistance. Mean LSIR range among resistant and susceptible parents was 2.15-2.55 and 7.83-8.22, respectively. The broad-sense heritability ranged from 0.40 to 0.71, and the mean number of effective factors ranged from 1.9 to 2.6. The resistance against S. inferens was largely governed by additive × additive ( i), followed by dominance ( d) and additive ( a) gene effects. Significant negative correlation (−0.27 to −0.96) was observed between LSIR and yield. The findings suggest reciprocal recurrent selection for development of new inbreds with resistance followed by their involvement in hybrid development to exploit additive and non-additive gene effects/variance. [ABSTRACT FROM AUTHOR]

As climatic change impacts would depend upon complex interactions between climatic and biological factors, crop simulation models would play an important role in predicting such an impact. Present study thus aimed at simulating climatic change impacts on crop-pest interactions through a coupled crop-pest model. Based on temperature-dependent development of pink stem borer, Sesamia inferens (Walker) at six constant temperatures viz ., 18, 21, 24, 27, 30, 33 and 35 ± 1 °C, thermal constants for eggs, larvae and pupae were determined as 47.6, 700 and 166.7° days, respectively through a linear model with corresponding lower development thresholds being 13.8, 10.6 and 12.7 °C. Besides, optimum temperature and upper developmental threshold, respectively were found to be 34.6 and 36.2 °C for eggs, 34.5 and 36.4 °C for larvae, and 31.7 and 37.0 °C for pupae of the pink stem borer through a non-linear model. Based on the thermal requirements, and biotic and abiotic mortalities, a mechanistic holometabolous population simulation model for S. inferens was developed and coupled to InfoCrop-rice model. This coupled InfoCrop model could satisfactorily simulate the PSB dynamics and crop-pest interactions. Validated model was used to simulate the impacts of climatic change on S. inferens population and rice crop in accordance with four 'standard special report on emissions scenarios', A1, A2, B1 and B2. Simulations revealed that S. inferens population would decline to the extent of 5.82-22.8 % by 2020 and 19.0-42.7 % by 2050 under Delhi conditions. Following decline in pest population, S. inferens induced yield losses also revealed a declining trend under changed climate. The coupled crop-pest model can be easily adapted to diverse agro-environments and applied to simulate the pest dynamics and crop losses under location-specific situations. [ABSTRACT FROM AUTHOR]

Field experiment was carried out at the Agricultural Research Station, Anand Agricultural University, Arnej during November 2017 to February 2018 to evaluate the efficacy of nine insecticides against the pink stem borer Sesamia inferens (Walker) infesting durum wheat. Spraying of chlorantraniliprole 18.5SC @ 0.006% was found significantly superior over other insecticides with maximum grain as well as straw yield (16.42 and 23.93 qt/ ha, respectively). Maximum ICBR was registered with seed treatment of chlorpyriphos 20EC (1:20.83) followed by chlorantraniliprole 18.5SC (1:10.46) and spraying of spinosad 45SC (1:9.52). [ABSTRACT FROM AUTHOR]

The pink rice stem borer, Sesamia inferens (Walker) (Lepidoptera: Noctuidae), is a major rice pest in China and elsewhere in Asia. While low winter temperatures are a major environmental constraint on the survival of most insect species, the mechanism of S. inferens’ cold tolerance in winter remains unknown. In this study, we elucidated the cold tolerance characteristics of S. inferens collected in the field from Oct 2012 to Apr 2013. The cold tolerance of overwintering larvae was found to vary significantly. Maximum S. inferens cold tolerance was observed in larvae collected on 30 Jan 2013. However, the SCP (supercooling points) of larvae did not vary insignificantly, with a mean of -6.80 °C. Before 9 Mar 2013, larval water content stabilized at the mean low level of 63.5 %, but subsequently rose significantly, to 75.2%. Low molecular weight sugars and polyols, closely related to freeze tolerance strategy, increased from low levels to their peaks in Jan (glycerol, 359.8 μg/g; trehalose, 20.5 mg/g; fructose, 69.8 μg/g; glucose, 377.3 μg/g; myo-inositol, 59.6 μg/g), after which levels declined. This study demonstrates that the Yangzhou population of S. inferens is freeze-tolerant. [ABSTRACT FROM AUTHOR]

The pink stem borer, Sesamia inferens (Walker), is a major pest of rice and is endemic in China and other parts of Asia. Small heat shock proteins (sHSPs) encompass a diverse, widespread class of stress proteins that have not been characterized in S. inferens. In the present study, we isolated and characterized three S. inferens genes that encode members of the a-crystallin/sHSP family, namely, Sihsp21.4, Sihsp20.6, and Sihsp19.6. The three cDNAs encoded proteins of 187, 183 and 174 amino acids with calculated molecular weights of 21.4, 20.6 and 19.6 kDa, respectively. The deduced amino acid sequences of the three genes showed strong similarity to sHSPs identified in other lepidopteran insects. Sihsp21.4 contained an intron, but Sihsp20.6 and Sihsp19.6 lacked introns. Real-time quantitative PCR analyses revealed that Sihsp21.4 was most strongly expressed in S. inferens heads; Whereas expression of Sihsp20.6 and Sihsp19.6 was highest in eggs. The three S. inferens sHSP genes were up-regulated during low temperature stress. In summary, our results show that S. inferens sHSP genes have distinct regulatory roles in the physiology of S. inferens. [ABSTRACT FROM AUTHOR]

The sex pheromone communication system in moths is highly species-specific and extremely sensitive, and pheromone receptors ( PRs) are thought to be the most important factors in males. In the present study, three full-length cDNAs encoding PRs were characterized from Sesamia inferens antennae. These three PRs were all male-specific in expression, but their relative expression levels were very different; SinfOR29 was 17- to 23-fold higher than the other two PRs. Phylogenetic and motif pattern analyses showed that these three PRs were allocated to different PR subfamilies with different motif patterns. Functional analysis using the heterologous expression system of Xenopus oocytes demonstrated that SinfOR29 specifically and sensitively responded to the major pheromone component, Z11-16: OAc [concentration for 50% of maximal effect ( EC50) = 3.431 × 10−7 M], while SinfOR21 responded robustly to a minor pheromone component Z11-16: OH ( EC50 = 1.087 × 10−6 M). SinfOR27, however, displayed no response to any of the three pheromone components, but, interestingly, it was sensitive to a non-sex pheromone component Z9, E12-14: OAc ( EC50 = 1.522 × 10−6 M). Our results provide insight into the molecular mechanisms of specificity and sensitivity of the sex pheromone communication system in moths. [ABSTRACT FROM AUTHOR]

Chilo suppressalis and Sesamia inferens are two important lepidopteran rice pests that occur concurrently during outbreaks in paddy fields in the main rice-growing areas of China. Previous and current field tests demonstrate that the transgenic rice line Huahui 1 (HH1) producing a Cry1Ab-Cry1Ac hybrid toxin from the bacterium Bacillus thuringiensis reduces egg and larval densities of C. suppressalis but not of S. inferens. This differential susceptibility to HH1 rice correlates with the reduced susceptibility to Cry1Ab and Cry1Ac toxins in S. inferens larvae compared to C. suppressalis larvae. The goal of this study was to identify the mechanism responsible for this differential susceptibility. In saturation binding assays, both Cry1Ab and Cry1Ac toxins bound with high affinity and in a saturable manner to midgut brush border membrane vesicles (BBMV) from C. suppressalis and S. inferens larvae. While binding affinities were similar, a dramatically lower concentration of Cry1A toxin binding sites was detected for S. inferens BBMV than for C. suppressalis BBMV. In contrast, no significant differences between species were detected for Cry1Ca toxin binding to BBMV. Ligand blotting detected BBMV proteins binding Cry1Ac or Cry1Ca toxins, some of them unique to C. suppressalis or S. inferens. These data support that reduced Cry1A binding site concentration is associated with a lower susceptibility to Cry1A toxins and HH1 rice in S. inferens larvae than in C. suppressalis larvae. Moreover, our data support Cry1Ca as a candidate for pyramiding efforts with Cry1A-producing rice to extend the activity range and durability of this technology against rice stem borers. [ABSTRACT FROM AUTHOR]

The general pathway of biosynthesis and degradation for Type-I sex pheromones in moths is well established, but some genes involved in this pathway remain to be characterized. The purple stem borer, Sesamia inferens, employs a pheromone blend containing components with three different terminal functional groups (Z11-16:OAc, Z11-16:OH, and Z11-16:Ald) of Type-I sex pheromones. Thus, it provides a good model to study the diversity of genes involved in pheromone biosynthesis and degradation pathways. By analyzing previously obtained transcriptomic data of the sex pheromone glands and antennae, we identified 73 novel genes that are possibly related to pheromone biosynthesis (46 genes) or degradation (27 genes). Gene expression patterns and phylogenetic analysis revealed that one desaturase ( SinfDes4), one fatty acid reductase ( SinfFAR2), and one fatty acid xtransport protein ( SinfFATP1) genes were predominantly expressed in pheromone glands, and clustered with genes involved in pheromone synthesis in other moth species. Ten genes including five carboxylesterases ( SinfCXE10, 13, 14, 18, and 20), three aldehyde oxidases ( SinfAOX1, 2 and 3), and two alcohol dehydrogenases ( SinfAD1 and 3) were expressed specifically or predominantly in antennae, and could be candidate genes involved in pheromone degradation. SinfAD1 and 3 are the first reported alcohol dehydrogenase genes with antennae-biased expression. Based on these results we propose a pathway involving these potential enzyme-encoding gene candidates in sex pheromone biosynthesis and degradation in S. inferens. This study provides robust background information for further elucidation of the genetic basis of sex pheromone biosynthesis and degradation, and ultimately provides potential targets to disrupt sexual communication in S. inferens for control purposes. [ABSTRACT FROM AUTHOR]

This study was conducted on Bt and normal maize hybrids during two successive sowing dates, early and late summer plantation. TheSesamia creticalarvae were observed for the first time on first week of April on different commercial maize hybrids. While there was no larva/plant on transgenic maize hybrids, YieldGard and Ageeb-YG, while larvae were found on last week of July by a very little number on maize hybrids for late one. In Early summer planting date showed highly significant differences in reduction percent, between tested compounds and control one, in the pink corn borer population. The bio-residual activity of the NeemAzal-T/S 0.5% on TWC310 was significantly less pronounced, i.e. 75.5%, than other tested ones; the highest percentage of reduction, 86.6%, was achieved by Chlorophan 0.005% on SC2031, followed by NeemAzal-T/S 0.5% on SC2031 83.5% and Chlorophan 0.005% on SC2030 83.4%, respectively. Also the average reduction percentage ofS. creticalarvae differed significantly from 69.6%, on NeemAzal-T/S SC2031, to 83.0%, on Chlorophan SC2031, in the late summer planting. The different treatments had positive effects on maize yield in the two planting dates. In the first plantation date, the increased rate of control ranged from 1.04 to 1.24, when NeemAzal-T/S acted on TWC310 and transgenic IYG, respectively. And in the second plantation date, rate of control obtained was 1.06–1.30, when NeemAzal-T/S acted on SC 2031 and transgenic IYG, respectively. The tested compounds played an important role in controlling the pink corn borer insect,S. cretica, and this study suggests thatCry 1Ab-expressing corn hybrids would provide a great value as a component of corn IPM in Egypt. [ABSTRACT FROM PUBLISHER]

Background: A large number of insect chemosensory genes from different gene subfamilies have been identified and annotated, but their functional diversity and complexity are largely unknown. A systemic examination of expression patterns in chemosensory organs could provide important information. Methodology/Principal Findings: We identified 92 putative chemosensory genes by analysing the transcriptome of the antennae and female sex pheromone gland of the purple stem borer Sesamia inferens, among them 87 are novel in this species, including 24 transcripts encoding for odorant binding proteins (OBPs), 24 for chemosensory proteins (CSPs), 2 for sensory neuron membrane proteins (SNMPs), 39 for odorant receptors (ORs) and 3 for ionotropic receptors (IRs). The transcriptome analyses were validated and quantified with a detailed global expression profiling by Reverse Transcription-PCR for all 92 transcripts and by Quantitative Real Time RT-PCR for selected 16 ones. Among the chemosensory gene subfamilies, CSP transcripts are most widely and evenly expressed in different tissues and stages, OBP transcripts showed a clear antenna bias and most of OR transcripts are only detected in adult antennae. Our results also revealed that some OR transcripts, such as the transcripts of SNMP2 and 2 IRs were expressed in non-chemosensory tissues, and some CSP transcripts were antenna-biased expression. Furthermore, no chemosensory transcript is specific to female sex pheromone gland and very few are found in the heads. Conclusion: Our study revealed that there are a large number of chemosensory genes expressed in S. inferens, and some of them displayed unusual expression profile in non-chemosensory tissues. The identification of a large set of putative chemosensory genes of each subfamily from a single insect species, together with their different expression profiles provide further information in understanding the functions of these chemosensory genes in S. inferens as well as other insects. [ABSTRACT FROM AUTHOR]

Abstract: Host searching by egg parasitoids faces a main constraint due to low detectability of cues from host eggs. Therefore egg parasitoids have developed distinctive strategies by exploiting cues that originate from non-target instars of the host and/or from plants. The scelionid Telenomus busseolae is specialized on concealed eggs of Sesamia nonagrioides and other noctuid stemborers. In this paper we show that oviposition by S. nonagrioides induces changes in the cues present on maize leaf surface, which arrest naïve females of T. busseolae. The induction appears to be systemic as the parasitoid also responds to leaves and leaf portions that are not directly affected by ovipositing females. Such oviposition-induced, short-range, plant synomones, acting in sequence with the kairomonal cues from scales left on the plant by the ovipositing host female, significantly increases parasitoid efficiency during host finding. The elicitor of plant response originates from the host female reproductive system, being contained both in the host’s ovarian eggs and in the colleterial gland secretion. Induction starts 24h after oviposition and lasts at least till 72h. The ecological role of this oviposition-induced plant synomone in host searching by T. busseolae is discussed. [Copyright &y& Elsevier]

The species composition, abundance and plant infestation of stem borers attacking maize and millet were investigated in farmers' fields during the cropping season of 2010 and 2011 in Maiduguri, Nigeria. Stem borers were collected via destructive sampling. In total, three stem borer species (Busseola fusca, Sesamia calamistis and Coniesta ignefusalis) were found, of which S. calamistis (64%) and C. ignefusalis (72%), respectively, were predominant on maize and millet. Across both years, whereas mean plant infestation ranged from 4.8% on millet to 20.8% on maize, mean stem borer abundance ranged from 1.6 individuals on millet to 13.8 individuals on maize. Mean total plant infestation and stem borer abundance varied with different years and both were significantly higher during the 2010 than 2011 cropping season. In spite of the generally low stem borer abundance per farmers' field, plant infestation particularly on maize plants seems to be moderate during different years. [ABSTRACT FROM AUTHOR]

Selection for reduced stalk tunnel length by the Mediterranean corn borer (MCB) (Sesamia nonagrioides Lef.) while maintaining yield under infestation has already been evaluated. Significant reductions for tunnel length were reported, but yield showed a nonsignificant tendency to decrease with selection that could be due to increased inbreeding or significant genetic correlation between yield and resistance. Simultaneously, the presence of major quantitative trait loci (QTL) for resistance in chromosome 4 has been suggested. In the present study, we investigated the genetic relationship between yield and stalk tunneling resistance by conducting one generation of selection each for yield alone, resistance alone, and yield and resistance combined in a broad-based population. In addition, we tested the effectiveness of marker-assisted selection at two markers on chromosome 4 for reducing tunnels by MCB. Evaluations were made for 2 yr at two locations under MCB infestation. Unfavorable genetic correlation between stalk tunnel length and yield has been confirmed and could prevent detection of major QTL for tunnel length by using selection mapping. Markers phi076 and umc1329 could be linked to QTL for plant height but are not useful markers for reducing tunnel length and hence damage caused by borers. Finally, results advise against selection for reduced tunnel length by MCB or any index involving yield and tunnel length. [ABSTRACT FROM AUTHOR]

Maize hybrids expressing the Cry1F toxin provide efficient control of lepidopteran pests. The Mediterranean corn borer, Sesamia nonagrioides (Lefèvre), is one of the most damaging pests of maize in the Mediterranean basin. In this work we firstly determined the efficacy of maize hybrids expressing the Cry1F toxin (event TC1507) to control neonates of S. nonagrioides. Leaf tissue feeding bioassays revealed that TC1507 maize is highly effective against this pest, and the percentage mortality obtained was comparable to that obtained with a Cry1Ab-expressing maize hybrid (Compa CB, event 176), which is known to be highly efficacious against S. nonagrioides. Secondly, interpopulation variation in the susceptibility to the Cry1F insecticidal protein was established for nine field-collected populations of S. nonagrioides (three Spanish, two French, two Italian, one Greek, and one Turkish). Estimates of the susceptibility of larvae to the Cry1F toxin showed low variability in lethal concentrations and growth inhibition concentrations among field populations. Moreover, no significant differences were found when they were grouped by geographical areas [Western Mediterranean (Spain and France) versus Eastern Mediterranean (Italy, Greece and Turkey)] or by history of exposure to Bt plants (Spanish vs. other populations). Therefore, the minor differences found in field populations can be attributed to natural variation in sensitivity to Cry1F. The importance of establishing baselines of susceptibility for resistance detection is discussed. Future changes in susceptibility of S. nonagrioides populations to Cry1F could be documented based on this baseline data. [ABSTRACT FROM AUTHOR]

The article focuses on a research conducted in order to evaluate the potential application of the bushmint, Hyptis suaveolens (H. suaveolens), for the control of infestation on maize, Zea mays caused by the pink stalk borer, Sesamia calamistis in southern Benin, West Africa. It discusses the comparison of the aqueous extract of H. suaveolens with the commercial insecticide furadan. The study revealed the importance of the aqueous extract of H. suaveolens as an inhibitor.

Species delimitation, an issue central to systematics and biodiversity studies, is addressed in the epunctifera group of the stem borer genus Sesamia Guenée (Lepidoptera: Noctuidae). This group is composed of four sub-Saharan species: Sesamia poephaga Tams & Bowden; Sesamia epunctifera Hampson; Sesamia penniseti Tams & Bowden; and Sesamia poebora Tams & Bowden, the taxonomic status of which was unclear. The first species was considered a possible synonym of the second, and the third species was considered a possible synonym of the fourth. An analysis combining morphological, ecological and molecular data enables us to conclude that S. epunctifera and S. poephaga are different species, and that S. poebora is a synonym of S. penniseti. Two new species were discovered: Sesamia firmata and Sesamia veronica Sesamia firmata has atypical genitalic morphology, suggesting a strong selection resulting in a reinforcement of pre-zygotic isolation. Some specimens previously identified as S. penniseti on the basis of morphology are sisters to S. epunctifera on the mitochondrial tree, and are connected to S. penniseti on the nuclear tree. The mitochondrial distance from S. penniseti and S. epunctifera is 7.6% and 3.9%, respectively, suggesting an ancient mitochondrial introgression from S. epunctifera into S. penniseti. The possible causes of the reinforcement and introgressive hybridization are discussed. This case of mitochondrial introgression, uncommon in Lepidoptera, in which females are the heterogametic sex, may be an exception to Haldane's rule. The hybrid is assigned the rank of species and named Sesamia pennipuncta [ABSTRACT FROM AUTHOR]

Abstract: We obtained a full-length cDNA encoding a carboxylesterase in Sesamia nonagrioides. The complete cDNA sequence is comprised of 1838bp with an open reading frame encoding 576 amino acid residues with predicted molecular mass of 64.24kDa. The deduced amino acid sequence showed high identity to JHE-Related of Trichoplusia ni (65% amino acid identity) and 49–46% amino acid identity to JHEs of other lepidopterans and contained all five functional motifs of insect JHEs. The gene has been termed as SnJHE-Related (SnJHER) to denote its similarity to other insect JHE genes and the occurrence of an unusual cysteine residue immediately adjacent to the catalytic serine, instead of the conventional alanine residue. Phylogenetic analyses localised SnJHER together with TnJHER in a branch of the lepidopteran''s JHEs group, with other carboxylesterases (COEs) occuring in separated groups. The JH analog methoprene did not affect the expression of SnJHER in contrast to other insect JHEs. Additionally, ecdysteroid analogs induced SnJHER gene expression. The SnJHER mRNA levels were higher in long-day non-diapausing larvae than in short-day diapausing ones. In the fifth instar of non-diapausing and ninth instar of diapausing larvae, the SnJHER mRNAs reached higher expression levels on the days close to each larval molt. In the last (sixth) non-diapausing larval instar, SnJHER mRNA levels peaked in the intermolt period but were lower than during the fifth instar. [Copyright &y& Elsevier]

Abstract: A three year (2003–2005) field study compared the susceptibility to the Cry1Ab toxin, expressed in Bt maize, of Mediterranean corn borer (MCB) Sesamia nonagrioides populations collected from areas with different adoption rates of Bt maize in Spain with Bt-free areas in Greece. Spain is the only European country where the cultivar Compa CB derived from the event Bt176 was commercially grown, from 1998 to 2005. The large decrease of the titer of the toxin in this cultivar at later growth stages represented the worst-case scenario for resistance development of MCB, since larvae of the second and third generations were exposed to sublethal concentrations of Cry1Ab toxin. Our data revealed that the variation in susceptibility to Cry1Ab for the MCB Spanish field populations analyzed in the three years was very low, with LC50 values fluctuating between 12 and 30ngCry1Ab/cm2, regardless of the region of origin, the type of maize (Bt or non-Bt) and the year. Furthermore, no significant differences were found when comparisons were made with a laboratory population (LC50 values: 18–26ngCry1Ab/cm2) or with field populations from Greece (Bt-free areas), which displayed LC50 values ranging between 22 and 27ngCry1Ab/cm2. Standardizing bioassay protocols proved to be essential for obtaining comparable results. These findings suggest that resistant MCB populations did not evolve in those Spanish maize areas where Compa CB was largely cultivated for eight years, contradicting the expected rapid development of resistance under these unfavourable conditions. Additionally, our results can be used as baseline indices in post-market resistance monitoring programs if Bt maize is introduced in Greece. Further studies should continue, since the insights gained from a resistance monitoring program may help to enhance the durability of Bt maize. [Copyright &y& Elsevier]

Although rice ( Oryza sativa L. ) lines that express Bacillus thuringiensis ( Bt ) toxins have shown great potential for managing the major Lepidoptera pests of rice in southern China, including Sesamia inferens, their long-term use is dependent on managing resistance development to Bt toxins in pest populations. The maintenance of "natural" refuges, non-Bt expressing plants that are hosts for a target pest, has been proposed as a means to minimize the evolution of resistance to Bt toxins in transgenic plants. In the current study, field surveys and greenhouse experiments were conducted to identify host plants of S. inferens that could serve as "natural" refuges in rice growing areas of southern China. A field survey showed that 34 plant species in four families can be alternative host plants of S. inferens. Based on injury level under field conditions, rice (Oryza sativa L.); water oat (Zizania latifolia Griseb.); corn (Zea mays L.); tidalmarsh flatsedge (Cyperus serotinus Rottb.); and narrowleaved cat-tail (Typha angustifolia Linn. ) were identified as the primary host plant species of S. inferens. Greenhouse experiments further demonstrated that water oat, corn, and narrow-leaved cat-tail could support the survival and development of S. inferens. Interestingly, greenhouse experiments showed that S, inferens preferred to lay eggs on tidalmarsh flatsedge compared with the other three nonrice host species, although no pupae were found in the plants examined in field surveys. Few larvae were found to survive on tidalmarsh flatsedge in greenhouse bioassays, suggesting that tidalmarsh flatsedge could serve as a "dead-end" trap crop for S. inferens, but is not a candidate to serve as natural refuge to maintain susceptible S. inferens. Overall, these results suggest that water-oat, corn, and narrowleaved cat-tail might serve as "natural refuge" for S. inferens in rice planting area of southern China when Bt rice varieties are planted. [ABSTRACT FROM AUTHOR]

Abstract: Sesamia nonagrioides (Lepidoptera: Noctuidae) larvae reared under long day (LD; 16L:8D) conditions pupate after 5 or 6 larval instars, whereas under short day (SD; 12L:12D) conditions they undergo up to 12 additional molts before pupating. This extended period of repeated molting is maintained by high levels of juvenile hormone (JH). Previous work demonstrated that both LD and SD larvae decapitated in the 6th instar pupate but further development is halted. By contrast, about one-third of SD larvae from which only the brain has been removed, undergo first a larval molt, then pupate and subsequently developed to the adult stage. Debrained LD larvae molt to larvae exceptionally but regularly pupate and produce adults. Implanted brains may induce several larval molts in debrained recipient larvae irrespectively of the photoperiodic conditions. The results of present work demonstrate that the prothoracic glands (PGs) and the corpora allata (CA) of debrained larvae continue to produce ecdysteroids and JHs, respectively. PGs are active also in the decapitated larvae that lack JH, consistent with the paradigm that CA, which are absent in the decapitated larvae, are the only source of this hormone. Completion of the pupal-adult transformation in both LD and SD debrained insects demonstrates that brain is not crucial for the development of S. nonagrioides but is required for diapause maintenance. Application of JH to headless pupae induces molting, presumably by activating their PGs. It is likely that JH plays this role also in the induction of pupal-adult transformation in debrained insects. Application of the ecdysteroid agonist RH 2485 (methoxyfenozide) to headless pupae also elicits molting: newly secreted cuticle is in some cases thin and indifferent, in other cases it bears distinct pupal or adult features. [Copyright &y& Elsevier]

Mediterranean corn borer (MCB) ( Sesamia nonagrioides Lef) and European corn borer (ECB) ( Ostrinia nubilalis Hbn) are the most important biotic stresses of maize in Europe. The first selection program to improve stalk resistance to MCB was carried out in the maize population EPS12. It has shown that selection was effective to improve stalk resistance to MCB and ECB, while yield was not significantly diminished. The objective of this research was to determine if correlated changes in EPS12 occurred due to selection for resistance to MCB. Cycles of selection per se and testcrosses to three testers were evaluated under MCB and ECB artificial infestation at two different Spanish locations during 2 years. Selection has significantly reduced cob damage, days to silking, plant and ear height, and 100-kernel weight; meanwhile early vigor was increased. These changes could rather be a consequence of unconscious selection and/or the genetic correlation of these traits with resistance than a consequence of genetic drift. [ABSTRACT FROM AUTHOR]

Abstract: Transgenic rice to control stem borer damage is under development in China. To assess the potential of Bacillus thuringiensis (Bt) transgenes in stem borer control, the toxicity of five Bt protoxins (Cry1Aa, Cry1Ab, Cry1Ac, Cry1Ba and Cry1Ca) against two rice stem borers, Sesamia inferens (pink stem borer) and Chilo suppressalis (striped stem borer), was evaluated in the laboratory by feeding neonate larvae on artificial diets containing Bt protoxins. The results indicated that Cry1Ca exhibited the highest level of toxicity to both stem borers, with an LC50 of 0.24 and 0.30μg/g for C. suppressalis and S. inferens, respectively. However, S. inferens was 4-fold lower in susceptibility to Cry1Aa, and 6- and 47-fold less susceptible to Cry1Ab and Cry1Ba, respectively, compared to C. suppressalis. To evaluate interactions among Bt protoxins in stem borer larvae, toxicity assays were performed with mixtures of Cry1Aa/Cry1Ab, Cry1Aa/Cry1Ca, Cry1Ac/Cry1Ca, Cry1Ac/Cry1Ba, Cry1Ab/Cry1Ac, Cry1Ab/Cry1Ba, and Cry1Ab/Cry1Ca at 1:1 (w/w) ratios. All protoxin mixtures demonstrated significant synergistic toxicity activity against C. suppressalis, with values of 1.6- to 11-fold higher toxicity than the theoretical additive effect. Surprisingly, all but one of the Bt protoxin mixtures were antagonistic in toxicity to S. inferens. In mortality-time response experiments, S. inferens demonstrated increased tolerance to Cry1Ab and Cry1Ac compared to C. suppressalis when treated with low or high protoxin concentrations. The data indicate the utility of Cry1Ca protoxin and a Cry1Ac/Cry1Ca mixture to control both stem borer populations. [ABSTRACT FROM AUTHOR]

Abstract: Transgenically expressed Bacillus thuringiensis insecticidal-protein Cry1Ab was quantified in target tissues of insect feeding of several YieldGard® corn hybrids. The Cry1Ab protein is intended to protect corn plants from two economically important stem borers, Chilo partellus and Sesamia inferens. A total of seven YieldGard hybrids, all with MON810 event, were field-tested in a total of fourteen locations during the dry season (October–March) of 2005/2006 and wet season (May–October) of 2006. S. inferens and C. partellus oviposit on leaves of young corn plants, 15–60 days after emergence (DAE). The neonates initially feed by scraping the leaf lamina before migrating to bore into the stem. Thus high concentrations of Cry1Ab in whorl leaf and stem tissues would ensure effective control of the borers. The mean tissue Cry1Ab concentrations during the oviposition window of the borers (15–60 DAE), ranged from 50.05 to 21.01ppm in whorl leaf, and between 9.26 and 3.47ppm in stem tissue during the same period in the dry season of 2005/06. Similarly, Cry1Ab concentrations in whorl leaf and stem between 15 and 60 DAE during the wet season of 2006 ranged between 19.30 to 11.08 and 14.28 to 4.69ppm, respectively. The baseline-sensitivity data of these insects to Cry1Ab in laboratory assays was determined. The concentrations of Cry1Ab in the target tissues as studied in seven YieldGard hybrids tested suggest effective management of the two borers. This paper also provides a summary of the expression of the Cry1Ab gene in various genetic backgrounds. [Copyright &y& Elsevier]

Abstract: The caterpillars of Sesamia nonagrioides developing under long-day (LD) photoperiod pupate in the 5th or 6th instar whereas under short day (SD) conditions they enter diapause and undergo several extra larval molts. The diapause is terminated within 1–3 instars upon transfer of SD larvae to the LD conditions. Brain removal from the 6th instar larvae promotes pupation followed by imaginal development; however, one third of the SD larvae and 12% of the LD larvae debrained at the start of the instar first undergo 1–2 larval molts. The incidence of larval molts is enhanced by the brain implants. Exclusively pupal molts occur in the LD larvae debrained late in the 6th instar. Decapitation elicits pupation in both LD and SD larvae, except for some of the 4th and 5th and rarely 6th instar that are induced to a fast larval molt. The pupation of decapitated larvae is reverted to a larval molt by application of a juvenile hormone (JH) agonist. No molts occur in abdomens isolated from the head and thorax prior to the wandering stage. Abdomens isolated later undergo a larval (SD insects) or a pupal (LD insects) molt. Taken together the data reveal that in S. nonagrioides (1) several larval molts followed by a pupal and imaginal molt can occur without brain; (2) an unknown head factor outside the brain is needed for the pupal–adult molt; (3) brain exerts both stimulatory and inhibitory effect on the corpora allata (CA); (4) larval molts induced in CA absence suggest considerable JH persistence. [Copyright &y& Elsevier]

A maize synthetic population was improved for resistance to the Mediterranean corn borer (MCB, Sesamia nonagrioides) while maintaining yield. The objectives of this research were to investigate whether yield and yield stability of the maize synthetic population named EPS12 were affected by selection for MCB resistance; also to determine which genotypic and environmental covariates could explain the genotype (G), environment (E) and genotype × environment (GE) effects for yield under corn borer infestation. Plants from three cycles of selection and their testcrosses to three inbred testers (A639, B93 and EP42) were evaluated at two locations in 2 years, under MCB and European corn borer infestations. After selection EPS12 was a more stable genotype. Hybrids derived from crosses between B93 and inbreds obtained from the initial cycles of selection could be recommended for cultivation in northern Spain. The yield of crosses between cycles of selection and testers increased when there were fewer days with temperatures >25°C and higher mean maximum temperatures. Differences in yield among these genotypes were mostly explained by resistance to corn borer attack. In general, among EPS12-derived materials, genetic characteristics that contribute to increased grain yield were also responsible for increased abiotic stress tolerance. [ABSTRACT FROM AUTHOR]

The lepidopteran stemborers Busseola fusca (Fuller) (Lepidoptera: Noctuidae), Sesamia calamistis (Hampson) (Lepidoptera: Noctuidae), and Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) are effectively controlled by Bt maize that expresses the CrylAb insecticidal protein. Another noctuid species, the cutworm Agrotis segetum (Denis and Schiffermüller) (Lepidoptera: Noctuidae), which is the most common and injurious pest of maize seedlings in South Africa, is exposed to Bt toxin for a part of its life cycle. The effect of this exposure to Bt maize has not been studied yet. The aims of this study were to determine the effects of Bt maize (events MON81O and Btll) on larval mass, development time, survival, and fecundity of A. segetwn. Laboratory studies were conducted with firstand fourth-instar larvae and moths. Results showed that the effect of CrylAb toxin on the biology of A. segetum larvae and moths were largely insignificant. The effects of the two Bt maize events on the different parameters measured in this study was not similar between the Bt events and their respective iso-hybrids. Compared with larvae that fed on conventional (non-Bt) maize, Bt maize did not affect survival of first-instar larvae. However, mean mass of larvae that fed on Bt maize (Btll) was significantly lower. Feeding on Bt maize did not have a significant effect on development and survival of fourth-instar larvae or moth longevity. It did, however, delay the development period to pupa formation. Fewer eggs were laid by moths fed as larvae on maize event Btll compared with MON81O. This study indicates that Bt maize will most likely not have any significant effect on the control of A. segetum under field conditions. [ABSTRACT FROM AUTHOR]

Abstract: In maize, the Mediterranean corn borer (MCB), Sesamia nonagrioides Lef, is the insect pest that causes the most significant yield losses in north-western Spain. A S1 recurrent selection program to improve resistance of EPS12 against MCB was evaluated previously. In the current study two experiments were conducted to determine if antibiosis and/or structural mechanisms were responsible for the improvement in resistance in this synthetic. Larval growth or survival of MCB was not significantly affected to consider the presence of antibiotic factors in the pith. Besides, pith puncture resistance, previously reported as a possible resistance trait in single inbred lines, did not show significant differences between cycles of selection. Length of the internode basal ring (LIBR) was the structural character most related to stem resistance improvement to MCB in the current evaluation. There was a high positive correlation between MCB tunnel length and LIBR (P ≤0.01, R 2 =0.99). The larvae would enter the plant throughout the internode basal area and, this way, they could avoid the increased thickness or hardness of the remaining rind area. LIBR might be a useful measure in future resistance breeding programs against this borer. [Copyright &y& Elsevier]

The ecto-larval parasitoid species, Bracon brevicornis Wesm. (Hymenoptera: Braconidae) was reared in the laboratory on three different insect host species; the corn borers, Ostrinia nubilalis Hb., Sesamia cretica Led. and the black cut worm, Agrotis ipsilon. Full grown larvae of each host were exposed individually to the parasitoid females for one or two days until death of the parasitoids. Mean numbers of parasitoid's progeny per host larva were 9.6 (on O. nubilalis), 9.3 (on S. cretica) and 7.3 (on A. ipsilon) when host larvae were exposed daily to the parasitoid female. Respective figures when host larvae were exposed every two days reached 17.1, 11.4 and 6.4 individuals. Sex ratio (male: female) was found to be 1: 0.9, 1: 0.3 and 1: 0.6, when the parasitoid was reared on O. nubilalis, S. cretica and A. ipsilon, respectively at one day exposure period. The respective sex ratios at the 2-day exposure period were 1: 0.4, 1: 0.5 and 1: 0.3. Among the studied three insect hosts, O. nubilalis seemed to be the recommended host for mass rearing of B. brevicornis. [ABSTRACT FROM AUTHOR]

A full-length Hsp83, named SnoHsp83, cDNA from the corn stalk borer, Sesamia nonagrioides, was cloned and sequenced. Genomic analysis showed that the SnoHsp83 gene is unique. The size of the SnoHsp83 cDNA was found to be approximately 2.6 kb. The deduced polypeptide comprised 717 amino acid residues, with a molecular mass of 82.6 kDa. It contained all the highly conserved amino acid motifs that characterize the cytosolic members of the hsp90 family. We investigated the expression of SnoHsp83 gene in response to diapause and heat/cold stress. SnoHsp83 is constitutively expressed in non-diapausing larvae and is induced 15-fold by heat. SnoHsp83 displays a similar pattern to SnoHsc70 under diapause conditions, when extra larval moults occur. Our results indicate that the SnoHsp83 gene could be involved in the developmental process that occurs between two moults. [ABSTRACT FROM AUTHOR]