Effect of Pheromone Blend Components,Sex Ratio,and Population Size on the Mating of Cadra cautella (Lepidoptera: Pyralidae)

The almond moth Cadra cautella (Walker), a key pest of storage facilities, is difficult to manage using synthetic chemicals. Pheromone-based management methods remain a high priority due to advantages over conventional management practices, which typically use insecticides. Cadra cautella females release a blend of pheromone including (Z, E)-9,12-tetradecadienyl acetate (ZETA) and (Z)-9-tetradecadien-1-yl acetate (ZTA). The effect of these components on mating of C. cautella and how response varies with the population density and sex ratio remain unknown. In this study, the mating status of C. cautella was studied inside mating cages under different ratios of ZETA and ZTA diluted in hexane and at different population sizes either with equal or unequal sex ratio. The lowest percentage of mated females (highest mating disruption [MD] effects), corresponding to roughly 12.5%, was produced by a 5:1 and 3.3:1 ratio of ZETA:ZTA. Populations with equal sex ratio showed the lowest percentage of mated females, at 20% and 12.5% under lower and higher density, respectively. The next lowest percentage of mated females was produced when the sex ratio was set to 1: 2 and 2:1 male:female, with just 25% and 22.5% of moths mated, respectively. This study shows that mating status of C. cautella is influenced by ZETA:ZTA ratio, sex ratio, and population size. This current knowledge would have useful implications for mating disruption programs.     

Rice striped stem borer, Chilo suppressalis (Lepidoptera: Pyralidae), overwintering in super rice and its control using cultivation techniques

Super rice has the potential to deliver very high yields but is also susceptible to attack by the striped rice stem borer, Chilo suppressalis. In this study, surveys and field trials were performed to examine this problem and efficient ways were found to lower the borer’s population density. It was found that larger super rice plants provided more refuges for borers to evade insecticide contact and had a longer growth period allowing borers to complete their larval development in an intact environment. The current cultivation regime was shown to favour outbreaks of borers. Super rice is harvested leaving tall field stubbles until the following growing season, thus providing food and cover in which borers may successfully overwinter. We found that borer larvae were distributed to a greater height in the plants of super rice than in common rice, making control through agricultural operations more feasible. Burning fields after harvest, which killed 84.5% of borers, seemed the best remedy, though this practice is forbidden in China for ecological reasons. Leaving short stubbles followed by appropriate treatment of the rice straw killed 74.0% of the borer population. In addition, spring irrigation after the pre-pupation dispersal movements of borers killed more than half of the overwintering population. Pre-winter rotary tillage had little effect on borer numbers but enhanced the population reduction effect of irrigation the following spring. Based on the results obtained, efficient control of borers on super rice can be achieved by harvesting leaving short stubbles, followed by rotary tillage and spring irrigation. This regime can reduce the borer population by more than 98%, minimising chemical use and maximising use of a reduced agricultural workforce.     

Plant age effect of rice cultivar IR46 on susceptibility to the yellow stem borer Scirpophaga incertulas (Walker) (Lepidoptera: Pyralidae)

Plant damage and grain yield losses of rice cultivar IR46 under field conditions were highest when attacked by yellow stem borer Scirpophaga incertulas (Walker) larvae in the tillering and flowering stages and lowest when plants were at the panicle initiation stage of growth. A screenhouse tests indicated that S. incertulas development was most rapid on the tillering and flowering stages and lowest on the panicle initiation stage. An action threshold of one egg mass per m² is suggested.     

Evaluation of the effect of processing techniques on the nutrient and antinutrient contents of pearl millet (Pennisetum glaucum) seeds

This work was undertaken to evaluate the effect of soaking, sprouting, cooking and fermentation or their combinations on the nutrient and antinutrient contents of pearl millet seeds. Standard assay procedures were adopted to determine both the nutrient and the antinutrient concentrations of the products. The synergistic effect of cooking and fermentation improved the nutrient quality. The antinutrients were reduced to safe levels to a greater extent than did any of the other processing techniques or their combinations employed.     

Management and cultivar effects on ruminant nutritional quality of pearl millet (Pennisetum glaucum (L.) R. Br.) stover: II. Effects of cultivar choice on stover quality and productivity

The paper investigates the variation in laboratory fodder quality traits in stover of 16 cultivars of pearl millet grown over 2 consecutive years and subjected to two different fertilizer regimes and planting densities. Stover quality traits were nitrogen and sugar content, in vitro digestibility and metabolizable energy content as well as yield of digestible and metabolizable stover. Significant (P < 0.05) cultivar-dependent variations were observed for all these quality traits. Stover nitrogen contents were mostly below the levels (1.2% of dry matter) considered to be the minimum required for efficient feed digestion in the rumen, but choice of cultivar plus nitrogen fertilizer application could raise nitrogen levels to near, equal or above this threshold. Stover sugar contents were below 5% and mostly concentrated in the stems. Across management regimes stover in vitro digestibility varied by about 4% units, and by about 3–5% units within individual management regimes. Stover metabolizable energy contents of cultivars varied such that stover from superior cultivars could provide the energy maintenance requirement of livestock and theoretically moderate levels of live weight gains, while livestock fed on stover from poor cultivars would lose live weight. Yields of digestible and metabolizable stover (yield of stover dry matter times stover in vitro digestibility/metabolizable energy) varied among cultivars by at least 1.7-fold. Stover quality traits and grain yields of cultivars were largely unrelated (P > 0.05) suggesting that high stover quality will not be achieved on the expense of grain yield. Heritabilities for stover quality traits were high (h² > 0.73) except for stover nitrogen content (h² > 0.56).     

Mechanically-applied wax matrix (SPLAT-GBM) for mating disruption of grape berry moth (Lepidoptera: Tortricidae)

An ATV-mounted mechanical applicator was designed to treat vineyards with SPLAT-GBM™ for mating disruption of grape berry moth, Paralobesia viteana (Lepidoptera: Tortricidae). SPLAT-GBM was applied to vineyards in 0.8 g drops at a density of 1544 or 3089 drops per hectare for a total of 1.3 or 2.5 kg per hectare. Trials were conducted in 2008 and 2009 in vineyards receiving grower-standard insecticide sprays for control of grape berry moth and other insect pests. In the first trial, SPLAT-GBM applied twice at 1.3 or 2.5 kg/ha caused a significant reduction in grape berry moth infestation at harvest on clusters at the border of the vineyards where infestation is highest, compared with the no-pheromone control, but three applications at 2.5 kg/ha did not result in lower infestation compared with both the control and other treatments. In the second trial, application of SPLAT-GBM 2.5 kg/ha in mid-June and late-July caused a significant reduction in grape berry moth infestation at harvest on clusters at the border of the vineyards. Application in early-May and late-June resulted in infestation that was similar to the other program, but not statistically different from the control. In both trials, there were no significant differences between any of the treatments of SPLAT-GBM and the control inside the vineyards where infestation is low. Among treatments of SPLAT-GBM, infestation was similar regardless of number, rate, or timing of the applications. This study shows that mechanical application of wax matrix drops to release pheromone is an effective method for control of grape berry moth using mating disruption.     

Determinants of ruminant nutritional quality of pearl millet [Pennisetum glaucum (L.) R. Br.] stover: I. Effects of management alternatives on stover quality and productivity

The paper investigates management and cultivar type effects on pearl millet stover yield and fodder quality. Sixteen pearl millet cultivars available to farmers in India were selected to represent three cultivar types: (1) traditional landrace germplasm from the arid/semi-arid millet production zones, (2) improved dual-purpose (grain and stover) open-pollinated varieties incorporating differing amounts of traditional landrace germplasm and (3) commercial, grain-type F1 hybrids, bred for use in the arid/semi-arid zone. The cultivars were grown for 2 years (2000 and 2001) at high fertility (HF: 65 kg N ha⁻¹ and 18 kg P ha⁻¹) and low fertility (LF: 21 kg N ha⁻¹ and 9 kg P ha⁻¹). Within each fertility level high (HP) and low (LP) plant population densities were established by varying sowing rate and then thinning to the target populations (HP: 11 plants m⁻² and LP: 5 plants m⁻²). Stover fodder quality traits (nitrogen concentration, sugar content, in vitro digestibility and metabolizable energy content) were analyzed using a combination of conventional laboratory analysis and near infrared spectroscopy. In general, fertility level and cultivar type had strong effects on grain and stover yields, and on a range of stover nutritional quality traits, but with significant year interactions. In contrast, the effect of population density on these variables was largely insignificant. Higher fertilizer application significantly increased grain and stover yields and stover nitrogen concentration, in vitro digestibility and metabolizable energy content. As a result, fertilization resulted in significant increases in the yields of both digestible and metabolizable stover. Landrace cultivars as a group produced higher quality fodder than modern hybrids, but at a significant cost in grain yield. Dual-purpose, open-pollinated cultivars were generally intermediate between the landraces and hybrids, in terms of both stover quality and grain yield, but produced the highest yields of both digestible and metabolizable stover. The paper discusses the implications of these findings for Indian pearl millet farmers with various resource levels and farming objectives.     

Effects of seed treatments and storage on the changes in lipids of pearl millet meal

Lipids in pearl millet meal showed a rapid hydrolytic decomposition during storage. The magnitude of such degradation was influenced significantly by the nature of the storage container used, the temperature and heat treatments given to the seeds. The hydrolytic breakdown of lipids was significantly low in the meals stored in polyethylene bags, plastic boxes and under refrigerated (5±2 °C) conditions. Hot water blanching at 98 °C for 10 sec and dry heating of seeds at 100 °C for 120 min were found to be most effective in minimising the undesirable changes in lipids of the meal during storage.     

Generation mean analysis of pearl millet [Pennisetum glaucum (L.) R. Br.] grain iron and zinc contents and agronomic traits in West Africa

Pearl millet is the most important staple food crop for millions of people across the world. Micronutrient malnutrition is the major problem for people living in the semi-arid regions of Africa. Identification of gene effects controlling the inheritance of grain Fe and Zn will be helpful in formulating suitable breeding strategies for biofortified pearl millet development. Hence, generation mean analysis was used to study epistasis and estimate gene effects for grain iron and zinc contents along with the agronomic and morphological traits. Six generations P₁, P₂, F₁, F₂, BC₁P₁ and BC₁P₂ were generated and were evaluated during the 2018–19 off season. Analysis of variance showed significant variability for all the traits in both generations. Six parameter model revealed predominance of additive gene effects for inheritance of grain iron concentration, and additive × additive type of non-allelic interactions. For grain zinc concentration additive gene effects were preponderant compared to non-additive gene effects, and only additive × dominance gene effects were significant among the three types of epistasis. Grain weight per plant was predominantly under non-additive gene effects and additive × additive and additive × dominance gene effects type of epistasis was detected in each cross. Likewise, for flowering non-additive gene effects were most important with the presence of dominance × dominance type of epistasis. For plant height, panicle circumference and length, additive × additive genes effects were the most important among the three type of non-allelic gene action.These findings can be helpful in enehancing the pearl millet breeding programs in Africa.     

Evidence of genetic transmission of antibiosis and antixenosis resistance of sorghum to the spotted stemborer, Chilo partellus (Lepidoptera: Pyralidae)

Spotted stemborer, Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae), is the most important pest of sorghum in Asia and south and eastern Africa. Host plant resistance is an important control tactic for controlling this pest. Two breeding lines 27B × PB 15881-3 and 463B × PB 15881-3 with their parents, resistant and susceptible genotypes were evaluated in the field, glasshouse and laboratory for different resistance parameters. Breeding lines and genotypes varied significantly in foliar damage ratings, percentage of stem length tunneled, percentage of plants with deadhearts, larval survival, larval and pupal weights, larval and pupal duration, and percentage pupation and adult emergence in diets amended with leaf powder of different sorghum genotypes. The breeding lines 27B × PB 15881-3 and 463B × PB 15881-3 showed antixenosis and antibiosis to C. partellus in terms of reduced eggs per plant, larval survival and development. The levels of antixenosis and antibiosis of both breeding lines were similar to their resistant parents. Results indicate that transmission of characteristics responsible for resistance to the progeny from the resistant parent occurred.     

斜纹夜蛾对植物挥发物及其与性信息素组合的触角电位反应

为了提高目前化学性诱剂的诱集效率,采用电生理方法测试斜纹夜蛾对4种植物气味化合物、4种植物叶片提取液及其与性诱剂混合组分的触角电位（Electroantennogram,EAG）反应。结果表明：这些植物挥发物均可刺激斜纹夜蛾产生触角电位反应,且随着浓度的增加,部分挥发物引起电位值呈逐渐上升趋势,剩余挥发物使电位值先上升后下降。试验所测单种植物挥发物对性诱剂均有显著的增效作用,而2种或2种以上气味化合物混合,只有苯乙醛和水杨酸甲酯同时存在时,对性诱剂才有增效作用,缺少其中任何1种,增效作用都不显著。此研究结果将为下一步开发研究斜纹夜蛾雄虫的引诱剂或性诱剂的增效剂提供重要的科学依据。     

Re-evaluation of sugarcane borer (Lepidoptera: Crambidae) bioeconomics in Louisiana

The sugarcane borer, Diatraea saccharalis (F.) (Lepidoptera: Crambidae), is the key insect pest of sugarcane, Saccharum spp., grown in Louisiana. For more than 40 years, Louisiana sugarcane farmers have used a value of 10% internodes bored at harvest as the economic injury level (EIL). Three plant-cane studies were conducted to re-evaluate the long-standing sugarcane borer EIL level using the most recently released varieties of sugarcane. Varieties were exposed to artificially enhanced borer infestations; the experimental treatments consisted of borer control with insecticides or no control. Data were collected on infestation intensity, damage intensity, and associated yield losses. Crop yields from plots were obtained by mechanical harvesting, and losses were classified as field losses, e.g. losses of gross tonnage in the field and factory losses, e.g., losses that were realized at the factory as cane is being milled. Farm income is based on the product of these two measures of yield, i.e. cane yield×sugar yield. In our study, seasonal stalk-infestation counts did not reveal any indication of preference by the borer moths for a specific variety; infestation pressure was generally uniform within a season among the varieties that we planted. Significant differences were detected among the varieties for harvest percentage of internodes bored as well as yields between borer-controlled and non-controlled plots (P<0.05). In general, varieties were less susceptible to losses in the field (sugarcane yields) than in the factory (sugar yields). As a group, the most recent varieties released to Louisiana growers exhibit more tolerance to the borer than varieties grown 40 years ago. The percent reduction in sugar/ha loss per 1% internodes bored has decreased from an average of 0.74 for varieties grown in the 1960s to 0.61 as a mean for the newly released varieties. Although the cost associated with an insecticide application for sugarcane borer control has increased nearly 4-fold from 1971 to present, sugar yields have increased by approximately 60% allowing farmers to offset some of these increased costs. Our economic analysis indicates that the EIL of 10% internodes bored is too high, considering the high yielding potential and susceptibility of currently grown varieties. For the most at risk farmer, the tenant farmer, a more appropriate value for the EIL is 6% internodes bored. However, this EIL can be raised 12% if a resistant variety is grown.     

Genetic diversity for grain nutrients contents in a core collection of finger millet (Eleusine coracana (L.) Gaertn.) germplasm

Finger millet is a promising source of micronutrients and protein besides energy and can contribute to the alleviation of iron (Fe), zinc (Zn) and protein malnutrition affecting women and preschool children in African and south-east Asian countries. The most cost effective approach for mitigating micronutrient and protein malnutrition is to introduce staple crop cultivars selected and/or bred for Fe, Zn and protein dense grain. Breeding finger millet for enhanced grain nutrients is still in its infancy. Analysis, detection and exploitation of the existing variability among the germplasm accessions are the initial steps in breeding micronutrient and protein-dense finger millet cultivars. Evaluation of finger millet core collection for grain nutrients and agronomic traits revealed a substantial genetic variability for grain Fe, Zn, calcium (Ca) and protein contents. The accessions rich in nutrient contents were identified and their agronomic diversity assessed. The accessions rich in Zn content have significantly higher grain yield potential than those rich in Fe and protein content. Grain nutrient-specific accessions and those contrasting for nutrient contents were identified for use in the strategic research and cultivar development in finger millet.     

Field assessment of novaluron for sugarcane borer, Diatraea saccharalis (F.) (Lepidoptera: Crambidae), management in Louisiana sugarcane

On-farm field experiments were conducted in 2004 and 2007 to assess the suitability of novaluron, a chitin synthesis inhibitor, for sugarcane borer, Diatraea saccharalis (F.), management in Louisiana sugarcane (Saccharum spp. hybrids). Aerial insecticide applications reproducing commercial production practices were made when D. saccharalis infestation levels exceeded a recommended action threshold. In addition to decreased D. saccharalis infestations, 6.3 – 14.5-fold reductions in end of season injury, expressed as the percentage of bored sugarcane internodes, were observed in plots treated with novaluron. D. saccharalis control in novaluron plots was equivalent to (P > 0.05) or better (P < 0.05) than that achieved with tebufenozide, an ecdysone agonist that has been extensively used for over a decade on sugarcane. With a numerical trend of a 3.1-fold decrease in percent bored internodes, the pyrethroid gamma-cyhalothrin seemed less effective than the biorational insecticides in protecting sugarcane against D. saccharalis. Using continuous pitfall trap sampling, no measurable (P > 0.05) decreases in predaceous and non-predaceous soil-dwelling non-target arthropods were associated with insecticides. However, numerical trends for decreases in immature crickets associated with novaluron and gamma-cyhalothrin were recorded in 2007. Our data suggest that novaluron will fit well in Louisiana sugarcane integrated pest management.     

Disruption of Darna pallivitta (Lepidoptera: Limacodidae) by Conventional and Mobile Pheromone Deployment

Identification of the Darna pallivitta (Moore) pheromone component n-butyl (E)-7,9-decadienoate (E7,9-10:COOn-Bu) has made it possible to investigate communication disruption to control this lepidopteran pest. Conventional communication disruption trials showed marked decreases in the mean number of male moths captured in E7,9-10:COOnBu-treated fields compared with control fields. For traps baited with E7,9-10:COOnBu, percent disruptions were 94.4% and 92.1% for septa (1 g pheromone/ha, 1-wk trial duration) and spirals (6 g pheromone/ha, 8-wk trial duration) respectively. For traps baited with virgin female moths, percent disruption was 73.3% using septa disruptors (1 g pheromone/ha, 1-wk trial duration). Mobile communication disruption using Bactrocera cucurbitae (Coquillett) as carriers for E7,9-10:COOn-Bu was evaluated in the following three areas: fly survivorship, attraction of male moths to treated flies, and moth disruption in a small-scale field trial. Topical application of E7,9-10:COOnBu showed no significant decrease in survivorship at 50 and 80 µg/fly. However, decreased survivorship was observed at 100 µg/fly and linear regression showed E7,9-10:COOnBu dose was significantly correlated with B. cucurbitae survivorship. Traps containing honey–pheromone-fed flies attracted and caught D. pallivitta over a 1-wk period, demonstrating the attractiveness of the carrier. Releasing E7,9-10:COOnBu-fed B. cucurbitae (∼2 g pheromone/ha, 1-wk trial duration) resulted in significantly reduced trap catches in treatment fields compared with control fields on the first 2 d of the field trial. Percent disruptions were 84.7% (day 1) and 56.0% (day 2). These results suggest that both conventional communication disruption and mobile communication disruption have potential to control D. pallivitta.     

Elicitation of resistance and defense related enzymes by raw cow milk and amino acids in pearl millet against downy mildew disease caused by Sclerospora graminicola

Modulation of physiological and biochemical defensive responses against downy mildew (DM) of pearl millet induced by raw cow milk (RCM) and five amino acids is reported in this paper. In vitro conditions, none of the inducer treatments showed inhibitory action on DM pathogen. Significant enhancement of seed germination and seedling vigor was observed in RCM and amino acids treated seeds. Under greenhouse conditions, significant protection against DM was provided by l-phenylalanine (68.6%), l-isoleucine (66.5%) and l-proline (55.7%) treatments. Among the RCM treatments, the 10% dilution proved to be the best by offering disease protection of 35%. Spatio-temporal time gap studies indicated that seed treatment with l-phenylalanine increased disease resistance four days after inoculation. Seed treatments with RCM and amino acids also enhanced the vegetative and reproductive growth parameters of pearl millet when compared to the control. A similar trend in protection against DM was evident in the field trials. At the biochemical level, defense related enzymes such as phenylalanine ammonia lyase (PAL), peroxidase (POX) and β-1,3-glucanase showed an increased activity in RCM and amino acids treated seedlings than in sterile distilled water control seedlings. The highest PAL activity was recorded in RCM (10 and 20%) whereas in case of amino acids, the highest activity was observed in l-proline and l-phenylalanine treatments. The highest activity of β-1,3-glucanase was recorded in RCM (20%) and l-phenylalanine.     

二化螟对双酰胺类杀虫剂的抗药性监测和交互抗性研究

【目的】为了及时了解我国主要稻区二化螟对氯虫苯甲酰胺和氟苯虫酰胺的抗药性发展情况,同时明确对氯虫苯甲酰胺原药和制剂的抗性水平是否存在差异及二化螟对新研发的双酰胺类杀虫剂溴氰虫酰胺、四氯虫酰胺及氯氟氰虫酰胺与氯虫苯甲酰胺、氟苯虫酰胺间是否存在交互抗性。【方法】采用稻苗浸渍法测定了2015年我国7省19地二化螟田间种群对氯虫苯甲酰胺和氟苯虫酰胺的抗药性,同时测定了浙江余姚和象山两个抗性种群对97.3%氯虫苯甲酰胺原药、20%氯虫苯甲酰胺悬浮剂制剂的抗药性及其对溴氰虫酰胺、四氯虫酰胺及氯氟氰虫酰胺与氯虫苯甲酰胺和氟苯虫酰胺间的交互抗性。【结果】浙江余姚和苍南种群对氯虫苯甲酰胺已达141.1倍和135.0倍的高水平抗性,象山种群为87.9倍的中等水平抗性;这三个种群对氟苯虫酰胺均表现为中等水平抗性(15.0~58.7倍)。二化螟对97.3%氯虫苯甲酰胺原药和20%氯虫苯甲酰胺悬浮剂制剂存在抗性差异,浙江余姚和象山种群对制剂的抗性更高。交互抗性研究结果显示,对氟苯虫酰胺和氯虫苯甲酰胺均产生了中到高水平抗性(27.6~133.6倍)的象山、余姚种群,对溴氰虫酰胺、四氯虫酰胺和氯氟氰虫酰胺同样也产生了中到高水平抗性(30.3~127.0倍)。【结论】各二化螟地理种群之间对氯虫苯甲酰胺和氟苯虫酰胺抗药性差异较大,分别表现出117.6倍和146.8倍的差异,浙江余姚和象山二化螟种群对20%氯虫苯甲酰胺悬浮剂制剂抗药性更高且三种新双酰胺类杀虫剂与氯虫苯甲酰胺和氟苯虫酰胺之间存在交互抗性。     

二化螟对杀虫单抗性现实遗传力与遗传方式

 以2001年田间采集的温州二化螟为起始种群，在室内饲养24代期间，用点滴法处理4龄幼虫进行杀虫单筛选19代，得到抗性品系WZ R；与敏感基线相比， WZ R品系对杀虫单抗性达774.5倍，比筛选前上升25.0倍；根据前期连续6代（F3~F8）筛选估计的抗性现实遗传力（h2，0.230）显著低于根据后期连续5代（F19~F23）筛选的h2（1205），而中间不连续筛选（F9~F18，10代中有4代未筛选）的h2最小（0.024）。用毒力回归线法对WZ R品系进行抗性遗传分析表明，杀虫单抗性为不完全显性（正反交显性度分别为0.56和0.63）、常染色体遗传，抗性不属于单个主基因控制。     

Comparative susceptibility of Ostrinia furnacalis, Ostrinia nubilalis and Diatraea saccharalis (Lepidoptera: Crambidae) to Bacillus thuringiensis Cry1 toxins

Transgenic corn hybrids that express toxins from Bacillus thuringiensis (Bt) are highly effective against the European corn borer, Ostrinia nubilalis (Hübner), and the closely related Asian corn borer, Ostrinia furnacalis (Guenée). Since the registration of Bt corn hybrids in the U.S. in 1996, there has been a great deal of information generated on O. nubilalis. However, relatively little information exists for O. furnacalis. To help determine whether the information generated for O. nubilalis can be leveraged for decisions regarding the use of transgenic Bt corn against O. furnacalis, experiments were designed to determine whether the pattern of sensitivity to various Bt Cry1 toxins is similar between the two species. Test insects included laboratory-reared O. furnacalis originating from Malaysia, a Bt-susceptible laboratory colony of O. nubilalis maintained at the University of Nebraska-Lincoln (UNL) and an out-group consisting of the sugarcane borer, Diatraea saccharalis (F.), from Louisiana which represents a different genus from the same family. O. furnacalis and O. nubilalis exhibited a similar pattern of susceptibility to all the Cry1 toxins and were highly susceptible to the range of Bt toxins tested including Cry1Aa, Cry1Ab, Cry1Ac and Cry1F. Both of the Ostrinia species were more tolerant to Cry1Ba compared with D. saccharalis, although sensitivity of O. furnacalis was intermediate and did not differ significantly from that of O. nubilalis and D. saccharalis. D. saccharalis was also susceptible to the range of toxins tested but unlike the two Ostrinia species, was more tolerant to Cry1F and more susceptible to Cry1Ba. These results indicate that both of the Ostrinia corn borer species are similar in sensitivity to the Cry1Aa, Cry1Ab, Cry1Ac, Cry1Ba and Cry1F toxins, thus suggesting shared toxin receptors and mechanisms of toxicity for the two species.