Non-target Pests Research Articles

Growth and arthropod community characteristics of transgenic poplar 741 in an experimental forest

Use of the Bt insect-resistance gene has provided substantial economic and ecological benefits. Full utilization of transgenic poplars requires a comprehensive understanding of the growth-related phenotypic characteristics and ecological risks associated with of genetically modified trees. In the present study, we assessed the effects of transgenic poplar 741 with different insect-resistant genes on plant growth and arthropod communities in the field. Transgenic lines carrying the Cry1Ac and Cry3A genes were used as model lines, and non-transgenic poplar 741 was used as a control. Over a period of 6 years, we analyzed plant growth and transcriptomic data, and monitored arthropod richness and abundance in an experimental forest comparing transgenic and control lines. Our results indicate that the Pb29 line had a similar plant height to CK, but a significantly lower diameter at breast height (DBH) than CK. The plant height and DBH of the CC84 line were slightly higher than those of CK, but the differences were not significant. Transcriptome data analysis showed downregulated and upregulated expression of growth hormone-related genes and lignin synthesis-related genes, respectively, in the Pb29 line compared with CK and the CC84 line. The survey data obtained in this study showed that annual trends in arthropod numbers in the ecosystem were consistent among transgenic poplar 741 and control lines, gradually decreasing with time since planting. The Cry1Ac line has selective resistance to Lepidoptera and exerted strong toxic effects on Arctiidae, Tortricidae, and Notodontidae, but had no obvious effects on Lyonetiidae or Geometridae. The Cry3A line exhibited significant resistance to coleopterans only in 2016 when the abundance of coleopteran insects was high. Both lines exhibited inhibitory effects on non-target pests. The two transgenic lines were similar to the control with respect to arthropod community structure, and there were no significant differences in arthropod diversity indices between transgenic and control lines, although richness was slightly higher for the Cry3A line than for the control. The results of this study showed that the insertion of Bt genes had no apparent inhibitory effect on the growth of poplar 741. Also, there was no adverse environmental impact of transgenic poplar 741 on ecosystem arthropod communities compared with conventional poplar 741.

Transformation and functional verification of Cry5Aa in cotton

Most of the cotton bollworm-resistant genes applied in cotton are more than 20 years and they all belong to Cry1Ab/c family, but the insect-resistant effects of Cry5Aa on cotton were rarely reported. The possible risk of resistance is increasing. The study synthesized a novel bollworm-resistant gene Cry5Aa artificially based on preferences of cotton codon. The new gene was transferred to cotton through the method of pollen tube pathway. The transgenic strains were identified by kanamycin test in field and laboratory PCR analysis. Meanwhile, an insect resistance test was conducted by artificial bollworm feeding with transgenic leaves and GK19 was used as a control in this study. Results showed that rate of positive transgenic strains with kanamycin resistance in the first generation (T1), the second generation (T2) and the third generation (T3) respectively were 7.76%, 73.1% and 95.5%. However, PCR analysis showed that the positive strain rate in T1, T2 and T3 were 2.35%, 55.8% and 94.5%, respectively. The resistant assay of cotton bollworm showed that the mortality rate of the second, third and fourth instar larva feed by the transgenic cotton leaves, were 85.42%, 73.35% and 62.79%, respectively. There was a significant difference between transgenic plant of Cry5Aa and GK19 in insect resistance. Finally, we also conducted the further analysis of gene expression patterns, gene flow and the effect on non-target pest in the study. The results showed that Cry5Aa gene had less environmental impact, and Cry5Aa has been transferred successfully and expressed stably in cotton. Therefore, the novel bollworm resistance gene can partially replace the current insect-resistance gene of Lepidoptera insects.

Effects of Bt-Cry1Ah1 Transgenic Poplar on Target and Non-Target Pests and Their Parasitic Natural Enemy in Field and Laboratory Trials

Increasing areas of artificial afforestation and poplar monoculture in China have led to serious problems with insect pests. The development of genetic engineering technology, such as transgenic modification with Bacillus thuringiensis (Bt) genes, provides novel solutions to the pest problem. We generated a Bt-Cry1Ah1 gene incorporating codon optimization and transferred it into Populus deltoides × P. euramericana cv “Nanlin895” using an Agrobacterium-mediated method. The resulting Bt-Cry1Ah1 transgenic poplars were planted in the field with permission from the State Forestry Administration in 2017. Field and laboratory studies were conducted in Jiangsu, China, to investigate the effects of these transgenic poplars expressing the Cry1Ah1 protein on target and non-target pests and their parasitic natural enemy. Target pests included Hyphantria cunea (Lepidoptera, Arctiidae), Micromelalopha troglodyta (Lepidoptera, Notodontidae), and Clostera anachoreta (Lepidoptera, Notodontidae). Plagiodera versicolora (Coleoptera, Chrysomelidae) served as the non-target pest. Laboratory trials showed that the six transgenic poplar lines exhibited resistance against the target insects. The corrected mortality rates of the target pest larvae fed leaves from the six lines were as high as 87.0%, significantly higher than that of the control. However, the corrected mortality rate of the non-target pest larvae was markedly lower and did not differ significantly from that of the control. Field experiments showed that transgenic poplar exhibited resistance against H. cunea and M. troglodyta. Field mortality rates were slightly higher than laboratory mortality rates. In addition, we investigated Chouioia cunea (Hymenoptera, Eulophidae) as a parasitoid of H. cunea pupae that had been fed transgenic poplar leaves. The emergence time, parasitism rate, and abundance of C. cunea did not differ significantly from those of the control. Therefore, Bt-Cry1Ah1 transgenic poplar can be used to effectively control damage by target insect pests without negatively affecting non-target insects and parasitoids.

Cross-negative effects of selective insecticides against different life stages of non-target pests, Dysdercus koenigii and Oxycarenus hyalipennis on transgenic cotton under laboratory conditions

Cross-negative effects of selective insecticides against different life stages of non-target pests, Dysdercus koenigii and Oxycarenus hyalipennis on transgenic cotton under laboratory conditions

Reduced Mythimna separata infestation on Bt corn could benefit aphids.

Use of genetically engineered plants that express insecticidal Cry proteins derived from Bacillus thuringiensis (Bt) have been proven efficacious for managing lepidopteran pests. However, in some cases herbivores that are not targeted by the Bt trait have increased in importance. It has been suggested that reduced caterpillar damage to Bt crops could lead to decreased levels of induced plant defensive compounds which might benefit other non-target herbivores. Here we investigated the potential effect of reduced damage by larvae of Mythimna separata on aphid populations in Bt corn. We compared the performance of Rhopalosiphum maidis feeding on non-Bt corn plants that had been infested by M. separata larvae or were uninfested. The results showed that caterpillar-infested corn plants significantly reduced the fitness of R. maidis leading to a prolonged nymphal development time, reduced adult longevity and fecundity compared to uninfested plants. Consequently, the population growth rate of corn aphids feeding on caterpillar-infested corn plants was significantly lower than on uninfested plants. As expected, the aphids performed significantly better on Lepidoptera-resistant Bt corn than on non-Bt corn when plants were infested with M. separata, since the caterpillars caused very little damage to the Bt plants. The current findings indicate that reduced M. separata infestation could benefit aphid development in Bt corn. Bt corn has the potential to be commercialized in China in the near future and aphids and other non-target pests should be monitored in the farming fields.

Effects of disruption of Grapholita molesta (Lepidoptera: Tortricidae) using sex pheromone on moth pests and insect communities in orchards

Mating disruption and mass trapping based on insect sex pheromones have been used to effectively control Grapholita molesta (Busck) (Lepidoptera: Tortricidae). However, due to the different disruption intensities of these two approaches, few reports have evaluated the differences in their ecological recovery in orchards. We investigated the dynamics of major Lepidopteran pests; infestation patterns of G. molesta in shoots and fruits; composition of the orchard insect community; and diversity, similarity, and stability indices, from 2015 to 2017, in peach orchards in northern China. Three orchards were considered, each subjected to either mating disruption, mass-trapping, or pesticides (control), from 2010 to 2013. Our results showed that moth pests and insect communities inhabiting these orchards responded differently to the two approaches. Mating disruption and mass trapping mainly affected the major and secondary non-target pests, respectively. Mating disruption had a greater effect on delaying the recovery of G. molesta than mass trapping. Mating disruption resulted in higher dominance index values and dominance concentration index values, and reduced the community stability while improving the community recovery. Mass trapping resulted in higher diversity index values, and the community exhibited contrasting effects. These results indicate that mating disruption may be more suitable than mass trapping for managing G. molesta in orchards.

Using model-based fungicide programing to effectively control Botrytis and Anthracnose fruit rots in Mid-Atlantic strawberry fields and co-manage strawberry sap beetle (Stelidota geminate)

Effective fruit rot management is essential for profitable strawberry production in the Mid-Atlantic. With recent fungicide resistance development in two high-impact fruit rot pathogens, Botrytis cinerea [the cause of Botrytis fruit rot (BFR)] and Colletotrichum acutatum [the cause of Anthracnose fruit rot (AFR)], there is increasing interest in using disease forecasting to reduce fungicide applications and thus preserve existing chemistries. We conducted field trials in the Mid-Atlantic over two years to evaluate use of a model-based fungicide program [the Strawberry Advisory System (StAS)] for: (1) efficacy in reducing fungicide applications, (2) ability to achieve fruit rot control similar to the existing calendar-based program, and (3) effects on non-target diseases and pests. Across the two years, fungicide applications were reduced by an average of 50% for BFR control and 58% for AFR control. The model and calendar-based programs resulted in similar yields in both years, based on both percent of marketable fruit and marketable fruit yields (P > 0.05). Confirming fungicide treatment efficacy, yields were significantly lower in the non-treated control (NTC) in 2016 (incidence: P = 0.024; fruit biomass: P = 0.012). Yields were uniform in 2017, with 94–96% of fruit marketable, and there was no treatment effect. AFR incidence in the calendar and model-based programs were similar in both years (P > 0.05). AFR incidence in the NTC was significantly greater than both fungicide treatments in 2016 (P = 0.004) but not in 2017 (P = 0.63), likely due to low AFR levels (<2% of fruit with AFR across treatments). BFR incidence in the model-based program was likewise similar in model and calendar programs in both year (P > 0.05). Neither program differed from the NTC in 2016 (P = 0.84), likely due to low BFR levels (>4% of fruit with BFR); in 2017 BFR incidence in the NTC was significantly greater than calendar program (P = 0.032). This study also revealed a 55% reduction strawberry sap beetle (Stelidota geminate) incidence in the model-based fungicide program compared to the NTC (P = 0.027) in 2016 due to reduction in fruit rots. Model-based spray programming therefore has the potential to mitigate fungicide resistance development in the Mid-Atlantic strawberry production while providing effective fruit rot control. Potential to co-manage strawberry sap beetle should be further examined and would greatly enhance industry profitability.

Like Parents, Like Offspring? Susceptibility to Bt Toxins, Development on Dual-Gene Bt Cotton, and Parental Effect of Cry1Ac on a Nontarget Lepidopteran Pest

An important step to devise appropriate pest management strategies for armyworms (Lepidoptera: Noctuidae) in Bacillus thuringiensis Berliner (Bt) crops is to determine the lethal, sublethal, and parental effects of Bt toxins on target and nontarget pest species. Here we documented the susceptibility of black armyworm, Spodoptera cosmioides (Walker), to three Cry toxins and its life-history traits feeding on dual-toxin Bt cotton and an artificial diet containing sublethal concentrations of Cry1Ac. In concentration-response bioassays, black armyworm larvae showed low susceptibility to Cry toxins, with 853 ng/cm2 as the lowest value estimated for the median lethal concentration (LC50). The decreasing rank of toxicity was Cry1F, Cry2Aa, and Cry1Ac. Foliage of dual-toxin Bt cotton varieties (Cry1Ac + Cry1F and Cry1Ab + Cry2Ae) caused higher larval mortality than Cry1Ac-expressing cotton. Black armyworms showed reduced larval weight when growing on the Cry1Ac-treated diet, yet they reached adulthood and produced offspring. Interestingly, these larvae were grown on the control diet and showed reduced weight gain associated with the toxin exposure of the previous generation, indicating a parental effect of the exposure to Cy1Ac. The reduced larval weight was recovered in later instars, and there was no significant change in the population fitness of the parental armyworms or their offspring. To our knowledge, this is the first study documenting the parental effects of Bt toxins in insects. These results advance our understanding of potential responses of nontarget species when exposed to Bt toxins and contribute to design pest management programs for armyworms and other nontarget lepidopteran species exposed to Bt crops.

Long-term impacts of Bt cotton in India.

Most scholarship on the closely-watched case of genetically modified Bacillus thuringiensis (Bt) cotton in India has focused on short-term impacts and has also ignored other major changes in India's cotton agriculture. This Perspective combines several data sources over a 20-year span to provide long-term comparisons of Bt adoption with yields and other inputs at both countrywide and state-specific scales. Bt cotton adoption is shown to be a poor indicator of yield trends but a strong indicator of initial reductions in pesticide use. Yield increases correspond to changes in fertilizer and other inputs. Bt cotton has continued to control one major cotton pest, but with Bt resistance in another pest and surging populations of non-target pests, farmers now spend more on pesticides today than before the introduction of Bt. Indications are that the situation will continue to deteriorate.

Influence of a Neonicotinoid Seed Treatment on a Nontarget Herbivore of Soybean (Twospotted Spider Mite) and Diet Switching by a Co-occurring Omnivore (Western Flower Thrips).

Insecticidal neonicotinoid seed treatments are a common agricultural insect pest management strategy; however, effects on nontarget pests and omnivorous arthropods are understudied. We used a series of experiments to evaluate impacts of the neonicotinoid seed treatment thiamethoxam on densities of herbivorous twospotted spider mites (Tetranychus urticae Koch [Acari: Tetranychidae]) and feeding behavior of western flower thrips (Frankliniella occidentalis Pergande [Thysanoptera: Thripidae]), an omnivore that feeds on spider mite eggs but is also a significant plant pest. Spider mite densities were higher on neonicotinoid-treated soybeans, but only when mites were not spatially confined. We then examined how availability of thiamethoxam-treated food items (i.e., eggs from spider mites reared on treated soybeans, soybean leaf discs, or a combination of the two), and previous exposure to thiamethoxam-treated soybean impacted thrips feeding. Regardless of the presence of leaf tissue, thrips consumed fewer spider mite eggs laid by females reared on treated soybeans, suggesting spider mite eggs can serve as poisoned prey. Overall, thrips consumed less treated soybean leaf tissue, and thrips on treated leaf discs had a lower percentage of herbivorous feeding events and consumed more nontreated spider mite eggs, indicating a dietary shift from herbivory to predation. The neonicotinoid status of spider mite eggs and prior exposure of thrips also caused shifts in the number and size of leaf scars, likely as a result of altered foraging behavior and/or movement. Shifts between herbivory and predation have implications for thrips damage, virus transmission, and pest management, especially in systems with mixtures of nontreated and neonicotinoid-treated plants.

Drip chemigation of flonicamid effectively controls cotton aphid (Aphis gossypii) and is benign to lady beetle (Coccinella septempunctata) and lacewing larva (Chrysoperla sinica)

Cotton can suffer from injury and yield loss caused by the cotton aphid (Aphis gossypii Glover). Current control of this pest relies heavily on insecticides, which is associated with hazardous effects on non-target organisms, environmental pollution, and pest resistance. The present study examined the efficacy of drip chemigation of flonicamid, a systemic insecticide, to control the cotton aphid and evaluated its effect on two natural enemies of aphids, seven spotted lady beetle adults (Coccinella septempunctata L.) and green lacewing larvae (Chrysoperla sinica T.) in a cotton field in Xinjiang, China in 2016 and 2017. The results showed that flonicamid applied via drip chemigation (700 g a.i. ha−1) effectively controlled cotton aphid for 40 days compared to 20 days when applied through foliar spray (75 g a.i. ha−1). Drip chemigation of flonicamid was safer to the two natural enemies compared to foliar spray. Additionally, the cost of drip application of flonicamid was lower than foliar spray as cotton plants were commonly irrigated via drip system in Xinjiang. Our results show that drip chemigation is much simpler, cheaper, and safer for application of flonicamid and more effective in aphid control compared to a conventional foliar spray, although the rate of flonicamid applied through drip irrigation was substantially higher than the foliar application.

Canopy-Dwelling Arthropod Response to Rynaxypyr and Lambda-Cyhalothrin Treatments in Maize

Abstract The technology of grain corn production has recently been continuously changing due to spreading of insecticidal in-crop treatments in Europe. The aim of these interventions is to prevent damage caused by serious lepidopterous pests in maize. We carried out in-maize field experiments using two different active ingredients of insecticides in four consecutive years (2014–2017). A field experiment was conducted to compare the effect of applications of rynaxypyr (ANT) and rynaxypyr + lambda-cyhalothrin (PYR) on the canopy-dwelling arthropod community in commercial maize grain acreage. The effects of both ANT and PYR treatments against Ostrinia nubilalis Hübner (Lep.: Crambidae) were tested through four-year field experiments. The quantitative and qualitative assemblages of the perished arthropods and diversity alterations measured by canopy netting and grounded tarpaulins greatly differed in the different insecticide treatments. A significant number of dead arthropods was recorded after PYR treatment. Populations of other natural enemies (Coccinellidae, Chrysopidae, etc.) and endangered species (Calomobius filum, Rossi) were also negatively affected. The arthropod community of the examined maize plots was drastically altered by sprayings, which, among other factors, may account for the mass appearance of the other non-target pest organisms (Aphidae: Rhopalosiphum spp., Miridae: Trygonotylus spp.).

Impact of Cover Cropping on Non-Target Arthropod Pests of Red Maple Trees in Nursery Production

Cropping practices can affect the complement of arthropod pests present in production. The impact of cover cropping on key red maple (Acer rubrum [L.]) (Sapindaceae) nursery pests was evaluated. Cover cropping has been identified as a sustainable management method for a key maple pest, flatheaded appletree borer (Chrysobothris femorata [Olivier]) (Buprestidae), but the impact of the cover crop on other non-target arthropod pests in maple production also must be taken into account when determining the usefulness of cover cropping as a pest management tool. In addition to flatheaded appletree borer, other important arthropod pests of red maple in the southeastern United States include maple shoot borer (Proteoteras aesculana [Riley]) (Tortricidae), maple leaftier (Episimus tyrius [Henrich]) (Tortricidae), potato leafhopper (Empoasca fabae [Harris]) (Cicadellidae), ambrosia beetles (e.g., Xylosandrus crassiusculus [Motschulsky]) (Curculionidae), and spider mites (Oligonychus aceris [Shimer] and Tetranychus urticae [Koch]) (Tetranychidae). In the fall of 2015, 400 red maple trees were transplanted into a cover cropped field of crimson clover (Trifolium incarnatum [L.]) (Fabaceae) and winter wheat (Triticum aestivum [L.]) (Poaceae). Four nursery tree row management treatments were evaluated: (1) cover crop, (2) cover crop + insecticide, (3) no cover crop, and (4) no cover crop + insecticide. Treatment plots consisting of 25 trees were replicated 4 times in a 2 × 2 factorial design. All trees were evaluated annually in 2016 and 2017 for damage by the previously mentioned arthropod pests. Overall, the cover crop did not increase damage by the common suite of red maple pests. However, the cover crop did compete with trees for nutrients, water, and space, thereby reducing tree growth and the formation of new maple shoots. The low number of new shoots on maple trees in the cover crop rows, and subsequent availability and suitability of host material was the main driver of pest damage differences among treatments.

Biological control of fruit flies in Brazil

Abstract: Fruit flies are the main pests of fruit growing in Brazil. They have been managed predominantly with the use of insecticides applied as cover spray and or/as toxic baits. Currently, the trend of management strategies is toward the adoption of methods that cause the lowest environmental impact in large areas. In this context, biological control is an excellent option to be used together with other management strategies, such as sterile insects, because it leaves no residues, does not disturb nontarget pests, and can be permanent if the natural enemy establishes itself in the field. This review paper addresses the current knowledge on the biological control of fruit flies in Brazil, highlighting the great biodiversity of its natural enemies, especially parasitoids, its biology and ecology. The classical biological control programs in Brazil are also reported, from the introduction of Tetrastichus giffardianus (Hymenoptera: Eulophidae), in 1937, to control Ceratitis capitata (Diptera: Tephritidae), to that of Fopius arisanus (Hymenoptera: Braconidae), in 2012, to control Bactrocera carambolae (Diptera: Tephritidae). Finally, the obtained advances are pointed out, as well as the main bottlenecks and perspectives for the effective use of biological control programs against fruit flies.

Densidades y Daños de Insectos Plaga en Algodonero Convencional y Bt en la Comarca Lagunera, México

The genetically modified cotton expressing Cry toxins from the bacteria Bacillus thuringiensis (transgenic or Bt cotton) was introduced to Mexico in 1996, achieving a high degree of adoption by cotton producers, due to its high effectiveness against lepidopteran pests, which resulted in a reduction of the use of insecticides and a significant increase in crop yields. This study was conducted to determine and compare the populations and levels of damage of the main insect pests in commercial conventional (non-Bt cotton) and transgenic cotton (Bt cotton) fields in the Comarca Lagunera, Mexico during 2016, after 20 years of planting Bt cotton. In four fields of each type of cotton samplings were carried out from June 30 to August 27 to evaluate densities and damages of bollworm, Helicoverpa zea (Boddie); beet armyworm, Spodoptera exigua (Hubner); pink bollworm, Pectinophora gossypiella (Saunders); boll weevil, Anthonomus grandis (Boheman); conchuela, Chlorochroa ligata (Say); and sweetpotato whitefly, Bemisia tabaci (Gennadius). Bollworm and beet armyworm populations were significantly lower in Bt cotton than in conventional cotton, with reductions from 70-100% and 90-98%. Damage to squares and bolls by these two pests were lower in Bt cotton than in conventional cotton, with reductions from 82 to 84%. The pink bollworm and tobacco budworm were not detected in any type of cotton. Damage to cotton bolls by boll weevils and conchuelas were low and did not differ between types of cotton. Sweetpotato whitefly populations did not differ between types of cotton and increased at the end of the crop season. These results show that Bt cotton (Bollgard II) expressing Cry1Ac and Cry2Ab toxins continues to be effective against bollworm and beet armyworm; while the pink bollworm and tobacco budworm are practically eradicated from this region. The Bt cotton showed no effectiveness against sweetpotato whitefly, boll weevil, and conchuela, as was to be expected because they are non-target pests.

Effect of Transgenic Maize on Abundance of the Corn Flea Beetle,Chaetocnema pulicariaMelsheimer, as a Non-Target Pest

Effect of transgenic maize Agrisure® VipteraTM 3111 event with Cry1Ab and Vip3Aa20 toxins of Bacillus thuringiensis Berliner that provide resistance to Lepidoptera and mCry3A to Coleoptera was tested on abundance of the corn flea beetle, Chaetocnema pulicaria Melsheimer, at Sinaloa, Mexico and compared to isoline maize with and without insecticide applied. Ten randomly selected plants were carefully inspected every 2 weeks, and abundance, frequency, and fluctuation of the pest were recorded. Abundance of C. pulicaria during crop development was a total of 2,239 insects on the three hybrids at both locations and did not differ among the hybrids. One-hundred percent frequency was found throughout the growing season on the three hybrids. The study showed that transgenic maize expressing Bt toxins did not negatively affect the abundance of C. pulicaria.

Influences of Insect-Resistant Genetically Modified Rice (Bt-T) on the Diversity of Non-Target Insects in an LMO Quarantine Field

This study was conducted to develop environmental risk assessments and biosafety guides for insect-resistant genetically modified rice in an LMO (Living Modified Organism) isolation field. In the LMO quarantine area of Kyungpook National University, the species diversities and population densities of non-target insects found on insect-resistant genetically modified rice (Bt-T), rice resistant to Cnaphalocrocis medinalis, and non-GM rice (Dongjin-byeo and Ilmi-byeo) were investigated. The Bt-T plants were, therefore, evaluated under field conditions to detect possible impacts on above ground insects and spiders. In 2016 and 2017, the study compared transgenic rice and two non-GM reference rice, namely Dongjin-byeo and Ilmi-byeo, at Gunwi. A total of 9,552 individuals from 51 families and 11 orders were collected from the LMO isolation field. From the three types of rice fields, a total of 3,042; 3,212; and 3,297 individuals from the Bt-T, Dongjin-byeo, and Ilmi-byeo were collected, respectively. There was no difference between the population densities of the non-target insect pests, natural enemies, and other insects on the Bt-T compared to non-GM rice. The data on insect species population densities were subjected to principal component analysis (PCA) without distinguishing between the three varieties, namely GM, non-GM, and reference cultivar, in all cultivation years. However, the PCA clearly separated the samples based on the cultivation years. These results suggest that insect species diversities and population densities during plant cultivation are determined by environmental factors (growing condition and seasons) rather than by genetic factors.

Relative safety of Beauveria bassiana (Bb 112) oil formulation to Cryptolaemus montrouzieri Mulsant

Biopesticides are promising alternatives to chemical pesticides, and they have opened up new panorama in insect pest management to aid in the promotion of safe, eco-friendly pest management. They are relatively host specific and do not interfere with other biotic systems. Research concerning the development of biopesticides has focused mainly on identification of virulent isolates of bioagents for effective management of the target pests. However, information pertaining to their effects on natural enemies, non-target pests, and environment is scanty. In the present study, oil formulation of fungal pathogen, Beauveria bassiana (Bb 112) was tested against adults of Cryptolaemus montrouzieri Mulsant (Coleoptera:Coccinellidae), under laboratory condition. Oil formulation of B. bassiana (Bb 112) has been found to be safer to C. montrouzieri adults with maximum adult survival of 92.62 per cent at the highest dose (10 8 spores ml -1 ) and 100 per cent survival at lower dose tested (10 4 spores ml -1 ) respectively.

Defoliation of Soybean Expressing Cry1Ac by Lepidopteran Pests.

Lepidoptera, stink bugs, and weevils are important pests in soybean. For lepidopteran control, insecticides and seed treatments are used. As an alternative, Bt soybean was developed to control primary pests of Lepidoptera such as Rachiplusia nu (Guenée) (Noctuidae), Chrysodeixis includens (Walker) (Noctuidae), Anticarsia gemmatalis Hübner (Erebidae), Helicoverpa gelotopoeon (Dyar) (Noctuidae), and Crocidosema aporema (Walsingham) (Tortricidae). However, the use of transgenic plants, and the resulting reduction of insecticide against target pests, may allow other pest species to become more prevalent in agricultural environments. Soybean expressing Cry1Ac against different lepidopteran nontarget and target insect pests was evaluated, and its performance was compared with non-Bt soybean with seed treatment. The treatments were Bt soybean, non-Bt soybean with seed treatment (Fortenza® diamide insecticide, Syngenta, Buenos Aires, Argentina), and non-Bt soybean without seed treatment. Larvae of H. gelotopoeon, Spodoptera albula (Walker) (Noctuidae), Spodoptera cosmiodes (Walker) (Noctuidae), Spodoptera eridania (Stoll) (Noctuidae), and Spodoptera frugiperda (J. E. Smith) (Lep.: Noctuidae) were used. The plants of each treatment were infested with larvae of each species, and the percentage of leaf damage produced by each species was recorded. The results showed that Bt soybean provided control of H. gelotopoeon and had a suppressive effect on S. frugiperda and S. albula. However, S. eridania and S. cosmiodes were not susceptible to the Cry1Ac protein in MON 87701 × MON 89788 soybean when evaluated by greenhouse infestation. Considering the performance of each species using non-Bt soybean without seed treatment, S. eridania would represent a potential risk in soybean crops.

Bt rice could provide ecological resistance against nontarget planthoppers.

SummaryGenetically engineered (GE) rice lines expressing Lepidoptera‐active insecticidal cry genes from the bacterium Bacillus thuringiensis (Bt) have been developed in China. Field surveys indicated that Bt rice harbours fewer rice planthoppers than non‐Bt rice although planthoppers are not sensitive to the produced Bt Cry proteins. The mechanisms underlying this phenomenon remain unknown. Here, we show that the low numbers of planthoppers on Bt rice are associated with reduced caterpillar damage. In laboratory and field‐cage experiments, the rice planthopper Nilapavata lugens had no feeding preference for undamaged Bt or non‐Bt plants but exhibited a strong preference for caterpillar‐damaged plants whether Bt or non‐Bt. Under open‐field conditions, rice planthoppers were more abundant on caterpillar‐damaged non‐Bt rice than on neighbouring healthy Bt rice. GC–MS analyses showed that caterpillar damage induced the release of rice plant volatiles known to be attractive to planthoppers, and metabolome analyses revealed increased amino acid contents and reduced sterol contents known to benefit planthopper development. That Lepidoptera‐resistant Bt rice is less attractive to this important nontarget pest in the field is therefore a first example of ecological resistance of Bt plants to nontarget pests. Our findings suggest that non‐Bt rice refuges established for delaying the development of Bt resistance may also act as a trap crop for N. lugens and possibly other planthoppers.