Baseline Plant-to-Plant Larval Movement of Spodoptera eridania in Bt and Non-Bt Soybean and Its Possible Impacts on IRM

2020 ◽  
Vol 113 (4) ◽  
pp. 1741-1752
Author(s):  
Thiago L M Fanela ◽  
Edson L L Baldin ◽  
Thomas E Hunt ◽  
Rodrigo D Faria
Keyword(s):  
Larval Mortality ◽  
Pest Species ◽  
Spodoptera Eridania ◽  
Refuge Strategy ◽  
Bt Toxins ◽  
Incomplete Resistance ◽  
Insect Populations ◽  
Transgenic Technologies ◽  
Lepidopteran Pest ◽  
Larval Movement

Abstract The widespread use of transgenic technologies has led to the emergence of insect populations resistant to Bt toxins. Some lepidopteran pest species also appear to naturally have some level of tolerance to certain proteins, such as some species of Spodoptera to Cry1Ac. One of the main strategies to manage resistance is the use of refuge areas, the success of which is in part dependent on larval movement of the target pest. Thus, in order to assess the viability of a refuge strategy addressing Spodoptera eridania Stoll (Lepidoptera: Noctuidae) in Bt soybean, it was evaluated the larval movement across plants in Bt and non-Bt soybean, as well as the larval development and mortality on Bt and non-Bt soybean cultivars. We concluded that apparent S. eridania incomplete resistance resulting from high larval mortality and low adaptability on Bt plants, high larval dispersal, nondirectional larval movement, and random larval spatial dispersion suggest that structured refuge is more suitable than mixed refuge for managing resistance in S. eridania populations.

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

2020 ◽  
Vol 113 (3) ◽  
pp. 1234-1242 ◽  
Author(s):  
Marcelo M Rabelo ◽  
João Marcus L Matos ◽  
Silvana M Orozco-Restrepo ◽  
Silvana V Paula-Moraes ◽  
Eliseu José G Pereira
Keyword(s):  
Pest Management ◽  
Larval Mortality ◽  
Parental Effects ◽  
Bt Cotton ◽  
Pest Species ◽  
Larval Weight ◽  
Parental Effect ◽  
Cry Toxins ◽  
Bt Crops ◽  
Bt Toxins

Abstract 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.

scholarly journals Evaluation of indigenous the nucleopolyhedrovirus (NPV) of Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) in combination with chlorantraniliprole against Spodoptera species

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Ghulam Sarwar ◽  
Naeem Arshad Maan ◽  
Muhammad Ahsin Ayub ◽  
Muhammad Rafiq Shahid ◽  
Mubasher Ahmad Malik ◽  
...  
Keyword(s):  
Larval Mortality ◽  
Adult Emergence ◽  
Lethal Concentration ◽  
Pest Species ◽  
Vegetable Crops ◽  
Chemical Insecticide ◽  
Larval Instars ◽  
Novel Method ◽  
High Larval Mortality ◽  
Lepidoptera Noctuidae

Abstract Background The armyworms, Spodoptera exigua (Hübner), and S. litura (Fabricius) (Lepidoptera: Noctuidae) are polyphagous pests of many cash crops. Heavy crop losses have been reported for the fruit and vegetable crops each year owing to the diverse impact on global economies. The present study was aimed to sort out a novel method of pest control using the insect’s own nucleopolyhedrosis virus (NPV) alone and in combination with a new chemistry insecticide chlorantraniliprole. Results In the study, the effect of indigenous isolated nucleopolyhedrovirus (NPV) and the chemical insecticide (chlorantraniliprole) formulations against the 2nd and 4th larval instars of S. litura and S. exigua, collected from the different geographical region of Punjab (Pakistan) province, was evaluated. Three concentrations of the NPV isolate, sub-lethal (1 × 104, 6 × 104 POB ml−1), lethal (3 × 105 POB ml−1), and chlorantraniliprole 0.01 μl l−1, were applied alone and in combination against the 2nd and 4th larval instars of both pest species. The lethal concentration of NPV + chlorantraniliprole exhibited synergistic interaction and caused high larval mortality against both instars, while in all other combinations, additive effect was observed. Moreover, NPV + chlorantraniliprole at lethal concentration exhibited decreased pupation, adult emergence, and egg eclosion. Conclusion The implications of using NPV alone and in combination with an insecticide are discussed briefly in this study.

scholarly journals Toxic Effects of Citrus aurantium and C. limon Essential Oils on Spodoptera frugiperda (Lepidoptera: Noctuidae)

2011 ◽  
Vol 6 (9) ◽  
pp. 1934578X1100600 ◽  
Author(s):  
Emilio Villafañe ◽  
Diego Tolosa ◽  
Alicia Bardón ◽  
Adriana Neske
Keyword(s):  
Essential Oil ◽  
Essential Oils ◽  
Spodoptera Frugiperda ◽  
Larval Mortality ◽  
Ethanol Extract ◽  
Toxic Effects ◽  
Citrus Aurantium ◽  
Ethanol Extracts ◽  
Pupal Mortality ◽  
Lepidopteran Pest

Citrus aurantium and C. limon were selected in the search for natural plant insecticides. The essential oils of C. aurantium and C. limon and ethanol extracts of the seeds, pulp, albedo, and peel of C. aurantium were incorporated into the larval diet of the lepidopteran pest Spodoptera frugiperda. Larval and pupal mortality were quantified and adult malformation was observed. C aurantium essential oil had antifeedant action and the mixture of albedo ethanol extract and C aurantium essential oil had toxic effects on S. frugiperda larvae at early stages, when they had not yet produced major damage to the crop. Our results indicated that a mixture of ethanol extract of albedo and C. aurantium essential oil (250 μg of extract mix per g of diet) deterred feeding by 46% and had the highest larval mortality (100%) of the materials tested. The peel extract (250 μg per g of diet) produced an increment in growth rate and diet consumption. However, 40% of the larval and 45% of the pupal populations died after 96 h of treatment. The blend of essential oil and C. aurantium albedo ethanol extract showed the lowest consumption and a poor nutrient conversion into biomass. Finally, the presence of D-limonene and nootkatone in the peel ethanol extract, and C. limon and C. aurantium essential oils, may be the cause of the response in the feeding behavior and toxic effects found on S. frugiperda.

scholarly journals Ichneumonids (Hymenoptera) and Tachinid Flies (Diptera) Associated to Leptidopterans in Soybean Crops

2018 ◽  
Vol 10 (7) ◽  
pp. 167 ◽  
Author(s):  
Angélica Massarolli ◽  
Ana Regina Lucena Hoffmann ◽  
Bruna Magda Favetti ◽  
Alessandra Regina Butnariu
Keyword(s):  
Biological Control ◽  
New Species ◽  
Natural Enemies ◽  
Management Strategies ◽  
Neotropical Region ◽  
The State ◽  
Pest Species ◽  
Mato Grosso ◽  
Control Programs ◽  
Lepidopteran Pest

Studies on natural enemies are important to find new species and to develop management strategies to preserve them to help control pests in biological control programs. For the state of Mato Grosso, Brazil, which comprises the Amazon, Cerrado, and Pantanal biomes, few studies have been conducted on the diversity of these parasitoids, possible endemic and/or new species, as well as their potential as natural enemies. Thus, the present study was aimed at describing the diversity of parasitoids of the families Ichneumonidae (Hymenoptera) and Tachinidae (Diptera) associated with pest lepidopterans in soybean crops. Weekly sampling of pest lepidopterans was carried out during four soybean seasons (2009/2010, 2010/2011, 2011/2012 and 2012/2013). Parasitoid larvae were observed in the main lepidopteran pest species of soybean during the four soybean seasons. Three genera of the Ichneumonidae family, belonging to the genera Microcharops Roman, Ophionellus Westwood, and Podogaster Brullé. Six genera of the Tachinidae family occur in the state of Mato Grosso in soybean fields. The following genera were recorded: Archytas spp. Jaennicke, Phorocera spp. Robineau-Desvoidy, Gymnocarcelia spp. Townsend, Lespesia spp. Robineau-Desvoidy, Eucelatoria spp. Townsend, Chetogena spp. Rondani. These parasitoids were found parasitizing caterpillars of the Noctuidae (Lepidoptera), in species that had not yet been reported as hosts for the Neotropical region. Further studies are needed on the beneficial entomofauna and their preservation in agricultural environments.

scholarly journals RNA interference as a gene silencing tool to controlTuta absolutain tomato (Solanum lycopersicum)

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2673 ◽  
Author(s):  
Roberto A. Camargo ◽  
Guilherme O. Barbosa ◽  
Isabella Presotto Possignolo ◽  
Lazaro E. P. Peres ◽  
Eric Lam ◽  
...  
Keyword(s):  
Rna Interference ◽  
Gene Silencing ◽  
Target Gene ◽  
Target Genes ◽  
Larval Mortality ◽  
Tuta Absoluta ◽  
Specific Gene ◽  
Gene Transcript ◽  
Pest Species ◽  
In Planta

RNA interference (RNAi), a gene-silencing mechanism that involves providing double-stranded RNA molecules that match a specific target gene sequence, is now widely used in functional genetic studies. The potential application of RNAi-mediated control of agricultural insect pests has rapidly become evident. The production of transgenic plants expressing dsRNA molecules that target essential insect genes could provide a means of specific gene silencing in larvae that feed on these plants, resulting in larval phenotypes that range from loss of appetite to death. In this report, we show that the tomato leafminer (Tuta absoluta), a major threat to commercial tomato production, can be targeted by RNAi. We selected two target genes (Vacuolar ATPase-AandArginine kinase) based on the RNAi response reported for these genes in other pest species. In view of the lack of an artificial diet forT. absoluta, we used two approaches to deliver dsRNA into tomato leaflets. The first approach was based on the uptake of dsRNA by leaflets and the second was based on “in planta-induced transient gene silencing” (PITGS), a well-established method for silencing plant genes, used here for the first time to deliverin planta-transcribed dsRNA to target insect genes.Tuta absolutalarvae that fed on leaves containing dsRNA of the target genes showed an ∼60% reduction in target gene transcript accumulation, an increase in larval mortality and less leaf damage. We then generated transgenic ‘Micro-Tom’ tomato plants that expressed hairpin sequences for both genes and observed a reduction in foliar damage byT. absolutain these plants. Our results demonstrate the feasibility of RNAi as an alternative method for controlling this critical tomato pest.

scholarly journals Resistance of Trichoplusia ni Populations Selected by Bacillus thuringiensis Sprays to Cotton Plants Expressing Pyramided Bacillus thuringiensis Toxins Cry1Ac and Cry2Ab

2014 ◽  
Vol 81 (5) ◽  
pp. 1884-1890 ◽  
Author(s):  
Wendy Kain ◽  
Xiaozhao Song ◽  
Alida F. Janmaat ◽  
Jian-Zhou Zhao ◽  
Judith Myers ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Trichoplusia Ni ◽  
Resistance Mechanisms ◽  
Vegetable Production ◽  
Bt Cotton ◽  
Content Type ◽  
Bt Toxin ◽  
Bt Toxins ◽  
Cotton Plants ◽  
Incomplete Resistance

ABSTRACTTwo populations ofTrichoplusia nithat had developed resistance toBacillus thuringiensissprays (Bt sprays) in commercial greenhouse vegetable production were tested for resistance to Bt cotton (BollGard II) plants expressing pyramided Cry1Ac and Cry2Ab. TheT. nicolonies resistant toBacillus thuringiensisserovar kurstaki formulations were not only resistant to the Bt toxin Cry1Ac, as previously reported, but also had a high frequency of Cry2Ab-resistant alleles, exhibiting ca. 20% survival on BollGard II foliage. BollGard II-resistantT. nistrains were established by selection with BollGard II foliage to further remove Cry2Ab-sensitive alleles in theT. nipopulations. The BollGard II-resistant strains showed incomplete resistance to BollGard II, with adjusted survival values of 0.50 to 0.78 after 7 days. The resistance to the dual-toxin cotton plants was conferred by two genetically independent resistance mechanisms: one to Cry1Ac and one to Cry2Ab. The 50% lethal concentration of Cry2Ab for the resistant strain was at least 1,467-fold that for the susceptibleT. nistrain. The resistance to Cry2Ab in resistantT. niwas an autosomally inherited, incompletely recessive monogenic trait. Results from this study indicate that insect populations under selection by Bt sprays in agriculture can be resistant to multiple Bt toxins and may potentially confer resistance to multitoxin Bt crops.

scholarly journals RNA interference as a gene silencing tool to control Tuta absoluta in tomato (Solanum lycopersicum)

2016 ◽  
Author(s):  
Roberto A Camargo ◽  
Guilherme O Barbosa ◽  
Isabella Presotto Possignolo ◽  
Lazaro E. P. Peres ◽  
Eric Lam ◽  
...  
Keyword(s):  
Rna Interference ◽  
Gene Silencing ◽  
Target Gene ◽  
Target Genes ◽  
Larval Mortality ◽  
Tuta Absoluta ◽  
Specific Gene ◽  
Gene Transcript ◽  
Pest Species ◽  
In Planta

RNA interference (RNAi), a gene-silencing mechanism that involves providing double-stranded RNA molecules that match a specific target gene sequence, is now widely used in functional genetic studies. The potential application of RNAi-mediated control of agricultural insect pests has rapidly become evident. The production of transgenic plants expressing dsRNA molecules that target essential insect genes could provide a means of specific gene silencing in larvae that feed on these plants, resulting in larval phenotypes that range from loss of appetite to death. In this report, we show that the tomato leafminer (Tuta absoluta), a major threat to commercial tomato production, can be targeted by RNAi. We selected two target genes [Vacuolar ATPase-A and Arginine kinase] based on the RNAi response reported for these genes in other pest species. In view of the lack of an artificial diet for T. absoluta, we used two approaches to deliver dsRNA into tomato leaflets. The first approach was based on the uptake of dsRNA by leaflets and the second was based on “in planta-induced transient gene silencing” (PITGS), a well-established method for silencing plant genes, used here for the first time to deliver in planta-transcribed dsRNA to target insect genes. Tuta absoluta larvae that fed on leaves containing dsRNA of the target genes showed an ~60% reduction in target gene transcript accumulation, an increase in larval mortality and less leaf damage. We then generated transgenic ‘Micro-Tom’ tomato plants that expressed hairpin sequences for both genes and observed a reduction in foliar damage by T. absoluta in these plants. Our results demonstrate the feasibility of RNAi as an alternative method for controlling this critical tomato pest.

scholarly journals Issues relating to the practical use of transgenic crops for insect pest management

2002 ◽  
Vol 55 ◽  
pp. 396-404
Author(s):  
D.A.J. Teulon ◽  
J.E. Losey
Keyword(s):  
Transgenic Plants ◽  
Pest Management ◽  
Insect Pest ◽  
Transgenic Crops ◽  
High Dose ◽  
Detailed Knowledge ◽  
Insect Pest Management ◽  
Costs And Benefits ◽  
Refuge Strategy ◽  
Bt Toxins

The implementation of transgenic plants for insect pest management requires a thorough evaluation of the risks costs and benefits Currently all commercialised transgenic crops for insect control contain genes expressing specific Bt toxins Excluding environmental and human health concerns the most apparent risk for these Btplants is development of resistance to Bt toxins The high dose/refuge strategy is accepted as most likely to delay or prevent pest resistance development This strategy is based on the best available information but has several incompletely tested assumptions The high dose/refuge strategy requires detailed knowledge of the plantinsect system and its implementation involves rigorous crop management There have been few documented instances of harmful impacts on predators and parasitoids from transgenic plants expressing Bt or other toxins The costs and benefits of using transgenic plants will depend on several factors including the plant species its complex of insect pests environmental conditions and alternative pest management tools and systems such as Integrated Pest Management Benefits of transgenic plants are most likely to outweigh costs and risks for insects that are difficult to control by any other method and/or require numerous insecticide applications

Drosophila, Chitin and Insect Pest Management

2020 ◽  
Vol 26 (29) ◽  
pp. 3546-3553 ◽  
Author(s):  
Yiwen Wang ◽  
Lujuan Gao ◽  
Bernard Moussian
Keyword(s):  
Pest Management ◽  
Management Strategy ◽  
Insect Pest ◽  
Fruit Fly ◽  
Pest Species ◽  
Insect Pest Management ◽  
Chitin Synthesis ◽  
Research Areas ◽  
Common Strategy ◽  
Insect Populations

Insects are a great menace in agriculture and vectors of human diseases. Hence, controlling insect populations is an important issue worldwide. A common strategy to control insects is the application of insecticides. However, insecticides entail three major problems. First, insecticides are chemicals that stress ecosystems and may even be harmful to humans. Second, insecticides are often unspecific and also eradicate beneficial insect species like the honeybee. Third, insects are able to develop resistance to insecticides. Therefore, the efficient generation of new potent insecticides and their intelligent delivery are the major tasks in agriculture. In addition, acceptance or refusal in society is a major issue that has to be considered in the application of a pest management strategy. In this paper, we unify two issues: 1) we illustrate that our molecular knowledge of the chitin synthesis and organization pathways may offer new opportunities to design novel insecticides that are environmentally harmless at the same time being specific to a pest species; and 2) we advocate that the fruit fly Drosophila melanogaster may serve as an excellent model of insect to study the effects of insecticides at the genetic, molecular and histology level in order to better understand their mode of action and to optimize their impact. Especially, chitin synthesis and organization proteins and enzymes are excellently dissected in the fruit fly, providing a rich source for new insecticide targets. Thus, D. melanogaster offers a cheap, efficient and fast assay system to address agricultural questions, as has been demonstrated to be the case in bio-medical research areas.

scholarly journals Geographic Monitoring of Insecticide Resistance Mutations in Native and Invasive Populations of the Fall Armyworm

Insects ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 468
Author(s):  
Sudeeptha Yainna ◽  
Nicolas Nègre ◽  
Pierre J. Silvie ◽  
Thierry Brévault ◽  
Wee Tek Tay ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Fall Armyworm ◽  
Sub Saharan Africa ◽  
Pest Species ◽  
Resistance Mutations ◽  
Chinese Populations ◽  
Bt Resistance ◽  
Native Populations ◽  
Sub Saharan ◽  
Lepidopteran Pest

Field evolved resistance to insecticides is one of the main challenges in pest control. The fall armyworm (FAW) is a lepidopteran pest species causing severe crop losses, especially corn. While native to the Americas, the presence of FAW was confirmed in West Africa in 2016. Since then, the FAW has been detected in over 70 countries covering sub-Saharan Africa, the Middle East, North Africa, South Asia, Southeast Asia, and Oceania. In this study, we tested whether this invasion was accompanied by the spread of resistance mutations from native to invasive areas. We observed that mutations causing Bt resistance at ABCC2 genes were observed only in native populations where the mutations were initially reported. Invasive populations were found to have higher gene numbers of cytochrome P450 genes than native populations and a higher proportion of multiple resistance mutations at acetylcholinesterase genes, supporting strong selective pressure for resistance against synthetic insecticides. This result explains the susceptibility to Bt insecticides and resistance to various synthetic insecticides in Chinese populations. These results highlight the necessity of regular and standardized monitoring of insecticide resistance in invasive populations using both genomic approaches and bioassay experiments.

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