Management Of Lepidopteran Pests Research Articles

Mass Trapping Lepidopteran Pests with Light Traps, with Focus on Tortricid Forest Pests: What If?

The management of Lepidopteran pests with light traps (LTs) is often achieved by luring adults to death at light sources (light trap-based mass trapping, or LTmt). Large-scale LTmt programs against agricultural pests initiated in the late 1920s in the United States were phased out in the 1970s, coinciding with the rise of pheromone-based management research. The interest in LTmt has surged in recent years with the advent of light emitting diodes, solar power sources, and intelligent design. The first step in implementing LTmt is to identify a trapping design that maximizes the capture of target pests and minimizes the capture of non-target beneficial insects-with a cautionary note that high captures in LTs are not equivalent to the feasibility of mass trapping: the ultimate objective of LTmt is to protect crop plants from pest damage, not to trap adults. The captures of egg-carrying females in light traps have a greater impact on the efficiency of LTmt than the captures of males. When LTmt is defined as a harvesting procedure, the biomass of females in LTs may be viewed as the best estimator of the mass trapping yield; biomass proxy has universal application in LTmt as every living organism can be defined on a per weight basis. While research has largely focused on agricultural pests, an attempt is made here to conceptualize LTmt as a pest management strategy in forest ecosystems, using spruce budworm as a case study. The mass trapping of female budworms is impossible to achieve in endemic populations due to the large spatial scale of forest landscapes (implying the deployment of a prohibitively large number of LTs); in addition, ovipositing female budworms do not respond to light sources at a low density of conspecifics. The light-based mass trapping of female budworms may provide a realistic management option for geographically isolated forest stands heavily infested with budworms, as a tool to prevent tree mortality. Somehow unexpectedly, however, one factor obscuring the feasibility of LTmt is as follows: the complex ('unknowable') economic valuation of forest stands as opposed to agricultural landscapes.

A meta-analytic investigation of the potential for plant volatiles and sex pheromones to enhance detection and management of Lepidopteran pests.

Effective early detection, monitoring and management methods are critical for reducing the impacts of insect pests in agriculture and forestry. Combining host plant volatiles with sex pheromones could enhance trapping methodologies, whilst the use of non-host volatiles could improve the effectiveness of pest management through repellency effects. In this meta-analysis approach, we analysed 51 studies that used electroantennograms (EAG), wind tunnels and/or field traps to evaluate the antennal and behavioural responses of Lepidoptera to sex pheromones combined with attractant or repellent plant volatiles. Proposed attractant plant volatiles had a positive association with female Lepidoptera responses to sex pheromone, but effects on males were highly variable, with unexpected repellency reported in some studies. Proposed repellent plant volatiles were significantly or near-significantly negatively associated with male attraction to sex pheromones but were scarcely studied. Sub-group analysis identified that male responses to sex pheromone were reduced when the dose of attractant plant volatile relative to sex pheromone was increased. Green-leaf volatiles were associated with the strongest positive effects for males in field traps. Multiple-compound attractant plant volatile blends were less effective than single compounds in field studies. Our analysis demonstrates, (i) the potential value of combining host plant volatiles with sex pheromones to capture females rather than only males, (ii) the importance of identifying appropriate host plant volatiles and optimal relative doses, and (iii) the potential for non-host plant volatile use in pest management strategies.

Synopsis of the parasitoid wasp genus Cotesia Cameron, 1891 (Hymenoptera: Braconidae: Microgastrinae) in Australia, with the description of seven new species

The genus Cotesia Cameron, 1891 is one of the most diverse of the Microgastrinae, a subfamily of wasps that are exclusively endoparasitic on lepidopteran larvae. Species of Cotesia are widely utilised as biological control agents across the world. In Australia, there are currently 10 confirmed native species as well as four species introduced for the management of lepidopteran pests. The genus is morphologically conserved and has not been studied in the Australasian region for many decades. In this study, we use both comparative morphology and sequence data from the COI gene to delineate species, and in so doing describe seven new species from Australia: C. lasallei sp. nov., C. medusae sp. nov., C. ocellata sp. nov., C. reidarum sp. nov., C. scripta sp. nov., C. tjapekki sp. nov. and C. wonboynensis sp. nov., raising the number of species of Cotesia formally recorded in Australia to 21. We also provide updated descriptions of the previously described native species, diagnoses for the introduced species and a key to all currently described species found on the continent and from Papua New Guinea. This study treats only a fraction of the likely diversity of Cotesia, but provides a solid framework for future work.

WITHDRAWN: Split release of egg parasitoid, Trichogramma japonicum Ashmead for biocontrol of rice yellow stem borer, Scirpophaga incertulas in Chhattisgarh plain of central India

Abstract Yellow stem borer (YSB), Scirpophaga incertulas Walker is considered as major pest of rice. An egg parasitoid, Trichogramma, is used for management of lepidopteran pests of rice worldwide. In order to optimize the time and number of releases of Trichogramma under field condition in Chhattisgarh plains, three different schedules of releases (each consisting of four split releases of wasps) of Trichogramma japonicum Ashmead were tested to manage YSB during rainy season 2017 and 2018 (June to October) under field condition. Each schedule was split into four releases of wasps (50,000 wasps/ha/release × four releases or 500 wasps/100 m2/release × four releases). The statistical analyses of two seasons data revealed that four split releases of T. japonicum at weekly interval on the 32nd, 39th, 46th and 53rd day after transplanting of rice had resulted the reduction of damage caused by YSB over control of 52.8% (2.51%) dead heart and 66.1% (0.62%) white ear in comparison with control (5.32% dead heart; 1.83% white ear). The results suggest that the time-specific four split releases of T. japonicum @ 50,000 wasps/ha/release × four split release can be the useful to attain biocontrol of YSB.

Prospects of entomopathogens in post-harvest integrated pest management:

In these exploratory experiments, entomopathogenic nematodes and fungi were investigated for the management of the populations of postharvest insect pests. Nematodes were screened for pathogenicity to Plodia interpunctella (Hubner), while nematodes and fungi were investigated for virulence to the maize weevil, Sitophilus zeamais (Motschulsky). Adults and larvae of P. interpunctellea were screened for susceptibility to the following six nematodes: Heterorhabitis bacteriophora Poinar (HP88, Lewiston and Oswego strains); H. indica Poinar, Karunakar and David (Homl strain); H. marelatus Liu and Berry (Point Reyes strain); H. megidis Poinar, Jackson, and Klein (UK211 strain); and H. zealandica Poinar (NZH3 strain). The nematodes that had the highest virulence to larvae and adults of P. interpunctellea were H. indica, H. megidis, and H. marelatus. Six strains of nematodes were studied, namely H. bacteriophora, H. indica, H. georgiana (K22), Steinernema feltiae SN and S. carpocapsae. All strains of fungi, Beauveria bassiana (GHA) and Metarhizium brunneum (F52) were evaluated for infectivity to adults of S. zeamais. The two strains of Steinernematidae nematodes and a strain of fungus, B. bassiana were found to cause significant mortality of the weevils compared to the rest of the entomopathogens and the control. To demonstrate the practical application of entomopathogens, wettable dust of B. bassiana were dispensed on jute bags after which weevils were exposed to the treated surfaces for 30 min. The exposed weevils recorded between 90 to 100% mortality 14-d after exposure. Additional study demonstrated that the parasitoid, Habrobracon hebetor (Say) (Hymenoptera: Braconidae) could be integrated with entomopathogenic nematodes. These experiments demonstrate the potential usefulness of entomopathogens in the management of stored product Lepidopteran and Coleopteran pests.

Residual toxicity of emamectin benzoate and chlorantraniliprole on Eupelmus tachardiae howard-A key parasitoid of lac insect Kerria lacca (kerr)

Residual response of emamectin benzoate and chlorantraniliprole against Eupelmus tachardiae Howard (Hymenoptera: Encyrtidae)-a key parasitoid of lac insect, Kerria lacca (Kerr) was assessed under laboratory conditions by exposing the adults on residual film of insecticides. Emamectin benzoate caused 0–14.44% mortality within 1 hr of exposure, 27.5–38.99% mortality within 3 hr, 53.61–96.67% mortality within 18 hr and 100% mortality within 24 hr of exposure except at a very low concentration (0.00025%). Whereas, no mortality with chlorantraniliprole was observed after 1 hr of exposure and within 3 hr of exposure only 3.33 and 8.61% mortality was at 0.0056 and 0.0074% concentration, respectively, which is the recommended dose in lac ecosystem for the management of lepidopteran pests. Within 24 hr of exposure, 30.20–65.31% mortality was observed with concentrations of chlorantraniliprole as against 19.68% in control. Based on mortality within 24 hr of exposure it can be inferred that the emamectin benzoate is relatively more toxic than the chlorantraniliprole. Relatively less toxicity of chlorantraniliprole to this parasitoid species might be attributed due to specificity of this insecticide.

Toxicidade de extratos de Anadenanthera macrocarpa (Fabaceae: Mimosoideae) e Bougainvillea buttiana (Nyctaginaceae) para lepidópteros-praga

http://dx.doi.org/10.5007/2175-7925.2017v30n2p15O uso de extratos vegetais apresenta grande eficiência no manejo de pragas, destinados a produções agrícolas de pequeno e médio porte, por controlar uma gama muito grande de artrópodes. O objetivo desta pesquisa consiste em avaliar os efeitos tóxicos dos extratos de Anadenanthera macrocarpa (Fabaceae: Mimosoideae) e Bougainvillea buttiana (Nyctaginaceae) em Helicoverpa armigera (Hübner), Spodoptera cosmioides (Walker) e Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae). Lagartas de H. armigera e S. cosmioides foram mantidas em discos foliares de soja, enquanto S. frugiperda foi mantida em discos foliares de milho, tratados com os extratos aquoso diluídos nas concentrações de: 0, 500, 1.000, 2.500, 4.000, 5.000, 10.000 e 15.000 mg.L-1. Foram mensurados os efeitos letais e subletais dos extratos sobre os insetos. De acordo com os resultados obtidos, a concentração de 500 mg.L-1 do extrato de A. macrocarpa causou o maior percentual de mortalidade (93,33%) em H. armigera. O extrato de B. buttiana causou 86,67% e 60% de mortalidade em H. armigera (1.000 mg.L-1) e S. cosmioides (4.000 mg.L-1), respectivamente. A redução da emergência dos adultos foi o principal efeito subletal constatado em S. cosmioides e S. frugiperda. Considerando os resultados obtidos, destaca-se que os extratos vegetais utilizados apresentam-se como uma alternativa em potencial para o manejo de lepidópteros-praga.

Efficacies and economics of some novel insecticides for management of major lepidopteran pests of tomato

Efficacies and economics of some new insecticides were evaluated for the management of major lepidopteran pests of tomato at Bidhan Chandra Krishi Viswavidyalaya, Kalyani, West Bengal during 2012–14. Three novel insecticides viz., pyridalyl 10 EC (56.25, 75, 112.5 and 150 g a. i./ha), indoxacarb 14.5 SC (56.25, 75, 112.5 and 150 g a. i./ha) and chlorfenapyr 10 SC (75, 100, 150 and 200 g a.i./ha) were applied twice with four doses along with two standard checks (chlorpyriphos 20 EC @ 350 g a. i./ha and triazophos 40 EC @ 350 g a. i./ha) and untreated control. Pooled results revealed that pyridalyl and indoxacarb @ 150 g a. i./ha were found to be very effective insecticides against Helicoverpa armigera (3.10 and 2.60% fruit damage) and Spodoptera litura (3.34 and 3.59% fruit damage) with 211.21 and 209.59 q/ha marketable yield, respectively. Results indicated that traditional insecticides such as triazophos and chlorpyriphos were most cost effective insecticides with 10.24 and 9.56 benefit: cost ratio, respectively, whereas pyridalyl and indoxacarb at lower doses showed cost efficiency for management of lepidopteran pests of tomato.

Characterization of protein phosphatase 5 from three lepidopteran insects: Helicoverpa armigera, Mythimna separata and Plutella xylostella.

Protein phosphatase 5 (PP5), a unique member of serine/threonine phosphatases, regulates a variety of biological processes. We obtained full-length PP5 cDNAs from three lepidopteran insects, Helicoverpa armigera, Mythimna separata and Plutella xylostella, encoding predicted proteins of 490 (55.98 kDa), 490 (55.82 kDa) and 491 (56.07 kDa) amino acids, respectively. These sequences shared a high identity with other insect PP5s and contained the TPR (tetratricopeptide repeat) domains at N-terminal regions and highly conserved C-terminal catalytic domains. Tissue- and stage-specific expression pattern analyses revealed these three PP5 genes were constitutively expressed in all stages and in tested tissues with predominant transcription occurring at the egg and adult stages. Activities of Escherichia coli-produced recombinant PP5 proteins could be enhanced by almost 2-fold by a known PP5 activator: arachidonic acid. Kinetic parameters of three recombinant proteins against substrate pNPP were similar both in the absence or presence of arachidonic acid. Protein phosphatases inhibitors, okadaic acid, cantharidin, and endothall strongly impeded the activities of the three recombinant PP5 proteins, as well as exerted an inhibitory effect on crude protein phosphatases extractions from these three insects. In summary, lepidopteran PP5s share similar characteristics and are all sensitive to the protein phosphatases inhibitors. Our results also imply protein phosphatase inhibitors might be used in the management of lepidopteran pests.

Molecular basis of female-specific odorant responses in Bombyx mori

Males and females of many moth species exhibit important differences in sexual behaviours. Much research in this field has focused on the male-specific behaviour, electrophysiology and molecular biology of sex pheromone reception. Female-specific behaviours have been less well studied although, like male-specific behaviours, they could provide opportunities for intervention and management of lepidopteran pests. Previously, we identified genes encoding putative odorant receptors (ORs) from the genome of the silkworm, Bombyx mori, some of which have higher levels of steady-state transcript in the antennae of adult females compared with males. We have identified the full-length cDNA sequences of some of these ORs and described a novel OR that is part of a female-biased clade. Using expression in Sf9 cells and a calcium-imaging assay, we tested a range of compounds for their ability to activate the most highly female-biased ORs, BmOR19, BmOR30, BmOR45 and BmOR47. BmOR19 responds to linalool, while BmOR45 and BmOR47 respond to benzoic acid > 2-phenylethanol > benzaldehyde. No activating ligands were found for BmOR30. RNA in situ hybridisation experiments reveal that BmOR19 is expressed in female olfactory sensory neurons that are co-located in the same sensilla as a second ORN expressing BmOR45 and/or BmOR47. Taken together the activity and expression of these receptors is likely explanatory of the observed electrophysiology of long sensilla trichoidea of female B. mori, previously shown to each contain one terpene (BmOR19) and one benzoic acid (BmOR45, BmOR47) sensory neuron. Plant volatiles such as linalool, benzoic acid, 2-phenylethanol and benzaldehyde are oviposition cues for females of some moths. These compounds have also been found in male-produced pheromone blends extracted from the hair pencils of many noctuid species. Hair pencil structures have not previously been reported for B. mori, but we have found hair pencil-like structures in adult male B. mori that are absent in female moths. It is proposed that BmOR19, BmOR45 and BmOR47 account for some of the female-specific odorant responses in B. mori, such as oviposition and/or detection of an as yet unidentified male-produced sex pheromone.

Integrated pest management approach for a new pest, Lacanobia subjuncta (Lepidoptera: Noctuidae), in Washington apple orchards.

Bioassays of Lacanobia subjuncta (Grote and Robinson) larvae established baseline LC50 values and identified the potential of reduced-risk, organophosphate replacement and naturally derived insecticides (eg chloronicotinyls, spinosyns, oxadiazines, insect growth regulators, microbial insecticides and particle films) to control this pest. The toxicities of these products were compared with those of organophosphate, carbamate, chlorinated cyclodiene and synthetic pyrethroid insecticides used in the management of lepidopteran pests in Washington apple orchards. Field trials were conducted comparing candidate insecticides to conventional alternatives. Several new insecticides (eg spinosad, methoxyfenozide, indoxacarb and an aluminosilicate particle film) proved to be effective for the management of L subjuncta. We summarize the goals and challenges of developing an integrated pest management program for new and resurgent pests as insecticide tools continue to change, and propose a hypothesis for the sudden increase in pest status of L subjuncta based on organophosphate tolerances. The role of novel insecticides with unique modes of action in resistance management and the encouragement of biological control are also discussed.

Sequential Sampling and Biorational Chemistries for Management of Lepidopteran Pests of Vegetable Amaranth in the Caribbean

Although vegetable amaranth, Amaranthus viridis L. and A. dubius Mart. ex Thell., production and economic importance is increasing in diversified peri-urban farms in Jamaica, lepidopteran herbivory is common even during weekly pyrethroid applications. We developed and validated a sampling plan, and investigated insecticides with new modes of action, for a complex of five species (Pyralidae: Spoladea recurvalis (F.), Herpetogramma bipunctalis (F.), Noctuidae: Spodoptera exigua (Hubner), S. frugiperda (J. E. Smith), and S. eridania Stoll). Significant within-plant variation occurred with H. bipunctalis, and a six-leaf sample unit including leaves from the inner and outer whorl was selected to sample all species. Larval counts best fit a negative binomial distribution. We developed a sequential sampling plan using a threshold of one larva per sample unit and the fitted distribution with a k(c) of 0.645. When compared with a fixed plan of 25 plants, sequential sampling recommended the same management decision on 87.5%, additional samples on 9.4%, and gave inaccurate recommendations on 3.1% of 32 farms, while reducing sample size by 46%. Insecticide frequency was reduced 33-60% when management decisions were based on sampled data compared with grower-standards, with no effect on crop damage. Damage remained high or variable (10-46%) with pyrethroid applications. Lepidopteran control was dramatically improved with ecdysone agonists (tebufenozide) or microbial metabolites (spinosyns and emamectin benzoate). This work facilitates resistance management efforts concurrent with the introduction of newer modes of action for lepidopteran control in leafy vegetable production in the Caribbean.

Effects of Transgenic Petunia Expressing Bacillus thuringiensis Toxin on Selected Lepidopteran Pests

Toxicity of 11 transgenic petunia lines expressing the CryIA (c) insecticidal crystal protein of Bacillus thuringiensis subsp . kurstaki was investigated using lepidopteran neonates Spodoptera exigua, Trichoplusia ni and Manduca sexta. Mortality of S. exigua, T. ni and M. sexta varied within and among transgenic petunia lines . Bioassay results demonstrated that levels of CryIA (c) expression obtained in 7 out of the 11 transgenic petunia lines produced at least 50% mortality in S. exigua and T. ni, and all 11 transgenic lines produced more than 80% mortality in M. sexta. Demographic analysis of the biological impact of transgenic petunia on S. exigua revealed that sub - lethal feeding on transgenic petunia significantly reduced larval weight and prolonged larval and pupal development times . Continuous feeding on transgenic petunia significantly reduced lifetime fecundity , egg hatch and longevity in female and male moths . Compared with insects fed continuously on non - transgenic petunia , lifetime fecundity and net reproductive rate were reduced by 58 and 84% in insects fed continuously on transgenic petunia respectively . Mean generation time was 8 days longer for insects fed continuously on transgenic petunia than for insects fed on non - transgenic petunia . Ovipositional attractiveness of transgenic petunia to S. exigua with respect to non - transgenic tomato or lettuce plants was similar , suggesting that petunia / tomato and petunia / lettuce may not be effective trap - cropping combinations . The potential and implications of using transgenic petunia as trap plants interplanted with crop plants for management of lepidopteran pests in the field are discussed .

Trichogramma Spp.: Concurrent Ground Application of Parasitized Eggs, Supplemental Heliothis zea Host Eggs, and Host-Seeking Stimuli1234

A high-clearance conveyance was modified to concurrently distribute Trichogramma -parasitized eggs of Heliothis zea (Boddie), and to apply supplemental H. zea host eggs and host-seeking stimuli (kairomones) for T. pretiosum Riley. The 3 components are parts of what we consider to be an essential package for full-season management of lepidopteran pests with Trichogramma spp.