Field evaluation of nucleopolyhedrosis virus and some biorational insecticides against Helicoverpa armigera Hubner (Noctuidae: Lepidoptera)

American bolloworm, Helicoverpa armigera Hubner (Noctuidae: Lepidoptera) is considered as a major pest of various crops all over the world. It is mainly controlled by indiscriminate use of synthetic insecticides in the world due to which this pest developed resistance to most of the available insecticides. Therefore, in the current study, the efficacy of virulent strain of HaNPV (0.5 × 10⁹ PIB/ml) alone and in combination with recommended doses of spintoram (20 g/100 L of water) and emamectin benzoate (200 ml/100 L of water) was tested in field. The combination of HaNPV with spintoram and emamectin benzoate 100% reduced the larval population as compared to emamectin benzoate and HaNPV alone. This suggested that the combination of spintoram and emamectin benzoate with HaNPV could be used in field to manage the infestation of H. armigera.     

Interaction of HaNPVs with two novel insecticides against Helicoverpa armigera Hubner (Noctuidae: Lepidoptera)

Nucleopolyhedrosis viruses can be utilized for effective management of agriculture pests. Their efficacy can be increased if they are mixed with certain insecticides. In the current study, HaNPV was mixed with two insecticides: spinetoram and emamectin benzoate in various combinations and applied to larvae of H. armigera in laboratory conditions. There were a total of 15 combinations of HaNPV with each of the two insecticides in addition to five doses of HaNPV and three doses of insecticides alone. The synergistic and antagonistic effects of combinations were explored. The results revealed that there was synergistic effect of HaNPV @ 0.5 × 10⁹ PIB/ml × Spinetoram @ 40, 20, 10 ml/100 L of water. In case of emamectin benzoate, synergistic effects were recorded at 1 × 10⁹ PIB/ml HaNPV × emamectin benzoate @ 100 ml/100 L of water. However, 0.5 × 10⁹ PIB/ml HaNPV has synergistic effects with all three doses of emamectin benzoate. The results suggested that HaNPV can be used in combination with spinetoram and emamectin benzoate for the management of resistant population of H. armigera.     

Densovirus Is a Mutualistic Symbiont of a Global Crop Pest (Helicoverpa armigera) and Protects against a Baculovirus and Bt Biopesticide

Mutualistic associations between symbiotic bacteria and their hosts are common within insect systems. However, viruses are often considered as pathogens even though some have been reported to be beneficial to their hosts. Herein, we report a novel densovirus, Helicoverpa armigera densovirus-1 (HaDNV-1) that appears to be beneficial to its host. HaDNV-1 was found to be widespread in wild populations of H. armigera adults (>67% prevalence between 2008 and 2012). In wild larval populations, there was a clear negative interaction between HaDNV-1 and H. armigera nucleopolyhedrovirus (HaNPV), a baculovirus that is widely used as a biopesticide. Laboratory bioassays revealed that larvae hosting HaDNV-1 had significantly enhanced resistance to HaNPV (and lower viral loads), and that resistance to Bacillus thuringiensis (Bt) toxin was also higher at low doses. Laboratory assays indicated that the virus was mainly distributed in the fat body, and could be both horizontally- and vertically-transmitted, though the former occurred only at large challenge doses. Densovirus-positive individuals developed more quickly and had higher fecundity than uninfected insects. We found no evidence for a negative effect of HaDNV-1 infection on H. armigera fitness-related traits, strongly suggesting a mutualistic interaction between the cotton bollworm and its densovirus.     

Dose dependency of time to death in single and mixed infections with a wildtype and egt deletion strain of Helicoverpa armigera nucleopolyhedrovirus

Recombinant insect nucleopolyhedroviruses lacking the egt gene generally kill their hosts faster than wild-type strains, but the response of insects to mixtures of virus genotypes is less well known. Here, we compared the survival time, lethal dose and occlusion body yield in third instar larvae of Helicoverpa armigera (Hübner) after challenge with wild-type H. armigera SNPV (HaSNPV-wt), a strain with a deletion of the egt gene, HaSNPV-LM2, and a 1:1 mixture of these two virus strains. A range of doses was used to determine whether the total number of OBs influenced the response to challenge with a mixture of virus strains versus single strains. At high virus doses, HaSNPV-LM2 killed H. armigera larvae significantly faster (ca. 20 h) than HaSNPV-wt, but at low doses, there was no significant difference in survival time between the viruses. The survival time after challenge with mixed virus inoculum was significantly different from and intermediate between that of the single viruses at high doses, and not different from that of the single viruses at low doses. No differences in lethal dose were found between single and mixed infections or between virus genotypes. The number of occlusion bodies produced per larva increased with time to death and decreased with virus dose, but no significant differences among virus types were found.     

棉铃虫核型多角体病毒与化学杀虫剂和卵磷脂混用的增效作用

棉铃虫核型多角体病毒(HaNPV)分别与三氟氯氰菊酯、溴氰菊酯、氰戊菊酯、灭净菊酯、灭多威、辛硫磷、甲基对硫磷和乙酰甲胺磷等化学杀虫剂混合饲喂棉铃虫幼虫,统计致死中浓度LC₅₀,计算增效比,测定虫体内与抗性有关的三种重要酶：多功能氧化酶(MFO)、羧酸酯酶(CarE)、乙酰胆碱酯酶(AChE)的活性。研究大豆卵磷脂对HaNPV致病性的影响。结果表明：HaNPV与化学杀虫剂混合饲喂抗性棉铃虫,生测统计增效比均大于1.0,特别是病毒与甲基对硫磷混用,增效比更是达到3.53,表现出良好的增效作用。混剂感染抗性棉铃虫,虫体内MFO的活性比化学杀虫剂单用时降低3～12倍,CarE和AChE的活性也比化学杀虫剂单用时低,HaNPV明显抑制了化学杀虫剂对MFO和CarE的诱导作用。HaNPV与大豆卵磷脂混用,提高了HaNPV对棉铃虫的感染致死率,缩短了致死中时间(LT₅₀)。     

粉纹夜蛾颗粒体病毒增效基因3'端2.5 kb片段在大肠杆菌中的表达

将粉纹夜蛾Trichoplusia ni颗粒体病毒增效基因3'端2.5 kb片段插入pQE-31中构建了重组表达载体pQE/enhancin,转化大肠杆菌M15(pREP₄)在IPTG诱导下成功表达出分子量约为96 kD的融合蛋白并命名为P96。初步纯化的P96显示了明显的增效活性,可提高棉铃虫核型多角体病毒对棉铃虫3龄幼虫感染死亡率27.40%～34.50%,缩短LT₅₀ 1.9天以上。     

Mitochondrial P-Glycoprotein ATPase Contributes to Insecticide Resistance in the Cotton Bollworm,Helicoverpa armigera (Noctuidae: Lepidoptera)

Cotton bollworm, Helicoverpa armigera, is one of the most damaging polyphagous pests worldwide, which has developed high levels of resistance to commonly applied insecticides. Mitochondrial P-glycoprotein (Pgp) was detected in the insecticide-resistant strain of H. armigera using C219 antibodies, and its possible role was demonstrated in the efflux of xenobiotic compounds using spectrofluorometer. The TMR accumulated in mitochondria in the absence of ATP, and effluxed out in presence of ATP; the process of efflux was inhibited in the presence of ortho-vandate, an inhibitor of Pgp, in insecticide-resistant larvae of H. armigera. The mitochondria isolated from insecticide-resistant larvae were resistant to insecticide-induced inhibition of oxygen consumption and cytochrome c release. Membrane potential decreased in a dose-dependent manner in the presence of higher concentration of insecticides (>50 µM) in mitochondria of insecticide-resistant larvae. In conclusion, mitochondrial Pgp ATPase detected in the insecticide-resistant larvae influenced the efflux of xenobiotic compounds. Pgp might be involved in protecting the mitochondrial DNA and the components of the electron transport chain from damage due to insecticides, and contributing to the resistance to the deleterious effects of insecticides on the growth of insecticide-resistant H. armigera larvae.     

Synergy between parasitoids and pathogens for biological control of Helicoverpa armigera in chickpea

The chickpea pod borer, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae), is an important pest of many legume crops, including chickpea, Cicer arietinum L. (Fabaceae). We field-tested the efficacy of two pathogens, Helicoverpa armigera nucleopolyhedrosis virus (HaNPV) and Bacillus thuringiensis Berliner subsp. kurstaki (Btk), both alone and in combination with the parasitoid Habrobracon hebetor Say (Hh) (Hymenoptera: Braconidae), for control of H. armigera larvae in chickpea fields. A randomized complete block design was used at two sites, so that wasp release treatments at one site would not contaminate pathogen-only treatments at the other. Pathogens were applied when most pest larvae were in the second instar, and wasp releases were made 2 days later. Number of H. armigera larvae per plant, number of damaged pods, yield (kg ha⁻¹), treatment cost (US$ ha⁻¹), and benefit:cost ratio were all determined. Treatments separated significantly at 14 days after treatment, with the HaNPV+Hh and Btk+Hh treatments providing the best control, suggesting a synergistic impact of the wasp and the pathogens when applied together. These treatments also produced the fewest damaged pods, the highest yields, and the greatest yield increments in comparison to untreated controls. However, costs were also highest for these combined treatments, which reduced their net benefit in comparison to use of Hh or Btk alone, although more efficient mass production of the pathogens might make combined applications feasible. We conclude that both HaNPV and Btk are suitable for integration with releases of H. hebetor against H. armigera in chickpea fields, provided parasitoid releases are delayed until 2 days after pathogen application.     

Timely inoculation of Helicoverpa armigera nucleopolyhedrovirus improves its efficiency in combination with benzoylphenylurea compounds

Helicoverpa armigera nucleopolyhedrovirus (HearNPV) is highly virulent against cotton bollworm, and its combination with peritrophic membrane affecting chemicals, especially benzoylphenylurea compounds, can increase the relative speed of kill, leading to early and timely pest control. The biological activity of three HearNPV isolates (IR03, IR18, and IR20) was primarily evaluated on the second instar larvae of H. armigera. The highly virulent isolate (IR18, LC₅₀: 8.43 × 10³ OB/ml) and four benzoylphenylurea compounds (diflubenzuron, teflubenzuron, flufenoxuron, and lufenuron) were assessed on the pest larvae according to four per orally diet inoculation schedules. The highest mortality values were obtained when the virus was inoculated on the second (schedule 1) and third (schedule 2) days after flufenoxuron contamination with 98.67% and 97.30%, respectively, followed by teflubenzuron. All the benzoylphenylureas showed the highest mortalities using these two schedules. Flufenoxuron had a higher relative efficiency percent than the other compounds in all the schedules. The second schedule yielded the lowest LT₅₀ value using flufenoxuron with the highest relative speed of kill (38.40%), followed by the first schedule (30.02%). The second schedule can be relatively considered the most appropriate method for the combined use of benzoylphenylurea and HearNPV.     

Disruption of a Cadherin Gene Associated with Resistance to Cry1Ac δ-Endotoxin of Bacillus thuringiensis in Helicoverpa armigera

A laboratory strain (GY) of Helicoverpa armigera (Hübner) was established from surviving larvae collected from transgenic cotton expressing a Bacillus thuringiensis var. kurstaki insecticidal protein (Bt cotton) in Gaoyang County, Hebei Province, People's Republic of China, in 2001. The GYBT strain was derived from the GY strain through 28 generations of selection with activated Cry1Ac delivered by diet surface contamination. When resistance to Cry1Ac in the GYBT strain increased to 564-fold after selection, we detected high levels of cross-resistance to Cry1Aa (103-fold) and Cry1Ab (>46-fold) in the GYBT strain with reference to those in the GY strain. The GYBT strain had a low level of cross-resistance to B. thuringiensis var. kurstaki formulation (Btk) (5-fold) and no cross-resistance to Cry2Aa (1.4-fold). Genetic analysis showed that Cry1Ac resistance in the GYBT strain was controlled by one autosomal and incompletely recessive gene. The cross-resistance pattern and inheritance mode suggest that the Cry1Ac resistance in the GYBT strain of H. armigera belongs to “mode 1,” the most common type of lepidopteran resistance to B. thuringiensis toxins. A cadherin gene was cloned and sequenced from both the GY and GYBT strains. Disruption of the cadherin gene by a premature stop codon was associated with a high level of Cry1Ac resistance in H. armigera. Tight linkage between Cry1Ac resistance and the cadherin locus was observed in a backcross analysis. Together with previous evidence found with Heliothis virescens and Pectinophora gossypiella, our results confirmed that the cadherin gene is a preferred target for developing DNA-based monitoring of B. thuringiensis resistance in field populations of lepidopteran pests.     

Expression of Cry1Aa in cassava improves its insect resistance against Helicoverpa armigera

Lepidopteran insects affect cassava production globally, especially in intercropping system. The expression of Cry toxins in transgenic crops has contributed to an efficient control of insect pests, leading to a significant reduction in chemical insecticide usage. Helicoverpa armigera is a Lepidopteran pest that feeds on a wide range of plants like cotton and cassava. In the present study, transgenic cassava plants over-expressing Cry1Aa, which we named as Bt cassava, were developed and used to evaluate its efficacy against H. armigera as a model. Insect feeding assays were carried out to test the effects of Bt cassava leaves on the development and survival of H. armigera. Significant reduction (P < 0.05) in the survival and weight were detected on larvae fed with Bt cassava leaves in comparison with those fed with wild-type cassava leaves. The higher expression of Cry1Aa in transgenic cassava caused the lethal effect in larvae, in contrast to the normal growth and development of adults and pupation observed when fed with wild-type leaves. Morphological observation on the larval midguts showed that the consumption of Bt cassava affected the gut integrity of H. armigera. The columnar cells of the midgut epithelium were dramatically damaged and showed loose or disordered structure. Their cytoplasms become highly vacuolated and contained disorganized microvilli. Our study demonstrated that the transgenic cassava expressing the Cry1Aa is effective in controlling H. armigera. Our Bt transgenic cassava plant would provide a long-term beneficial effect on all crops in intercropping system, which in-turn, will be profitable to the farmers.     

Antifeedant and larvicidal activities of Rhein isolated from the flowers of Cassia fistula L.

Antifeedant and larvicidal activities of rhein (1,8-dihydroxyanthraquinone-3-carboxylic acid) isolated from the ethyl acetate extract of Cassia fistula flower were studied against lepidopteron pests Spodoptera litura and Helicoverpa armigera. Significant antifeedant activity was observed against H. armigera (76.13%) at 1000 ppm concentration. Rhein exhibited larvicidal activity against H. armigera (67.5), S. litura (36.25%) and the LC₅₀ values was 606.50 ppm for H. armigera and 1192.55 ppm for S.litura. The survived larvae produced malformed adults.     

Formulation and optimisation of various nuclear polyhedrosis virus isolates and assessment of their insecticidal activity against Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) larvae

Helicoverpa armigera (Hubner) is a pest that poses serious threat to the tomato crop in India. Larvae of this species are susceptible to the nucleopolyhedrovirus (NPV), which has attracted interest as a potential biocontrol agent. Rearing of larvae in natural diet resulted in less number of pupae, while in artificial diet more pupae and healthy adults were obtained. The NPV was tested for its insecticidal action against H. armigera in natural and artificial diets. The bioassay results of inoculated H. armigera nucleopolyhedrosis virus (HaNPV) with different concentrations indicate that the 4.0 g/l dosage caused maximum mortality (70.3% and 60.54%), and minimum mortality 46.83% and 44.08% was recorded in the 0.5 g/l dosage under laboratory and pot culture conditions, respectively. Polyhedral inclusion bodies (PIBs) were estimated using a standard haemocytometer. According to the estimate, purified PIBs were found at a concentration of 1 × 10⁹/ml. The different formulation of NPV, i.e. wettable fine powder with a hue of white, had a particle size of 100 μm with a concentration of 1 × 10⁸/ml. The encapsulated product was found to be in the form of beads and was red in colour with a concentration of 1 × 10⁸ PIBs/ml. The effectiveness of NPV against H. armigera larvae was noted at maximum LC₅₀ values at a concentration of 1 × 10⁹/ml. Qualitative analysis estimates showed that protein polyhedrin and enzyme chitinase had a molecular weight of 33 and 45 kDa, respectively. Viral DNA was isolated from NPV-infected larvae and was then separated using SDS-PAGE. The estimated polyhedrin with a molecular weight of 33 kDa, which is responsible for the increased mortality percent of larvae, was confirmed by the bioassay. Hence it was concluded that NPV is ecofriendly in the management of pests on tomato and other crops.     

Biocontrol Potential of Steinernema thermophilum and Its Symbiont Xenorhabdus indica Against Lepidopteran Pests: Virulence to Egg and Larval Stages

Under laboratory conditions, the biocontrol potential of Steinernema thermophilum was tested against eggs and larval stages of two important lepidopteran insect pests, Helicoverpa armigera and Spodoptera litura (polyphagous pests), as well as Galleria mellonella (used as a model host). In terms of host susceptibility of lepidopteran larvae to S. thermophilum, based on the LC₅₀ 36 hr after treatment, G. mellonella (LC₅₀ = 16.28 IJ/larva) was found to be more susceptible than S. litura (LC₅₀ = 85 IJ/larva), whereas neither host was found to be significantly different from H. armigera (LC₅₀ = 54.68 IJ/larva). In addition to virulence to the larval stages, ovicidal activity up to 84% was observed at 200 IJ/50 and 100 eggs of H. armigera and S. litura, respectively. To our knowledge this is the first report of entomopathogenic nematode pathogenicity to lepidopteran eggs. Production of infective juvenile (IJ) nematodes/insect larva was also measured and found to be positively correlated with rate of IJ for H. armigera (r = 0.990), S. litura (r = 0.892), as well as G. mellonella (r = 0.834). Both Phase I and Phase II of symbiotic bacteria Xenorhabdus indica were tested separately against neonates of H. armigera and S. litura by feeding assays and found to be virulent to the target pests; phase variation did not affect the level of virulence. Thus S. thermophilum as well as the nematode’s symbiotic bacteria applied separately have the potential to be developed as biocontrol agents for key lepidopteran pests.     

混合感染后杆状病毒间的增效作用——病毒蛋白及核酸的初步分析

AsNPV+HasNPV、AsNPV+HaNPV、AsNPV+PsNPV分别感染烟青虫、棉铃虫和粘虫幼虫,对分离到的核型多角体病毒(AsNPV+HasNPV)-Helicoverpa assulta、(AsNPV+HaNPV)- H.Armigera和(AsNPV+PsNPV)-Pseudaletia separata,经电镜观察,多角体蛋白及病毒粒子蛋白SDS-PAGE电泳,病毒核酸的限制性内切酶酶解分析等研究,证明各病毒的多角体形态不规则,大小差异极大,病毒粒子为杆状,(AsNPV+HasNPV)-H.Assulta 和(AsNPV+HaNPV)-H.Armigcra病毒粒子有单粒和多粒包埋类型, (AsNPV+PsNPV)-P.Separata为多粒包埋型。各病毒的多角体蛋白基本上只有一种多肽,分子量为25 000道尔顿左右。(AsNPV+HasNPV)-H.Assulta、(AsNPV+HaNPV)-H.armigera和(AsNPV+PsNPV)-P.Separata的病毒粒子分别有10、14、5条多肽,分子量大小在13 500～98 000,13 000～88 000,18 500～52 000道尔顿之间。病毒核酸经EcoRI,HindIII,HindIII+BamHI酶解,其DNA的酶切位点,大小及DNA的总分子量与AsNPV和原寄主的Has-NPV,HaNPV和PsNPVDNA的酶切图谱存在一定差异,混合病毒侵染昆虫后新复制的病毒核酸发生一定的变化,从而导致病毒蛋白和病毒形态的变化。混合感染后AsNPV对Has-NPV、HaNPV和PsNPV的侵染有明显的增效作用,其机理有待深入研究。     

New Resistance Mechanism in Helicoverpa armigera Threatens Transgenic Crops Expressing Bacillus thuringiensis Cry1Ac Toxin

In Australia, the cotton bollworm, Helicoverpa armigera, has a long history of resistance to conventional insecticides. Transgenic cotton (expressing the Bacillus thuringiensis toxin Cry1Ac) has been grown for H. armigera control since 1996. It is demonstrated here that a population of Australian H. armigera has developed resistance to Cry1Ac toxin (275-fold). Some 70% of resistant H. armigera larvae were able to survive on Cry1Ac transgenic cotton (Ingard) The resistance phenotype is inherited as an autosomal semidominant trait. Resistance was associated with elevated esterase levels, which cosegregated with resistance. In vitro studies employing surface plasmon resonance technology and other biochemical techniques demonstrated that resistant strain esterase could bind to Cry1Ac protoxin and activated toxin. In vivo studies showed that Cry1Ac-resistant larvae fed Cy1Ac transgenic cotton or Cry1Ac-treated artificial diet had lower esterase activity than non-Cry1Ac-fed larvae. A resistance mechanism in which esterase sequesters Cry1Ac is proposed.     

Susceptibility of larvae ofHeliothis zea,H. virescens,andH. armigera [lep.: Noctuidae] to 3 baculoviruses

The pattern of virulence (based on inclusion bodies) for 3 baculoviruses ofHeliothis, i.e. a unicapsid, nuclear polyhedrosis virus (HzSNPV); a multicapsid, nuclear polyhedrosis virus (HaMNPV); and a granulosis virus (HaGIV) was the same (HzSNPV>HaMNPV>HaGIV) for 3 species ofHeliothis. Based on numbers of nucleocapsids, however, the HaGIV was ca 2X more virulent than the HaMNPV for larvae ofH. virescens, (F.), and the HaMNPV was about 6X more virulent than the HaGIV for larvae ofH. armigera (Hübner). The fastest rate of larval mortality was obtained with HzSNPV. Although the mortality rate for HaGIV was faster than that of HaMNPV forH. virescens andH. armigera, it was slower than that of HaMNPV for larvae ofH. zea (Boddie). The pattern of susceptibility ofHeliothis species to HzSNPV and HaMNPV wasH. zea>H. virescens>H. armigera. Differences in susceptibility of the least susceptible species (H. armigera) and the most susceptible species (H. zea) to HzSNPV was ca. 1.6 X. Larvae ofH. zea, however, were ca. 4 to 6 X more susceptible to HaMNPV than were larvae ofH. virescens orH. armigera. A different pattern of susceptibility was recorded for HaGIV when larvae were challenged with HzSNPV and HaMNPV. Larvae ofH. virescens were ca. 20 and 35 X more susceptible to HaGIV than were larvae ofH. zea andH. armigera, respectively.     

A novel insecticidal GroEL protein from Xenorhabdus nematophila confers insect resistance in tobacco

Xenorhabdus nematophila is an entomopathogenic bacteria. It secretes a GroEL homolog, XnGroEL protein, toxic to its larval prey. GroEL belongs to the family of molecular chaperones and is required for proper folding of cellular proteins. Oral ingestion of insecticidal XnGroEL protein is toxic to Helicoverpa armigera, leading to cessation of growth and development of the larvae. In the present study, the insecticidal efficacy of XnGroEL against H. armigera has been evaluated in transgenic tobacco plant expressing the protein. A 1.7-kb gene encoding the 58-kDa XnGroEL protein was incorporated into the tobacco genome via Agrobacterium-mediated transformation. The stable integration of the transgene was confirmed by Southern blot analysis and its expression by RT-PCR and western blot analyses in transgenic plants. The transgenic lines showed healthy growth and were phenotypically normal. Insect bioassays revealed significant reduction of 100 % in the survival of larvae (p < 0.001) and 55–77 % reduction in plant damage (p < 0.05 and p < 0.001) compared to the untransformed and vector control plants. The results demonstrate that XnGroEL is a novel potential candidate for imparting insect resistance against H. armigera in plants.     

A Comparison of Growth and Development of Three Major Agricultural Insect Pests Infected with Heliothis virescens ascovirus 3h (HvAV-3h)

Ascoviruses are double-stranded DNA viruses that are pathogenic to lepidopteran hosts, particularly noctuid larvae. Infection of a larva is characterized by retarded growth, reduced feeding and yellowish body color. In this paper, we reported the growth and development of three major agricultural noctuid insect pests, Helicoverpa armigera (Hübner), Spodoptera exigua (Hübner) and Spodoptera litura (Fabricius), infected with Heliothis virescens ascovirus 3h (HvAV-3h). Using 10-fold serial dilutions (0 to 7) of HvAV-3h-containing hemolymph to infect S. litura larvae, we found no significant difference in larval mortalities from 0 to 10³-fold dilutions; however, significant differences were observed at 10⁴-fold dilution and above. Using a 10-fold dilution of HvAV-3h-containing hemolymph to infect H. armigera, S. exigua and S. litura larvae, we found that the growth and development were significantly affected. All infected larvae could not pupate; the survival times of treated H. armigera, S. litura and S. exigua larvae were significantly longer than untreated control larvae. Body weight showed significant difference between treated and untreated control group from day 1 after inoculation in H. armigera and S. exigua, but day 2 in S. litura. Additionally, food intake also showed significant difference between treated and untreated control group from day 2 after inoculation in H. armigera and S. litura, but day 3 in S. exigua.