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Genetically modified crops are proven to protect crops from pest and diseases. Most of the GM crops either have insect resistance gene or weedicide resistance gene or both. In India only GM crop approved for commercial cultivation is cotton expressing cry1Ac and cry2Ab gene against bollworms. Other crops that where genetically modified against major insect pests by introducing cry genes in India are paddy, chickpea, mustard and eggplant. Albeit the empirical evidence of its efficacy against insect pests, commercial cultivation of these food crops is being kept on moratorium due to biosafety issues. [ABSTRACT FROM AUTHOR]

The cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae), is an invasive pest of cotton, apart from several other important crops, and poses a serious threat to agricultural economy all over the world. Studies on the biology and population growth parameters of P. solenopsis on the five most preferred host plants, namely cotton (Gossypium hirsutum L.) (Malvaceae), China rose (Hibiscus rosa-sinensis L.) (Malvaceae), tomato (Lycopersicon esculentum Mill.) (Solanaceae), congress grass (Parthenium hysterophorus L.) (Asteraceae) and okra (Abelmoschus esculentus (L.) Moench) (Malvaceae) were undertaken in the laboratory under controlled temperature and relative humidity. The mean cumulative development time of females was 16.61 days on cotton, 14.16 days on China rose, 14.13 days on okra, 14.00 days on tomato and 13.57 days on congress grass. The longest oviposition period was recorded on cotton (15.20 ± 1.87 days), while it was in the range of 9-10 days in the remaining host plants. Females lived longer (27.40 ± 1.76 days) when reared on cotton, while their life was shortest on tomato (14.60 ± 0.96 days). The highest fecundity was observed on cotton (328.30 ± 23.42), whereas it was found to be in the range 178-212 on the other hosts. The survival frequency from crawler to adult in females was highest on cotton (27.53%), while it was the lowest on tomato (15.87%). The highest net reproductive rate (284.3 females/female/generation), mean length of a generation (31.24 days), and intrinsic rate of increase (0.19 day−1) were recorded on cotton. The finite rate of increase was in the range of 1.18-1.20 (females/female/day) for all the selected host plants. The weekly multiplication rate was highest on China rose and congress grass (3.78), while it was the least on tomato (3.28). The corrected generation time was dissimilar in all the selected host plants, being highest on cotton (31.39 days) and the least on congress grass (27.71 days). The doubling time was shortest on congress grass (3.61 days), while it was longest on tomato (4.11 days). Hence, the host plant species significantly affects population growth of P. solenopsis. [ABSTRACT FROM AUTHOR]

Pink bollworm (PBW),Pectinophora gossypiellais one of the most destructive pest’s globally inflicting huge economic losses in cotton even during later stages of crop growth. In the present investigation, the population genetic structure, distribution, and genetic diversity ofP. gossypiellain cotton growing zones of India using partial mitochondrial DNA cytochrome oxidase-I (COI) gene was addressed. The overall haplotype (Hd),number of nucleotide differences (K), and nucleotide diversity (π) were 0.3028, 0.327, and 0.00047, respectively which suggest that entire population exhibited low level of genetic diversity. Zone-wise clustering of population revealed that central zone recorded low level ofHd(0.2730) as compared to north (0.3619) and south (0.3028) zones. The most common haplotype (H1) reported in all 19 locations could be proposed as ancestral/original haplotype. This haplotype with one mutational step formed star-like phylogeny connected with 11 other haplotypes. The phylogenetic relationship studies revealed that most haplotypes of populations are closely related to each other. Haplotype 5 was exclusively present in Dharwad (South zone) shared with populations of Hanumangarh and Bathinda (North zone). The result indicated that there is no isolation by distance effect among the Indian populations of PBW. The present study reports a low genetic diversity among PBW populations of India and H1, as ancestral haplotype from which other haplotypes have evolved suggests that the migration and dispersal over long distance and invasiveness are major factors. [ABSTRACT FROM PUBLISHER]

Cotton seed based artificial diet has been standardized for continuous rearing of pink bollworm Pectinophora gossypiella (Saunders) at the Central Institute for Cotton Research, Regional Station, Coimbatore. The ingredients of the diet are easily available and are cost effective. Basic ingredients of the diet are cotton seed flour (processed) and chick pea flour, Carbohydrate, Protein, Fat sources, multi vitamin, antimicrobial agents and agar as thickening agent are used as other ingredients. Micro centrifuge tubes with lid were used as rearing containers. Individual neonate larvae were released on each piece of the diet inside the micro centrifuge tube and the lids were closed. This prevented larval escape, retaining them inside the tubes and also prevented diet dehydration. The recovery of insect reared on diet was recorded as 95.56%. Egg hatchability and adult emergence were 100% while pupal malformation was nil. Eggs, larval and pupal periods were recorded as 4.8 ± 0.632, 25.10 ± 0.994 and 7.9 ± 0.88 days, respectively. Larval and pupal weights were recorded as 21.40 mg ± 3.63, 18.00 mg ± 2.73, respectively. [ABSTRACT FROM AUTHOR]

survey was conducted in 47 locations in nine cotton-growing states of India to identify the composition of mealybug species occurring on cotton. Results of the taxonomic study showed that two mealybug species, the solenopsis mealybug, Phenacoccus solenopsis (Tinsley), and the pink hibiscus mealybug, Maconellicoccus hirsutus (Green), were found to infest cotton plants from all nine cotton growing states of the country. However, P. solenopsis was found to be the predominant mealybug species, comprising 95% of the samples examined. P. solenopsis, which was hitherto not reported to occur in India, now appears to be widespread on cotton in almost all cotton-growing states of the country. P. solenopsis is an exotic species originated from the USA and was reported to damage cotton and crops of 14 families. This report discusses the implications of the introduction of this exotic polyphagous pest species and the necessary steps to mitigate its potential threat to agriculture in India. [ABSTRACT FROM AUTHOR]

Abstract: A simple lateral-flow immuno-chromatographic ‘dipstick’ kit was developed in a novel single strip format to test/verify the label claim of active ingredient in commercial insecticide formulations of endosulfan and the type-II synthetic pyrethroids, cypermethrin, deltamethrin and fenvalerate. Polyclonal antisera were raised in rabbits against immunogens developed by conjugating proteins (bovine serum albumin, BSA and keyhole limpet hemocyanin, KLH) to endosulfan-diol, 4′-hydroxy-cypermethrin and 2′-hydroxy-cypermethrin using an activated ester method through a spacer attachment. Immunoglobulin (IgG) was purified through protein-A affinity chromatography and conjugated to horse radish peroxidase (HRP) and colloidal gold. A competitive ELISA was designed to determine the ability of the test insecticides to compete with the relevant hapten–protein conjugate. A combination of antiserum-4′-OH-Cyper-KLH with the 4′-OH-Cyper-BSA as coating hapten resulted in the highest absorbance (Amax: 1.32) low background value (Amin: 0.05) and good competitive inhibition with cypermethrin (IC99: 2034μg/L), deltamethrin (IC99: 2297μg/L) and fenvalerate (IC99: 3546μg/L). For endosulfan, a combination of antiserum raised against endosulfan-KLH with endosulfan-BSA as the coating hapten gave the highest absorbance (Amax: 1.42), low background value (Amin: 0.05) and good competitive inhibition with endosulfan (IC99: 2378μg/L). A novel format was designed using the combinations for development of the lateral-flow strip, so as to enable the detection of pyrethroids and endosulfan on a single strip. The strips were designed such that two intensely coloured purple lines appeared when the strip is dipped in a solution devoid of any insecticide. The minimum concentration of the test insecticides, endosulfan (1800μg/l), cypermethrin (800μg/l), deltamethrin (1000μg/l) and fenvalerate (1400μg/l) was determined, which would be adequate to inhibit the appearance of either of the two lines, when the strip is dipped in a solution containing any one of the diluted insecticides prepared from authentic insecticide formulations. When samples of substandard insecticide formulations are diluted as per the pre-determined dilutions, the aliquots are expected to contain less than the quantity specified above, and would result in the appearance of two purple lines, with one of them at the sample line region of the membrane, the intensity of which would be inversely proportionate to the concentration of the test analyte. The strip can be considered as suitable for on-the-spot analysis of test sample formulations either by farmers, extension workers, quality control officials etc., to generate preliminary prima facie evidence in case of doubtful samples of substandard insecticide formulation. [Copyright &y& Elsevier]

Abstract: The geographical variability in Helicoverpa armigera susceptibility levels to Cry2Ab toxin expressed by transgenic maize (not currently commercialized in India) was determined through log dose probit assays conducted on populations collected during 2004–05 (from 25 districts) and 2007–08 (from 22 districts) across India. While 2004–05 is the year prior to commercialization of dual gene Bollgard-II-Bt cotton that expresses Cry2Ab in addition to Cry1Ac, 2007–08 is two years after its commercial release. LC50 values ranged from 6.0 to 28.6 μg Cry2Ab/ml of diet in 2004–05 and from 2.46 to 34.7 μg Cry2Ab/ml of diet in 2007–08. The IC50 range in 2004–05 and 2007–08 was from 0.31 to 2.3 μg/ml and 0.10–3.4 μg/ml of diet, respectively. The probit analysis data of 2004–05 can be used as baseline indices to monitor for changes in the H. armigera susceptibility to Cry2Ab, subsequent to the introduction of Bollgard-II cotton in India. The probit analysis data of 2007–08 showed that the baseline has not undergone any significant changes two years after cultivation of Bollgard-II in India. The relatively low toxicity of Cry2Ab and its higher expression late in the cotton season compared with Cry2Ab, compounded with its presence in Bt hybrids on a separate linkage group from Cry1Ac suggest problems of resistance in the future. [Copyright &y& Elsevier]

Abstract: The mode of inheritance of resistance to Cry1Ac toxin of Bacillus thuringiensis in the cotton bollworm, Helicoverpa armigera (Hübner), was elucidated through bioassay analysis of the response of resistant, susceptible, F1 hybrid and backcross H. armigera progeny to Cry1Ac using semi-synthetic diet and transgenic Bt cotton plants. The dominance value estimates ranged between 0.42 and 0.57. Resistance was found to be monogenic, autosomal and inherited as a semi-dominant trait. Genetic studies of response of H. armigera to transgenic Bt cotton showed that the effective resistance on transgenic Bt cotton plants was also inherited as a semi-dominant trait. [Copyright &y& Elsevier]

Tobacco armyworm, Spodoptera litura (Fab), a polyphagous insect, is an important pest of groundnut ( Arachis hypogaea L). It is one of the insect pests which had developed resistance to insecticides. Currently there are no cultivars of groundnut which express high level of resistance to S. litura. Wild species of groundnut, which show high levels of resistance, have been identified. Arachis kempff-mercadoi is one such wild species, which is reported to be resistant to S. litura, and indicated that in wild species three flavonoids chlorogenic acid, quercetin and rutin are involved in the components of resistance. In the present study, although these flavonoids had an effect on larval mortality, statistical analysis revealed that quercetin had a major effect due to high correlation of quercetin with chlorogenic acid and rutin. Interspecific derivatives were obtained as a result of crossing cultivated groundnut with A. kempff-mercadoi. In vitro studies showed high percentage of neonate larval mortality when fed on the foliage of interspecific derivatives, majority of interspecific derivatives were detrimental to larval development and had considerable effect on its subsequent progeny. Resistant derivatives were found to have high levels of flavonoids and antibiosis mechanism prevented larval growth. Susceptible derivatives and the female parent, A. hypogaea have low levels of flavonoids. [ABSTRACT FROM AUTHOR]

The semilooper, Anomis flava Fab is a foliage feeding lepidopteran insect, often found occurring in the cotton ecosystem during the first 60–75 days of sowing. Its occurrence overlaps or just precedes the incidence of Helicoverpa armigera. This study reports the impact of mechanical wounding or of prior herbivory by semilooper larvae on cotton host-plant resistance to H. armigera. It is proposed that cotton plant damaged by semilooper or by mechanical means is less preferred for the growth of H. armigera. This is probably due to a reduction in the nutritive quality, induction of allelochemicals, such as chlorogenic acid and of oxidative enzymes, such as lipoxygenases and peroxidases in the damaged plants. [Copyright &y& Elsevier]

Insecticide resistance to representatives of commonly used insecticide groups (pyrethroids—cypermethrin; organophosphates—chlorpyriphos; cyclodienes—endosulfan) was determined in five major insect pests of cotton from the main cotton growing regions of India with emphasis on Andhra Pradesh and Maharashtra. The cotton bollworm Helicoverpa armigera (Hubner) exhibited widespread resistance to cypermethrin with 23–8022-fold resistance being recorded in field strains. Resistance to endosulfan and chlorpyriphos was low to moderate in H. armigera. The overall resistance of the pink bollworm Pectinophora gossypiella (Saunders) to pyrethroids was low. However, high resistance levels of 23–57-fold to endosulfan were recorded in some areas of Central India. Resistance to chlorpyriphos was high in the Medak, Bhatinda and Sirsa strains from North India. The majority of the Spodoptera litura (Fab.) strains collected in South India exhibited high resistance levels of 61–148-fold to cypermethrin. Resistance to endosulfan was high only in two strains, collected from Bhatinda and Karimnagar in North India. The S. litura strains from South India exhibited high levels of resistance at 45–129-fold to chlorpyriphos. Insecticide resistance in Earias vittella (Fab.) was low to moderate in the Sirsa and Sriganganagar strains from North India. Bemisia tabaci (Genn.) exhibited moderately high levels of resistance to cypermethrin, but resistance to endosulfan and chlorpyriphos was negligible in the field strains tested. The implications of resistance for cotton pest management in India are discussed. [Copyright &y& Elsevier]

The baseline toxicity of Cry1A δ-endotoxins (derived from Bacillus thruringiensis (Kurstaki)) on field populations of the cotton bollworm, Helicoverpa armigera (Hub.), was determined through log dose probit analysis. All the three Cry1A proteins were found to be toxic to the bollworm larvae. Cry1Ac was found to be the most toxic followed by Cry1Aa andCry1Ab. LC[sub 50] values ranged from 0.07 to 0.99 μg/ml(14- fold) for Cry1Aa, 0.69 to 9.94 μg/ml (14-fold) for Cry1Ab and 0.01 to 0.67 μg/ml of diet (67-fold) for Cry1Ac. The LC[sub 50] values deduced from the cumulative log dose probit response of the data pooled from all assays, were 0.62 μg/ml for Cry1Aa, 4.43 μg/ml for Cry1Ab and 0.100 μg/ml of diet for Cry1Ac. The respective LC[sub 50] values represent the baseline susceptibility indices for resistance monitoring through the conventional log dose probit assays. The LC[sub 99] values derived from the cumulative data were 515 μg/ml for Cry1Aa, 13385 μg/ml for Cry1Ab and 75 μg/ml of diet for Cry1Ac. These values represent the diagnostic doses for routine monitoring of resistance to the respective toxins through discriminating dose assays after the introduction of Bt transgenic crops. [ABSTRACT FROM AUTHOR]