Improved bioassay method for evaluation of oviposition deterrents against Old World bollworm, Helicoverpa armigera (Hübner)

Old world bollworm Helicoverpa armigera (Hübner) is one of the serious pests of agricultural crops with more than 184 recorded hosts including cotton. In cotton, H. armigera usually causes yield losses up to 40% with 20-80% damage intensity. In the Indian context it has already developed resistance to most conventional classes of insecticide and its survival on Bt cotton also has been reported in some isolated places. Under such situation, application of semiochemicals can serve as an alternative management option. Among the semiochemicals, oviposition deterrent ones are known to be the most effective as they minimize the infestation at first line of attack by deterring the female moths and protecting the host from oviposition. However, before applying at field level, it is important to develop and standardize a bioassay method for evaluation of oviposition deterrent compounds under laboratory condition. Here, we report a suitable improved bioassay method for evaluation of effect of oviposition deterrents against H. armigera. The five days duration of bioassay method was finalized according to the peak activity of adult moth in terms of mating and fecundity. This investigation presents a method, for finding promising oviposition deterrent compound which will be helpful for researchers to identify the most potent molecule/compounds against H. armiger

Cotton Crop Protection Strategies 2018

uploaded by Dr. M. Sabeshcotton crop protection strategies for the year 201

Improved bioassay method for evaluation of oviposition deterrents against Old World bollworm, Helicoverpa armigera (Hübner)

851-857Old world bollworm Helicoverpaarmigera (Hübner) is one of the serious pests of agricultural crops with more than 184 recorded hosts including cotton. In cotton, H. armigerausually causes yield losses up to 40% with 20-80% damage intensity. In the Indian context it has already developed resistance to most conventional classes of insecticide and its survival on Bt cotton also has been reported in some isolated places. Under such situation, application of semiochemicals can serve as an alternative management option. Among the semiochemicals, oviposition deterrent ones are known to be the most effective as they minimize the infestation at first line of attack by deterring the female moths and protecting the host from oviposition. However, before applying at field level, it is important to develop and standardize a bioassay method for evaluation of oviposition deterrent compounds under laboratory condition. Here, we report a suitable improved bioassay method for evaluation of effect of oviposition deterrents against H. armigera. The five days duration of bioassay method was finalized according to the peak activity of adult moth in terms of mating and fecundity. This investigation presents a method, for finding promising oviposition deterrent compound which will be helpful for researchers to identify the most potent molecule/compounds against H. armigera

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Not AvailablePlant growth-promoting rhizobacteria (PGPR) have multifarious beneficial activities for plant growth promotion; act as source of metabolites, enzymes, nutrient mobilization, biological control of pests, induction of disease resistance vis-a-vis bioremediation potentials by phytoextraction and detoxification of heavy metals, pollutants and pesticides. Agrochemicals and synthetic pesticides are currently being utilized widely in all major field crops, thereby adversely affecting human and animal health, and posing serious threats to the environments. Beneficial microorganisms like PGPR could potentially substitute and supplement the toxic chemicals and pesticides with promising application in organic farming leading to sustainable agriculture practices and bioremediation of heavy metal contaminated sites. Among field crops limited bio-formulations have been prepared till now by utilization of PGPR strains having plant growth promotion, metabolites, enzymes, nutrient mobilization and biocontrol activities. The present review contributes comprehensive description of PGPR applications in field crops including commercial, oilseeds, leguminous and cereal crops to further extend the utilization of these potent groups of beneficial microorganisms so that even higher level of crop productivity and quality produce of field crops could be achieved. PGPR and bacteria based commercialized bio-formulations available worldwide for its application in the field crops have been compiled in this review which can be a substitute for the harmful synthetic chemicals. The current knowledge gap and potential target areas for future research have also been projected.Not Availabl

Degree day-based model predicts pink bollworm phenology across geographical locations of subtropics and semi-arid tropics of India

Abstract There is a global concern about the effects of climate change driven shifts in species phenology on crop pests. Using geographically and temporally extensive data set of moth trap catches and temperatures across the cotton growing states of India, we predicted the phenology of cotton pink bollworm Pectinophora gossypiella (Saunders). Our approach was centered on growing degree days (GDD), a measure of thermal accumulation that provides a mechanistic link between climate change and species’ phenology. The phenology change was predicted by calculating absolute error associated with DD and ordinal date, an alternative predictor of phenology, for peak moth abundance. Our results show that GDD outperformed the ordinal dates in predicting peak moth abundance in 6 out of 10 selected locations. Using established thresholds of 13.0/34.0 °C, mean DD accumulated between the consecutive moth peaks across different years were estimated at 504.05 ± 4.84. Seven generations were determined for pink bollworm in a cropping season, the length of which varied between 35 and 73 days in response to temperature. Pink bollworm population reached its peak during third generation which can be the target for management actions. The study provides essential information for developing pink bollworm management strategies under climate change

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Not AvailableThe potential of cyanobacteria-based compost formulations was evaluated in cotton crop at two agro-ecological locations (Nagpur and Sirsa) as plant growth promoting (PGP) and biocontrol agents. Compost-based formulations fortified with Calothrix sp. or Anabaena sp. enhanced germination and fresh weight of plants, and microbiological activity by 10–15%, besides increased available nitrogen (by 20–50%) in soil at Nagpur. In the fungi-infected fields at Sirsa, Anabaena–T. viride biofilmed formulation performed the best, recording 11.1% lower plant mortality than commercial Trichoderma formulation. Scanning electron microscopy confirmed the colonisation of inoculated cyanobacteria/biofilms on roots. Significant correlation between mortality, increased activity of hydrolytic enzymes and fresh weight of plant roots were recorded. Calothrix sp. and Anabaena sp. proved promising as both PGP and biocontrol agents, while biofilmed formulations substantially reduced mortality of cotton plants in sick plots. This study illustrates the promise of cyanobacteria as viable inoculation option for integrated nutrient and pest management strategies of cotton.Not Availabl