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

Understanding Root Biology for Enhancing Cotton Production

Cotton is an important commercial crop grown in India. It occupies an area of about 12.7 million hectares and is grown both in irrigated as well as rainfed tracts. In such situations, roots are very important organ for plant growth and development, since they act as anchors, providing mechanical support, and chemical extractors for the growing plant. Root length density sets the proportion of water uptake both under wet conditions and dry soils. Cotton plants with efficient root system capture water and nutrients from soil having these features of longer tap root. It is widely accepted that breeding efforts on aboveground traits are not sufficient to the necessary yield advantage. Shifting the emphasis to analyzing the root system would provide an additional means to enhance yield under changing climatic condition. Belowground image analysis studies point to the importance of root system architecture for optimizing roots and rhizosphere dynamics for sustainable cotton production. In this review, we describe the cotton root biological context in which root-environment interactions providing an overview of the root growth morphology species wise, phytohormone action that control root growth, root anatomical significance in drying soils, biotic and abiotic stresses involved in controlling root growth and environmental responses

Plant Parasitic Nematodes Of Cotton-Farmer’s Hidden Enemy

Not AvailableEver since the dawn of civilization, cotton has played a major role in weaving social, economic and political fabric of our country and still occupies place of pride in Indian economy. Unfortunately, despite having maximum area under cotton cultivation, productivity of cotton in India at 319 Kg lint / ha lags far behind as against productivity of 1709 Kg lint / ha in Israel. One of the ways to increase cotton productivity so as to meet the projected demand of 190- 200 lakh bales by next decade and make Indian cotton competitive in world market is to optimize environment in which crop is grown and neutralize damaging biotic factors so that inherent yield potential comes close to realization. Plant parasitic nematodes in last few decades have been recognized as important limiting factors for crop production, particularly, in the tropics. Several species of plant parasitic nematodes have been reported to cause serious losses in this high value commercial crop. However, non-specificity of symptoms often leads to nematode problems being diagnosed as due to nutritional or soil factors. Nematode diseases can be said to be 'Life Style Diseases' of crop plants and these have been accentuated due to replacement of traditional agriculture with modem farming practices. The present bulletin attempts to present a brief diagnosis of nematode problems and their management practices that could be followedNot Availabl

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

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

The comparison of species diversity and abundance of insect natural enemies in the domesticated species of cotton using the yellow pan trap method

Abstract India is the world’s largest cotton producer and the only country that grows all four cultivated cotton species. There have been very few studies on the diversity and abundance of natural enemies of cotton insect pests in these cultivated cotton species. Therefore, the current study (2016–2018) was conducted to assess the diversity and abundance of natural enemies that cultivated cotton species harbour. Phule Dhanwantari, Suraj, Suvin, RCH-2, and DCH-32 were the five genotypes used in the study, each with a distinct genetic background. Using the adiv 2.0.1 and vegan R packages, we identified significant differences in natural enemies in terms of species diversity, richness, evenness, and abundance. Analysis of Similarity (ANOSIM) and Non-metric Multidimensional Scaling (NMDS) indicated substantial differences in the natural enemy community structure among the examined genotypes. A total of 17,279 natural enemies were collected and identified across genotypes from seven predatory families and five parasitoid families. The percentage share of these natural enemy families across genotypes and years, in descending order, is Coccinellidae (28.23%) < Tachinidae (19.23%) < Braconidae (12.68%) < Chrysopidae (11.65%) < Chalcididae (9.41%) < Aphelinidae (6.33%) < Pentatomidae (3.29%) < Ichneumonidae (2.37%) < Syrphidae (2.33%) < Vespidae (1.81%) < Asilidae (1.79%) < Geocoridae (0.89%). Coccinellidae, Tachinidae, Braconidae, Chrysopidae, Chalcididae, and Aphelinidae are the six major families that account for more than 85% of all recorded natural enemies. These six families have a higher percentage share in Phule Dhanwantary (90%) compared to the other genotypes. The conservation and better utilization of these natural enemies are crucial for the ecological and safe management of insect pests in the cotton ecosystem