Host Plant Resistance of Bioregulator Treated Cotton to Bolloworms and Sucking Complex and its Impact on Yield and Yield Components

Abstract

The studies on evaluation of growth regulators for the management of insect pests of cotton were conducted in randomized complete blocks design with four replicates. Different growth regulators, Pix, Atonic, Cytokin and cytoplex were sprayed either alone or in combination with insecticides for the induction of Pseudo resistance against insect pests in the cotton. Results revealed that growth regulators treated cotton plant harboured lower population of jassids, thrips, white flies and bollworms. Host plant resistance studies indicated that Red RBGL and Rerd okra were moderately resistant to the attack of jassides and thrips. Whereas Red okra and AEH-8 were observed less susceptible to the attack of pink and spotted bollworms. Hence, these lines can be effectively used for integrated control programme of insect pests of cotton. Pix treatment in different doses reduced the infestation of sucking complex and bollworms infestation in cotton. However, combination of pix 100 g/ha with insecticide were observed more suitable in reducing the infestation of insect pests of cotton. Highest G.O.T. was recorded in treatment of insecticide alone. Feasibility studies of integration of different bioregulators and insecticides indicated that Cytokin + Cytoplex treatment significantly increased the number of bolls per plant and size of the cotton bolls which subsequently increased the seed cotton yield. The cotton bollworms infestation remained below the economic threshold level in Cytokin + Cytoplex treated plots. Boll rot disease was also less in the Cytokin + Cytoplex treated plots. Although seedcotton yield was higher in Cytokin + Cytoplex + insecticide treated plots but it was satistically at par with Cytokin + Cytoplex. It is concludrd that Cytokin in combination with Cytoplex can effectively be used to develop resistance in cotton against bollworms and to enhance the seed cotton yield. Studies on the evaluation of four bioregulators (Atonic, Cytokin, Cytoplex and Pix) revealed that maximum seed cotton yield and minimum infestation of pink and spotted bollworms were recorded in pix and Cytokin treated cotton. Both of the bioregulators enhanced the boll size and boll retention power of the plant and maximum number of bolls and large boll size were recorded from the plots treated with Pix or Cytokin. Bioregulators, pix and cytokine were also more effective to check the infestation of jassids, thrips and white flies as compared to Atonic and cytoplex treatments. Atonic and Cytoplex did not prove effective against cotton bollworms and for the enhancement of seed cotton yield. Maximum yield of seed cotton was recorded from the areas treated with Pix + Nuvacron and Pix + Plytrin-C. Pix in combination with insecticides significantly reduced the infestation of sucking complex (jassids, thrips and white files) as compared to insecticides alone. Moreover, the treatment of Pix with insecticide (two sprays) saved two sprays of insecticides with ultimately reduced the environmental pollution and protected the beneficial insect fauna.