Comparison of bio-efficacy of some plant extracts and new chemistry insecticides against Bemisia tabaci (Gennadius) and Water Productivity of Cotton Varieties under High Efficiency Irrigation System

Abstract

Cotton is an important cash crop in Pakistan. But insect pests attack and emerging water scarcity glitches are alarming the crop yield on sustainable basis. Hence, the present research trial was executed to probe out the toxic effects of plant extracts and some insecticides against cotton whitefly, Bemisia tabaci. Different concentrations of the plant extracts and insecticides were applied. Results showed that highest mean incidence (10.6 adults/plant) of whitefly population was observed in case of BS-15 variety, was under double Lateral+30 cm P×P distance while in case of NIAB-878, the value was 13.1 adults/plant. Results to toxicity bioassays showed that maximum population reduction (79.10%) was recorded in case of pyriproxyfen while comparative less reduction (51.17%) was observed in case of dine to furon after exposure period of 72 (h.). . The values were after 48 and 24 h. In case of plant extracts, highest mortality (51.46%) was noted in case of A. indica whereas comparatively low mortality (46.32%) was recorded in case of M. oleifera extract at 30% concentration of plant extracts after exposure period of 72 (h.). 20 and 10% concentrations of the tested plant extracts showed relatively lower mortality values. Data of morphological growth showed that plant height got increased by increasing planting distance from 30 to 40 cm in case of the both varieties. Number of leaves and boll size did not increase with increasing planting distance in case of BS-15 variety whileincreased in case of NIAB-878 variety and the values were 105.1 (number of leaves), 44.4 (number of bolls) and 10.2 cm2 (boll size). Crop water productivity of variety BS-15 was higher (0.51 kg m-3) as compared to NIAB-878 (0.49 kg m-3). It is concluded that the variety BS-15 performed better under single lateral system while variety NIAB-878 performed better under double lateral system. Plant to plant distance of 30 cm was found better than 40 cm distance. Keywords: Cotton varieties, morphogical characteristics, drip irrigation, Planting geometry.