Population dynamics in relation to abiotic factors and management of citrus psylla in Punjab Sharma D.R. Department of Horticulture, Punjab Agricultural University, Ludhiana, 141 004. Corresponding author's: E-mail: drajsharma@rediffmail.com
Abstract The studies on population dynamics revealed that adult population of Diaphorina citri Kuwayana was very low during December and January but with the increase in temperature in the end of February, the activity of adults increased. At the same time a low population of nymphs was also recorded and thereafter, the population of both adults and nymphs increased but significant increase in nymphal population was observed during March (41–47 nymphs). A decrease in nymphal population was recorded during May–June but attained the maximum infestation during July when the adult population was 92–111/25 leaves. The nymphal population also remained quite high during August, when the weather factors, viz. minimum, maximum, mean temperature (°C), relative humidity (%), sunshine (hours) and rainfall (mm), respectively ranged from 26.0–27.2, 33.5–34.9, 30.4°C, 74–84 percent, 6.3 to 9.3 hours and 24.5 to 297.7 mm. Analysis of correlation between population (mixed, nymphs and adults) of citrus psylla and different abiotic factors revealed that minimum, maximum and mean temperatures, relative humidity and vapour pressure had a positive relation with both nymphal and adult population whereas wind velocity had very low impact on adults. The data on bio-efficacy of different insecticides indicated that except dimethoate (0.05%) with 69.7 percent nymphal mortality after 12 days of spray all other insecticides namely dimethoate (0.075%), oxydemeton methyl (0.075%), imidacloprid (0.008%), chlorpyriphos (0.1%), triazophos (0.1%), thiamethoxam (0.008%) and quinalphos (0.075%) had significantly high (91–100%) nymphal reduction of D. citri compared to either 3 or 7 days data. Top Key words Diaphorina citri, population dynamics, management, citrus psylla, abiotic factors. Top |