~ 1113 ~ Journal of Entomology and Zoology Studies 2018; 6(4): 1113-1115 E-ISSN: 2320-7078 P-ISSN: 2349-6800 JEZS 2018; 6(4): 1113-1115 © 2018 JEZS Received: 17-05-2018 Accepted: 20-06-2018 A Ghosh Department of Agricultural Meteorology and Physics, Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India M Bhattacharyya Department of Agricultural Entomology, Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India Correspondence A Ghosh Department of Agricultural Meteorology and Physics, Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India Impact of agroclimatic factors on pest population of summer brinjal A Ghosh and M Bhattacharyya Abstract One field experiment was to study the population dynamics of jassids and white fly in brinjal in relation to the prevailing weather conditions conducted at Regional Research Station, New Alluvial Zone, Nadia, West Bengal, India in the year 2017 during last week of March to last week of June. Numbers of jassids and white fly per leaf varied from 6.9 to 4.1 and 2.7 to 6.0 respectively. Results showed that jassid population was negatively correlated with the maximum air temperature (-0.44) and positively correlated with the minimum air temperature (0.27). On the other hand maximum air temperature showed positive association with whitefly population (0.14) while minimum air temperature (-0.10) had adverse effect on the numbers of white fly per leaf. Best-fit regression equations indicated that each weather factor exhibited polynomial relationship with the numbers of insect. Keywords: Brinjal, correlation, jassid, weather parameters, white fly 1. Introduction Brinjal (Solanum melongena) is one of the important vegetable crops grown in India [3] . In India, the crop is cultivated in 0.47 M ha area with 7.67 MT production and an average productivity of 16.30 MT/ ha [9] . Production of this crop was adversely affected by pest incidence. A large number of sucking insect may attack this crop [4] . White fly (Bemisia tabaci Gennadius) and jassid (Amrasca biguttula biguttula) are important insect pests of summer brinjal. Brinjal crop is very much susceptible to damage by jassids. Optimum temperature range for development of white fly is 20 ˚C to 30 °C [13] . Life cycle of jassids is greatly influenced by temperature [1] . Jassid population are greatly hampered by several weather parameters. Earlier experimental results showed that jassid and white fly population in summer brinjal were at the peak level during the month of April and May respectively [6] . Crop in its vegetative phase is more vulnerable to damage by sucking insects because of the succulent nature of the plant due to the abundance of chlorophyll [10] . Temperature and relative humidity have direct and linear relationship with jassid population. The optimum ranges of temperature, relative humidity and vapour pressure deficit for jassid population were 32.0 to 34.0 °C, 81-92 per cent and 1.0 to 6.0 mm of Hg, respectively [11] . This study was carried out to find the population dynamics of jassid and white fly in summer sown brinjal in relation to the prevailing agro-climatic condition. 2. Materials and methods 2.1 Details of the experiment: One field experiment was conducted at Regional Research Station, New Alluvial Zone, Nadia, West Bengal, India in the year 2017 during last week of March to last week of June to study the population dynamics of jassids and white fly in brinjal. The crop was transplanted on 9 th March. Name of the variety was Muktakeshi. Numbers of jassids and white fly were counted every day and average numbers of jassids and white fly per leaf were calculated. 2.2 Agroclimatic factors: Mean and accumulated weather parameters viz. mean maximum (T max) and minimum (T min) air temperatures, total rainfall (R), mean evaporation (E), mean morning relative humidity (RH I) and afternoon relative humidity (RH II), mean morning vapour pressure (VP I) and afternoon vapour pressure (VP II) for each SMW (Standard Meteorological Week) were recorded from the principal agro meteorological observatory. 2.3 Statistical analysis: Correlation analysis was carried out between insect numbers per leaf