Weather factors influencing population dynamics of major insect pests of Brinjal in Mandsaur district of Madhya Pradesh

The field experiment was conducted at K.N.K, College of Horticulture, Mandsaur (M.P.) to study the population dynamics of aphid, jassid and lady bird beetle in 2022-23 and 2023-24. Aphid population started in 40th SMW in 2022-23 (0.43 aphids/leaf) and 41st SMW in 2023-24 (1.08 aphids/leaf) and it peaked in 2022-23 and 2023-24 (10.2 and 22.37aphids/leaf) during 2nd and 4th SMW, respectively. Jassid population was recorded on brinjal during 2022-23 & 2023-24, with 0.05 and 0.34 jassid per leaf on 41st SMWs, respectively. Maximum population of jassid noted during 2022-23 (3.06 jassid/leaf) at 51st SMW and in 2023-24 (3.23 jassid/leaf) on 1st SMW. Lady bird beetles appeared 46th and 48th SMW with initial populations of 0.04 and 0.05 per plant, peaked at 0.68 and 1.07 per plant in 3rd & 4th SMW in 2022-23 and 2023-24 respectively. Highly significant negative association was observed between aphid and maximum and minimum temperature (r = -0.774 &-0.775) in both years of study. Morning relative humidity (r = 0.483**) and evening relative humidity (r = 0.432**) showed positive and significant relation in 2022-23 while, in 2023-24 evening relative humidity (r= 0.422**) obtained a significant positive correlation. In 2022-23 a negative and highly significant correlation was found between maximum and minimum temperature and the jassid population (r= -0.716, -0.651). The association of pest population was positive and significant with morning relative humidity (r= 0.427**) and evening relative humidity (r= 0.515**). In the year 2023-24 the association of pest population had a significant and positive association with evening relative humidity (r= 0.387**). Minimum and maximum temperature exhibited highly significant negative association with Coccinellids population. The interaction between aphids and Coccinellids was found to be very strong. Aphids and their predator Coccinellids showed a positive and highly significant association in 2022–2023 (r=0.78) and 2023–2024 (r=0.50).