Effect of some abiotic factors on population buildup of Idioscopus clypealis (Lethierry) in western Uttar Pradesh.

Idioscopus clypealis (Lethierry) is commonly known as mango leaf hopper. The hopper reduces mongo production by causing non setting of flower and dropping of immature fruits. The first appearance of hoppers (0.12 and 0.16) on the branches of mango trees was recorded in February which is correlated with increase in maximum (23.89 degrees C and 24.29 degrees C) and minimum temperature (11.46 degrees C and 11.88 degrees C) and decrease in relative humidity (88.15% and 86.85%). Peak hopper population (5.88 and 6.46) was recoded in May on temperature range of(40.34 degrees C and 40.88 degrees C) and (27.22 degrees C and 27.62 degrees C) as maximum and minimum, which was very high, whereas, relative humidity was very low (55.80% and 55.09%). With the increase in maximum and minimum temperature and decrease in relative humidity hopper population raised. Thus, maximum and minimum temperature positively affected the hopper population, whereas, relative humidity had negative effect, but rainfall showed no significant effect, as it was fluctuating.