Population dynamics of safflower aphid, Uroleucon compositae (Theobald) as influenced by weather parameters

摘要

Field experiments were conducted during two consecutive rabi seasons of 2007-08 and 2008-09 at All India Co-ordinated Research Project on Safflower, Zonal Agricultural Research Station, Solapur, M. S. (India) with treatment comprising two varieties and the influencing abiotic factors viz., average minimum and maximum ambient temperature, relative humidity and rainfall. The results revealed that the safflower aphid (Uroleucon compositae Theob.) was active during 47th to 1st SMW on elongation and branching stages of safflower crop, but its appearance on crop totally depends upon prevailing climatic conditions. Low temperature and high humidity were conducive for the multiplication of this pest. Accordingly, aphid population attained a peak of 147.5 aphids/5 cm twig/plant in the 52nd SMW when the mean minimum and maximum temperatures, morning and evening relative humidity were 31.6°, 11.4°C, 71 and 28%, respectively. Thus, for the effective and efficient control of safflower aphid and producing higher seed yields, two sprayings of recommended 0.005% thiamethxam 25 WG or 0.004% acetamiprid 20 SP at ETL i. e. 40-45 DAS (46th to 47th SMW, min. temp, below 20°C) and second spray at 55-60 DAS (48th to 49th SMW, min. temp, around 15°C) are recommendedparticularly in the safflower growing scarcity zone of Maharashtra (India).