Abstract

Forewarn studies were undertaken on the weather based relationship of sorghum shoot fly, Atherigona soccata during rabi 2011–12 and 2012–13 at the Main Agricultural Research Station, Dharwad in early, normal and late sown conditions. Resistant variety M-35-1 was selected and attempt was made to determine the relationship of egg load with weather factors. Seasonal incidence of shoot fly eggs per plant in case of M-35-1 was noticed from 44th standard week, it attained maximum level (1.95±0.37) eggs per plant during 46th standard week. Maximum per cent deadheart (31.75±1.03) was noticed in late planting in M-35-1 followed by normal and least in early sown crop. The analysis comprised correlations between the deadheart with prevailing weekly meteorological parameters during 1, 2, 3 and 4 weeks lead time (prior) and same week of the observations. Results indicated that increase in 1 day rainfall would lead to decrease mean number of shoot fly eggs per plant in early own crop. Forecast models for M-35-1 in all the aforesaid correlated weeks, evening RH (4 weeks before) was consistently significant and negative association with deadhearts with 64.40% in early sown crop. However, in M-35-1, per cent deadheart could be forewarned to the extent of 71.60% accuracy as minimum temperature was highly significant and positively correlated in late sown crop. No significant influence was observed in normal sown crop.