Development of forewarning models for shoot fly, Atherigona soccata Rondani and its validation based on abiotic factors in resistant variety M-35-1 in rabi sorghum

摘要

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 varietyM-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 perplant 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-35-1in 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.