Indian Journal of Plant Protection

Pectinophora gossypiella (Saunders) moth catch-weather relations were established based on eleven years’ data (1985 to 1995) recorded at Nagpur of Maharashtra under rainfed cotton growing zone of Indian subcontinent to aid in population predictions. Aggregate and mean models predicting the moth catches were developed through step down regression analyses. Qualitative approach of evolving criteria by comparing moth catches and weather factors of normal and epidemic years together, besides curve fitting of current moth catch abundance alongside of epidemic year were tested. While, quantitative models indicated negative influence of evening relative humidity of previous two weeks on the P. gossypiella, the criteria of maximum temperature greater than 34^oC during 40^th standard week, minimum temperature less than 17^oC in 44^th standard week, evening and morning relative humidity less than 33 and 70% in respect of 44 and 46 standard weeks, and dry spell followed by rains coinciding with 41 and 42 standard weeks predicted the severity of P. gossypiella. Validations of prediction approaches over four years (2001 to 2004) revealed over as well as under estimations of the quantitative models.