Population Dynamics and Forecasting of Cotton Pink Boll Worm (Pectinophora Gossypiella, (Saundars) Lepidoptera: Gelechiidae) in Punjab, Pakistan

Abstract

C otton (Gossypium hirsutum L.) is the most important crop of Pakistan. It contributed 1% share in GDP of Pakistan and 5.2% in the agriculture value addition with and annual production of 10.671 million bales in 2016-17 (Zalucki andFurlong, 2005). Cotton crop is attacked by a hundred of insect pests Abstract | Pink boll worm (Pectinophora gossypiella, S. Lepidoptera: Gelechiidae) is one of the most destructive pests of cotton. Observations were recorded about pest infestation. Metrological data was collected of each district's head quarter on daily basis for the year 2017. For accumulation of degree days model, Huber's method was adopted and data for calculation of generations by accumulating progressive degree days was observed highly significant i.e., P>0.0001. In the present study, the accumulation of degree days for its forecasting was calculated from 1st January by using the metrological data and base line temperature and found 7 generations of pink boll worm to be found in all districts. Data for moths trapped in sex pheromone traps was noted as highly significant i.e., P>0.0001. Peaks of moth catches in 14 districts were observed in the month of September to October while for pest survey P= 2 X 10-16 were highly significant meaning that all variables had significant result in response to ETL. The results by pest survey of pink boll worms in cotton fields depicted that the spots above economic threshold level (AETL) was varying between 0.4% in districts viz., D G Khan and Rajanpur to a maximum of 5.0% in district Vehari. Below economic threshold level (BETL) was varying between 0.4% in districts D G Khan and Rajanpur to a maximum infestation found in district Vehari at 23.1%. The population peaks indicate the overlapping seven generations of pink boll worm out of which 5 active generations were in cotton season giving the thresh hold time of start of emergence of 1 st generation and its 50% emergence.