M.L. Chatterjee

Seasonal influence on cotton mealybug (Phenacoccus solenopsis Tinsley, Hemiptera: Pseudococcidae) population and correlation with weather parameters in alluvial zone, West Bengal, India

The impact of weather parameters on population fluctuation of cotton mealybug, Phenacoccus solenopsis Tinsley was evaluated for monitoring the seasonal and annual trend of 2010–11 and 2011–12 at Institutional Research Farm of Bidhan Chandra Krishi Viswavidyalaya, Kalyani, Nadia, West Bengal, India. The mealybug population was found to be increasing during 11th and 9th weeks in 2011 and 2012, respectively, after sowing of cotton i. e. the 8th and 6th standard weeks during respective years. The peak population 81.37 per 10 cm upper shoot was recorded during 14th standard week in 2011 and 127.44 during 16th standard week in 2012. Correlation studies revealed that population of mealybugs exhibited a significant positive correlation (r=0.733 and r=0.780) with minimum temperature, but significant negative correlation with relative humidity (r=0.646 and r=0.689) and rainfall (r=0.566 and r=0.523) during 2011 and 2012, respectively.

Melon fruit fly (Bactrocera cucurbitae Coq.) infestation and management on bottle gourd in West Bengal, India

Seasonal trends in infestation level of Bactrocera cucurbitae were analyzed to determine the factors that influence the infestation by melon fruit fly in the field and adoption of suitable insecticidal management on bottle gourd. The experiment was conducted during pre-kharif and kharif seasons in 2012 and 2013. Percentage of infestation was recorded on the basis of infested and total fruits. The highest fruit infestation i. e. 56.56 and 49% was recorded during 25th (17th June) and 24th (9th June) standard weeks during respective years. The correlation coefficient between per cent infestation by melon fly with weather parameters exhibited a significant positive correlation with maximum temperature and negative correlation with RH-I and RH-II. In case of management chlorphenapyr, acephate, spinosad and deltamethrin were most effective bio-rational insecticide for managing melon fly and provided higher yield.