Increasing abundanace of rice blackbug Scotinophora lurida (Burmeister) in relation to climatic variability during kharif at Aduthurai (Tamil Nadu)

Abstract

Rice black bug Scotinophara lurida (Burmeister) (Podopidae: Hemiptera) is an emerging insect pest on rice in Cauvery Delta region of Tamil Nadu and their abundance in light trap is a measure of their activity. S. lurida monitored using light trap at Aduthurai (Tamil Nadu) during kharif of 2013-2016 indicated their mean and peak populations (nos/trap/week) as 119, 3822, 1243 and 414 and 800, 60083, 23808 and 6564 in respect of 2013, 2014, 2015 and 2016. While onset of population in 2014 and 2015 was during July 1st week, 2013 had onset in July IInd week. Peak emergence varied between 30 and 34 standard meteorological weeks (July III to August IIIrd weeks). The peak abundance of S. lurida was higher whenever pre-kharif abundance was high. Aestivation coincided with second fortnight of June during 2014 and 2015 as against mid-June to first week of July and last week of June till mid-July during 2013 and 2016, respectively. Climatic variability in terms of reduced minimum temperature and increased rains on many rainy days during July-August had a profound effect on S. luridaabundance. Deployment of additional light traps during July and August followed by proper destruction of adult collections must be encouraged for their management. Long-term management strategies of black bugs should incorporate compulsory crop rotation with a pulse crop during summer with focus on off-season management of aestivating stages of black bugs in rice stubbles and along field bunds.