Vol. 12, Issue 6 (2023)

Author(s):
J Ramkumar, B Venudevan, S Arokiamary and P Arunkumar

Abstract:
The present experiment was conducted at ICAR-Krishi Vigyan Kendra, Aruppukottai during 2020-21. In fixed plot survey, the aphid damage was noticed from 42 to 51 standard weeks ranging from 1.6 to 16.0 percent. The percent dead heart damage was recorded from 43-49 standard weeks ranged between 0.8 – 9.6%. The mean no. of coccinellids and spiders per plant observed from 42-49 and 46-49 standard weeks respectively. The population of aphids was positively correlated with minimum temperature and negatively correlated with evening Relative humidity. Dead heart due to stem borer was positively correlated with rainfall (r=0.56). The population of coccinellid was negatively correlated with morning and evening RH and positively correlated with maximum temperature, minimum temperature and rainfall. Spider was positively correlated with rainfall (r=0.646). In Roving survey, the percent aphid damage and dead heart recorded at Mallangkinaru village was 15-20% and 7-13% respectively, whereas it was 12-17% and 8-10% at Tharumathupatti village and in Kovilankulam village it was >10% and 6-12%.