Abstract

Detailed field studies conducted on greengram at Agricultural College and Research Institute, Killikulam, Tamil Nadu in the year 1995-96, to workout simple correlations between important weather factors and damage level of major pests of greengram, showed that in the kharif 1995, significant positive correlation was found on the incidence of galerucid beetle, Madurasia obscurella (Jacoby), with relative humidity. The thrips, Megalurothrips distalis (Karny) population was positively influenced by sunshine and rainfall was positively correlated with podborers damage and the correlation coefficient values (r) of the above are 0.663, 0.293 and 0.418 respectively. The other factors like maximum and minimum temperature, wind velocity exhibited negative correlation. The incidence of stemfly. Ophiomyia phaseoli (Tryon) was positively correlated (r=0.900) with wind velocity, while leaf hopper, Empoasca kerri (Pruthi) showed positive trend with maximum temperature (r=0.592) and negative with relative humidity (r=0.343) in the rabi 1995, while other weather factors were found negatively correlated with their incidence.

Keywords: Greengram, stemfly, galerucid beetle, leafhopper, flower thrips and podborers weather relationship