Influence of weather factors on population dynamics of major insect pests in moringa (Moringa oleifera Lam.) in south Tamil Nadu

Abstract

The field experiments were conducted to study the relationship of major moringa pests infesting buds (budworm), flowers(ants) and pods (podfly) with weather factors (maximum and minimum temperature and relative humidity and rainfall) during the rabi-summer and kharif seasons of 2021 and 2022 in Dindigul district, Tamil Nadu. The pest population data indicated that the infestations were found to vary with the seasons as well as years. The correlation with weather parameters revealed that the budworm infestation was significant and positively correlated with maximum temperature (r= 0.459***) and negatively correlated with morning relative humidity (r= -0.277*), evening relative humidity (r= -0.584***) and rainfall (r= -0.459***).  While in infestation by ants, it was positively correlated with the maximum temperature (r=0.42**) and minimum temperature (r= -0.296*), relative humidity (evening) (r= -0.649***) and negatively correlated with rainfall (r= -0.382**). The moringa pod fly infestation had a strong significant positive correlation with relative humidity (evening) (r= 0.7***) and rainfall (r= 0.517***) and a negative correlation (r= -0.518***) with maximum temperature. The stepwise linear regression showed that all the weather factors collectively influenced the budworm infestation by up to 60.7 %, ants infestation by 50.5 % and up to 60.7 % in podfly infestation.