Analysing Climate-driven Shifts in Pest Phenology and Crop Damage in Jamun
S. Suganya Kanna *
Department of Fruit Science, Horticultural College and Research Institute (TNAU), Periyakulam, Tamil Nadu, India.
C. Vijayaraghavan
Cotton Research Station (TNAU), Srivilliputhur, Tamil Nadu, India.
Ga. Dheebakaran
Department of Agro climatic Research Center (TNAU), Coimbatore, Tamil Nadu, India.
S Saraswathy
Department of Fruit Science, Horticultural College and Research Institute (TNAU), Periyakulam, Tamil Nadu, India.
*Author to whom correspondence should be addressed.
Abstract
Jamun (Syzygium cumini Skeels) is an underexploited indigenous fruit tree of India valued for its nutritional and medicinal properties. This study assessed the seasonal incidence of major insect pests and natural enemies of jamun and examined their associations with weather parameters in Periyakulam and Andipatti blocks of Theni district, Tamil Nadu, during 2023–2024. A fixed-plot survey was conducted using ten randomly selected trees, with weekly monitoring of pest populations, damage, natural enemies, and weather variables obtained from an Automatic Weather Station. Correlation and regression analyses were performed using DSAASTAT. At Periyakulam, whiteflies, fruit flies, and gall insects showed positive associations with average temperature, whereas several pest groups showed negative associations with rainfall, relative humidity, or wind speed. At Andipatti, leaf miner incidence was positively associated with relative humidity and negatively associated with average temperature, rainfall, and wind speed. Leaf twisting weevil, helmet caterpillar, gall insect, whitefly, and fruit fly incidences were positively associated with average temperature. Fruit fly incidence was greatest during periods of high rainfall and humidity. The observed differences between the two locations indicate that weather–pest relationships varied among pest taxa and sites. The findings provide baseline information on seasonal pest occurrence, crop damage, natural-enemy activity, and weather associations in jamun-growing areas of Tamil Nadu.
Keywords: Jamun, Syzygium cumini, insect pests, pest phenology, seasonal incidence, crop damage, weather parameters, temperature, rainfall, relative humidity, whiteflies, natural enemies