IMPACT OF ABIOTIC FACTORS ON INSECT PESTS AND NATURAL ENEMIES IN A RICE GERMPLASM

ABSTRACT

To evaluate the impact of weather parameters on insect pests and natural enemies in a rice germplasm, a field experiment was carried out in Zonal Agricultural and Horticultural Research Station, Navile, Shivamogga during Kharif 2023. The incidence of insect pests and natural enemies were observed in the field at fortnightly interval from 15 DAT to 105 DAT and correlated with weather parameters. The results revealed that highest incidence of green leafhopper and grass hopper was observed at 45 DAT, leaf folder and white leafhopper was peak at 60 DAT, gundhi bug incidence was maximum at 75 DAT and yellow stem borer incidence was highest at 90 DAT. Whereas, rove beetles were peak at 60 and 75 DAT, dragonfly, damselfly and coccinellids were peak at 75DAT and spiders were maximum at 90 DAT. Leaf folder, green leafhopper, white leafhopper, grasshopper were negatively correlated with T_max and positively correlated with T_min, RH-I, RH-II respectively. Yellow stem borer was significantly positively correlated with T_max and significantly negatively correlated with T_min, RH-I, RH-II. The natural enemies (predators) i.e., dragonfly, damselfly, spiders, coccinellids and rove beetles were positively correlated with T_max and negatively correlated with T_min. Similarly those are negatively correlated with RH-I and RH-II except rove beetles where those are positively correlated with RH-I and RH-II. All the insect pests and natural enemies were negatively correlated with Rainfall.

Keywords: insect pests; natural enemies; weather parameters; pest incidence; rice germplasm;