Intercropping of Rice Varieties Reduces Green Leafhopper and White Stem Borer Infestation

A system of crop management by intercropping of diverse rice varieties in the field provides an effective way to control rice disease, but its effectiveness to control rice pest insects is not well known. Our research evaluated the impact of four rice varieties planted by strip intercropping on populations of green leaf hopper Nephotettix virescens and incidence of rice white stem borer Scirpophaga innotata in Sulawesi, Indonesia. The average number of green leafhopper insects caught by five consecutive passes with a sweep net on Pulut putih, Lapang, Fatmawati, Ciliwung varieties planted by monoculture, between 30 and 58 days after planting in a Sidrap plantation was respectively 0.6 - 4.3, 1.0 - 6.0, 1.7 - 6.7 and 2.3 - 6.0 adults, while in rice grown in strip intercropping the catch was respectively 0.7 - 2.5, 0.4 - 2.7, 0.5 - 2.6, and 1.4 - 3.5 adults. The average incidence of white stem borer observed between 30 and 65 days after planting on the same varieties in Sidrap planted by monoculture was respectively 1.8 - 9.7, 5 - 40%, 10.0 - 23.2, and 0.0 - 28.5% and in the strip intercropping was respectively 1.5 - 11.6%, 8.0 - 27.5%, 4.2 - 12.8%, and 2.0 - 7.2%. The average incidence of white stem borer in the Wajo plantation using monoculture was respectively 22.5 - 35.4%, 30.2 - 60.5%, 24.0 - 35.0%, and 17.5 - 28.5% and in the rice planted by strip intercropping was respectively 26.0 - 36.1%, 28.1 - 57.0%, 24.0 - 35.0%, and 15.0 - 23.2%. These data demonstrate that intercropping of rice varieties results in a reduction of rice pest infestation.