Population and damage intensity of the yellow rice stem borer and its natural enemies in the jajar legowo rice planting system

Abstract

Jajar legowo (Jarwo) is a rice planting system that is widely practiced by farmers, but information regarding its effects on pests and natural enemies is limited. This study aimed to identify how the Jarwo planting system affects the population and damage intensity of the yellow rice stem borer (Scirpophaga incertulas) and its predators. The research was conducted in Wonosari-Klaten, Central Java, during the dry season of 2020. The Jarwo 2:1 planting system was used in this study. The variables of the research were population of S. incertulas, its damage intensity, and its natural enemies. Observations by field inspection were carried out every week from 14 to 94 days after transplanting (DAT). The results showed that the population of egg clusters and damage intensity of the rice stem borer in the Jarwo planting system were lower than in the conventional planting system (control plot). However, this planting system did not affect the kinds of predators and parasitoids. The predators found were generalists, which were dominated by spiders, namely Atypena sp. (Araneae), Araneus sp. (Araneae), Lycosa sp. (Araneae), Plexippus sp. (Araneae), and Oxyopes sp. (Araneae), Paederus sp. (Coleoptera) was recorded as predatory insects. Meanwhile, the main egg parasitoid found was Telenomus sp. (Hymenoptera) with 31.2% parasitization.