Species and Population Dynamics of Main Pests at Perennial Rice Field

Purpose To identify species of main pests at perennial rice field, analyze its population dynamics and occurrence, to provide a scientific basis for pest control at perennial rice field.

Method With the sweep sampling, plate beating and visual inspection, the five points sampling method was used to record the number of insect species, roll leaves, white panicle and dead heart seedlings at perennial and conventional rice field. Quartile method was used to analyze the case of main insects occurrence.

Result 17 species of pests were collected at perennial rice field (the 1^st season) and conventional rice field, the main pests were rice planthopper, Chilo suppressalis, Tryporyza incertulas and Cnaphalocrais medinalis; 13 species of pests were collected at perennial rice field (the 2^nd season), the main pests were rice planthopper and C. medinalis, 12 species of pests were collected at conventional rice field, the main pests were rice planthopper, C. suppressalis, T. incertulas and C. medinalis. The trend of the main pest population dynamics in the perennial rice fields and the conventional rice field was basically the same. At perennial rice field, the main season of rice planthopper was from tillering stage to booting stage at the 1^st season and from jointing stage to flowering stage at the 2^nd season, the population of planthopper in perennial rice (season second) was higher than the 1^st season, and the population of planthopper in perennial rice (season 1^st and 2^nd) were higher than conventional rice. The main occurrence period of C. medinalis is from heading stage to milk ripening period whether it’s the perennial or conventional rice. In the 1^st season of perennial rice, the difference of the damage by C. medinalis between the perennial and conventional rice was not significant. The damage at the 2^nd season were significantly higher than the 1^st season and the conventional rice.

Conclusion The species of main pests and their main season at perennial rice were the same as conventional rice, but the damage by main pests at the second season were higher.