Abstract:

The population dynamics of Chlorops oryzae and its relationship to rice yield loss in rice fields of mountain and semi-mountain areas in 2000-2004 in Zhejiang province, East China were systematically studied, and the life table of field populations of this pest was constructed. The results showed that the mortalities of egg, larva, pupa and adult of this pest in fields were 42.7%, 14.5%, 4.4% and 12.6% for the first generation, and 32.8%, 16.5%, 18.9% and 15.6% for the second generation, respectively. The incidences of injured plants and yield loss were positively related to egg (larva) density in both seedling and after transplanting periods. The time from adult emerging peak to egg hatching peak was proposed as the optimal control period. The control thresholds were determined as 10 eggs per 100 rice plants or 1% injured plants in seedling bed, while 1 egg per hill or 3%-5% injured plants in the paddy after transplanting.

Key words: Rice, Chlorops oryzae, population dynamics, damage and yield loss, action threshold.