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对浙江省象山县山谷小平原直播稻区的稻水象甲种群动态和田间分布进行了系统调查。稻水象甲成虫在山坡地和直播稻田埂等越冬场所出蛰后取食杂草,并于5月初同期出现成虫高峰。这些成虫约7d后直接迁入直播稻田,形成直播稻田稻水象甲的迁入高峰。稻水象甲在直播稻田的取食、产卵和分布表现出明显的喜水习性。在同一丘直播稻田内,离田边越近,越冬代成虫和一代卵、幼虫、茧蛹的数量越大;在同一畦内,畦边多于畦中。稻水象甲在直播稻田完成一个世代约需50d,增殖倍数(一代成虫峰值/越冬代成虫峰值)为7.23,明显低于移栽稻田,主要原因是稻水象甲在直播稻上的产卵量较低。7月底一代成虫向山坡地和直播稻田埂等越夏越冬场所回迁。根据直播稻区稻水象甲种群动态和分布特点,提出了相应的虫情调查和测报防治建议。
A systematic investigation was carried out on the dynamics and field distribution of the rice water weevil in the direct seeding rice area of the Xiaoban Plain in Xiangshan County, Zhejiang Province. Weevil asiatica weeds feed on weeds in the winter pastures such as hillsides and direct seeding rice fields, and adult worms peak in early May. After about 7 days, these adults directly moved into direct-seeded rice fields to form the peak of in-stream rice water weevils. Rice water weevil fed on the direct-seeded rice fields, spawning and distribution showed obvious hi-water habits. Within the same mound direct-seeded rice field, the closer to Tianbian, the greater the number of overwintering generations of adults and eggs, larvae and cocoon pupal; in the same 畦, 畦 side more than 畦 in. Rice water weevil completed a generation about 50 days in direct-seeded rice fields, multiplication multiples (peak of adult generation / peak of adult overwintering) were 7.23, significantly lower than that of transplanted rice fields, mainly due to the oviposition of rice water weevil on direct seeding rice The amount is low. By the end of July, the first generation of adult migrated to the hillsides and live-in paddy fields and other over-wintering winter sites. According to the dynamic and distribution characteristics of rice water weevil in direct seeding rice area, the corresponding insect investigation and forecasting prevention and control recommendations were put forward.