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鉴江平原地区包括信宜、高州、化州、吴川、茂名四县一市及电白、廉江两县部分公社的范围.水田面积约240万亩.是人口稠密、耕作复杂,复种指数较高的地区.1964～1975年基本稳定在两稻一冬种的三熟制,1976年起开展以调整作物布局和调节植期为主要内容的耕作制度改革,把原来的早稻、晚稻、冬薯(或冬麦),改为早稻、中稻、秋薯(或秋麦、秋花生),获得了粮食大幅度的增产.水稻三化螟在鉴江平原每年发生五个世代,温度较高的1973年及1975年发生六个世代.在改制前实行“抓一防二,抓三防四”的治螟策略,即抓秧田治螟压大田螟害,是普遍成功的,但改制后,这种情况有所变动.一、改制后三化螟发生特点及其变动水稻栽培制度影响着螟虫生存和繁殖,引起螟虫的发生基数和生活环境条件的改变.1976年起进行调整作物布局和调节植期的耕作制改革,新、旧耕作制并存,植期的提早,品种的复杂化,秧苗自2月至8月中旬连续不断种植,稻田经常都有一定面积的分蘖期及孕穗期禾苗存在,极利于蚁螟的侵入为害,客观上构成三化螟集散的桥梁田,使三化螟在年中的为害有所改变.在目前混栽情况下,有利于螟虫的生存、繁殖及扩散与旧耕作制比较,三化螟的发生有五个新变化、新特点:
The Jianghu plain includes the areas of Xinyi, Gaozhou, Huazhou, Wuchuan and Maoming counties and one municipality and some communes in Dianbai and Lianjiang counties, with a paddy field area of about 2.4 million mu, which is densely populated, with tillage and complex cropping index High areas .1964 ~ 1975 basically stable in the two rice and a winter-type three cooked system, in 1976 to carry out to adjust the layout of crops and adjust the planting as the main content of farming system reform, the original early rice, late rice, winter potato (Or winter wheat), replaced by early rice, middle rice, autumn potato (or autumn wheat, autumn peanut), access to a substantial increase in grain production. Rice borer in Jianjiang plain occurs five generations each year, the higher the temperature in 1973 And took place in six generations in 1975. The implementation of the strategy of “controlling one against two and grasping three against four” before the system reform, that is, grasping the seedling for the control of rice stem borer, is generally successful. However, after the reform, This situation has changed.First, the characteristics and the changes of the stem borer after the restructuring Rice cultivation system affects the survival and reproduction of stem borers, causing the occurrence of stem borer base and living environment conditions change.From 1976 onwards to adjust the layout and adjustment of crops The farming system reform at the planting stage and the coexistence of new and old farming systems, The earlier period and the more complex varieties, the seedlings are continuously planted from February to mid-August. The paddy field often has a certain area of tillering stage and seedling stage at the booting stage, which is very conducive to the invasion of the rice stem borer, Distributed bridge fields, so that the borer in the mid-year damage has changed in the current mixed planting situation, is conducive to the survival, reproduction and proliferation of stem borer and old farming system, the occurrence of three borer occurred in five new changes New features: