摘要
用自然感虫与人工控制虫量的方法 ,研究棉铃虫三代和四代的虫口密度与棉花产量之间的关系。结果表明 ,棉花对于三代棉铃虫为害的补偿能力比四代的强。根据田间小区试验结果得出百株虫量与产量损失的关系为 ,Y三代 =1 .0 + 1 .379lnx± 2 .4;Y四代 =- 7.91 0 + 3.855lnx± 1 .92 ,按照防治的直接收益与直接成本 ,确定了本省的不同产量水平下棉铃虫的经济阈值 ,即三代为百株幼虫6～ 1 0条 ,或百株累计卵量 36～ 60粒 ;四代为百株幼虫 1 7～ 2 0条 ,或百株累计卵量 60～ 96粒。
Field tests on the damage and economic threshold of cotton bollworm ( Helicoverpa amigera Hbn) to cotton were carried out at Changde,Hunan province in 1995～1997. The field survey included following aspects:the injuries due to different generations of the bollworm and the population densities of each and the compensative ability of cotton plants.The results showed that there were enough time for the cotton to copmensate its loss of squares caused by the third genreation infestations,but that time is shorter caused by the fourth generation infestation,because the latest useful period for flowering of cotton plants is 20th September in Hunan province almost every year. According to the relationship between the population density of the third or the fourth generation cotton bollworm and the lint yield loss of cotton,the expression of lint loss(Y), and the number of the larvae per 100 plants(x),were given as:Y 3=1.0+1.379ln x±2.4,Y 4= 7.910+3.855ln x 1.92.Based on the direct benefit and cost,the economic threshold of the third and the fourth generation cotton bollworms at various yield levels are as follows: the third generation:6～10 larvae per 100 plants or the accumulative of eggs 36～60 per 100 plants;the fourth generation:17～20 larvae per 100 plants or the accumulative of eggs 60～96 per 100 plants.
出处
《棉花学报》
CSCD
北大核心
2000年第4期202-204,207,共4页
Cotton Science
基金
湖南省科委"九五"应急攻关项目! ( 95-0 1 -0 1 )
关键词
棉铃虫
棉花
产量损失
经济阈值
Hunan province
Helicoverpa armigera
Gossypium hirsutum
economic threshold
yield loss
cotton
