螟黄赤眼蜂在棉田的有效扩散距离及其影响因素的研究

1994～1995年，在山东禹城棉田进行了田间释放螟黄赤眼峰Trichogramma chilonis试验，结果表明：①螟黄赤眼峰的有效扩散距离与日照时数有关， 日照时间越长，有效扩 散距离越远；②螟黄赤眼蜂在棉田的群体有效扩散距离与放蜂期间的田间平均气温呈显著正相关， 田间气温较高时(>24℃)，螟黄赤眼蜂可扩散到25m以远；当田间平均气温较低时(<20.7℃)，使100%的蜂个体都仅仅分布在距放蜂点25m的范围内。6～8月份， 螟黄赤眼蜂在田间的有效扩散距离为10～25m；③降雨可严重抑制赤眼蜂的田间扩散；④湿度与螟黄赤眼蜂在棉田有效扩散距离呈显著负相关，当湿度太大时(相对湿度>89%)，使螟黄赤眼蜂聚集在放蜂点附近；⑤风速和风向不仅可影响螟黄赤眼蜂的田间有效扩散距离，而且也影响赤眼蜂的田间扩散方向。

INFLUENCE OF CERTAIN WEATHER FACTORS ON DISPERSAL DISTANCE OF TRICHOGRAMMA CHILONIS IN COTTON FIELD

Releasing experiments of the parasite, Trichogramma chilonis, for control of the cot ton bollworm Helicoverpa armigera were conducted in cotton fields in Yucheng, Shandong Province in 1994 and 1995. The results indicated that: the effective dispersal distance (EDD) of T. chilonis was positively related to both the length of sunshine and the average field temperature (AFT) duringthe releasing periods. When the temperature was higher than 24℃, most of the patasites dispersed beyond 25 m and when it was lower than 20.7℃, all of them distributed within 1-25 m. During June-August, their EDD varied from 10 m to 25 m. Rairffall severely influenced their EDD and parasitizing rate. EDD of the egg parasite showed a significant negative correlation with the field relative humudity (FRH), when FRH was above 89% their EDD became greatly shortened and most of them distributed near the releasing site.