应用参数和辅助剂对昆虫病原线虫Steinernema carpocapsae All品系于小白菜叶面存活和黏附数量的影响

测定了叶面应用参数(喷雾压力、高度、线虫悬浮液浓度、线虫悬液量、温度和湿度)以及辅助剂对昆虫病原线虫S．carpocapsaeAll于小白菜叶面的存活率和叶面黏附数量的影响。结果显示：(1)喷雾压力对线虫于叶面的黏附数量有负影响；(2)线虫悬浮液浓度高于2000IJs／mL时，随着线虫浓度的增加，叶面上黏附的线虫数量也明显提高；(3)喷洒的线虫悬液量越多(从3．3mL到19．8mL)，叶面上黏附的线虫数量也就越多(从10．1IJs／cm^2到45．5IJs／cm^2)，但是当线虫悬液量超出19．8mL时，叶面上黏附的线虫数量不再提高；(4)感染期线虫在叶面存活率随着暴露时间的增长而下降；(6)加入黄原胶和表面活性剂可以提高线虫在叶面的存活率和黏附数量，其中加入0．3％黄原胶的线虫悬浮液在叶面存活的线虫数量是清水对照的150倍。线虫喷洒叶面停留24小时后，2％甘油的线虫悬浮液的线虫在叶面上的存活率大约是清水对照液的62倍，叶面上存活线虫数量也是清水对照液的53倍。

EFFECTS OF APPLICATION PARAMETERS AND ADJUVANTS ON THE FOLIAR SURVIVAL AND PERSISTENCE OFENTOMOPATHOGENIC NEMATODE STEINERNEMACA RPOCAPSAE ALL STRAIN ON CABBAGES

Effects of the critical parameters (spray pressure, the distance between a sprayer and the sprayed plant, the concentration of infective juveniles (IJs), volumes of the sprayed suspension of IJs, the temperature and humidity combinations) and the addition of various adjuvants on the survival and persistence of entomopathogenic nematode Steinernema carpocapsae All strain on leaf surfaces of the Chinese cabbage Brassica pekingensis were determined. The results showed that (1) The pressure of a sprayer had negative influence on the persistence of IJs on the leaf. (2) The numbers of the living IJs collected on the leaf significantly increased with the IJ dosages applied on the leaf when the dosage was over 2 000 IJs per mL. (3) More IJs (from 10.1 IJs/cm2 to 45.5 IJs/cm2) were collected on the leaf when more volumes of IJ suspension (from 3.3 mL to 19.8 mL) were sprayed. However, when the highest volume of IJ suspension was used, the IJ numbers collected did not increase. (4) In general, the survival of the IJs on the leaf decreased with the exposure time. (5) The formulation of IJs by adding xanthan gum, a sticker and detergent surfactant enhanced the survival and persistence of IJs. The number of living IJs on the leaf with 0.3 % of xanthan gum was 150 times higher than that of the IJs with water alone. IJ suspensions with different concentrations of glycerin and with 0.5 % molasses and 0.01 % detergent surfactant showed similar effects.