桔盾蚧初龄若虫活动行为的研究(英文)

Studies on Crawler Behavior of Citrus Snow Scale

1989年在美国佛州柑桔研究教育中心开展了桔盾蚧初龄若虫活动行为的研究。试验结果表明;光照强度在初龄若虫爬行定向上起重要作用。在人工光照条件下(光强<1.5×10~2lx),初龄若虫明显趋光,而在自然光下(光强>2.8×10~4lx),初龄若虫即避光,在试验果实向阳部分的初龄若虫的定着率随光强的增加而下降,其线性回归式为:y=56.40-4.63x,得出50％爬虫避光的阈值为1.38×10~4lx。重力对初龄若虫在枝条上的分布范围有影响,但对定着率无显著影响。田间初龄若虫活动时间的观察结果显示:在晴朗天气条件下活动高峰期出现在午间12点钟左右,因而认为在傍午或午间喷施农药可能获得较高的防治效果。田间的日照强度与初龄若虫的活动数量明显相关,而温、湿度和树下光照则未见到有显著影响作用。桔盾蚧初龄若虫在叶片上的定着率显著低于枝条,叶面和叶背相比,叶背显著高于叶面,对枝条的不同部位,初龄若虫的定着嗜好没有差异。另外,雌雄初龄若虫在爬行轨道和爬行速度上有明显差异。以此可用于区分初龄若虫的性别。

Studies on crawler behavior of citrus snow scale were carried out at the Citrus Research and Education Center, Lake Alfred, Florida, USA, in 1989. The results obtained showed that light intensity played an important role in the orientation of crawler wandering, of citrus show scale. Under conditions of artificial light (L. I. <1.5X102lx), the crawlers were definitely positive to light, whereas in case of sunlight (L. I. >2. 8X 104lx), the percentage of crawlers found on the light side of the fruit decreased as the light intensity increased. Its linear regression equation was Y= 56. 40- 4. 63X and the light threshold for 50% crawlers repelling was 1. 38X 104lx. Gravity appeared to have influence on the distribution range of the crawlers, but no significant effect occurred on their settlement rates, The observation on crawlers' active time in groves revealed that the peak of crawlers' activity occurred around 12 o' clock on fine days conditions. It is suggested that chemical spray might be made in late morning or at noon to achieve optimum control. The sunlight intensity in groves bore good correlationships with the number of acting crawlers, while temperature, relative humidity and the light intensity under the tree canopy were poorly correlated to it. Citrus snow scale crawlers settled significantly more often on the back梥ide than upper梥ide of leaves. The percentage of settlement on leaf was significantly lower than that on shoot, There was no significant difference occurred among settling rate of different parts of a shoot. The walking track and speed between male and female crawlers were obviously different, which might be helpful for the distinguishment of crawlers' sex.