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我国已知隶于切根属和地虎属的地老虎达17种以上,其中发生面积最大,为害最严重的主要是小地老虎和黄地老虎。这两种地老虎每年在不同地方都造成一定损害,需耍进行防治。防治地老虎能否掌握住施药适期,失决条件是准确的虫情测报。要想测报准确,在进行虫情调查时,就必须正确识别幼虫龄期。区别地老虎幼虫龄期的办法很多,但在田间应用起来都很困难。田间调查往往要求在短时间内调查较多的虫子,这就更需要有一种简易的区别龄期办法,“地老虎幼虫各龄体长示意图”(图1)就是针对这个实际问题绘制的。 示意图绘制了小地老虎和黄地老虎幼虫一到六龄(二者基本均为六龄,仅少数有五龄或七龄),各龄蜷曲图、各龄平均最短(实线部分)和最长(实线加虚线)体长,在体长的下面注明了相应的最短最长数据。其所以要绘制蜷曲图,原因在于在田间进行调查时,捉住了幼虫,它总是蜷成一团呈假死状,耍经过1、2分钟才开始爬行。如果再触动它,它又会蜷曲起来,所以在田
In our country, there are more than 17 species of ground tiger belonging to the genus Geotrichum and the genus Gecko, of which the area is the largest and the most serious are the small tigers and the yellow tigers. These two kinds of tigers each year cause some damage in different places and need to be controlled. Prevention and control of the tiger can take the drug application period, the conditions of the loss is accurate insect detection. To accurately measure the newspaper, during the investigation of insects, we must correctly identify the larval age. There are many ways to differentiate tiger larvae, but they are difficult to apply in the field. Field surveys often require that more worms be investigated in a short period of time. This calls for a more simple method of differentiation of ages. The “length of each larvae of a tiger larvae” (Figure 1) is drawn up for this practical issue. Schematic drawing of small tiger and yellow tiger larvae one to six years old (both basic six-year-old, only a few fifth or seventh age), curled at all ages, the average age of the shortest (solid line) and the most Long (solid plus dashed line) body length, below the body length indicate the corresponding shortest and longest data. The reason for this is that the curled figure is drawn because in the field the investigation landed the larvae and they always curled up into mortises and did not begin to crawl after 1 or 2 minutes. If you touch it again, it curls up again, so in the field