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小蠹总科Scolytoidea的害虫一般身体较小,种、属特征很容易混淆。在实践中,我们发现用它们整齐而规律性极明显的为害状来区别种类,往往迅速而准确。许多小蠹种类的为害状各具特点,肉眼观察方便,在鉴定时,如果把成虫标本和为害状标本结合起来,就会收到更好的效果,在林间调查中尤为适用。 这里把西北地区常见主要小蠹虫种为害状图解如下,供参考。 脐腹小蠹Scolytus schevyrevi Sem。为害白榆、旱柳的衰弱枝干,形成单纵坑道。母坑长约5—6厘米,子坑密集,有的交叉,在木质部坑迹明显,色灰白(图1)o 黄须球小蠹Sphaerotrypes coimbaterensis Stebb.为害核桃、枫杨。成虫在越冬前的补充营养期蛀食健康活立木的一年生枝顶芽下部,蛀孔圆形,直径约0.2厘米;顶芽因之而枯死。翌春,成虫蛀入衰弱枝干,在树皮下为害,形成单纵坑道。母坑长约0.3—0.4厘米,子坑排列紧凑,整个坑道(包括母坑、子坑、蛹室)均在木质部表面有明显而整齐的迹印,呈灰白色(图2)。 铁杉球小蠹Sphaerotrypes isugae Tsiai et Yin为害铁杉倒木的中下部。寄居皮下,成单纵坑道。母坑
Bumblebee Scolytoidea common pests generally smaller, species, is a very confusing character. In practice, we found that it is often quick and accurate to distinguish species by their regular and neat regularity. Many pest beetles have their own peculiarities of pest damage and are easy to be observed with the naked eye. In the identification, if the adult specimen and the pest specimen are combined, the better effect will be obtained, which is especially suitable for the forest survey. Here to Northwest common bark beetle pests like the following diagram for reference. Scolytus schevyrevi Sem. Damage elm, the weak branch of the willow, the formation of single vertical tunnel. The mother pit is about 5-6 cm in length with dense sub-pits and some crosses. The pit-pits are obvious in the xylem with grayish gray (Figure 1) o Sphaerotrypes coimbaterensis Stebb. Adults in the winter before the nutritional supplement period eaten healthy live standing branch of the annual branches below the bud, bore holes round, about 0.2 cm in diameter; the top bud thus died. The next spring, adult worms into the weak branches, under the bark damage, the formation of single vertical tunnel. The pit is about 0.3-0.4 cm in length and has a compact sub-pit arrangement. The entire tunnel (including the pit, pit and pupa chamber) has a clear and neat trace on the surface of the xylem, with an off-white color (Figure 2). Sphaerotrypes isugae Tsiai et Yin Damage to the middle and lower parts of the fallen hemlock. Habitat subcutaneous, into a single vertical tunnel. Mother pit