File:The common red spider. (Tetranychus bimaculatus Harvey) (1909) (14742362646).jpg

Identifier: commonredspidert2104chit (find matches)
Title: The common red spider. (Tetranychus bimaculatus Harvey)
Year: 1909 (1900s)
Authors: Chittenden, F. H. (Frank Hurlbut), 1858-1929 United States. Bureau of Entomology United States. Dept. of Agriculture
Subjects: Agricultural pests Spider mites Tetranychus
Publisher: Washington, D.C. : U.S. Dept. of Agriculture, Bureau of Entomology
Contributing Library: U.S. Department of Agriculture, National Agricultural Library
Digitizing Sponsor: U.S. Department of Agriculture, National Agricultural Library

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is accomplished by leaf-feederssuch as caterpillars. Sometimes, however, very considerable defolia-tion is caused by the attack of this species. This was very noticeableduring the summeF of 1906, when the foliage of various shade treesin the city of Washington was injured. Attack was first observedduring the third week in July and was manifested by the leaves hav-ing turned yellow on the upper surface. The leaves on the lowerbranches showed the presence of numerous feeding colonies. TheKentucky coffee tree suffered most of all of our city trees. On oneof these trees the leaves continued to drop throughout the remainderof July and August, but by September, partly owing to an unpre-cedented rainfall of three weeks duration, the mites were less in evi- (Cir. 104) dence and many branches from which the leaves had fallen developednew clusters of fresh leaves. Two years later it was noticed that many of the lower brancheswhich had suffered most from defoliation by the red spider were dead,
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Fig. 2.—Kentucky coffee tree, showing partial defoliation by the red spider on lowerbranches; upper branches have put out new leaves. (Original.) without doubt owing to the attack of this insect. The accompanyingillustration (fig. 2) was taken after the hew leaves had become well (Cir. 104) developed. Two or three weeks before that time the lower half ofthe tree bore only a few leaves. This same form of injury was repeated in 1908, the tree lookingconsiderably worse than shown in figure 2. N ATURAL ENEMIES. The predaceous and parasitic insect enemies of the red spider, men-tioned below, were observed by the writer on the Kentucky coffeetree at Washington, D. C, during July and early August, 1906. Scymnus punctum Lee, a very small black ladybird, was observedJuly 21, chiefly as a nearly full-grown larva, and was the most activenatural enemy. At that time it was for the most part attached to theleaves for pupation, and a single pupa was found then and many afew days later. Nearly all

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