58 



. The white scale {Hemichionaspis minor) has not often 

 occurred as a serious pest of cotton in the West Indies. 

 This is due to the fact that it is held in check by parasitic 

 insects. The parasites of the white scale are very minute, 

 almost miscroscopic in size, but their effect is very beneficial. 

 The presence of these parasites may be determined by the 

 punctures in the scales, as in the case of the black scale, and 

 t is likely that in the event of a serious attack of this pest, 

 parasitized material might be introduced in the same man- 

 ner as is suggested for the black scale. 



BED SPIDER (Tetranychus gloveri, Banks). Acarina. 



Cotton is sometimes, especially in very dry weather, 

 attacked by a very small mite, the cotton red spider, which 



lives on the under side of the 

 leaves. Enormous numbers of 

 this mite occur on each leaf, and 

 the effect of their feeding is to 

 'cause the leaves to dry up. The 

 red spider can be distinguished 

 only by careful examination of 

 the infested leaves, when it 

 may be seen actively running 

 about often under or among the 

 very delicate threads of a sparse 

 web. Small patches of a red- 

 dish colour, in the body of cer- 

 tain of the mites, will probably 

 be the first thing to attract the 

 eye to these small, but very 

 harmful, organisms. 



If it becomes necessary to 

 resort to remedial measures for 

 the control of the red spider, 

 the use of any contact in- 

 secticide, or of sulphur and lime, 

 in equal parts, applied dry as a 



Fig. 57- The cotton red spider, dust will be effective. In mak- 



Adult, much , enlarged. (U.S. i ng such an application, it must 



Dept.Ag.) ^ remembered that the red 



spider lives almost entirely on the under side of the leaf, and 



therefore, it is necessary to apply the insecticides to this 



olace, 



