432 



starling, are probably an important controlling factor, since larvae are 

 usually rare in those localities in which these birds are abundant. 

 Live-stock are useful in clearing the ground of undergrowth in which 

 the larvae can hide during the daytime, and in this connection the 

 pasturing of sheep on infested areas is suggested. Further investi- 

 gations on the life-history of X. praefectafa would be necessary before 

 the last-named operation could be successfully carried out. Predaceous 

 insects occurring in the same areas as X. praefectata apparently do not 

 control the latter to any appreciable extent. The parasites of this pest 

 require further investigation. In the absence of flax, larvae have been 

 found on other plants, including bulrushes, and these may therefore 

 be of importance in determining methods of control [see also this 

 Review, Ser. A, iii, p. 302]. 



Pest and Diseases of Cotton and their Control. — West Indian Bull., 

 Barbados, xv, no. 4, 1915, pp. 315-318. [Received 2nd August 

 1916.] 



During the fifth day's proceedings of the West Indian Cotton Con- 

 ference, held in March 1916 in St. Kitt's, some points remaining from 

 the previous discussion on pests and diseases of cotton [see this Revieiv, 

 Ser. A, iv, p. 384] were considered. A most unusual outbreak of cock- 

 roaches occurred in St. Kitt's, the insect eating down young cotton 

 plants in the fields. Crickets and grasshoppers to a less extent, also did 

 some injury in St. Kitt's. These were controlled with a poisoned bait. 

 Damage was done in Anguilla by a grey weevil YLachnopvs\ which 

 gave trouble in Antigua, Tortola and Nevis. It attacks the cotton 

 plant when very small ; a poisoned bait is the only remedy yet 

 suggested against it. The weevils often hide among the foliage at the 

 tips of the branches of the cotton plants where they may be collected. 



The juice of ripe oranges is considered to be probably the best trap 

 for cotton-stainers, Dysdercus. In Montserrat and St. Vincent, the 

 two islands in which internal boll disease attracted most attention, 

 the prevailing species of cotton-stainer is not the one prevalent on 

 St. Kitt's. When cotton growing was first started in the West Indies, 

 the species most abundant in Montserrat was Dysdercus andreae, which 

 was common in St. Kitt's and also occurred in Antigua, and in 

 the north and west of Jamaica ; this is now no longer the case. The 

 predominant species in Montserrat is the southern form, D. delauneyi, 

 which occurs alone in Grenada and St. Vincent, and which perhaps 

 occurs in the Virgin Islands in company mth Z). andreae. In St. 

 Vincent, where the greatest trouble has been experienced, D. delauneyi 

 is the pest concerned. The destructive powers of B. andreae (white 

 stainer) and D. delauneyi (red stainer) appear to be equal. Internal 

 boll disease has been known in Antigua for many years, though 

 D. delauneyi does not occur there. 



Mr. Harland related his experience with the use of starch and Paris 

 green [see this Review, Ser. A, iv, p. 42]. While vegetation dusted 

 with lime is avoided by insects, it was found that a mixture of Paris 

 green and low-grade arrowroot or cassava starch in the proportion of 

 1 to 60 can be spread very thinly and that cotton worms {Alabama 

 argillacea) will eat it at once. While hme is easily dissolved by rain- 

 water, starch is more adhesive. In experiments with maize, lime 



