, 393 



after tlie main cotton crop has been reaped. After the compulsory 

 destruction of the old cotton in January the insects survive on native 

 plants, including the John Bull tree {Thespesia populnea), the silk- 

 cotton tree {Eriode)idron anfractuoswm) and many shrubby and her- 

 baceous Malvaceae, from which they migrate to the young cotton in 

 July or August. No effective means of control is known, though i^he 

 destruction of their native food-plants and diligent hand-picking 

 should check them in the earlier part of the year. 



Watts (Dr. F.). Experiments at the Botanic and Experiment Stations, 

 and Special Entomological Investigations. — i^ep^. Agric. Dept. 

 St. Vincent for 1913-1916, Barbados, 11th December 1916, 

 pp. 5-23. 



Cotton Avas attacked by Alabama argilkicea (cotton worm), Erioplujes 

 gossypii (leaf blister mite), Saissetia major (black scale), Colaspis 

 fastidiosa (bronze beetle) and the Tingid bug, Corytliuca sp., but in a 

 minor degree by all. Two new pests have been observed, a beetle, 

 whose larva tunnels in the stem near the ground, and a thrips found 

 attacking the leaves and bolls of both wild and cultivated cotton. 

 Experimental investigations on Dysdercus dekmnegi (cotton stainer) 

 showed that no internal boll disease appeared in the absence of these 

 insects. The following insects have been observed attacking cassava : 

 Cryptorhynclms sp. (cassava borer), the control of which might be 

 effected by disinfecting the cuttings and by instituting a close season 

 to prevent young plants becoming infected from old ones ; Dacty- 

 lopius sp. (mealy-bug) which is controlled by the larva of an unidentified 

 Syrphid fly, and the larva of an unidentified moth ; it could also be 

 controlled by a close season, the burning of affected stems, and the 

 planting of only healthy stocks ; a weevil, Diaprepes spengleri, for 

 which no method of control has yet been attempted ; Erinnyis ello, L. 

 (cassava hawk-moth), of which only the eggs, parasitised by a small 

 Hymenopteron, have hitherto been found ; two species of thrips, 

 Corynothrips stenoptera and FranhJiniella meJanommatus, for which 

 no control has been attempted ; Cecidomyia manihot, Felt (cassava 

 gall-maggot), an insect which is extensively parasitised by two minute 

 Hymenoptera, and which causes no particular damage ; and finally, 

 the cassava mite [Tetranychus bimaculatus]. The insect pests of 

 maize are chiefly mole-crickets [Scapteriscas didadylus], which 

 destroy 15-25 per cent, of the young plants, and for which no serious 

 methods of control have been undertaken ; Lap)hygnia frugiperda 

 (corn- worm) [see this Review, Ser. A, i, p. 517], which feeds on no 

 plants except those capable of affording protection from the wasp 

 Polistes annularis ; Diatraea saccharalis, F. (lesser moth borer of 

 sugar-cane), which can be controlled only during the egg -stage, 

 the eggs being parasitised by Prophanarus alecto and by Tricliogramma 

 minvtam ; the insect prefers to lay eggs on maize, hence the 

 importance of clearing away old maize stalks from the fields ; Heliothis 

 obsoleta (boll worm), which is held in check by Trichograinma 

 minutwn, an egg-parasite ; and Agromyza sp. (leaf-miner) which is 

 extensively parasitised by Chalcids. Calpodes ethlius (arrowroot 

 worm) caused extensive defoliation, but was completely controlled, at 

 first by three species of Tachinid flies, and later by an unidentified 



