311 



The results of this survey have proved quite conchisively that 

 rotation of crops is of no vakie as a means of control of this insect. 



The winter-host factor appears to be the most active in the spread 

 of this Aphid in northern Colorado. A comparison of the degree of 

 infestation in all fields of those parts where the narrow-leafed cotton- 

 wood trees {Populus angustifolia) are most abundant with that 

 in fields where they are relatively few, shows a constant higher degree 

 of infestation in fields within half a mile of these trees. 



The hea^y infestation of the western, as compared with the eastern 

 portions of the sections surveyed, seems to point to the wind being 

 an active factor in dissemination, since, during early summer, while 

 the heaviest migration of P. betae from the winter host is taking place, 

 the prevailing winds of northern Colorado are westerly, and by this 

 means the insects might easily be carried from the mountains many 

 miles out on to the prairies. 



Ballou (H. a.). The Pink Bollworm {Gelechia gossypiella) in Egypt. 

 Jl. Econ. Entom., Concord, N.H., xi, no. 2, April 1918, pp. 236-245. 



This paper deals comprehensively with the subject of Pectinophora 

 (Gelechia) gossypiella (pink bollworm) in Eg}^t, as regards its native 

 home and distribution, food-plants, life-history and habits, and the 

 nature of the injury caused by it [see this Review, Ser. A, iv, pp. 232, 277, 

 etc]. Control of the insect in the seed by treatment with hydrocyanic 

 acid gas is not practicable owing to the lack of responsible labour in the 

 cotton ginneries of Eg}'pt, and also to the danger to public health 

 of liberating large quantities of poisonous waste gases in so densely 

 populated a country. Carbon bisulphide also, owing to its highly 

 inflammable and almost explosive character, is not suitable for use in 

 close proximity to cotton ginneries where the atmosphere is laden 

 with fine particles of cotton. The most suitable agent for the destruc- 

 tion of the pink bollworm in cotton seed in Eg^'pt is hot air [see this 

 Review, Ser. A, iii, p. 505, iv, pp. 472, 491, vi, p. 42]. 



The natural enemies of the pink bollworm do not occur in sufficient 

 numbers or at the right time of year to exercise any great degree 

 of control. 



The losses due to this pest are enormous, amounting to anything 

 between £(E.)3,600,000 and £(E.)4,800,000 in 1916. 



Becker (G. G.). Notes on the Woolly Aphis. — Jl. Econ. Entom., 

 Concord, N.H., xi, no. 2, April 1918, pp. 245-255. 



This paper records the results of investigations on Eriosoma lani- 

 genim, Hausm., which aimed at working out the life-history of this 

 Aphid in the Ozark Mts. ; studying the relative immunity of various 

 hosts, and of the relationship of these hosts to the species ; studying 

 the immunity of Northern Spy stock to the attacks of this species ; 

 and determining whether E. crataegi, Oestl., is identical with 

 E. lanigerum. 



In the Ozarks this Aphid winters on elm in the egg-stage and on 

 the roots of apple, and in wounds, knots and rough places on the 

 trunk above the ground of apple and Crataegus as apterous viviparae. 



