10 



CoAD (B. R.). Killing Boll Weevils with Poison Dust.— f/.S. Dept. 



Agric, Washington, D.C., Yearbook 1920, 1921, pp. 241-252, 



2 figs. [Received 2nd November 1921.] 



As the result of a long series of experiments, which are here described, 



it has been proved that the cotton boll weevil [Anthonomus grandis] 



can be controlled by a calcium arsenate dust. Details are also given 



of suitable machinery for dusting. Experiments with this poison 



were extensively carried out in 1920, and the reasons for their success 



and failure are discussed [cf. R. A.E., A, viii, 245, 302, 457]. 



McAtee (W. L). Farm Help from the Birds.— C/.5. Dept. Agric, 



Washington, D.C., Yearbook 1920, 1921, pp. 253-270, 18 figs. 



[Received 2nd November 1921.] 



An account is given of the beneficial effects of the various birds 



that are predacious on injurious insects in the United States. The 



legislation on protection of birds is reviewed, and the need for 



encouraging their increase and preservation is emphasised. 



Walton (W. R). The Green Bug or Spring Grain Aphis : How to 

 Prevent its Periodical Outbreaks. — U.S. Dept. Agric., Washington, 

 D.C., Farmers' Bull. 1217, June 1921. 11 pp., 9 figs. [Received 

 2nd November 1921.] 

 The spring grain aphis ( Toxoptera graminum) is distributed through- 

 out the United States and Canada, being particularly destructive in 

 the Mississippi Basin in early spring. In 1907 an outbreak of this 

 pest caused a loss of 50 million bushels of oats and wheat in one 

 district and 70 per cent, of the wheat crop in another. This Aphid 

 feeds on most graminaceous plants and small grains, but is chiefly 

 injurious to wheat and oats. 



The parthenogenetic females, which may be winged or wingless, are 

 practically always present and produce young all the year round in 

 the southern latitudes. The wingless egg-laying females occur in the 

 north only in the autumn, and there the winter is passed in the 

 egg, or as active nymphs or adults. South of the 35th parallel, except 

 at high altitudes, breeding is continuous. The eggs are deposited in 

 autumn and hatch in spring. The Aphids mature in 6 or 7 days and 

 produce young. There may be at least 20 generations a year. A 

 single female may produce 1-8 young a day for at least 2-3 weeks. 

 The damage caused is recognised by the presence of yellow areas on 

 the leaf blades, which turn reddish-brown and die. 



Lysiphlebus ( Aphidius) testaceipes is the chief parasite that keeps 

 this pest in check. Unfortunately, as it can only multiply in compara- 

 tively warm weather, remedial measures are essential. The most 

 important is the destruction of all self-sown crops, especially wheat 

 and oats, during the summer and early autumn. This is essential 

 in Texas, Oklahoma, Kansas and Missouri, where serious outbreaks 

 are liable to occur at any time. 



Fryer (J. C. F.) & others. Report on the Occurrence of Insect and 

 Fungus Pests on Plants in England and Wales for the Year 1919. — 



Minist. Agric. & Fisheries, London, Misc. Pubn., no. 33, 1921, 



pp. 6-25. [Received 2nd November 1921.] 

 The pests damaging cereals in the year under review were : Lema 

 melanopa, Hylemyia coarctata, Oscinella [Oscinis) frit, Chlorops taeni- 

 opns in barley, Tylenchus scandens, and wirewomis. Experiments 



