17 



ing from April to September, but in the case of scales having 

 three or four generations a year, the period is prolonged. Though the 

 experiments described only record a dispersal up to 450 feet, it may take 

 place over a much greater distance. The practical importance of 

 carrying on fumigation work over as large an area as possible is thus 

 emphasised. 



EocKWOOD (L. P.). Sporotrichum ghhuliferum, Speg., a Natural Enemy 

 of the Alfalfa Weevil. — Jl. Econ. Entom., Concord, ix, no. 5, 

 October 1916, pp. 493-499. 



The fungus, Sporotrichum globuUferum, was first found infesting the 

 alfalfa weevil [Hypera variabilis] near Salt Lake City, Utah, on 14th 

 March 1914, the time of its greatest abundance being from 21st^29th 

 April. The death of the adults at this time, i.e., before and during 

 oviposition, is of considerable importance, as it helps to reduce the 

 destructive new generation of larA'ae when no other natural enemy of 

 importance has been observed. The weevils are specially exposed to 

 infection in early spring, when optimum conditions for the fungue 

 occur and the insect is frequenting the ground. The macroscopic 

 appearance of the fungus found on weevils killed by it differs from that 

 found on those infested after death from some other cause. Weevils 

 killed by the fungus are usually found in a life-like attitude with legs 

 and antennae extended. In a series of eight laboratory experiments 

 it was found that the resistance to infection by the weevils is con- 

 siderable, when the conditions most closely approach the natural ones. 



Experiments made with Melarrhizium anisopliae showed a 50 per 

 cent, less mortahty among the vreevils treated under similar conditions 

 than in the case of S. globuUferum. 



Maxon (A. C). Some unpublished Notes on Pemnliigus bstae. Doane. 

 — Jl. Econ. Entom., Concord, ix, no. 5, October 1916, pp. 500-504. 



Some additional facts in the life-history of this Aphid are given [see 

 this Review, Ser. A, iii, pp. 351-578]. By digging in old beet-fields it 

 was found that considerable numbers of the apterous form survave 

 the winter in the soil. Apterous forms also occur on Achillea sp., 

 Aster midtiflora, Solidago sp., Rumex sp., Agropyron sp., and Polygo- 

 num aviculare ; though, as the different species of the genus Pemphigus 

 cannot at present be distinguished in this stage, some of these may not 

 be food-plants of P. betae itself. Summer colonies were found on the 

 roots of Chenopodium album, garden beets, sugar beets, and Cycloloma 

 atriplicifolium. Since the reduction of the percentage of sugar in beets 

 is of vital interest to the sugar manufacturer, a series of tests were made 

 to ascertain the effect of this Aphid in this respect. These showed that 

 the yield of beet was reduced by 2 "25 tons per acre where about half 

 the crop was infested, while infested samples contained nearly 1 per 

 cent, less sugar than the uninfested. Spring irrigation has been proved 

 to be the most effective method of control. 



The natural enemies include the larvae of a Syrphid fly and a 

 Capsid, which prey on the hce while in the galls, and the fungus 



(C336) B 



