278 



species of Solenococcus on avocado from Guatemala ; Parlatoria 

 chinensis, Marl., on two species of Pyrus from China ; and Eulecanium 

 {Lecanium) coryli, L., on an undetermined plant from England. 



Ball (E. D.). The Potato Leafhopper and its Relation to the Hopper- 

 burn. — Jl. Eco7i. Entom., Concord, N.H., xii, no. 2, April 1919, 

 pp. 149-155, 1 plate, 5 figs. 



This is an ampUfication of a previous article [see this Revieiv, Ser. A, 

 vi, p. 489]. In the summer of 1918 scorching of potato foUage occurred 

 in difTerent parts of the Northern United States, receiving a different 

 name in each locality. All injured leaves examined showed signs 

 of the presence of Emjpoasm mali, Le B. (potato leaf -hopper). This 

 fact combined with cage experiments has led to the conclusion that 

 this insect is directly responsible for the scorched appearance on 

 potato leaves as well as on dahlias, box elder, apple and raspberry. 

 It is not yet proved whether the relation of the disease to the insect 

 is specific or not. The appearance of the disease varies according 

 to temperature and moisture. The burned margin increases until 

 the leaf dies and eventually the W'hole plant succumbs. Rapid 

 growing varieties of potato suffer the least. Probably the disease 

 referred to in the past as " tipbum " was due to this leaf -hopper. 



Empoasca mali produces two generations on potatoes ; the adults 

 appear when the early potatoes come up and lay their eggs on the 

 stems and midribs of the leaves. The nymphs feed on the under- 

 surface of the leaf and only migrate to other leaves when the first 

 one is dead. In July and August the adults of the first generation 

 either oviposit on the plants on which they themselves have been 

 bred or migrate to late potatoes, on which they give rise to the second 

 generation. 



Affected plants should be sprayed every 8-10 days with strong 

 kerosene emulsion or Black-Leaf 40 ; one pint to 100 U.S. gals, should 

 be used, with the addition of 5 lb. of soap. The spray must be applied 

 to the under-surface of the leaves and will kill both nymphs and 

 adults. 



Burgess (A. F.). Organisation for Insect Suppression. — Jl. Econ. 

 Entom., Concord, N.H., xii, no. 2, April 1919, pp. 136-141. 



Insect suppression falls into two classes ; the control of widely 

 distributed insects and the control of newly established pests in a 

 limited area. It is suggested that closer relations should be established 

 between the State and Federal Authorities to facilitate the efforts 

 of the officials engaged in this work. 



As regards the problem of introduced pests the Federal Government 

 has recognised its responsibility, but the work of the entomologist 

 has often to suffer from incompleteness owing to want of funds. 

 The successful organisation of insect suppression involves good business 

 management as well as entomological knowledge. 



O'Kane (W. C.). Limitations in Insect Suppression.— JZ. Econ. Entom. 

 Concord, N.H., xii, no. 2, April 1919, pp. 155-162. 

 Some of the problems and difficulties arising when starting a cam- 

 paign against new and serious insect outbreaks are discussed. One 



