ENTOMOLOGY. 675 



arlilicial insecticide methods it is believed that the insect can not l)e thus exterminated 

 or even lield sufticiently in check. Great hopes, however, are expressed for the 

 ultimate beneficial effects of the use of white muscardine as a fungus disease for 

 destroying the beetles. 



Methods and results of field insecticide work against the San Jose scale, 

 1899-1902, 8. A. Forbes {Illmois Sta. Bui. 80, ]ip. 463-503, pis. 9).— In this bulle- 

 tin a rcjiort is made on extensive operations conducted in a practical manner and 

 under ordinary conditions in exterminating San Jose scale in infested orchards. 

 During the progress of this work 4 treatments were used in winter, viz, hydrocyanic- 

 acid gas, whale-oil soap, kerosene emulsion, and lime-sulphur-salt wash. It was 

 found that all of these methods were effective under favorable conditions. Fumiga- 

 tion with hydrocyanic-acid gas is believed to be practically restricted to comparatively 

 small trees and quiet weather, while the California wash has a decided advantage in 

 the persistence of its cffei-tiveness. The 4 insecticides differ in convenience of appli- 

 cation, and safety. Considerable injury was done to the peach, and in 1 case to an 

 apple tree, by a kerosene emulsion of only 20 per cent. The total cost of preiaaration 

 and application did not differ greatly for the 4 insecticides. The fumigation pro- 

 cess is much more expensive with respect to cost of materials. From the standpoint 

 of convenience of application the author prefers kerosene emulsion and California 

 wash. As a result of the whole comparison of these 4 insecticides it is concluded that 

 the best treatment for ordinary use against the San Jose scale consists in spraying in 

 winter with the California wash. 



The use of hydrocyanic-acid gas in greenhouses, G. C. Butz {Pennsylvania 

 Sta. lipt. 1901, pp. 319-395). — Experiments were made in fumigating greenhouses 

 containing a considerable variety of plants. It is apj)arently possible to fumigate 

 greenhouses successfully without injury to the j^lants, provided only 1 or 2 species of 

 plants of about equal hardiness are kept in each house. In conservatories and green- 

 houses wi h a large assortment of plants the gas can not be used without injury to 

 the more tender species. In the experiments reported in this paper fumigation was 

 begun at about sundown, while the plants were dry, and the length of exposure in 

 every case was 25 minutes. The insects which it was sought to destroy by these 

 experiments were thrips, mealy bug, plant lice, scale insects, and red spider. In 2 

 greenhouses 0.15 gm. potassium cyanid per cubic foot of air sj^ace was employed, 

 while in the third only 0.12 gm. was useil. As a result of these experiments a con- 

 sideraljle difference in the resisting power of different plants to hydrocyanic-acid gas 

 was found. The various plants in the greenhouses are arranged in 3 categories 

 according as they were uninjured, slightly injured, or totally killed. Ferns, grasses, 

 mosses, begonias, etc., were uninjured; fuchias, geraniums, heliotropes, nasturtiums, 

 palms, cacti, etc., had the tender leaves injured; while Pellea and Tradescantia bicolor 

 were killed. Plant lice were all destroyed by the fumigation. Isolated mealy bugs 

 were killed, but where they occurred in large masses the older individuals and the 

 eggs were not destroyed. Scale insects were killed, except eggs under old scales. 

 Eed spiders were killed only to the extent of about 10 per cent. 



The white fly or plant-house aleurodes, W. E. Britton ( Connecticut State Sta. 

 Bill. 140, pp. 17, pis. 4, figs. 5 ). — The white tly has been the most serious pest of tomatoes 

 in forcing houses for the past 8 years. It also lives on outdoor plants in the garden 

 throughout the summer. Notes are given on its relationship to other insects and on 

 the nature of its injuries and its habits and life history. A detailed description is 

 given of the insect in its various stages, chiefly based on the notes of Westwood. 

 The insect is most injurious in forcing houses to tomato, cucumber, and melon plants, 

 while florists comjilain of its injury to lantana, heliotrope, and ageratum. A list is 

 given of the food plants upon which the author observed the insect in its nymph 

 stage. A number of remedies have l)ecn tried in combating this insect. Fumigation 



18909— No. 7—03 5 



