REPORT OF THE ENTOMOLOGIST AND BOTANIST. 



209 





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Fig. 14. — San Jose Scale ; a, pear moderately in 

 fested ; 6, female scale enlarged. 



for most other plants. It was found advisa- 

 ble to repeat the sprayings at intervals of 

 about a week. The young scale insects were 

 noticed on May 19th at Riverside, Ind., and 

 the females, viviparous in habit, gave birth 

 to young for a full month. This was upon 

 peach trees, and it was found that the Resin 

 wash killed the scales more quickly than the 

 P /•' I \ very much diluted Kerosene emulsion. As 



Mr. Howard points out, this rapidity of the 

 work is important, since where a full grown 

 female is sprayed Avith Kerosene emulsion, 

 she may live for three or four days, during 

 which time she brings forth young ; whereas 

 if sprayed with Resin wash, fewer young 

 scales are produced. The resin wash, how- 

 ever, is readily carried off by the rains, while 

 the Kerosene emulsion is more resistant. 



In Prof. J. B. Smith's investigations in 

 Pennsylvania, it is recorded in Insect Life 

 (VII., p. 159) that "he has visited the local- 

 ity at Atglen, Pa., and found that in an 

 orchard of over 7,000 trees, all of certain 

 varieties, and a few of others were infested 

 by the scale. As a result of his recommend- 

 ations, Kerosene emulsion has been applied 

 three times to most of the trees at intervals 

 of ten days, up to the first week in June. 

 The treatment has been absolutely success- 

 ful."' 



For winter washes, the Kerosene emulsion and Resin washes may be made stronger. 

 The stock Kerosene emulsion has been used diluted with only i\ parts of water, and for 

 the Resin wash the same ingredients were used in the following proportions : Resin, 30 

 lbs., caustic soda, 9 lbs., fish oil, 4J pints, water, 100 gallons. 



" The most favoured winter remedy in California, however, is the lime, salt, and 

 sulphur mixture. This consists of unslaked lime 10 lbs., sulphur 5 lbs., stock salt 5 

 lbs., water to make 15 gallons. This wash will do great damage to the ti-ees if applied 

 during the growing season, and should be used only in winter. All the sulphur and half 

 the lime are placed in a kettle, and 8| gallons of water added ; after which, the contents 

 of the kettle are boiled briskly for about an hour. The solution, which at first is yellow 

 from the sulphur, will turn very dark brown, assuming more or less of a reddish tint, 

 and will finally change from a thick batter to a thoroughly liquid condition, the product 

 being ordinary sulphide of lime. All the salt is added to the remaining 5 pounds of 

 lime, and the latter slaked ; after which, the slaked lime and salt are added to the sul- 

 phide of lime already obtained, the whole being then diluted with water to make. 15 

 gallons. This should be strained before application, as it does not form a perfect liquid 

 solution, on account of the considerable quantity of undissolved lime, which will soon 

 sink to the bottom, unless the solutionis constantly stirred while being sprayed." (L. O. 

 Howard, Circular No. 3.) 



The third method of fighting scale insects is known as the Gas Treatment. This 

 has been extensively used in California, but is an expensive operation, and the materials 

 necessary are very poisonous and dangerous to have about a house. It consists, briefly, 

 of covering the tree to be treated with an air-tight tent, and then filling the tent with the 

 poisonous fumes of hydrocyanic acid gas, which is generated by placing 1 oz. of cyanide 

 of potassium, 1 fluid ounce of sulphuric acid and 3 fluid ounces of water in an earthen- 

 ware vessel beneath the tent. The gas is very light and rises to the top of the tent, and 

 if this be kept on the tree for half an hour, every scale will be destroyed. The quantities 

 of ingredients given above are sufficient for a tent inclosing 150 cubic feet. 

 8c— 14 



