772 EXPERDklENT STATION RECORD. 



ag-cncy of ants in spreading infestation by the aphis. The same species 

 of ants attiMid on the corn aphis and strawl)orry root aphis. 



The currant gall mite (Ph5rtoptus ribis), Duke of Bedford and S.U. 

 Pickering {Wohu/'n Evpt. Fruit Faina Bjtt. 1900, 2>2>. 7-SJf,Jigs. J^). — 

 Experiments with insecticide treatments against this insect were made 

 by the authors with the assistance of Miss Ormerod and Mr. Newstead. 

 The mites are found in large numbers in each infested bud, 3,000 

 being found in some buds. This species is so minute that its trans- 

 portation by wind and other agencies is rendered comparatively eas}'. 

 Its period of activit}' extends apparent!}' over the whole season during 

 which currants bear leaves. During the time that the mite is inclosed 

 in the bud it is well protected from the action of insecticides. In 1896 

 Baldwin Black currants showed signs of being infested b}^ the mite 

 and the galls were removed. The infestation increased, however, 

 during the next year and extended to the Black Naples currant. The 

 galls were again removed, but a further increase in infestation was 

 noticed the following year. Although the affected buds were removed 

 each year, the number of infested buds on the currant bushes was 

 doul)led in 1 case and increased fourfold in another. The method 

 of removing the infested buds seems, therefore, to promise little 

 success. In the first series of experiments with insecticides from 

 December, 1897, to Octol)er, 1898, each experiment involved 30 bushes 

 in a double row sul)iected to the same treatment. All liquid insecti- 

 cides were applied from a rose can or spraying apparatus. Some of 

 the Imshes were lifted and dipped bodily into some insecticide, while 

 still others were painted with the insecticide. The insecticides Avhich 

 were used included carbolic acid 0.8, 1.6, and 2.1 per cent, calcium 

 sulphate 1.5, 3, and 1.5 per cent and mixed to the consistency of paint, 

 3 qts. to 10 lbs. of cla}', kerosene emulsion in a mmiber of strengths, 

 Antinonnin, and turpentine. One week after each treatment twigs 

 from bushes in all experiments where insecticides had been used at 

 their maximum strength were subjected to microscopical examination. 

 The results for the most part were of a negative character. Bushes 

 treated with Antinonnin were reported to have been infested with the 

 greatest number of mites on Februaiw 26. while on March 22 similar 

 observations were made as to both mites and eggs on bushes treated 

 with Antinonnin. On April 22 currant bushes which were treated 

 with the strongest Antinonnin and carbolic acid showed about 50 per 

 cent of the mites dead. On August 20 following the bushes which 

 were treated with the strongest Antinonnin and strongest carbolic acid 

 were reported to be free from mites. In all other cases the mites were 

 found to be swarming with the single exception of bushes treated 

 with turpentine. The success with turpentine, Antinonnin, and car- 

 bolic acid was, however, onh' apparent, since the currant bushes were 

 killed l)y the insecticides. Currant bushes sprayed with the strongest 



