APHIDS INJURIOUS TO ORCHAED FRUITS. 39 



may be increased when a larger quantity of spray is needed. This 

 stock sohition is used against aphids at the rate of 1 gallon to 7 or 8 

 gallons of water. Kerosene emulsion should not be added to a lime- 

 sulphur spray. 



SPRAYING FOR APPLE APHIDS. 



Experiments made by the Bureau of Entomology and several of 

 the agricultural experiment stations, notably those of Colorado and 

 Oregon and the Geneva, N. Y., station, show that the aphids attack- 

 ing the fruit and foliage of the apple are best controlled by spray- 

 ing in the early spring just as the buds are breaking to destroy the 

 stem-mothers. At this time the insects are hatching from the win- 

 ter eggs, and are so exposed that one thorough treatment should 

 destro}' from 95 to 98 per cent of them and prevent their increase 

 to such an extent that they will not cause serious injury later in the 

 season. This applies especially to the oat aphis, the rosy aphis, and 

 the clover aphis. 



In the case of the green apple aphis, which lives on the apple 

 throughout the year, the suppression of stem-mothers in the spring 

 does not always guarantee freedom from this insect during midsum- 

 mer, and supplementary treatments sometimes are desirable. In the 

 case of young orchards, where the green apple aphis is principally to 

 be considered, the bud spray should be given, but additional applica- 

 tions should be made in summer if found necessary. 



Figure 29 illustrates the condition of apple buds when the first 

 spraying should be done, and figure 30 shows the buds too far ad- 

 vanced for successful work, as the aphids have penetrated the 

 spreading leaves and are very hard to reach. In the bud spray the 

 nicotine may be used in the winter strength lime-sulphur solution 

 employed for the San Jose scale, thus effecting the control of both 

 insects by the one application. If the bud spray has been omitted 

 and the aphids are present in numbers, 40 per cent nicotine sulphate 

 should be used in the dilute lime-sulphur solution which is used for 

 the first scab spray and also for the codling moth spray following 

 the dropping of the blossoms. These later applications, however, 

 are not nearly so valuable as the bud spray and merely serve to check 

 the insects. 



In spraying apple aphids very thorough work is essential, with 

 good pump pressure, so that the spray may be driven as much as 

 possible against the insects. Results in spraying will vary, depend- 

 ing upon the size of the trees as affecting the thoroughness of the 

 application. On large trees results are frequently less satisfactory 

 than on medium and smaller trees. 



Spraying in the fall for the destruction of the fall migrants and 

 the egg-laying females has been tried to a limited extent, but the 

 adequacy of the treatment has not yet been proven. 



