October, '22] wadley: strawberry leaf- roller 359 



favorable to spraying. Mr. DLxon used a modem orchard sprayer with 

 a row attachment. Three applications of lead arsenate were made; 

 about June 15, July 20 and August 15, respectively. Several acres 

 were left unsprayed the first time and nearly all plants in this area were 

 killed. Many larvae were present on the sprayed area, but their num- 

 bers were so reduced that little injury was accomplished. This first 

 application, in the writer's belief, saved a large portion of the plants. 

 The second and third sprays were applied to all the strawberry acreage. 

 The leaf -rollers were held in check all season. Though some larvae 

 were always present, serious injury was averted. They became scarce 

 by fall and were not troublesome in 1919. These results in large scale 

 spraying by a grower are very gratifiying, especially considering the 

 unusual severity of the outbreak. Although 100 percent control was not 

 achieved, injury was effectually checked. 



Recommendations 



Lead arsenate with a soap spreader is well adapted to control of the 

 leaf-roller, adhesiveness being especially desirable. Any fairly good 

 spraying apparatus will do to apply it, and underspraying is unnecessary. 

 The grower should spray only when the insect threatens to assume 

 injurious numbers. One or two applications as the plants begin blossom- 

 ing will reduce the numbers of the first generation, and probably also 

 of saw-fly larvae if present. Growers will be reluctant to spray after 

 berries begin setting. Should injury continue after harvest, further 

 sprays'should be applied. Mowing and cultivating aid in control where 

 practiced, but are not always sufficient. Leaf-rollers should not be al- 

 lowed to injure the plants during simmier and fall, as the plants which 

 will bear next year's crop are then developing. New plantings are very 

 liable to injury late in the season. 



Since one appHcation gives about two-thirds control, several at short 

 intervals should bring an outbreak to an end so far as serious injury is 

 concerned. There is little advantage in spraying at intervals of less 

 than two weeks in dry weather in summer and fall, but in rainy 

 weather shorter intervals are better. Sprays a month apart during the 

 summer have given practical control of the worst outbreak the writer 

 has seen, though more frequent applications would probably have given 

 more nearly perfect control. 



Spraying as outlined throughout the season, both before blossoming 

 and at intervals from midsummer until early fall, will protect the crop 

 against unusual outbreaks. Usually, however, such frequent spraying 



