PREFACE. 



T-he present series of articles on deciduous fruit insects and insecti- 

 cides, Parts I to VII, comprises Bulletin 97. 



The first article deals with the grape leafhopper in the Lake Erie 

 Valley. This insect, always more or less present in vineyards, 

 becomes excessively abundant and destructive during certain years, 

 when its control becomes very essential in the production of grapes 

 of high quality. In this paper report is made on large-scale experi- 

 ments in vineyards with a nicotine spray directed principally against 

 the insect while in an immature stage. It has been found practicable 

 so to destroy the nymphs of the first brood that the insect is unable, 

 as the season progresses, to attain sufficient numbers to cause impor- 

 tant injury. 



The second paper is on the life history and control of the codling 

 moth in reference to its occurrence on pears in California and pre- 

 sents results of spraying operations in pear orchards, which show 

 beyond doubt that injuries from this insect on pears may be pre- 

 vented quite as satisfactorily as in the case of apples. The spraying 

 schedule developed as the result of these experiments has been 

 adopted by a large number of pear growers in California. 



The third paper gives results of experiments against the rose- 

 chafer as an enemy of grapes in the Lake Erie Valley. This is another 

 insect which periodically causes very serious damage to vineyards, 

 as well as to many other horticultural crops, especially in regions 

 where the soil is sandy. The results, on the whole, do not show the 

 degree of benefit that may be obtained by spraying operations against 

 many other insects; nevertheless they point out the desirability of 

 this work during periods of excessive abundance of the insect. 



The fourth paper, dealing with the California peach borer, is the 

 result of observations made on this insect covering a period of two 

 or three years and relates particularly to its life history. The meth- 

 ods of control given, however, are those thought to be best under 

 California conditions. 



The fifth paper, on the peach and plum slug, gives the results of 

 observations on the life history and habits made during a period of 

 abundance of this insect in the vicinity of Tallulah, La. The reme- 

 dial measures suggested, while not actually tested under field con- 

 ditions, will be, it is thought, entirely effective in preventing injury 

 without burning of the foliage by the spray. 



