40 MASS. EXPERIMENT STATION BULLETIN 428 



varieties Blue Hubbard, Warren Turban, and Buttercup squash averaged 3.31 

 borer injuries per vine. Six varieties of Cucurhita pepo, including pumpkin, 

 gourd, and four types of summer squash, averaged 2.23 borer injuries per vine, 

 with the straightneck summer squash the most heavily infested. Cucurbita 

 moscJiata, represented by the Butternut squash, was not infested and appeared 

 to be immune. 



Cucumis sativis, the cucumber; C. melo, the cantaloupe; and Citrullus vulgaris, 

 the watermelon, also were not infested. 



New Insect Pests of Importance in 1944. (W. D. Whitcomb, Waltham.) 

 Outbreaks of the spotted tentiform leaf miner (Lithocollefis blanc'harddla Fab.) 

 occurred in a few orchards in the Nashoba district causing serious injury to apple 

 foliage and accentuating drouth damage. These outbreaks were located in 

 orchards where the infestation was light in 1943. The orchards which were 

 heavily infested in 1943 had little or no infestation in 1944. Six species of para- 

 sites were reared from L. hlanchar delta, which apparently explains the absence of 

 the leaf miner following heavy infestations the previous year. 



Spraying Log Piles to Prevent Scolytid Infestation of Elm Logs. (W. B. 



Becker.*) In the spring, between 10 and 21 uninfested elm logs (with bark up to 

 1 inch thick on xylem up to 11 inches in diameter) were scattered uniformly 

 throughout log piles measuring 4x4x4 feet. Power sprayers were then used to 

 direct various sprays into the piles from the ends of the logs and the top of the 

 pile. At Springfield, a single-nozzle, adjustable-stream spray gun was used at 

 400 pounds pressure; at Great Barrington, a similar spray gun was used at 100 

 to 250 pounds pressure; and at Amherst, a six-nozzle spray boom was used with 

 a power sprayer which gave 400 pounds pressure. The results are based on the 

 number of exit holes per square foot of elm bark found in the logs after late fall. The 

 figures following each spray mixture indicate the proportion of ingredients and 

 the amount applied per log pile. 



Percent Prevention 

 At Springfield (practically all the elm scolytids were Scolylus inultisU-iatus) 



Orthodichlorobenzene and No. 2 fuel oil (1-8, 20 gals.*) 100.0 



Bordeaux and water (1 lb. - 5 gals., 20 gals.) 61.2 



Gesarol SH5 (S%DDT in a summer spray oil) and water (1-100, 20 gals.) .... 78.1 



At Great Barrington (Hylurgopinus riifipes was the only or predominant elm 

 scolytid present) 



Gesarol SH5 and water (1-100, 35 gals.) 64.3 



Orthodichlorobenzene and No. 2 fuel oil (1-8, 8 gals.) 6.3 



No. 2 fuel oil alone (8 gals.) 86.0 



At Amherst (H. rufipes was the only elm scolytid present) 



Gesarol SH5 and water (1-100, 14 gals.) 92.8 



Gesarol SH5 and kerosene (1-100, 14 gals.) 93.6 



Orthodichlorobenzene and No. 2 fuel oil (1-8, 16 gals.) 100.0 



♦Approximately 300 cc. per square foot of bark. 



Spraying Log Piles to Kill Elm Scolytids. (W. B. Becker.) In midsummer, log 

 piles of the same size used for the prevention sprays, but containing logs from 

 which beetles were ready to emerge, were similarly sprayed with the same equip- 

 ment. The percentages given are based on the number of exit holes per brood gallery, 

 as compared with the emergence from unsprayed logs. The figures follov/ing each 

 spray mixture indicate the proportion of ingredients and the amount applied 

 per log pile. 



*The author is deeply indebted to Mr. L. Fletcher Prouty, Assistant Superintendent in the 

 Springfield Department of Public Parks, who provided much material assistance in carrying out 

 all the experiments in Springfield. 



