ANNUAL REPORT, 1944-45 35 



Striped Cucumber Beetle. DDT was verj^ toxic to striped cucumber beetles. 

 Within a short time after treatment the beetles became inactive and ceased 

 feeding, and in 24 hours all were dead, while all beetles dusted with rotenone 

 succumbed within 12 hours. DDT was not quite so rapid in its actual killing 

 effects as rotenone; but since all treated beetles ceased feeding and became in- 

 active within a few hours after treatment, from a commercial standpoint they 

 ceased to function as pests so that the actual time of death was of secondary- 

 importance. No injury to foliage was noted in laboratory tests. The beetles 

 appeared late in the season when the plants had made considerable growth and 

 no injury from the treatment was observed such as was reported from tests in 

 other states where applications were made in early season when the plants were 

 small and very tender. 



Squash Bug. This insect was relatively scarce in the vicinity of Amherst and 

 only laboratory tests on a few specimens were possible. In each series DDT killed 

 young-stage bugs up to and including half-grown nymphs. Later stages were 

 quite resistant, and adult bugs seemed to be only slightly affected. 



Black Scale. Gesarol A-20 at a dosage of 4 pounds to 100 gallons proved very 

 effective in the control of black scale on gardenias. The immediate effects were 

 very pronounced and the material showed a definite residual action which pre- 

 vented reinfestation and from a commercial standpoint eliminated the pest. 



Plum Curculio, Codling Moth, and Apple Maggot. Insectary poison studies 

 at Waltham with a commercial preparation of DDT (Gesarol A-20) used at the 

 rate of M, H, M. and 1 pound of DDT per 100 gallons of water showed this 

 material to be surprisingly ineffective against the plum curculio on apples. 

 Further studies on a caged apple tree sprayed with the material corroborated 

 the insectary studies with plum curculio, but indicated promising effectiveness 

 against codling moth and apple maggot flies. 



Flies. Experiments against adult flies were conducted mainly in the college 

 piggery. On June 21 two pens were sprayed with a solution of 2 gallons of water 

 and 38 cc. of Gesarol SH5, and two pens were sprayed with a solution of 2 gallons 

 of water and 18 grams of Gesarol A-20. An immediate reduction in flies occurred. 

 Dead flies were found on both the treated and the untreated sides. Daily in- 

 spections revealed a comparative absence of flies until June 24, when a few were 

 found on the treated side of the piggery during a heavy rain. At the end of a 

 week the flies were present in relatively the same number on both the treated 

 and the untreated sides. Troughs treated with DDT remained free from flies 

 during the experiment. 



Experiments against fly larvae in infested manure were conducted. Applica- 

 tions were made on July 19 to 3 pens in the sheep barn. A solution of 1 pint of 

 Gesapon-18 to 10 gallons was employed at rates of 3, 6, and 9 gallons to 27 square 

 yards. In addition 15 square yards of fly-infested soil near the feeders were 

 treated with the material at the rate of 1 gallon of 1 percent solution per square 

 yard. The following day, examination revealed the presence of live larvae in all 

 treatments, both in the sheep barn and at the piggery, indicating that DDT at 

 the concentrations used was not effective. Subsequent examinations bore this 

 out. 



The Value of Control Measures to Supplement the Standard Spray Program 

 for Apple Pests in Massachusetts. (A. I. Bourne, in cooperation with the De- 

 partments of Pomology and Plant Pathology.) The tests in 1944 included 

 studies of the effectiveness in insect control of more accurate timing of applica- 



