were present on Gravenstein apples. 

 Such damage is sufficient indication 

 that growers should follow the rec- 

 ommendation of the Pest Control 

 Schedule for the special Curculio 

 sprays: "Spray first those varieties 

 which grow most rapidly . . . Proper 

 timing just ahead of or at the be- 

 ginning of a hot period is essential 

 to control Curculio irrespective of 

 the materials used." 



Environment Affects Control 



The effect of orchard environ- 

 ment also has an important bearing 

 upon Curculio attack and may 

 largely determine the success or 

 failure of the control program. Plum 

 Curculio adults pass the winter in 

 sheltered places in and around the 

 orchard. Studies in life history and 

 habits of the insect have revealed 

 that stone walls, hedge rows, woods, 

 and brushy areas offer excellent pro- 

 tection for these hibernating beetles. 

 Many growers, however, still do not 

 fully appreciate the serious threat 

 such conditions offer. 



The factors of environment were 

 studied, and all materials tested 

 were applied in triplicate to com- 

 pensate for different types of ex- 

 posure. One series adjoined 

 woodland, a second series was placed 

 along the margin of the orchard 

 next to an open field in a cultivated 

 area, and the third series ran 

 through the center of the block. 



According to the record of fruit 

 at harvest from trees adjoining 

 woodland, the Curculio damaged 

 90 percent of the fruit in the check 

 plots compared to 53 percent from 

 plots in the center of the orchard or 

 along grassland and a cultivated 

 area. 



In the plots where insecticides 

 were applied, Curculio damage 

 averaged 2 percent of the fruit in 

 the less exposed areas and a mini- 



Part of skin and flesh re- 

 moved to show curculio 

 eggs in cavities of a small 

 apple. 



mum of 0.9 percent in the center of 

 the orchard. In places adjoining 

 woodland, from 4 to 6 percent of 

 the fruit were damaged in spite of 

 equally good spraying and timing — 

 clear indication that trees thus ex- 

 posed to woods and brushland are 

 subject to early and heavy attack 

 by the beetles. 



Since successful control of this 

 pest requires carefully timed and 

 thorough application of the most 

 effective materials available even 

 under the best of orchard condi- 

 tions, growers should be constantly 

 reminded that failure to eliminate 

 dangerous environmental conditions 

 may largely neutralize their best ef- 

 forts at control and that they should 

 supplement their spray program by 

 removing such hazards as stone 

 walls, hedge rows, woods, and brushy 

 growth within and along the mar- 

 gins of their orchards. 



A cooperative experiment with Professor 

 Warren D. Whitcomb, Waltham Field 

 Station, and workers in other New Eng- 

 land States. 



