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lations o£ those insect and mite species known to cause injury in 

 British Columbia apple orchards, and by spraying only when those 

 species were found to occur in numbers sufficient to cause economic 

 injury. The species were: codling moth, San Jose scale, fruittree 

 leafroller, thrips, plant bugs, white apple leafhopper, apple aphids, 

 and three species of plant-eating mites. Now, it is true that the 

 apple maggot and plum, curculio are not known to occur in British 

 Columbia, and that these are two of our most potentially injurious 

 apple pests in Massachusetts. On the other hand, codling moth and 

 mite injury is usually much more severe in British Columbia than 

 here . 



The approach that these researchers used to control codling 

 moth and mites is particularly instructive. To monitor codling 

 moth populations, they utilized sex attractant traps Pherocon ICP 

 type traps, manufactured by Zoecon Corporation, Palo Alto, Califor- 

 nia). These traps contain a small capsule of the synthetic sex 

 odor of female codling moths, which is a strong attractant for the 

 males. This odor was discovered and sythesized 4 years ago by Dr. 

 Wendell Roelofs and his associates of the New York Agricultural 

 Experiment Station at Geneva. Male codling moths attracted to this 

 odor are captured by a stick substance inside the trap. Dr. Madsen 

 and his colleagues installed these traps at a density of one trap 

 per hectare (about 2.5 acres) of orchard. They advised the growers 

 to apply a spray against codling moth only when the trap catches 

 averaged two or more male codling moths per hectare per week. Pre- 

 vious studies had shown them that virtually no codling moth larval 

 injury to the fruit occurred when fewer than this num.ber of male 

 moths was captured. 



By spraying for codling moth only when the traps indicated it 

 was necessary, less insecticide was applied. As a result, certain 

 natural enemies (predators) of the mites were able to survive, and 

 in some orchards began to build up into numbers which, by the end 

 of 1974, were sufficiently great to control the mites without need 

 for any miticide application. It would be a significant advance 

 if we in Massachusetts were able to succeed in reducing the spray 

 program as well as these British Columbia growers have done. 



In the next issues of Fruit Notes , I will explore some of the 

 reduced spray programs that are being studied in places closer to 

 home than British Columbia. 



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