The Effects of Travel Speed, Nozzle 

 Arrangement, and Application Volume on 

 Pesticide Distribution in Apple Trees 



Daniel R. Cooley 



Department of Plant Pathology, University of Massachusetts 



Spraying recommendations may seem as though they 

 are based only on common sense rules of thumb, or worse, 

 nothing at all. So it is encouraging when scientific facts are 

 generated that support spraying recommendations. 



Dr. Jim Travis and Dr. Turner Sutton, plant patholo- 

 gists at Pennsylvania State University and North Carolina 

 State University, respectively, recently completed studies 

 on spray deposits in apple trees. The usual recommenda- 

 tion to direct 2/3 of the sprayer output toward the top 

 1 /3 of the tree, and 1 /3 of the output at the bottom 2/3 of 

 the tree is based on work done in 1965. Since that time, in 

 spite of the significant changes in tree size and pesticide 

 formulation, that recommendation has continued to be 

 made. Travis and Sutton found that the recommendation 

 is still relatively sound, if trees are of medium size (ap- 

 proximately 13 ft high X 12 ft in diameter). However, as the 

 tree size decreases to 9.5 ft high x 9.5 ft in diameter, a 50:50 

 ratio (half directed at the top 1/3 and half directed at the 



bottom 2/3) gives the best deposit throughout the tree, and 

 the lowest variability from one part of the tree to another. 

 Of course, there are many other factors which affect 

 spray deposition. Of those examined in the recent study, 

 the following were found to optimize spray deposition: 



1. A tractor speed of 2 mph was found to be better than 1.5 

 or 2.5 mph; 



2. A rate of 66 gal/acre was better than 40, 100, or 400 gal/ 

 acre; 



3. Well pruned trees were better than moderately to 

 poorly pruned trees. 



Adhering to these guidelines could improve spray 

 deposition and distribution in fruit tree foliage, making 

 pesticide applications more effective and more efficient. It 

 is important to note that the tests were made under a 

 specific set of conditions, which may or may not have 

 relevance to each particular orchard. However, if these 

 practices can be tried, they can help control costs. 



:(: * 4: 



Biological Control of Apple Blotch Leafminers 

 in Massachusetts Apple Orchards 



Roy G. Van Driesche, Ronald J. Prokopy, and William M. Coli 



Department of Entomology, University of Massachusetts 



T. Bellows 



Department of Entomology, Division of Biological Control, University of California, 



Riverside, CA, 92521 



Introduction 



The apple blotch leafminer (ABLM), Phyllonorycter 

 crataegella (Clemens) is a small (1/4 inch) moth in the 

 family Gracillariidae that has become a significant pest in 

 Massachusetts apple orchards since the mid 1970's. This 

 problem has occurred due to the development of resis- 

 tance to common orchard cover spray materials, such as 



azinphos-methyl (Guthion™), which formerly suppressed 

 populations as a side effect, although there was no con- 

 scious effort on the part of the growers to do so. 



Following the first detection of resistance in ABLM 

 populations in Massachusetts, resistance spread rapidly 

 throughout the region. Densities of mines rose sharply as 

 the pest was controlled neither by cover sprays (which no 

 longer affected the moth), nor, in commercial orchards, by 



