-20- 



Figure 2. Bacterial Canker: Factors Interacting With the Disease on Peach 



Healthy Tree 



Pseudomonas 



Cytospora 



Cold Stress 



Compartmentalization 



runing 



No Compartmentalization 



J 



i 



Healthy Tree 



Declining Tree 



materials have both bactericidal and fungicidal activities, and may be use- 

 ful in controlling the disease, though we are not sure at the present time. 

 In two orchards where Bordeaux or streptomycin were used, no incidence of 

 cankering was found in 1984, though adjacent orchards had the problem, and 

 one of the orchards had a history of the problem. 



Because there is potential for economic loss from this problem, we 

 developed an analysis that could be used to estimate losses. 



Our conservative estimate, based on orchard visits, is that approxi- 

 mately fiO to 80% of the orchards in Massachusetts suffered from 1% to \^% 

 tree damage. If you limit observations to trees from 1st to l?th leaf, the 

 percent loss is much more substantial, with approximately 50% - 90% showing 

 some damage. A written survey of 19 of the larger orchards in the state 

 indicated that 11 had serious loss, where approximately 15% of their total 

 trees were affected. Of the young trees, growers estimated 10% of their 

 trees lost, and damage on another 20%. 



Economics of growing trees indicate that, in 1980 dollars, in eastern 



New York (an area similar to Massachusetts) it cost $6174 to grow an acre of 



trees to 5 years of age, or $39.80 per tree. At this point, and for the 

 next 7 years, each tree would return approximately $9 annually. 



