7 - 



Results 



In the spring of 1986 all treated trees appeared free of X-disease 

 symptoms. However, in late July and August, nine of the 27 injected trees 

 began to display X-disease syrrptoms. Most of these trees were the most 

 severely affected trees in the fall of 1985. One of these trees died by the end 

 of the growing season. The remaining 18 trees stayed in remission through 

 fruit harvest and fall coloration. Fruit yields on these trees were normal. The 

 wounds from the injection completely closed by the end of the 1986 growing 

 season. 



Discussion 



The effect of OTC therapy on this block was a partial success, with most 

 trees remaining free of X-disease synptoms in 1986. Since most of the trees 

 that went out of remission were in poor condition before injection, there may 

 be limited effectiveness of OTC therapy on trees in advanced stages of the X- 

 disease. The Mauget capsule delivery system for the OTC antibiotic appeared to 

 be an effective and sinple technique for injection therapy in this experiment. 

 Additional research is needed to evaluate further this preliminary study. We 

 are particularly interested in establishing levels of injury at which treatment is 

 effective, and levels where treatment is not effective. 



Outlook 



The effect of Mauget injection of OTC for X-disease control currently is 

 being evaluated in 5 commercial orchards in central and western Massachusetts. 

 Trees in these orchards were injected after harvest in September and October, 

 1986. An update of this research project will be made in the fall of 1987. 



Literature Cited 



1. Lacy, G.H. 1982. Peach X-disease: Treatment site damage and yield 



response following antibiotic infusion. Plant Disease Reptr. 66:1129 - 

 1133. 



2. Sands, D.C. and G.S. Walton. 1975. Tetracycline injections for control 



of eastern X-disease and bacterial spot of peach. Plant Disease Rept. 

 59:573-576. 



Acknowledgements 



The authors wish to thank Dorence Green, Steven Smedberg, and George 

 Swain of Green Acres Orchards for their assistance and cooperation during this 

 study. We also thank the J.J. Mauget Connpany for supplying us with the 

 Mauget OTC capsules for these experiments. 



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