Phony Peach Disease (PPD) is caused by the bacterium Xylella fastidiosa. The same organism causes plum leaf scald, Pierce's disease of grapes, citrus variegated chlorosis, and leaf scorch of almond and other plants. PPD is spread by leafhoppers.
Starting in early July, phony trees appear more compact, leafier, and darker green than normal trees because of short-internodes. Fruit size and number is drastically reduced. The trees hold their leaves longer in the fall. The picture shows a cross section of a primary scaffold limb. Note the black dots characteristic for infected trees.
Control. There is no cure for this disease. Control efforts are limited and focused on preventing disease spread (leafhopper control). For details see the Pest Management Handbook.
2009 Phony Peach Survey (Fred Singleton, Program Coordinator and State Apiarist, Dept. Plant Industry with Clemson). Plant Industry marked about 95 trees for Phony in Saluda County near Ridge Spring this month. I don’t recall marking this many trees on the ridge ever, unless more have been marked in the distance past. More can probably be marked for removal, but we are terminating the survey this year because of our other inspection obligations. Also, one grower in Allendale pushed over 700 trees on his own accord. Over the years, Allendale County has been a hot bed of phony disease. In recent years we have not been surveying intensely in Allendale County. The last 100 percent coverage of Allendale was in 1997.
Example of phony disease tree counts in past years: In 1965 we had 150 phony tree counts statewide. In 1979 we had 2,639 phony tree counts statewide. In 1996 we had 311 phony tree counts and these were all in Allendale, Hampton, and Orangeburg Counties. I assume since 1961 and thru the early 1990’s the phony peach survey was done mainly in Edgefield, Allendale, Hampton, and Orangeburg Counties. I’m not sure about the Spartanburg and Greenville county areas.
Since the early 1990’s we have concentrated our phony surveys in Allendale, Hampton, and Orangeburg counties. Allendale County can easily produce 100 or more phony diseased trees each year.
Peaches of trees infected with X. fastidiosa are small and twigs are shorter (more compact) than usual.