Date of Award


Document Type


Degree Name

Master of Science (MS)


Plant and Environmental Science

Committee Chair/Advisor

Juan Carlos Melgar

Committee Member

Guido Schnabel

Committee Member

Sruthi Narayanan


This project evaluated possible causes of peach skin bronzing, a brown-blotchy skin discoloration on mid to late-season peaches that causes drastic decreases to grower incomes in the Southeastern U.S. It is known that there is no bacterial, insectile, viral, or fungal cause of bronzing; thus, these studies focused on potential nutrient imbalances within the peach. On the ‘PF23’ variety, factors of irrigation, potassium fertilization, and transpiration-inhibiting sprays were tested to see the various effects on the incidence and severity of bronzing. The hypothesis was that excessive irrigation and excessive soil potassium concentrations would induce a higher incidence and severity of bronzing because of a sudden increase in transpiration and nutrient movement; the addition of transpiration inhibitors, such as Transfixâ, would decrease the incidence of bronzing; the application of soil amendments such as mulch and mulch with poultry litter will decrease bronzing incidence and severity by balancing soil nutrients; and that bronzed areas will have higher amounts of potassium than control areas. While the root of the bronzing problem still requires further research, these studies showed how the amount of water and nutrients in the soil, or high transpiration, were not always conducive to increased bronzing, and possibly other environmental factors such as relative humidity or temperature may influence it. This study also showed how excessive irrigation was not the issue inducing bronzing, and transpiration inhibitors do not consistently work in reducing bronzing. Imbalanced fertilization in orchards certainly does not help to prevent bronzing, but there was no consistent data on a specific nutrient that could be inducing bronzing when in excess.

Author ORCID Identifier

Available for download on Sunday, December 31, 2023