Managing Stink Bugs on Peaches

By Breanna Kendrick

At the recent Stone Fruit Field Day, Cory Penca gave a presentation on managing key pests of peaches in Florida. Penca is an entomology Ph.D. candidate and a student in the Doctor of Plant Medicine program at the University of Florida. His presentation covered stink bugs, Caribbean fruit flies, plum curculio and mites.  Penca’s pest management practices have been developed during his research in three seasons of field work.

According to Penca, stink bugs can be difficult to manage, and it doesn’t take a lot of them to cause crop losses. During the spring when the peach crop is beginning to develop, stink bugs are hunting for a food source, and peaches are one of the ideal crops for the pest to feed on. Stink bugs come from outside the orchard and stab the fruit as it is developing. The stabbing damage will develop into an injury called cat-facing, in which the fruit expands slower at the point where it was fed on. At the feeding point, the peach becomes folded because the cells there cannot expand.

Pests like stink bugs can be monitored with a yellow pyramid trap design with a pheromone lure applied to it. “It’s a really good method because it tells you about the stink bug population in the entire area around the orchard, and you can even find information about the stink bug population before the fruit has developed,” said Penca. “It gives you an idea early on if you have a population of stink bugs already present as soon as January or February. From my data, I’ve found in some locations that stink bugs, at relatively high levels, are present before the fruit has even passed the petal fall stage (this means when the flower is still on the tree, but not fruit). So, they’re obviously feeding on something else in the area and then switch over to the peaches when they are available.”

Penca said a low number of stink bugs could cause problems, but the pest is hard to find at low levels. Also, depending on the time of day and the conditions, stink bugs might not be as present, so growers might underestimate their problem. He said finding just one or two stink bugs could imply a high population of the pest. “Often, when you are looking, you will find no stink bugs at any given time; this does not mean you don’t have a stink bug problem,” Penca advised.

Broad-spectrum chemicals are necessary for stink bug management. Recommendations from the Southeast Spray Guide are to mix neonicotinoids and pyrethroids, not pyrethroids alone. “You need to control early when the peaches are very young and developing,” said Penca. “This is when they are the most vulnerable, but you want to control up until harvest.”