The client’s peach trees kept getting gummy, sticky stuff on the fruit. Thus, the fruit ends up uneatable. The clients asked how to fix the problem.
DIAGNOSIS / RECOMMENDATION: After receiving photos from client, the issue on the fruit was diagnosed most likely as being caused by the Oriental Fruit Moth in various growth cycles/stages. The photos of leaves also showed issues; the cause could not be determined from the pictures but possibly was a nutrient deficiency, climate issues, or bacterial infection.
From The Bedford Extension MG Help Desk
Editor: Betsy B., Bedford Extension Master Gardener
ADDITIONAL INFORMATION: The Oriental Fruit Moth (OFM), Grapholita molesta, is a common pest on peaches, as well on other stone and pome fruit.  It can cause significant damage to fruit and causes some damage to twigs. The twig damage appears as flagging at the ends but is less a concern than is the fruit damage. There are 4-5 OFM generations per year in Virginia, and timing of controls is critical. In larger orchards (5 or more acres), mating disruption with pheromones may be possible. However, that approach will not work in smaller orchards or with only a few trees. [1, 2, 3]
The OFM overwinters in tree bark, dead leaves, or other debris as a fully-grown larva enclosed in a cocoon. In early spring, larvae develop into pupae and emerge as adults in mid-March to early April, depending on location and weather conditions. [2, 3] Removal of dropped fruit and dead leaves at the end of the season also may help to some extent by reducing pupation sites. Most summer cocoons are formed on the tree.
To effectively control OFM, a combination of monitoring through the use of pheromone traps and degree day (DD, base 45°F) determinations are used. Prior to first adult emergence (during pink to early bloom on peaches), pheromone traps should be placed in the orchard (the number depends on the size of the orchard). Beginning at the first sustained adult trap catch (the biofix point), the DD accumulation must be recorded to predict the proper insecticide timing. A max./min. thermometer, or other recording device, such as a pre-programmed degree day accumulator may be used.
The timing of insecticide treatments is based on the DD accumulations, along with continued monitoring. [1, 2, 3] A spray schedule needs to be followed to adequately control this pest. [4, 5]
All resource links accessed (January 2, 2017)
*Photo credits given in source link
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Answers provided herein were based on specific situations and growing conditions.These recommendations may or may not be appropriate for all circumstances.For specific recommendations for your particular situation please contact your local Cooperative Extension Office.
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–A Bedford Area Master Gardeners Association (BAMGA) Publication–