The Crux of Fruit Tree Care: Part III-Insects

The Crux of Fruit Tree Care: Part III-Insects

Critter Concerns

Insects like fruit trees for many of the same reasons we like fruit trees, sweet smelling, pollen filled flowers and ripe, juicy fruits and seemingly sweet leaves and bark.  While we want to attract and protect pollinators and beneficial insects, injurious insects can cause serious damage, inhibiting fruit production or fouling fruit, stunting or gnarling growth and generally stressing out the trees. Described herein are some of the more common fruit tree pests, again, this list is by no means all inclusive and your property should be assessed by an arborist to determine when and where treatments are needed.


Codling moth larvae burrows into apples and pears feeding on flesh and seeds. Evidence, as pictured, is the frass-filled hole usually found at the bottom of fruit. Larvae will be difficult to control due to protection by the fruit, preemptive treatments will need to be applied in mid-July with follow up applications for the remainder of the summer.


Apple maggot larvae feed on the flesh of the fruit leaving brownish tunnels inside. Larvae are protected from control by the fruit itself, so treatments need to precede egg laying which usually occurs mid-July. Renewal applications may need to be performed for the remainder of the summer.


Pictured here is the adult fly of the apple maggot with its distinctive wing pattern. These will emerge from the soil in late June-early July and begin laying eggs approximately 10 days after.



Fecal secretions or “honeydew” from Psylla accumulate on branches and twigs and provide a host for sooty mold.


Pear Psylla feed on pear leaves injecting a salivary toxin defoliating tree. As temperatures reach 50 degrees adults become active and begin mating, earliest eggs to hatch will be prior to leaf out. A dormant oil treatment preceding bud break will be the most effective.









Trunk borers are a class of insects and larvae that feed on bark and wood inside the trunk of a tree. Young trees with diameters of less than 4 inches are especially susceptible.





winter moth caterpillar

Wintermoth caterpillars are major broad spectrum defoliators, they have been known to feed on maples, oaks, cherries, apples, crabapples, ash, fringetree and blueberry. Proactive treatment of eggs with horticultural oil along with follow up treatments throughout the summer provides the best control



eastern tent caterpillar

Eastern tent caterpillar, forest tent caterpillar and fall webworm all produce nests that appear as giant, inclusive webs. They are major defoliators and prefer ornamentals and fruit trees.













Pest Panacea

There may be some culturally curative measures that can be put in place making landscape fruit trees less prone to insect damage, but for the most part, correctly timed and accurately applied chemical treatments yield the best results.  There are many organic options and inert ingredients, such as horticultural oil and BT,  that provide effective treatments when applied precisely. Timing is everything when attempting to eradicate insect issues on your landscape, protecting pollinators and beneficial insect communities is still a high priority and must be considered when planning pest management.  NEVER spray a tree (or request a tree sprayed) while flowering and consult with your arborist and plant healthcare technician to come up with the most effective and environmentally responsible plan for keeping your landscape pest free!