Ask a Gardener - Peach Borer
Question: I am seeing evidence of peach borer. Is it to late to trap? What are my other options to care for my trees? - Jodele
It’s not too late to set out traps for peach borers. In fact, setting out traps will give you some crucial info for timing further controls. And peach borer control is all about timing.
Adults are small moths with clear wings. They emerge in the late spring to early summer (i.e. right now), flying around during the day and laying eggs. Lots of eggs. One adult female can lay up to 400 eggs on a tree. Immediately after they hatch, the larvae begin burrowing into the sapwood of the tree. This is when the peach borer does its damage. The deep gouges the feeding larvae leave can disrupt nutrient flow, weakening or even killing the tree. They continue to feed and develop until winter sets in. After the winter, they reach the pupal stage, sometime in May or June. After a pupation of 2 to 4 weeks, the adult moths emerge and the cycle starts again.
Peach borers can be hard to control since the damage is done while they are living inside the tree. The best way to control peach borers is well-timed applications of preventative insecticides right when the adults are laying eggs and when the larvae are just hatching. This is the only time the borers are outside of the tree and vulnerable. Sticky fly traps or pheromone traps placed around your tree will tell you when adult peach borer moths are present. Once you see evidence of adult borers, spray around the base of the tree.
One of the best insecticides for peach borer, is Fertilome’s Fruit Tree Spray. It’s a mix of pyrethrins, the most commonly recommended borer killer, and neem oil, a natural horticultural oil made from extracts of the neem tree. It kills all stages of bugs; adults, eggs and larvae. It’s also safe to use on edibles and can be applied up to the day of harvest.
Another common deterrent used for peach borers is old fashioned moth balls. The CSU Extension Office gives these instructions:
After clearing away leaves and other debris from around the tree base, place the moth balls in a band 1 to 2 inches from the base of the tree trunk. Cover them with enough soil to create a 5- to 10-inch packed mound around the plant. Moth balls release a gas at temperatures above 60 degrees F. The gas penetrates the trunk to kill peach tree borer larvae. Applications are best made in late September or early fall but also can be applied in late spring. To avoid plant injury, follow these precautions:
1.Do not allow the crystals to touch the tree bark.
2.Adjust the amount of crystals used by tree size. Use 1/4 ounce on a first-year tree, 1/2 ounce on a 2-year-old tree, 3/4 ounce on a 3- to 5-year-old tree, and 1 to 2 ounces on a large, well-established tree.
3.Remove the soil mound three weeks after the application.
Once the lifecycle is broken, take extra special care of your tree. Make sure it's well pruned, watered and feed to help build up resistance.