The heady aroma of summer nectarines and peaches means it’s time to be on the lookout for peach twig borers.
While examining my nectarines for ripeness, I spotted a reddish-brown larva with white bands undulating across a twig. Of course, I picked it up and dropped it in a little plastic bag and sealed it up tight, until I could look it up. That’s what I learned that even the nicest tree cage has its limits.
Peach twig borer description
The reddish brown larva I saw was relatively mature. They hatch out white with a black head. As they feed, the color darkens. Unlike other larval pests of peaches, the peach twig borer has white bands around its abdomen, though the bands are not always as obvious as they are in the photo above. The pupae are 1/4 to 1/2 inch long and brown. They do not have a cocoon. Adult moths are small, slender, and a mottled grey color, with fringed wings and a false snout. Oval eggs are yellowish-orange and laid on fruit, twigs, and leaves.
Peach twig borer damage
Not only do these pests kill off new twigs, buds, and blossoms, they can also damage existing fruit. Fruit damage is most likely to occur just before the fruit is ripe. Unfortunately, members of the stone fruit family do not ripen off the tree, so an early harvest won’t help. Peach twig borers feed on all members of the stone fruit family, including almonds, plums, and nectarines. Peach twig borers are not to be confused with peach tree borers, which do most of their damage deeper in the wood and at the base of the tree.
Peach twig borer control
Tachinid flies and braconid wasps provide natural controls. When that isn’t enough, you can spray environmentally sound insecticides, such as Bacillus thuringiensis (Bt) or spinosad, just as blossoms appear, for added peach twig borer control. Dormant oil can also be used in winter, when combined with the same insecticides, to kill off the overwintering larvae. The oil will not kill peach twig borers by itself. Pheromone traps can be used to interfere with mating and to monitor for these pests. Just be aware that hanging a pheromone trap can actually attract pests to your trees if handled incorrectly. Read the label.
So, as you check your nectarines and peaches for ripeness each summer, be on the lookout for these tiny pests. Also, add preventative treatments to your garden calendar while you’re thinking about it.
You can grow a surprising amount of food in your own yard. Ask me how!
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