Peach Twig Borers [ Identify And Control ]

About Peach Twig Borers?

Peach twig borers are voracious pests. They can cause various types of damage, especially in young trees.

In spring and early summer, the larvae destroy shoots and shoots, and the offspring feed mainly on the developing fruit.

Young trees are most susceptible to damage from feeding new shoots, as they kill terminal growth and can develop side shoots. This will affect the tree’s ability to bear fruit during the season.

You will notice that your trees look wilted and their growth may be stunted.

Ripe and ripe fruit are also vulnerable.

The larvae forage under the skin of the fruit and are most vulnerable when the color falls off, gradually changing from green to the ripe color of the fruit until harvest.

They can gouge out areas inside the fruit and leave exit holes.

Second-generation larvae are active in early summer and severely damage ripe fruit in late July and August.

The second and third generations overlap in late July and early August, so the fruit is often infested with larvae from both generations.

In warmer climates, moths can produce fourth, and possibly fifth, generations, and their larvae migrate down their limbs to forage and cause damage before hibernating.

Identify

Identifying this pest can be difficult because the damage it often causes is similar to that of the eastern fruit moth (Grapholia molesta).

You can identify peach branch borer larvae by the black head and chocolate brown color, with alternating light and dark stripes around the abdomen. When fully grown, they are about half an inch long.

Other types of larvae found in drupes don’t look like this. For example, the larvae of the eastern fruit moth are white or pink with a brown head.

Peach branch borer is common in the Mediterranean region and is also found in other parts of Europe, Asia and North America. To date, it has not been found in Japan or Oceania.

Adult moths are gray with mottled wings, one-third to one-half inch long, and have prominent tentacles (modified mouthparts) that look like a snout.

Biology And Life Cycle

Peach branch borers can produce three to five generations per year, depending on the climate.

In cooler climates like Washington, these insects typically produce three generations. However, in warmer climates like Texas, they can have four or five.

After mating, the moths lay about 80-90 pale yellow or orange eggs on the foliage or fruit surfaces of trees.

Eggs hatch in about 5 to 8 days when the temperature is right, and up to 18 days when the weather is cool.

When the larvae hatch, they feed on twigs, fruits and buds. When they are full, they pupate.

The larvae do not pupate in the cocoon. Instead, they seek shelter on trees or dig into fruit tree trunk cavities.

In warm summer, pupae mature in as little as 7 to 11 days, but in cooler spring temperatures it can take up to 30 days.

Then the adults emerge, mate, and the cycle begins again.

What about winter? Larvae can overwinter in tiny silk cells, called hibernating cells, that can penetrate deep into cracks in bark, cuts, or the crotch of a branch.

You can identify these spots by the piles of red debris extending from them. In case you were wondering, it’s bug poop.

Overwintering larvae emerge in the spring when temperatures reach around 60°F and migrate along branches to enjoy newly emerging leaves, twigs and shoots.

They can also feed on the bark of trees before they reach the pink bud stage. This is the stage known as “pre-bloom,” when the flower buds are just beginning to open and reveal the petals.

As the ends of the limbs grow and develop, the larvae burrow into the center of individual shoots, causing the ends to wither.

Dead shoots caused by this feeding are called shooting strikes.

These larvae then settle and pupate within two weeks of late spring and emerge as adults. Soon after, the next set of larvae develop, producing moths in early summer.

These moths lay eggs and produce more larvae.

Monitoring

During the growing season, care should be taken to spray the spray before the larvae hatch and then burrow into the shoots or fruit.

Commercial growers use a method called grade day monitoring to time pesticide application, but that is beyond the scope of this article.

You need to monitor the emergence of larvae and moths so that you can apply treatment when they are most effective.

So how do you know when the larvae hatch?

You can double-check your trees for signs of emergence early in the season, and you can use pheromone traps to monitor adult populations.

Treating early in the season will help reduce the severity of summer infections.

Insecticide applications during the summer months are difficult to time accurately without degree day monitoring, as they must be applied when the larvae are actively feeding.

Monitor The Hibernacula

When a tree emerges from dormancy, a period called “delayed dormancy” refers to the time between when the buds swell and when green shoots appear.

This is usually when the overwintering larvae begin to emerge from hibernation. Double-check your tree for hibernation, which can be identified by erythema.

Monitor Shoot Strikes

Withered branches are easy to spot, and you should monitor trees of all ages for branch tap in the spring. They are most easily seen on young trees.

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Monitor the Adults By Pheromone Trap

Monitoring adult populations with pheromone traps will help you confirm that the pest in your orchard is peach branch borer and not some other type of insect.

Larger, more mature trees may have difficulty detecting damage. So if you’re concerned about adults, you can act accordingly.

In early spring, once the leaves start to grow, you should use pheromone traps to monitor when adults emerge.

Scentry Plastic Delta Trap 

Check for traps twice a week. When dust or dirt builds up, you will need to replace the trap floor.

Once you see more than a few moths per trap, you know you need to monitor more closely.

Check for the presence of eggs, which usually hatch within 5 to 11 days depending on temperature, and plan your treatment accordingly.

Once you’ve found an adult, be sure to use the spray detailed below during the dormant period to prevent an infestation during the next growing season.

Control Methods

Knowing when to treat this pest can be tricky. For best results, dormancy and early season treatments can prevent future generations from damaging your crops.

Crop control may include pruning and removal of hibernation during dormant periods, as well as pruning damaged shoots early in the season to remove larvae.

Commercial growers can use a number of different pesticides to control peach branch borer, but for home growers, spinosyn and Bacillus thuringiensis kustaki are more environmentally friendly options.

Pyrethrins are also effective, but they usually only provide 5 to 7 days of protection, so careful timing is required to ensure application coincides with the emergence of larvae.

Dormant Tree Sprays

Treatment During Bloom

If you use pesticides while your trees are in bloom, you could inadvertently harm your local bee population—even if the pesticides are marked as safe during bloom.

Bees can pick up pesticide residues in pollen and bring them to the hive. There it is fed to bee larvae. The efficacy of this insecticide is unknown, but it is wise to exercise caution when other options are available.

Again, Btk is a good option for killing peach branch borer larvae without harming bees.

Ideally, two applications of Btk should be used: the first when 10% to 20% of the flowers are in bloom, and the second when they are in bloom but before the petals drop.

Spinosyn and pyrethroids are also effective at this stage, but are toxic to bees.

Get Rid Of Peach Twig Borer Easily