Organically Controlling Cherry Fruitworm

In the months of May and June, a sole egg is laid on cherries by the small gray adult moths that will produce the cherry fruitworms. Typically this process begins in late May, although you may notice the gray adult moths flying about in mid-May. The single eggs laid by the tiny gray moths will produce small pink-colored larvae, which hatch in just 10 days.

The larvae is about three-eights of an inch in length and will bore into-and feed upon--the fruit where they are placed. A black head, along with a caterpillar-like body, distinguishes the cherry fruitworm. In addition to cherries, this pest can also harm blueberries, especially in the eastern part of Northern America, according to Michigan State University.

Organically Controlling Cherry Fruitworms: Overwinter Practice

Whereas the cherry fruit flies and the cherry fruit sawflies both fall into the soil and go underground to pupate, the cherry fruitworms overwinter, instead, in the stubs of the pruned fruit tree branches or in its bark crevices. This fruit pest will produce one generation of fruitworms annually, and it only affects cherries and blueberries.

Cherry Fruitworms: Signs

The cherry fruitworm has the potential to be very damaging to cherry crops and the only sign of its existence visually is the rotten fruit it produces. Rotten flesh is indicative that the fruitworm is feeding on the fruit food from the inside and immediate removal and destruction of the damaged fruit is important to halt the fruitworm damage to the rest of your cherry or blueberry crop(s).

Organic Remedies for Cherry Fruitworms

Cherry fruitworms create an entrance wound into the fruit that they are attacking, but they destroy it from within. Therefore, to control them you have to kill them in the egg-laying stage, which is towards late May. Bees will be around during that period, so a bee-safe product is needed.

The biological insecticide Bt is the organic remedy used for cherry fruitworms, and it is also a safe biological insecticide to use around bees. But it needs to be applied the first week of June, to halt the eggs from ever growing and entering the fruit.

Other Related 'Organically Controlling' Articles Include:

Organically Controlling Cherry Fruit Flies
Organically Controlling Cherry Fruit Sawflies
Organically Controlling Apple Maggots
Organically Controlling Aphids on Fruits

Source
"The Gardener's A-Z Guide to Growing Food Organically" by Tanya L.K. Denckla
Michigan State University