When gooseberry and currant growers find hollowed out, discolored berries that fall off early, it is time to look closely for other signs of invasive gooseberry fruitworms.
Gooseberry fruitworms are the larval stage of the gooseberry moth (Zophodia convolutella). This insignificant looking moth can cause significant damage.
Gooseberry moth description
Adult gooseberry moths are grey with a 1” wingspan. You may be able to see a white fringe on the back of the rear wings, and white horizontal stripes on the forewings, as well as a brown spot. More often, all you will see is a small, narrow-bodied greyish-brown moth.
Larvae are 3/4” long. At first, they are a pale green. As they mature, the head turns brown and dark stripes can be seed down the sides of the body. Sadly, I was unable to track down a photo. Please share one in the Comments if your berries have been so afflicted.
Gooseberry moth lifecycle
Adult moths lay eggs on currants and gooseberries. When the eggs hatch, larvae burrow into the fruit and begin feeding on the pulp. This discolors the fruit and causes it to drop prematurely. A single larva will feed on several berries. Berries may be held together by a silken thread. There is usually only one generation each year but, being invasive insects, the lack of natural predators may cause that to change.
Gooseberry moth controls
Handpick and destroy any larvae you see, or feed them to your chickens. Bacillus thuringiensis and spinosad can also be used against these pests. Treatments should be applied when fruit is first developing and again 10 days later.
You can grow a surprising amount of food in your own yard. Ask me how!