The past 3 years we have had a worm in many of our North Star tart cherries....

Asked May 2, 2015, 4:31 PM EDT

The past 3 years we have had a worm in many of our North Star tart cherries. I have not been able to get a comsistent idea for treatment of this problem. When the cherries are pitted there will be a little white worm with a black head inside.can you tell me how to prevent these worms from growing inside my cherries. There doesnt seem to be a blemish on the outise of teh cherry in most cases.

Hennepin County Minnesota fruit trees fruit trees horticulture cherry trees

4 Responses

Thank you for the question. There are two possible culprits for this condition: the cherry fruit fly or the spotted wing drosophila. The females of both these insects lay their eggs in the cherries, and the small worms you are seeing are the larva. The female adult does pierce the cherry with her ovipositor to lay the egg that turns into the larva. Look very closely and you will most likely see the hole. There is no effective remedy for the larva, so the control must be accomplished on the adult fly prior to the egg laying. Larva of cherry fruit fly and spotted wing drosophila look very similar so it's best to monitor for adults so you can tell which insect is causing the problem. This can most easily be done by constructing some simple traps as described in the publications I'm providing here for you:

1. http://www.extension.umn.edu/garden/yard-garden/fruit/integrated-pest-management-for-home-stone-fruit-growers/cherry-fruit-flies/index.html

2. http://www.extension.umn.edu/garden/yard-garden/fruit/integrated-pest-management-for-home-stone-fruit-growers/spotted-wing-drosophila/index.html

Once you have identified the pest, treatment is similar for either one and is usually most effective when sanitation and insecticides are used together. It is very important to remove and dispose of all infected fruit because the larva can overwinter in fruit on the ground and several generations of spotted wing drosophila can be produced in a single season. Be sure to throw the cherries in the garbage and not the compost pile. Use an insecticide at the same time to kill the adult insects.

Please follow the label on the insecticide container exactly because the label is the law. The publications I provided will guide you in your choice of insecticide.

Thank you for contacting Extension.

Thank you so much for your response. I really apprecite your quick turn around.
do you have any idea where to buy the yellow sticky cards. I have checked at Bachmans,Otten Brothers,Dundee, Tonkadale nursery and Home Depot and noone has them or heard of them.
i really appreciate your help.


There are many online options to mail order them. Google "Yellow sticky traps for insects" and you will be presented with many options reasonably priced. I even saw a YouTube video showing how to make your own traps. Of course, I can't vouch for the homemade trap's effectiveness but you can decide for yourself.
If I hear of any local store with them, I'll pass the information along to you.

Our University of Minnesota Extension Entomologist Jeffrey Hahn suggested you try this website: http://www.gemplers.com/

Good Luck!