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The cherry fruitworm
(Grapholita packardi Zeller) feeds on a number of host plants including apple, cherry, blueberry, rose and hawthorn.Facts:
- Adults lay their eggs on both the fruit and foliage of blueberry plants.
- Larvae hatch and bore into the first fruit encountered, often entering the calyx cup of the berry.
- When larvae are about one-half to three-quarters grown, they move to an adjacent berry in the cluster, boring from one fruit to another at the point of contact and lining the junction with silk.
- Some larvae attain their full size within the second fruit, while others may feed on additional berries.
- After larvae develop into caterpillars, they leave the fruit and excavate small burrows in a dead blueberry cane, a pruning stub or the stem of a dead weed nearby.
- Larvae remain inactive within these burrows for the remainder of the growing season and throughout the following winter.
- With the onset of mild temperatures, the larvae pupate within their burrows and emerge as adults.
- Look for a pin-sized entry hole near the stem of any small berries that have begun to turn blue, and then open adjacent berries to find the reddish colored larva.
- A premature color change in the fruit is often the only visible sign of an infestation.
- In order to prevent damage by cherry fruitworms, two applications of a residual pesticide are usually needed during the adult's flight period in the spring.
- Sprays applied against the cranberry fruitworm and plum curculio should also give adequate control of cherry fruitworms.
- Check with your local Cooperative Extension Service office for control measures for your area.
Cline, Bill and Meyer, John R. 1997. Cherry Fruitworm
. Blueberry Pest Management. Retrieved 02 September 2011.