- Common mullein
The campylomma bug (or mullein plant bug) causes some damage in Utah apple orchards. Damage is inflicted by nymphs, which feed on developing fruit causing dimpling and fruit distortion. As apple fruits mature they become less susceptible to campylomma injury. Injury appears shortly after petal fall as small corky areas alone or small corky areas surrounded by a depression. Golden Delicious is typically more susceptible to damage tahn Red Delicious. Pear fruit rarely suffer damage, even at high campylomma populations.
Eggs are 1/28 inch long and sac shaped, and are typically inserted into the bar or under budscales with only the lid exposed, making the egg almost impossible to see. Nymphs are translucent white and oval shaped, and are damaging to developing fruit. Adults are 1/10 inch long, greenish brown to grayish brown, and shaped like an elongated oval.
Campylomma overwinter as eggs laid in the young twigs of apple, pear and other rosaceous plants. These eggs begin hatching in the spring at about pink stage of apple bud development. The insect has about three to four generations per year. A portion of first generation adults migrate from orchard trees to herbaceous weeds particularly common mullein. However, campylomma can be found in apple and pear orchards throughout the growing season. Late nymphal stages and adults are beneficial predators of aphids, mites, and pear psylla. In late summer through fall, adults on herbaceous weeds will migrate into orhcards to lay overwintering eggs.
- Dimpling and fruit deformity on developing fruit
- Small corky areas alone or surrounded by depression
- Severe injury can cause cat-facing
- Golden Delicious apples appear to be more sensitive to injury than darker skinned cultivars
At the present time, there are no effective cultural tactics for campylomma. In additon, no effective natural enemies have been discovered. Therefore, control efforts currently rely on properly timed application of chemicals.
There is a narrow opportunity for control between when the eggs hatch and when fruit damage by the nymphs occurs. Fruit is susceptible to injury from bloom until fruit reaches about ½ inch in diameter. However, the bloom through petal fall stage is the most susceptible to injury. Therefore chemical controls applied by late bloom are the most effective. If there has been a history of campylomma problems in an orchard, Lorsban can be used in the delayed dormant application to provide some suppression of spring nymph densities.
- acetamiprid (Assail)H
- formetanate hydrochloride (Carzol) - toxic to bees and predatory mites; during bloom, apply at night; do not use after petal fall
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Remember that the adult is a beneficial predator. Do not control unless necessary.