Adult Campylomma verbasci
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Campylomma verbasci (Meyer)
(Hemiptera: Miridae)
Mullein plant bug
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by Bradley S. Higbee (bhigbee@apple.yarl.ars.usda.gov
), USDA-ARS, Yakima, Wa.
Campylomma is a generalist predator of apple
and pear orchard pests including mites, aphids, and pear psylla. Unfortunately
it is also recognized as a pest of apple fruit and in rare instances
may cause damage to pear. Adults and nymphs are predacious, but may
feed on fruit (causing cosmetic damage to skin of fruit) if available
prey are reduced to very low numbers. Campylomma occurs in most
deciduous fruit growing regions of the northern U.S. and southern Canada.
Appearance
The adult is green-brown, elongated oval in
shape, and about 1/10 inch (2.5mm) long. It has a dark spot
on the first antennal segment and black spines on the legs.
The nymphs are ovate and translucent when first hatched, but
gradually turn pale green. The egg is about 1/28 inch (0.87mm)
long and sac-shaped. It is inserted into the bark, stems, and/or
leaves of host plants with only the operculum (cap or cover)
exposed.
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Habitat
Campylomma is found in both pome fruit trees
and herbaceous plants, particularly mullein.
Pests Attached
Common prey include aphids, mites, thrips, and pear psylla.
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Third instar nymph of Campylomma feeding
on third instar pear psylla. |
Life Cycle
Campylomma overwinters as an egg in apple and pear bark and
perhaps other woody deciduous hosts. Eggs hatch in the spring before
bloom of apple and pear. Nymphs develop through five instars in about
21 days at 72 degrees F (21 C). The period of nymphal development of
the first generation is the time fruit is most likely to be damage by
Campylomma feeding. Adults first appear in mid to late May in
the Pacific Northwest and a portion of the population moves into surrounding
herbaceous hosts, particularly mullein (hence the common name), where
they feed on thrips and other available prey. They migrate back into
the orchards in late summer, where they mate and lay overwintering eggs.
There are from two to four generations per year in the Pacific Northwest.
Relative Effectiveness
Campylomma can have a major impact on pear psylla populations in
pear and aphid populations in apple. This mirid predator appears to be
tolerant to many insecticides and is one of the few predators ruotinely
found in heavily sprayed orchards.
Pesticide Susceptibility
Certain pesticides are known to be highly toxic to Campylomma,
chlorpyrifos and formetanate hydrochloride are used when control is necessary,
while others may have suppressive or little effect.
Conservation
Campylomma must be monitored closely early in the season in order
to distinguish between beneficial and potentially damaging populations.
Although apparently tolerant of many pesticides, use of pesticides that
have a narrow spectrum of activity will help conserve this predator.
Commercial Availability
C. verbasci is not known to be commercially available.
References
Beers, Elizabeth H., et al.1993. Orchard Pest Management, A resource
book for the Pacific Northwest. Good Fruit Grower. Yakima, Wa.
McMullen, R. D., and C. Jong. 1970. The biology and influence of
pesticides on Campylomma verbasci (Hemiptera: Miridae). The
Canadian Entomologist 102: 1390-94.
Thistlewood, H.M.A. et al. 1990. Seasonal abundance of the mullein
plant bug, Campylomma verbasci (Hemiptera: Miridae), on apple
and mullein in the Okanagan Valley. The Canadian Entomologist 122:
1045-58 .
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Suggestions, corrections, and/or comments are appreciated: Contact
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