Weevil pest of cherries, Anthonomus consors
Anthonomus consors is a native species of weevil that can cause serious injury to cultivated tart cherries. Like all weevils, adults have an elongated, slender beak that curves slightly. Adults of this species are about 2.75 mm (1/10 inch) with reddish-brown bodies. The larvae are legless, cream colored, and inhabit the pit of the fruit. This pest is distributed in regions of the state associated with native stands of chokecherry. Museum specimens of this species originated from Larimer, Jefferson, Durango, Fremont, and Boulder counties.
- Anthonomus consors is a species of weevil. All adult weevils have a distinct elongated snout or beak and are in the family Curculionidae. This species is a native pest of chokecherry and can cause significant injury to cultivated tart cherries.
- Oviposition, larval development, and pupation all occur within the pit of the host fruit. Oviposition and feeding wounds are evident on the surface of infested fruits.
- Management options include conserving natural enemies, shaking branches to remove adults from host plants, isolating cultivated tart cherries from chokecherry, and chemical controls.
Adult Anthonomus consors feeding on developing chokecherry. Feeding injuries are evident on the fruit surface and a single fruit can have multiple injuries. Image credit: Whitney Cranshaw, Colorado State University, Bugwood.org
Adult A. consors on developing chokecherry. Note the slight curvature on the elongated snout. Image credit: Whitney Cranshaw, Colorado State University, Bugwood.org
Immature cherry with a late-stage larva inside the pit. Image credit: Whitney Cranshaw, Colorado State University, Bugwood.org
Immature cherry with injuries due to oviposition of A. consors. Note that there are multiple wounds. Image credit: Whitney Cranshaw, Colorado State University, Bugwood.org
Life history and habits
Adults overwinter in sheltered debris or clumps of grass near previously infested plants. Overwintered adults can fly and disperse short distances to blossoming host plants in the spring. They tend to be most active in exposed areas of the plant, namely the upper crown and exterior.
Eggs are laid in the developing pit during the husk shedding stage when fruits are roughly pea sized. After the egg is inserted into the pit, the wound is usually sealed with a plug of excrement. Egg laying occurs for 2-3 weeks and peaks when cherries are half of their full size. The larvae develop and pupate within the pit. After emerging from the puparium, adults chew through the pit and emerge at around the time of ripening. The new generation of adults are active for less than two weeks before moving to winter shelter until the following spring.
Adults feed on blossoms near the fleshy base, which can destroy the developing ovaries. Adults will also feed at the fruit and stem junction early in the season, resulting in fruit drop. The feeding punctures are distinct and can extend into the developing pit on small fruit. This feeding can produce dark scars on the surface of the feeding site and toughened tissue that can bind skin to the pit. Through the 4-6 weeks of spring activity, a single beetle can make over 100 feeding punctures and there can be multiple feeding injuries on a single fruit. Oviposition scars are similar in appearance to those produced by feeding but tend to be broader internally.
It is recommended that cultivated plantings of cherry be isolated from chokecherry. Some control can be achieved in small plantings by shaking branches over sheets laid underneath the trees, which will dislodge adults. Shaking is recommended at temperatures of 65-70°F, and branches should be repeatedly shaken to dislodge tightly clinging adults. After dislodging from the host plant, adults will retract their legs to appear dead.
While insecticides have not been specifically tested for managing this pest, some insecticides labeled for use in cherry against other fruit feeding weevils can be effective. If treatments are attempted, it is suggested that applications be made after blossom fall when weevils are cutting stems and feeding on small fruits. A repeated application can also be made after husks have fallen from small fruits.
Colorado State University. (n.d.). Cherry Curculio. Colorado State University – Extension. Available https://webdoc.agsci.colostate.edu/bspm/arthropodsofcolorado/Cherry-Curculio.pdf