Diaprepes abbreviatus

Citrus Root Weevil

Synonym(s): Curculeones japonensis, Curculio brevis, Curculio festivus, Curculio irregularis, Curculio quadrilineatus, Diaprepes distinguendus, Diaprepes guadeloupensis, Diaprepes guadelupensis
Class: Insecta
Order: Coleoptera
Family: Curculionidae


Photographer: Keith Weller
Source: USDA Agricultural Research Service

Description

Adult Description: The adult citrus root weevil (Diaprepes abbreviatus) can vary in color morphology. The body can range in color from gray to yellow and stripes can range from orange and black. The dorsal side of the body has longitudinal stripes from the head towards the end of the body. Adults range from 10 to 19 mm long.

Larva Description: Eggs are laid in clusters with a white uniform appearance that darken just before they hatch (7-10 days after they are laid). The larvae are white or yellowish in color and attain a length of 2.5 cm after 8 to 15 months. At this time the larva enter a pupal stage in which they are in a pupal chamber within the soil for 15-30 days.

Host Plant: Most common hosts are: citrus trees, papayas, sweet potatoes, ornamental plants, sugarcane, panicum grasses, peanut, corn, and other plant species. The Citrus Root Weevil is known to feed on over 270 species of plants from 59 different families.

Ecological Threat: This species is able to penetrate larger structural roots, causing plant death by removing water supplies and nutrients. When a tree becomes a larval feeding site, economic loss is exacerbated with the death of the tree and spreading of the weevil through the grove or field.

Biology: Diaprepes abbreviatus adults have a short life span of 3 to 4 months. However, within this time a female can lay up to 5,000 eggs. Eggs are laid in clusters of 30 to 260 between two leaves. As adults emerge to lay their eggs leaf notching damage may appear from feeding. The majority of their life span is spent in the soil where the larvae and nymphs will girdle the roots and prevent the plant from absorbing proper nutrients and water. After D. abbreviatus larvae hatch they move down into the soil and attach themselves to the plant roots.

History: Diaprepes abbreviatus is native to the Caribbean and was transferred to Florida by mistake in 1964 in an ornamental plant shipment from Puerto Rico. It was found in the Rio Grande Valley in 2000, southern California in 2005, and most recently found in the Houston area in 2009. The populations located in south Texas resulted in a quarantine to treat infected areas in 2001.

U.S. Habitat: Grasses, citrus trees, soil surrounding plant roots

Distribution

Native Origin: Caribbean

U.S. Present: Florida, Southern California and Texas

Texas: Rio Grande Valley, Houston

Resembles/Alternatives

The appearance of leaf notching from adult D. abbreviatus feeding on leaves of the host plant may be confused with grasshopper damage.

Management

To prevent Citrus Root Weevils proper drainage of soil surrounding citrus trees or grasses is crucial. Larvae cannot burrow into, and adults cannot emerge from dry, packed soil. Proper fertilization of areas surrounding infected trees and clearing of weeds helps prevent spread. Although monitoring systems do not exist for larval forms, adult populations can be estimated by setting traps around the base of citrus trees. Nematodes can be deposited into the soil to control populations without harming the plant. Foliar spray can also be used for adult and larval population management.

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References

Grafton-Cardwell, Elizabeth. 2004. Diaprepes Root Weevil. University of California Peer Reviewed 8131.

McCoy, C. W., and L. W. Duncan. 2000. IPM: An emerging strategy for Diaprepes in Florida citrus. In Diaprepes short course. Lake Alfred: Florida Agricultural Experiment Station. 90-104.

McCoy, C. W., D. I. Shapiro, L. W. Duncan, and K. Nguyen. 2000. Entomopathogenic nematodes and other natural enemies as mortality factors for larvae of Diaprepes abbreviatus (Coleoptera: Curculionidae). Biol. Cont. 19: 182-190.

Skaria, M., and J. V. French. 2001. Phytophthora disease of citrus associated with root weevils in Texas. Phytopath. 91(6) Supplement: S203.

Internet Sources

http://www.texasento.net/abbreviatus.html
http://edis.ifas.ufl.edu/

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