February 25, 2018

Grape Flea Beetle

 

Suzanne Wold-Burkness, E.C. Burkness, and Tederson Galvan, Department of Entomology, University of Minnesota

Grape flea beetles, Altica spp. (Coleoptera: Chrysomelidae) are small beetles that have enlarged rear legs that allow them to jump like a flea when disturbed. Two species of grape flea beetle, Altica chalybea and A. woodsi have been found in Minnesota, however, only the presence of A. woodsi has been confirmed. Both species are often found at the same time on the same host plant, Vitis spp. and Virginia creeper, Parthenocissus quinquefolia, and are capable of causing economic damage to grapes.

Identification

Grape flea beetle on a grape bud  (E.C. Burkness & T.L. Galvan, U of MN)

Grape flea beetle on a grape bud
(E.C. Burkness & T.L. Galvan, U of MN)

Grape flea beetles are small insects, approximately 0.3 – 0.5 cm long, shiny, with enlarged hind legs used for jumping. In the field, they can be identified by their size and coloration. A. chalybea is dark blue or blue-purple, larger than A. woodsi, and the body is 0.3-0.5 cm long, whereas A. woodsi is blue-green in color and somewhat smaller (0.4 cm).

Biology & Life Cycle

Both species have similar biology, life cycle, and feeding behavior, but differ slightly in their oviposition behavior. A. chalybea oviposits on buds and bark crevices, whereas A. woodsi oviposits on the underside of leaves later in the season.

Both Altica spp. overwinter as adults under the soil surface, in wood crevices, under rocks and fallen trees, and in vineyards. In the early spring, adults emerge from overwintering sites, feed upon grape buds, and mate. Females lay cylindrical shaped eggs near grape buds under the bark of the grape vines.

Grape flea beetle larvae (E.C. Burkness & T.L. Galvan)

Grape flea beetle larvae (E.C. Burkness & T.L. Galvan)

Grape flea beetle larvae (E.C. Burkness & T.L. Galvan)

Larvae emerge in about two weeks, and feed on leaves. First instars of A. chalybea feed on the upperside of leaves, while those of A. woodsi feed on the underside of leaves.  Newly hatched larvae are dark brown but eventually turn light brown and are 0.7 to 0.9 cm in length at maturity.  Between late June and late July, larvae fall on the ground to pupate just below the soil surface.  Adult beetles emerge in late July to early August, feed on grapevine leaves, but do not mate or lay eggs. Adults move to overwintering sites in the fall. There is one generation per year.

Damage

Damage is caused by adult beetles feeding on primary buds, which prevents them from developing into shoots, thus resulting in a decreased yield. The greatest economic loss occurs when beetles feed on buds from “bud swell” until the “first leaf separates from the shoot tip” stages (see Appendix A). Once shoot growth reaches 7 cm, damage caused by the grape flea beetle normally does not affect yield. Location of vines can affect the intensity of an infestation, with vines on the borders of the vineyard and next to wooded areas having higher infestations. In addition, weather can also affect the intensity of the damage. Cooler springs will extend the period of development when buds are more susceptible to the beetle feeding, thus increasing the chance of economic loss.

Grape flea beetle adult on grape bud (E.C. Burkness & T.L. Galvan)

Grape flea beetle adult on grape bud (E.C. Burkness & T.L. Galvan)

Grape flea beetle damage to a grape bud (E.C. Burkness & T.L. Galvan)

Grape flea beetle damage to a grape bud (E.C. Burkness & T.L. Galvan)

Management

Monitoring Grapes should be sampled during the “bud swell” to the “first-leaf separated from shoot-tip” stages, which is generally during late April – early May. Sampling should be done twice per week by checking for damaged buds and flea beetle adults. The current suggested threshold is 5% damaged buds.

Cultural & Physical Control

Remove debris and leaf litter on the edges of wooded areas located near vineyards to eliminate overwintering sites. In addition, shallow disking the area between grape rows can also help destroy overwintering pupae.

Chemical Control

Several insecticides provide good control of grape flea beetle, and can be found in the Midwest Small Fruit Pest Management Handbook.


References

Bordelon, B., M. Ellis, and R. Foster [eds.]. 2007. Midwest Commercial Small Fruit & Grape Spray Guide. http://hort.agriculture.purdue.edu/pdfs/07SprayGuide.pdf

Dami, I., B. Bordelon, D.C. Ferree, M. Brouwn, M.A. Ellis, R. N. Williams, and D. Doohan. 2005. Midwest Grape Production Guide. The Ohio State University Extension Service. 155 pp.

Ellis, M. D. Doohan, B. Bordelon, C. Welty, R. Williams, R. Funt, and M. Brown. 2004. Midwest Small Fruit Pest Management Handbook. The Ohio State University Extension. pp. 125-129. http://ohioline.osu.edu/b861/

Flaherty, D. L., L. P. Christensen, W. T. Lanini, J. J. Marois, P A. Phillips, and L. T. Wilson. 1992. Grape Pest Management, 2nd edition. University of California, Division of Agriculture and Natural Resources.

Galvan, T. L., E. C. Burkness, and W. D. Hutchison. 2007. Grape Flea Beetle. http://www.vegedge.umn.edu/vegpest/grapes/FleaBeetle.htm

Minnesota Grape Growers Association. 1999. Growing Grapes in Minnesota. MN Grape Growers Association, Lake City, MN.

Weigle, T. H., and A. J. Muza [eds.]. 2007. New York and Pennsylvania pest management guidelines for grapes. Cornell and Penn State Cooperative Extension. http://ipmguidelines.org/grapes/.

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