Grape Flea Beetle - Commercial Fruit Production in Minnesota

Grape Flea BeetleSuzanne Wold-Burkness, E.C. Burkness, and Tederson Galvan, Department ofEntomology, University of MinnesotaGrape flea beetles, Altica spp. (Coleoptera: Chrysomelidae) are small beetles that haveenlarged rear legs that allow them to jump like a flea when disturbed. Two species ofgrape 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 oftenfound 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.IdentificationGrape flea beetles are small insects, approximately0.3 – 0.5 cm long, shiny, with enlarged hind legsused for jumping. In the field, they can be identifiedby their size and coloration. A. chalybea is dark blueor blue-purple, larger than A. woodsi, and the body is0.3-0.5 cm long, whereas A. woodsi is blue-green incolor and somewhat smaller (0.4 cm).Grape flea beetle adult (E.C.Burknss & T.L. Galvan, U of MN)Biology and Life cycleBoth species have similar biology, life cycle, andfeeding behavior, but differ slightly in their ovipositionbehavior. A. chalybea oviposits on buds and barkcrevices, whereas A. woodsi oviposits on theunderside of leaves later in the season.Grape flea beetle larvae (E.C.Burkness & T.L. Galvan, U of MN)Both Altica spp. overwinter as adults under the soilsurface, in wood crevices, under rocks and fallentrees, and in vineyards. In the early spring, adultsemerge from overwintering sites, feed upon grapebuds, and mate. Females lay cylindrical shapedeggs near grape buds under the bark of the grape vines. Larvae emerge in about twoweeks, 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 aredark 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 soilsurface. Adult beetles emerge in late July to early August, feed on grapevine leaves, butdo not mate or lay eggs. Adults move to overwintering sites in the fall. There is onegeneration per year.

DamageGrape flea beetle adult on adamaged bud (T.L. Galvan & E.C.Burkness, U of MN)Damage is caused by adult beetles feeding onprimary buds, which prevents them from developinginto shoots, thus resulting in a decreased yield. Thegreatest economic loss occurs when beetles feed onbuds from “bud swell” until the “first leaf separatesfrom the shoot tip” stages (see Appendix A). Onceshoot growth reaches 7 cm, damage caused by thegrape flea beetle normally does not affect yield.Location of vines can affect the intensity of aninfestation, with vines on the borders of the vineyardand next to wooded areas having higher infestations.In addition, weather can also affect the intensity ofthe damage. Cooler springs will extend the period ofdevelopment when buds are more susceptible to thebeetle feeding, thus increasing the chance ofeconomic loss.Although primary damage is caused by adult fleabeetle to the developing buds, larval damage canalso occur on the foliage and is typically limited toseveral leaves and vines. However, larval damagedoes not usually affect grape quality or yield.Grape flea beetle damage togrape bud (E.C. Burkness & T.L.Galvan, U of MN)ManagementMonitoringGrapes should be sampled during the “bud swell” to the “first-leaf separated from shoottip”stages, which is generally during late April – early May. Sampling should be donetwice per week by checking for damaged buds and flea beetle adults. The currentsuggested threshold is 5% damaged buds.Cultural/Physical ControlRemove debris and leaf litter on the edges of wooded areas located near vineyards toeliminate overwintering sites. In addition, shallow disking the area between grape rowscan also help destroy overwintering pupae.Chemical controlSeveral insecticides provide good control of grape flea beetle, and can be found in theMidwest Small Fruit Pest Management Handbook.

ReferencesBordelon, B., M. Ellis, and R. Foster [eds.]. 2007. Midwest Commercial Small Fruit &Grape Spray Guide. http://hort.agriculture.purdue.edu/pdfs/07SprayGuide.pdfDami, 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 ExtensionService. 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 ofAgriculture 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.htmMinnesota Grape Growers Association. 1999. Growing Grapes in Minnesota. MNGrape Growers Association, Lake City, MN.Weigle, T. H., and A. J. Muza [eds.]. 2007. New York and Pennsylvania pestmanagement guidelines for grapes. Cornell and Penn State Cooperative Extension.http://ipmguidelines.org/grapes/