April 19, 2018

Apple Twig Borer (Grape Cane Borer)

Suzanne Wold-Burkness, Department of Entomology, University of Minnesota

The apple twig borer, Amphicerus bicaudatus (Coleoptera: Bostrichidae), also referred to as the grape cane borer, is a wood feeding beetle that is widely distributed from the eastern U.S. west to the Rockies

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Apple twig borer adult (T.L. Galvan, U of MN)

Adults are elongate, approximately 0.5-1 cm long with a reddish brown to brownish black color. Larvae are white with brown head and about 1 cm long when mature.

The apple twig borer overwinters as an adult within burrows made in live canes. As weather warms, they become active in late April and early May. Adults emerge in early spring and deposit eggs from April to June in the bark of grape vines.

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Apple twig borer adult in a vine (T.L. Galvan, U of MN)

Young larvae burrow into the vine, usually to the pith, and tunnel along the stem, packing their frass behind them. Larvae mature and pupate in fall and early winter. Many pupae transform to adults in fall. Adults usually overwinter with head downward in larval galleries through winter. Some adults emerge in fall and move to new, living twigs where they burrow in and overwinter. There is one generation per year.

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Apple twig borer tunnel in a vine (E.C. Burkness, U of MN)

Vine damage occurs from mid-September into the fall season, when adult beetles burrow into live canes in search of over-wintering sites. However, adult beetles can be found boring into healthy canes, which ultimately leads to cane death.

Feeding by the grape cane borer can reduce node survival and fruitfulness, the number of clusters per cane, and cluster weight. Their damage can also delay establishment of the training system in young vineyards.

Although damaged canes can be pruned out, this requires extra time and labor to accomplish. Also, because the damage is difficult to see, damaged canes are sometimes retained, thus contributing less to the overall yield.

References

Allen, L.J.S., Strauss M.J., Thorvilson, H.G. and Lipe, W.N. 1991. A preliminary mathematical model of the apple twig borer (Coleoptera: Bostrichidae) and grapes on the Texas High Plains. Ecological Modelling. 58: 369-382.

Beiriger, R., 1988. The bionomics of Amphicerus bicaudatus (Say), the apple twig borer, on the Texas High Plains. M.S. thesis. Texas Tech. Univ. Lubbock, TX. 56 pp.

Beiriger, R., Thorvilson, H., Lipe, W. and Rummel, D., 1988. The life history of the apple twig borer. Proc. Texas Grape Growers Assoc., 12: 101-106.

Hessler, S., G. Loeb, and T. Martinson. 2007. Grape Cane Borer. http://www.nysipm.cornell.edu/factsheets/grapes/pests/gcb.pdf.

Popenoe, E. A. 1888. Observations on two insect pests. Kansas State University, Bulletin No. 3. http://www.oznet.ksu.edu/historicpublications/pubs/sb003.pdf.

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