
Grape flea beetle, Altica chalybea Illiger
This is a metallic blue-green beetle that is almost
5 mm long. Adults overwinter in debris in and near the vineyard. They
become
active early in the spring and lay eggs in cracks in the bark, at bases
of buds, between bud scales, and on leaves. Eggs are light yellow and
are
laid in masses; they hatch in a few days and larvae feed on grape
leaves
for 3-4 weeks. Larvae are brown with black spots, and reach a length of
10 mm (image
shared by H. Hogmire). Larval feeding damage
consists of characteristic chain-like feeding
marks on leaves, although occasionally this injury may appear more
extensive (image
shared by H. Hogmire). However, the damage by adult grape flea beetles
is more important.
The beetles eat holes into the sides of buds and gouge out the contents
as the buds swell. Such injury occurs most prominently on thick-leaved
grapes which have large buds, such as the American cultivars `Concord'
and `Niagara'. It should be noted that climbing cutworms can cause
similar
damage. However, damage by the latter pest complex is usually more
ragged
in appearance. Adults also feed on the unfolding leaves.


When larvae are mature they drop to the ground
and
pupate in an earthen chamber. Adults emerge 1-2 weeks later, in July
and
August. These adults feed for the rest of the summer but cause little
damage.
The injury consists of small patches eaten out of leaves (See Cornell
photo). In the fall they seek protected places in which to
overwinter.
In addition to wild and cultivated grape varieties, grape flea beetles
feed on Virginia creeper.
The grape flea beetle is more common in neglected
vineyards, but some Virginia commercial growers consider this species
their
main insect pest. Sprays and fall vineyard cleanup for grape
berry
moth aid in controlling flea beetles, but sprays may need to be
directed
against this pest early in the season. This pest may escape proper
identification
because of its injury being mistaken for that caused by climbing
cutworms.
Injury be the latter is more likely to be ragged in appearance, though
there is overlap in appearance. Proper identification is increasingly
important
as we depart from the use of broad spectrum organophosphates; control
provided
by many new tools may not be as effective for Coleoptera as for
Lepidoptera.
(see Cornell
photo)
This is taken primarily from an extension
bulletin
by D. G. Pfeiffer & P. B. Schultz, entitled "Major Insect and Mite
Pests of Grape in Virginia" (Va. Coop. Ext. Serv. 444-567 (1986))
See New York fact
sheet
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