Q. Over the past two days, my two Concord grape vines have
been completely defoliated by a larva-like worm. It is yellow in color
with black bands around the body and a wider blue band at each end of the
body. Is the vine infected and needs to be removed or can the grape vines
be saved? The damage is done, but is there a preventative action I should have
taken?
A. This is the grape leaf skeletonizer, a dark blue black
moth that lays its eggs on the underside of grape leaves. They usually begin
laying eggs around April and that’s when control measures need to begin.
 |
| Grape leaf skeletonizer adult. A blue black moth. |
The egg
hatches and out comes a larva, fitting your description. This worm or larva begins
to skeletonize, or nearly defoliate the grape leaves leaving behind the veins
of the leaf. Hence the name, grape leaf skeletonizer.
hatches and out comes a larva, fitting your description. This worm or larva begins
to skeletonize, or nearly defoliate the grape leaves leaving behind the veins
of the leaf. Hence the name, grape leaf skeletonizer.
 |
| Grape leaf skeletonizer larva or worm eating the surface of a grape leaf. This is not my picture but I can’t find who sent it to me so my apologies to whomever it was. |
Control is
pretty simple and effective with organic pesticides containing Bt or Spinosad.
Sprays should be applied in April prior to egg-laying or just after.
pretty simple and effective with organic pesticides containing Bt or Spinosad.
Sprays should be applied in April prior to egg-laying or just after.
If you
follow my blog via my newsletter or my tweets on twitter, I announce when to
make these applications like these ahead of time. Otherwise, just mark your next
years’ calendar and make this application some time in the first two weeks of
April, depending on the weather.
follow my blog via my newsletter or my tweets on twitter, I announce when to
make these applications like these ahead of time. Otherwise, just mark your next
years’ calendar and make this application some time in the first two weeks of
April, depending on the weather.
Make sure
you spray the undersides of the leaves, not just the tops. The spray will work
now as long as the larvae, or the worms, present. It doesn’t work on the adult
moths. Your grape vine will put on new leaves to replace the damaged one so
just be patient.
you spray the undersides of the leaves, not just the tops. The spray will work
now as long as the larvae, or the worms, present. It doesn’t work on the adult
moths. Your grape vine will put on new leaves to replace the damaged one so
just be patient.
Thank you for the info.