Q. I am finding a large worm varying from 2 – 5 inches in length
on my grape vines. It is roughly 1/2 inch in diameter. The body color varies,
green, pink, grey, and brown worms have been removed
and destroyed. Each worm has white
diagonal stripes over the length of the segmented body.
What is it, and how do I avoid it in the future?
on my grape vines. It is roughly 1/2 inch in diameter. The body color varies,
green, pink, grey, and brown worms have been removed
and destroyed. Each worm has white
diagonal stripes over the length of the segmented body.
What is it, and how do I avoid it in the future?
A. You will notice a stiff, semi-curved spine sticking up from its
rump as well. This is the hornworm, this spine contributing to its name. The
hornworm is commonly found on tomato so it is usually called the tomato
hornworm but also damages peppers and eggplants as well.
rump as well. This is the hornworm, this spine contributing to its name. The
hornworm is commonly found on tomato so it is usually called the tomato
hornworm but also damages peppers and eggplants as well.
 |
| Not my picture and not from southern Nevada bud demonstrates the “spine” |
This is a larva or immature form of the
hummingbird or sphinx moth which is a very beautiful large moth. The moth began
laying eggs sometime in around March and April so the hornworms have been
damaging garden plants since around April or May.
hummingbird or sphinx moth which is a very beautiful large moth. The moth began
laying eggs sometime in around March and April so the hornworms have been
damaging garden plants since around April or May.
The hornworm is avoracious eater and can defloiate a plant making it leafless in a very short
time. Because of their green color they are hard to see on garden plants even
though they are large. On a windless day you can watch your garden for a few
minutes and see the plant or leaves move because of their size and weight. This
way you can identify their locations.
You can also look for defoliation, entire leaves
missing from plants, and that is also a very good sign they are present. Their
excrement is large so seeing that is another way to identify their presence. If
you have a blacklight that you used for “seeing” bark scorpions at
night you can use this at night as well. Hornworms “fluoresce” or
shine a different color at night from plants and can usually be easily found
this way.
missing from plants, and that is also a very good sign they are present. Their
excrement is large so seeing that is another way to identify their presence. If
you have a blacklight that you used for “seeing” bark scorpions at
night you can use this at night as well. Hornworms “fluoresce” or
shine a different color at night from plants and can usually be easily found
this way.
Control is fairly easy by handpicking when you see them and
hunt them down or use the same biological spray that you use for grape leaf
skeletonizer or tomato fruitworm; Bt or Spinosad.
hunt them down or use the same biological spray that you use for grape leaf
skeletonizer or tomato fruitworm; Bt or Spinosad.
Both Bt and
Spinosad can be used by organic gardeners safely. Spinosad is a little rougher
on bees than Bt so it is always best to spray any pesticide at dusk or early
dawn when bees have not started to forage. Always follow label directions for
use.
Spinosad can be used by organic gardeners safely. Spinosad is a little rougher
on bees than Bt so it is always best to spray any pesticide at dusk or early
dawn when bees have not started to forage. Always follow label directions for
use.