The
tobacco hornworm is easily confused with the closely related tomato
hornworm. Both caterpillars are the larval form of hawk moths,
and both like to nibble on your tomato plants, but the tobacco hornworm
has seven white lines running down each side of its body while the
tomato hornworm instead has eight Vs.
Some gardeners resort to
hand-picking their hornworms, while others
believe that planting marigolds or basil between their tomato plants
keeps the pests at bay. I just ignore the hornworms of both
types. In our diversified environment, parasitic wasps quickly
lay their eggs in each plump hornworm, and the wasp larvae eat the
caterpillar alive from the inside out. By the time these white
cocoons show up on the back of the hornworm, he has long ago stopped
nibbling on my tomatoes, so I am careful to leave hornworms like
this in place to hatch out the next generation of parasitic wasps.
(I know I left you
hanging about the tomato
blight. It turned out I had too much to say to fit in one
post (surprise, surprise), so you'll hear all about it in a lunchtime
series next week.)
Huh -- what are the wasps good for? I think of them as being mostly good for stinging people. :^(