A few weeks ago, my remodeling contractor asked me if I knew what the humming bird-like moth was at his feeders. I told him he was seeing the adult form of the Sphinx Moth (or Hummingbird Moth) and that it would become the more familiar green worms that appear in his garden from time to time.
Next, one of our Facebook friends posted that she was on the lookout for them in her garden up in Maine. That was incentive enough for me to start inspecting my Pennsylvania garden on an occasional basis. Inspection at this point mostly consists of looking for missing leaves near the top of the plant (where a "stem skeleton" is all that's left), small piles of dark brown excrement lower down, and big bites out of green fruit. Basically, not much was happening - just a lot of growth to reposition inside the wire supports I'd installed. Then I got distracted and missed a few days. When I resumed my inspections, I was shocked to see what had happened in the meantime.
A major part of the canopy on a couple of plants was gone! And sure enough, the tell-tale signs of excrement were present below. I immediately abandoned "inspection mode" and went straight to "search & destroy".
Turns out this is a banner year for these pests. So far, I've found about 6 on my "Health Kick" plant (which makes me wonder if they can read and are into good health) and an equal number on the four Celebrity tomatoes I'd planted. More in two days than I usually find in an entire season!
So, how to manage them? First, you need to find them. The best time of day to look is when the sun is low, either early or late in the day - not at high noon. The only defense these guys have is their coloring and ability to live upside-down (belly up), hanging by their toes from stems and protected beneath leaves from sun and predators, so they are good at hiding.
I'd be remiss if I didn't mention that I could have prevented the problem by spraying Hot Pepper Wax regularly before the hornworms grew big. Since it's too late for that, I chose to remove them with my pruners (as close to the stem as I can without touching them). I toss them where the birds will find them -- that means under the bird feeders this year. Some were gone just an hour later and I'm sure all will be gone by sundown. There are other, more gruesome alternatives for control, but this solves my problem and helps the birds at the same time.
Since I had so many indivuals to choose from this year, I'm including some pictures of this year's crop of Tobacco Hornworm larvae, signs of their presence, and a borrowed pic of the adult moth. One of the most damaging insects for tomatoes, they're also one of the easiest to control when in the larval stage. (Adults are good pollinators, so leave them alone and just remove the larvae causing damage.) Happy hunting...
Linda Grotzinger
Damage to foliage and hidden larva - can you find it?
Excrement on lower leaves
Damage to green fruit
Larva upside down and protected by foliage
Close-up of tobacco hornworm - tail (horn) is red
Adult moth
