Maximum Yield Australia/New Zealand March/April 2020 | Page 61

The hornworm derives its name from the distinct hook-like
horn protruding from its posterior. These hooks are often
mistaken for stingers, but in truth, are harmless. Fascinating
little creatures resembling a hummingbird when mature,
they are destructive little devils during their multi-stage
transformation into caterpillars.
Hard to Spot
Hornworms are masters of
camouflage. Although more than
10 centimetres long, their near
perfect colour-match of your
green tomato vines affords them
virtual invisibility. You really
have to look carefully to see
them. Once you do though, it’s
almost an aha! moment. But don’t limit your inspection to just
tomato plants. These worms also feed upon potatoes, peppers,
and eggplants, and can defoliate a plant rather quickly.
Though you may not see a hornworm, look for tell-tale signs
revealing their presence. Check any leaves beginning to
droop or vines that appear stripped of leaves. Take the time
to look your plants over thoroughly because once laid, their
eggs hatch quickly, usually within four to five days. Once
hatched, these newbies are voracious and destructive eaters.
Careful inspection can be the difference between a good
harvest and a good cry.
All in the Family
The tomato hornworm isn’t alone when it comes to eating
plants and dreams. Its cousin, the tobacco hornworm
(manduca sexta), can be just as devastating to its namesake,
the tobacco plant. Strangely, both are drawn to plants of
the nightshade family to include tomatoes, green peppers,
tobacco, eggplants, and potatoes. So, you may find a tobacco
hornworm on a tomato plant and vice versa.
While quite similar in looks, the tomato and tobacco horn-
worms are distinguishable. The tomato hornworm sports a set
of white, v-shaped markings along its sides with a black horn
on its tail end. The tobacco hornworm displays vertical white
lines with a red-coloured hook adorning its back bumper.
The pneumonic I use to remember which-worm-is-which is
associating the v-shaped markings of the tomato hornworm
with V-8 Juice, made from tomatoes.
Both insects pupate underground over the winter months
and emerge as moths in the spring. Time is of the essence
and reproduction is numero uno on their bucket list. After
breeding, the female deposits her eggs on the verso of the
leaf. When they hatch, the next four weeks are spent feeding
on your plants until reaching maturity, at which time they
drop back into the earth to pupate and reset the cycle.
Plant Friendly Pest Control
Gardeners wishing to avoid potentially dangerous chemicals
have some effective options. Here are some simple homestyle
remedies for dealing with hornworms.
The simplest, time-tested method to rid your plant(s) of
tomato hornworms is the hands-on/bugs-off approach. It’s
as uncomplicated as it sounds. You manually pluck the
hornworm off your plants with gloved fingers. Some use
water to blast them off but you run the risk of damaging the
plant and besides, it’s so messy.
“The simplest, time-tested
method to rid your plant(s)
of tomato hornworms is the
hands-on/bugs-off approach.”
Regardless of method, once removed, you can free-fall
the little critter into a container of water and effectively
drown him, or simply drop him to the ground and do your
best Bigfoot impression.
Spraying Your Tomatoes
Another deterrent to the hornworm and other garden
pests is to make up a sprayable solution from a base
of biodegradable, liquid dish soap. There are no set
proportions for the recipe. Just add water to a little
soap until it’s somewhat soapy then sprinkle in some
cayenne powder/pepper. Spray your plants down with
this solution. The soap helps the pepper-laden elixir
stick to the plant.
This has proven to be an effective treatment. Many
garden pests are repelled by the smell and taste of this
concoction. As an added benefit, this potion won’t harm
your plants. Reapply as needed.
Note: Should you discover a hornworm with a cluster of
white eggs attached to its back, give thanks. Those eggs
are not the eggs of the hornworm but of a garden-friendly
parasitic wasp (Braconid Wasp) that lays its eggs on the
back of the caterpillar. When those eggs hatch, it’s role
reversal. The wasp larvae become the diners and the
hornworm becomes the dinner.
Not to mention you’ll soon have a little army of wasps
(harmless to people) that feed on the tomato/tobacco
hornworm larvae while helping defend your garden
against other harmful insects.
For additional protection, place sheets of plastic on
your garden floor. This will help prevent the moth from
breaking through the ground come spring. This is also
effective weed control.
Nature vs Nature
Other methods of combating hornworms include the use
of pesticides. But good ones. Bacillus thuringiensis, or
BT as it is also known, is a safe biological pesticide or
living organism. It is a soil-dwelling bacterium that kills
a variety of garden pests including hornworms. Another
perquisite, BT is harmless to vegetation.
BT begins to work after an insect has eaten a leaf from
the treated plant. Once ingested, a specific protein is
produced that causes the insect to completely lose its
appetite. We all know what happens when you don’t
eat. BT can be readily purchased wherever gardening
supplies are sold and even online. Begin treatment early
or at the first sign of leaf damage.
And there you have it. With a bit of discipline and a little
help from Mother Nature, you too can enjoy a healthy
tomato/garden harvest and go from having a little green
worm to a big green thumb!
Maximum Yield
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