Monday, July 2, 2018

Fighting Those Garden Pests: Tomato Horn Worm, Cabbage Worms and Squash Bugs and How to Control Them

Summer is the time that the insects (garden pests) come out in force.  I don't mind sharing a little with them, but sometimes images from The Very Hungry Caterpillar enter my dreams and suddenly I'm waking up in cold sweats.  My hankering for a TRUE garden tomato begins to far outweigh my generosity with my little garden friends.  I am sure most gardeners are feeling the same right now as you probably went out recently to peruse your beautiful garden and found your cabbage eaten to pieces or whole branches on your Super Sonic tomatoes with no leaves.  Not to worry.  All your work is not wasted, that is as long as your still checking on your veggie babies in the hot temps!  You are, right?! With a little diligence and helpful hacks you can still savor a great harvest.  Here are 3 common pests you will encounter at some time in your garden careers and the basics how to combat them, Organically and Economically.  I emphasize Organically and Economically.  Many Organic pesticides exist but I am trying to use what you may already have at hand or can get easily. 

Cut Worm eating tomato

Tomato Horn Worm

These vicious little creatures are the caterpillar (larva stage) of the Five-Spotted Hawk Moth.  The moth will lay eggs on the leaves of your tomato vines.  The horn worm then hatches and proceeds to fill up his belly on your beautiful tomato vine.  They are voracious eaters.  They eat the entire leaf and stem and even the tomato as the picture illustrates.  Damage can be quite rapid, so it is best to check your plants daily for evidence of damage. They will start out as small green worms but will increase in size quickly developing the tell-tale horn and white stripes. Often times you will find white capsules on their backs as well which are the eggs of a parasitic wasp. You may also find piles of their frass (excrement).
Tomato foliage after worm ate it!

 If you're not too squeamish, my favorite (because it works) way to control this pest is to inspect the plant thoroughly (ALL over the plant!) and remove all worms and eggs and destroy.  They are camouflaged quite well so as the plant gets bigger this can be a little more daunting and problematic.  An infusion or tea made from Calendula (Pot Marigold) flowers mixed with dish soap, to help it adhere to the leaves, is a great deterrent.

Large Tomato Cut Worm
RECIPE Steep 1 cup crushed up dry or fresh Caledula flowers in 2 cups of water.   After cooled, add 1 1/2  quarts water and 1/2 tsp dish soap.  Spray on foliage.

You can also use a similar concoction by making a tea from Cayenne peppers, which are a natural insecticide.  Companion planting Insect Deterrent plants such as Dill, Calendula, Lavender, Petunias, and Thyme is also a great way to protect your beauties and harvest the benefits as well.


Cabbage Worm

Very much like the Tomato Horn Worm these worms are a larva stage and very voracious eaters. They can be controlled much the same way as the Tomato Horn Worm, but keep a close eye out.  These worms are typically much smaller and tend to come in droves.  You can identify them by their solid green color, which nearly matches the color of the foliage on their Brassica family hosts.  You can also find them by small and round, black or brown droppings, and the sections missing on the leaves from their dinner.  You can remove and destroy them but since they come in such large quantities all at once, it is best to try preventative measures first.

Make your garden an inviting place for beneficial insects by planting flowering plants and avoid using chemical insecticides designed to kill every moving insect in sight.  You can spray your plants with Tansy oil mixed in water which will deter eggs being laid on your plants.  You can always plant plants that are insect deterrents like Pot marigolds, members of the onion family, and Tansy.  Garden netting as row covers works quite well as the fruit that you will harvest will not need pollinated.  The plant will flower and seed after you harvest so using a good garden cloth to cover your plants will work nicely.

If they have already been invaded you can of course remove them as aforementioned.  If you are too squeemish for that task and  have chickens you are in luck.  Chickens love them and will eat all of them. You can also dust with a light powder of Diatomaceous Earth.  The worms will eat it and die.
Squash Bug eggs on bottom of leaf


Squash Bug

Like the others in this garden criminal line up, these pests are hungry and can cause severe damage to your squash plants.  They also appear in large groups seemingly overnight.  The first thing, if you are lucky, is to locate a mating pair.  2 to 3 of these mating pairs can lay enough eggs in a very short time to create an infestation so if you can destroy these early interlopers you might have them licked.  Others will more than likely appear, though, so keep an eye out.  They will mostly lay their red colored eggs on the underside of the squash leaf but you may find them on the top if lucky.  If found, remove the eggs and destroy. Often each bunch of eggs will probably total up to nearly 50, so be careful to inspect the whole plant and destroy all of them.  Missing one batch could result in allowing a small hungry army.  If they have hatched you will find small black or gray, soft shelled nymphs.  They are unable to fly at this point, so catching them might be easier than adults but both the nymphs and the adults will eat the foliage and fruit of the squash.  If they have hatched spraying them with a mild solution of dish soap water will slow them down making them easier to catch and may even kill them on contact. 

Beyond destroying the eggs, nymphs, and adults, a light coating of Diatomaceous Earth on the plant might do the trick.  You can also try a light spraying of Organic Neem oil or Horticultural Oil to deter them from your plants.  Of course my favorite go-to's are my cayenne pepper powder or tea and insect deterrent plants like mentioned earlier.  Nasturtiums, Petunias, and Dill planted nearby provide a deterrent for Squash Bugs, as well.

Overall Insect Prevention Methods

As always there are some very good general practices that you can start today that will work for most if not all insect invaders.
1) Visit your garden regularly.  Inspect for damage and identify the culprit.  Early detection can help to prevent major damage before it occurs.
2)  Keep your garden neat.  Remove diseased plants.  Control weeds and avoid planting your plants too close.  This allows for air circulation and helps for visually detecting the invaders.
3)  Practice staggered planting.  By planting a small amount of a crop several times over a period of time, you can hopefully eliminate the pest from the earliest plants before they invade your later plantings increasing your chances for a harvest.
4)  In the earliest stages of planting, you can use a row cover or netting.  This garden fabric will allow for light and moisture while keeping the door closed on invaders.  As the plant grows you will want to remove the cover as it keeps all insects out including beneficials and pollinators.  As your garden plants bloom they will need these insects for fruiting to develop.

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1 comment:

  1. As a general rule, if the Brix level of your plants is high enough insects won't bother them. There are some exceptions though as the pests you mentioned tend to eat any plant, regardless of how well mineralized the soil is. You can also use a spray that contains BT (sometimes called BTI) that is a natural, organic means of killing worms.