Summer brings with it some of our favorite garden vegetables: tomatoes, peppers, cucumbers, zucchini, to name just a few. But summer also brings some of the garden's most notorious pests whom, if left out of control, will devour those vegetables before they have a chance to make it to our table. Today I'm sharing a few of the pests we've encountered the most often in our zone 6b garden, and what's worked for us to combat them naturally.
Much of this post is dedicated to methods of cultural control; meaning the surrounding environment is “tweaked” in order to avoid pests. This is accomplished through companion planting, physically removing the pests either by hand or by a forceful stream of water, introducing a natural predator, or by crop rotation.
Sometimes however, those methods don't work well enough and as gardeners we have to make a decision to either lose the crop, or take a further step at controlling the pest. This further step usually involves a pesticide of some sort.
As a strong believer in natural gardening, I do not recommend conventional pesticides. However, as a natural gardener who is trying to earn an income from my crops, I will sometimes consider organic sprays under certain conditions. I'm including those in this post as well, along with cautions (if any) that should be taken.
Please remember: Never assume that just because a spray is marked “organic” it is safe for you, your pets, or for other beneficial insects you'd really like to have around. Always, always, always read the label and follow the instructions to the letter.
The very first summer that I planted a vegetable garden, I knew very little about tomatoes and even less about the pests they attracted. Imagine my surprise then, when rummaging through a jungle of tomato vines, I found myself face to face with a tomato hornworm. Thinking my beautiful tomato foliage had been invaded by tiny green aliens overnight, I was terrified.
As my gardening experience grew, I learned that this was not an alien — it was in fact a tomato hornworm.
Hornworms love to feast on the leaves of tomato plants and occasionally on those related to the tomato such as the pepper and eggplant. If left to their own devices, they can completely defoliate the plant. Not good.
Because these worms are a pretty good size and relatively easy to spot, the best way to combat them is to simply pull them off by hand. Toss them into a bucket full of warm soapy water and when they have ceased to exist, toss the bucket into your compost pile (you do have one, don't you?).
Observe your hornworms carefully: occasionally a small parasitic wasp will lay its eggs on the worm itself, forming numerous little white cocoons all over the hornworm's back. If you notice something like this, it is best to leave it alone. The parasitic wasps are friendly bugs and once hatched, will proceed to feast on the worm. There's no need to get rid of this worm — just let nature do its thing.
Another idea would be to plant borage amongst your tomatoes. Borage is a lovely, easy-to-grow herb that reportedly repels the hornworm.
If you must spray: Bacillus Thuringiensis aka “BT” will handle the hornworm as well as a few other pests such as leaf hoppers and cabbage worms. BT is a naturally-occurring bacterial insect disease that reportedly will not harm other beneficial insects, animals, or humans.
In our garden if we have tomatoes, we will have spider mites. It isn't a question of “if” it is more a question of “how many” and “how soon”. Mites are typically brought on by the summer heat and cause their damage by piercing and then sucking nutrients from the leaf leaving a series of tiny brown spots on the plant. If not brought under control, they will ultimately kill your tomatoes.
Unlike the tomato hornworm, spider mites themselves are difficult to spot so one has to look for signs and symptoms: tiny, pinprick “polka dots” on the leaves, webbing similar to spider webs, and frass (mite droppings).
Another way to look for them is to hold a white sheet of paper under the leaves. Shake the plant and then watch the sheet of paper. If you have mites, they'll slowly start moving around on the paper. They are tiny and typically red, but may be green or yellow.
One way of control is through prevention. While marigolds are a common favorite garden annual and also reported to be a great companion plant for tomatoes, they can potentially attract spider mites (at least in our area). If you must have marigolds, consider planting them a good distance away from your tomatoes.
Another means of control is to attempt to dislodge the mites with a forceful steady stream of water. Every week or so, take the hose to your tomato plants and wash them down.
Spider mites have predators — such as the lacewing. A few organic gardening suppliers offer a “herd” of these insects either as eggs to be hatched or in adult form. They can be purchased and released in your garden.
If you must spray: a pyrethrin spray can be used on a regular basis. A pyrethrin is a naturally occurring insecticide derived from the daisy. If you choose to go this route, please use with caution for two reasons:
- Pyrethrins can cause damage to beneficial insects.
- Some formulas utilize a carrier oil such as canola.
Canola is a GMO crop. I realize this can seem like a hairsplitting issue — and we're talking about very small amounts here — but I personally feel this is something to take into consideration.
Squash Vine Borer
My least favorite villain, and one that I seem to battle in my garden every summer, is the squash vine borer. This little guy tunnels through the stem of your squash (or cucumber) plant disrupting the flow of water and nutrients. One day you will have a beautiful, healthy plant, and the next day it will appear sad and wilted.
Other tell-tale signs include a mealy mass of greenish yellow frass (excrement) oozing from the stem. Usually however, by the time you notice you have a problem, the damage is pretty well done. There isn't a whole lot you can do to save your plant. Prevention then, is the best way to manage the borer.
Crop rotation is one way — avoid planting your squash in the same spot every year.
Floating row covers can be used to keep the borer moth from laying her eggs, but then you need to be sure that your flowers can still be pollinated or you won't get any squash.
Another suggestion would be to plant later on in the season. Louise Riotte, author of Carrots Love Tomatoes, indicated that she had few problems with squash vine borers when squash was planted closer to the fall.
Other gardeners suggest planting new seeds every two weeks to try and stay one pace ahead of the pest.
I have had reasonably good success by wrapping the base of the plant with knee high panty hose, preventing the borer from entering. This isn't 100% effective, and requires a lot of work, but it is worth it to get some summer zucchini.
If you do discover that you have a borer, try one or both of these things before giving up all as lost. First, slice open the stem and remove the borer, then bury the part of the stem that has been damaged. This may not save the plant, but it might perhaps prolong it enough for you to get some squash. Second, inject the stem with a shot of BT in hopes of killing the worm. Again, not always reported to be effective. In my opinion prevention and cultural control will be your best bet.
This unpleasant looking little guy draws his nourishment from the plant by piercing the tissue and thereby injecting it with a toxic substance. The result is a vine that turns black and begins to dry out. A few squash bugs may not kill a larger established plant but they can kill off small plants and small runners of larger plants, possibly decreasing the production of squash.
As with the borer, the best way to avoid the bug is prevention through crop rotation and removal of diseased squash plants. Don't compost them.
While working about in your garden, take the time to examine your squash leaves for beady little orange squash bug eggs on the undersides. Learn to recognize them and take them out before they hatch.
Another suggestion is to arrange a few 2×4 boards alongside your squash plants. During the night, the bugs will congregate underneath. Early in the morning, before the bugs are active, they can be removed from the boards and disposed of in a pail of soapy water.
If you must spray… you really don't have many options. Sprays that I could recommend are not effective against the squash bug. So, as with the borer, cultural control and prevention is the way to go.
A Few More Tips
Here are a few more tips for keeping things under control.
- Keep your plants strong and healthy. Make sure their proper water and nutrient needs are met. Pests are much more likely to prey upon a weak plant.
- Make it a daily habit to walk through your garden keeping a look out for signs of pests and disease. Try to take care of things as soon as you notice them, nipping potential problems right in the bud.
- Always remove any diseased plant tissue. Keeping the garden clean will also help keep pests at bay. Diseased plant tissue should not be composted.
- Learn to recognize beneficial insects, and leave them alone to do their job.
What pests do battle in your garden and how do you handle them?
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