By: Amy Grant
Swiss chard is a member of the beet family grown for its large nutrient rich leaves rather than its root. Delicious and high in iron, magnesium and vitamin C, it is enjoyed not only by people, but by bugs that attack it. If you’re desperate to save your plants, read on to find out about common Swiss chard insects and pests.
Common Pests Found on Swiss Chard
It isn’t just us who enjoy those delicious, nutritious leafy greens. Sometimes it seems like there’s no battling the insects for our produce. In order to control the pests, it is important to learn to identify them. Bugs that attack Swiss chard, for example, are equal opportunists. Some, such as blister beetles, love the veggie, as do leaf miner larvae. Lygus bugs and their nymphs feed on the leaves and the buds of flowering plants.
Of course, it seems that aphids will eat anything, and Swiss chard is no exception. These small, soft-bodied insects feed on the underside of the leaves in droves, sucking the nutrients from them and leaving them curled and covered with honeydew.
Slugs also love to nibble on your greens as they sloth their way through the garden. Another beetle, the flea beetle, is a small, black beetle that feeds on seedlings, often killing them.
So with all these insects competing for our produce, what kind of Swiss chard pest control can be implemented before there’s none left for us?
Swiss Chard Pest Control
In the case of controlling aphid pests on Swiss chard, the use of insecticidal soap or a strong stream of water to dislodge them should do the trick.
Slugs, or in my case snails as well, can be controlled by hand picking or with either pesticides or traps. Also, avoid drenching the area where the chard is growing; these guys love moist conditions.
Beetles can be controlled by hand picking or with insecticides at seeding or after the emergence of the seedlings.
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Read more about Swiss Chard
Not all leafminers zigzag their way through leaves. If you see a similar whitish transparent blotch, this could also be the result of a leafminer. Blotchy leafminer damage is often mistaken for some type of disease. Columbine is almost guaranteed to have a few, if not several leaves showing the classic squiggly line damage. Plants in the spinach family, like Swiss chard and beets, are also favorites, but leafminers will also feast on cucumber, celery, eggplant, lettuce, pea, potato, and tomato leaves, Yes, that's pretty much everything in the vegetable garden. They will even chew their way through tougher shrubs and trees, like boxwood and citrus.
The damage is rarely severe enough to kill the plant unless there is a severe or repeated infestation that could stress the plant and weaken it, though it is certainly unsightly. In the case of vegetables grown for their leaves, like spinach, lettuce, chard and beet greens, leafminers can mean the total loss of a crop.
Ninety-five percent of home gardeners grow tomatoes. Hybrid varieties grown to resist bugs and disease are genetically altered, and the seed cannot be used the next year. The popular heirloom tomato ‘Brandywine’ remains the same plant generation to generation because it is not genetically altered. Bugs that typically become a problem on tomatoes are aphids, whitefly, and hornworms. Plant borage and nasturtiums near tomatoes to repel harmful bugs. Use a garlic/onion/pepper spray at the first sign of hornworm.
- There are several ways to grow bug resistant vegetables using organic, sustainable gardening methods.
- Hybrid varieties grown to resist bugs and disease are genetically altered, and the seed cannot be used the next year.
Beneficial insects are insects that you can attract to your garden or buy from catalogues that prey on harmful insects or their larvae. There are many different species for specific problems, and more information is available at several of the links listed on this page.
Brachonids, Chalcids and Ichneumon Wasps
These small beneficial insects destroy leaf-eating caterpillars. You can attract them to your garden by planting carrots, celery, parsley, caraway and Queen Anne’s lace, all members of the Umbelliferae family. These plants are easy to grow, and some should be left to flower. It’s the flower that attracts the insects.
These common insects consume aphids, mites, whiteflies, and scale. Planting members of the daisy family (Compositae), tansy, or yarrow will attract them to your garden. Ladybugs are also available from online catalogue.
Lacewings are avid consumers of aphids, and their larvae eat aphids and other varieties of other insect pests. They are attracted to “composite” flowers, such as yarrow, goldenrod, black-eyed Susans, and asters. Lacewings can also be purchased online at the sources listed below and released directly into your garden.
Hover-flies are avid consumers of aphids, and the larvae of hover-flies eat aphids and other insect pests. Like the Lacewings, they are attracted to “composite” flowers, such as yarrow, goldenrod, black-eyed Susans and asters. Seeds for these flowers are available online or at most garden centers.
These large insects have an appetite for most garden pests. Praying mantis eggs are set out in the garden where they hatch and quickly grow to adult size. The eggs are available through mail order and online catalogues.
Nematodes are effective against cutworms, a common pest that destroys sprouts before they can grow into seedlings. Nematodes are also effective against beetles and root weevil larvae.
Nematode eggs are microscopic and come in a small sponge a million at a time. These are mixed with water and applied to the soil, where they hatch and go to work. If they get on foliage, wash them off to the ground.
Nematodes are harmless to humans and pets. They are available in some garden centers, through mail-order catalogues, and at the businesses linked below.
TIP: Create Your Own Garden 'Mini Insectary'
You can set aside a small garden plot of flowering plants designed to attract and harbor beneficial insects. These ‘good’ insects prey on many common garden insect pests and offer the gardener a safer, natural alternative to pesticides. Read our guide for more information about creating a Garden Mini Insectary.
What's eating my beets, Swiss chard and spinach?
Sonia, who has a neighbouring community garden plot to mine, remarked something was attacking her beet leaves upsetting her plans to include some in her bread. The cause is a common insect pest that attacks beets, spinach and Swiss chard, known alternately as beet leaf miner or spinach leaf miner. For many, damaged beet leaves are not a huge deal (Sonia doesn't agree), but for Swiss chard and spinach where the leaf is the edible part, leaf miner attack is not a minor issue.
The damage - initially small, irregular brown patches on the leaf but gradually growing in size and becoming papery, resembling a blister, with black pepper-like particles inside - is caused by small yellow or white larvae as they tunnel between the top and bottom leaf surfaces. They start out as small white eggs laid singly or in groups of two to 10 on the underside of the leaf by a small grey fly in late May. The eggs hatch within a week and the larvae chew their way through the leaf epidermis to start feeding. The larvae mature after one to two weeks and drop to the soil to burrow five to eight centimetres below the surface to then change into pupae. After two to four weeks of further development, adult flies emerge to start the cycle over again. There is usually more than one generation per year.
Every year, a few of my beet leaves are attacked, but not enough to be overly concerned. And Sonia doesn't really have many affected leaves either. But since the attack starts in May, small plants can be susceptible to attack and become stunted and weak under heavy infestations.
It is nearly impossible to control the adult stage, and once the larvae are tunneling through the leaf, there are likewise few control options as they are protected by the leaf surfaces. But there are a few ways to limit their numbers and impact. Start with good weed control. Beet leaf miner can complete its lifecycle on lamb's quarter, nightshade, chickweed and other weeds. Removing these hosts will limit their food source and reduce adults reaching maturity. Next, as soon as you notice damage, remove and destroy affected leaves before the larvae mature - do not compost. If you notice the damage later, after the larvae have dropped to the ground, you can disturb the soil around the plants in the hopes of damaging or exposing the pupae. After harvest and/or before planting, rototill the soil to expose the pupae to adverse environmental conditions and to birds that will gladly swoop down to consume them. If you have a large garden, move your beets, spinach or Swiss chard to a different location every year. Finally, start your crop early and optimize soil moisture and fertility to maximize plant size to reduce the overall impact of an attack.
Shirley's easy refrigerator beet pickle
If you like pickled beets but hate the mess of canning, here's a quick and easy recipe from my friend's mom.
Bring 2 cups sugar, 2 cups vinegar and 2 cups water to a gentle simmer. Stir until the sugar is dissolved. Remove from heat. Add 1 tablespoon each of whole allspice and whole cloves plus 2 or 3 sticks of cinnamon steep at room temperature for 30 minutes. Pour over 6 to 8 cups of diced, cooked beets. Refrigerate. They will be ready to eat after two days. These beets will keep in the fridge for up to four weeks.