Trouble With Swiss Chard: Common Swiss Chard Diseases And Pests

Trouble With Swiss Chard: Common Swiss Chard Diseases And Pests

By: Mary H. Dyer, Credentialed Garden Writer

Swiss chard is generally a trouble-free veggie, but this cousin to the beet plant can sometimes fall prey to certain pests and diseases. Read on to learn about common problems with Swiss chard, and explore possible solutions that may save the huge, nutritious, flavor-rich leaves.

Fungal Trouble with Swiss Chard

Fungal Swiss chard diseases are the most common culprits responsible when your plants fall ill in the garden.

Cercospora Leaf Spot – This fungal disease tends to affect lower leaves first. It is recognized by brownish-grey or black spots with reddish-purple halos. In humid weather, the leaves may take on a fuzzy appearance due to the silvery-gray spores.

Downy mildew – Humid conditions or excess moisture may result in downy mildew, a fungal disease that is unsightly but usually not deadly. Downy mildew is recognized by a whitish or grey, powdery substance on the leaves.

To prevent and treat fungal Swiss chard diseases, leave plenty of space between plants to provide adequate air circulation. You may also need to thin out the Swiss chard leaves. Water at the base of the plant and avoid wetting the leaves. Avoid excess moisture and water only when needed, since Swiss chard generally only requires irrigation during hot, dry weather.

If more aggressive treatment is required, use a fungicide containing copper.

Swiss Chard Pests

Occasionally insect pests are to blame when you have Swiss chard problems in the garden. The most common include:

Flea beetles – Leaves with a wilted or “shot hole” appearance may be a sign of flea beetles – small, black, bluish, bronze, gray, or sometimes striped pests. Sticky tape is an effective control, or you can apply a commercial spray containing pyrethrins or a homemade spray consisting of five parts water, two parts rubbing alcohol and 1 tablespoon (15 mL.) of liquid dish soap.

Spinach leafminer – Long, narrow tunnels are usually the work of leafminer larvae – pale white, carrot-shaped maggots. Cover the rows with cheesecloth or fine-mesh netting, or apply an insecticidal soap spray or pyrethrin-based spray.

Aphids – This common garden pest is easy to treat with insecticidal soap spray, although several applications may be needed. Avoid pesticides, which kill beneficial, aphid-eating insects such as lady beetles, syrphid flies, or green lacewings.

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Read more about Swiss Chard


How to Grow

How to Grow

  • Keep weeds under control during the growing season. Weeds compete with plants for water, space and nutrients, so control them by either cultivating often or use a mulch to prevent their seeds from germinating. Avoid disturbing the soil around the plants when weeding.
  • Keep plants well watered during dry periods to promote rapid, uninterrupted growth. Plants need about 1 inch of rain per week during the growing season. Use a rain gauge to check to see if you need to add water. It’s best to water with a drip or trickle system that delivers water at low pressure at the soil level. If you water with overhead sprinklers, water early in the day so the foliage has time to dry off before evening, to minimize disease problems. Keep the soil moist but not saturated.
  • If flower stalk appears, remove it to prolong the harvest.
  • Monitor for pests and diseases. Check with your local Cooperative Extension Service for pest controls recommended for your area.

Planting and Care

Greens are generally considered cool-season vegetables. This includes spinach, collards, kale, mustard, and turnip greens. In Florida, the season to plant these is August through February. Planting dates vary based on where you are in the state, of course. For more information on planting, we recommend consulting the Florida Vegetable Gardening Guide. It contains valuable information, including planting dates, depth, and spacing.

If the weather is already warming up it is probably too late to plant cool-season crops. But you haven't missed your chance to enjoy home-grown greens this year! Swiss chard can be planted later in the year than most greens. Plant chard as late as May (March in South Florida).

New Zealand spinach and Malabar spinach also grow well during warm months in Florida. If you're planting in the warmer months, consider adding these greens. Neither is a true spinach, but their flavor and texture are similar.

A row of leafy greens at the UF student gardens. Raised rows help control moisture and weed levels.

Once you've chosen your crops and cultivars, you're ready to plant. Raised rows or beds are excellent strategies for a garden of greens. If your soil quality is poor, improve it a couple weeks before planting. You can do this by adding compost or another organic soil amendment. For high yields of quality greens, control the weeds in your beds. This is especially important during the first four to six weeks after planting.

For greens, insects are usually more of a problem than diseases. Collards, kale, mustard, and turnip greens are all very closely related. As a result, they suffer from many of the same pests as cabbage. The insects that do the most damage are often larval forms (caterpillars) of moths and butterflies. Integrated Pest Management (IPM) can help you save your greens. You'll also avoid pesticides that may harm our vulnerable pollinator population.


Watch the video: How to transplant swiss chard and natural pest control in the garden!