Seedlings Cut Off at Base Signals Cutworm
Cutworms completely sever the stems of Swiss Chard seedlings at or below the soil surface. They are 1- to 2-inch long, dull-colored, plump, soft-bodied larvae, or grubs, that curl up when disturbed. Cutworms feed at night and hide in the soil during the day. A simple preventive measure, if you think you have a problem, is to make a barrier around each seedling by fastening a piece of stiff paper, 3 inches wide, around the stem of the seedling, pushing some of the “collar” into the soil. Or make a trap by sprinkling 1/2 teaspoon of corn meal or bran meal on the soil around each plant. Spread it in a circle leading away from the stem of the plant. The cutworm will eat the meal and die. For more information see the file Dealing With Cutworms
Ragged Holes In The Leaves And Bits Of Green Excrement Are Signs Of Imported Cabbage Worms.
The white female butterfly zips about from plant to plant, depositing her eggs at the base of the leaves. In about a week, tiny green caterpillars hatch and begin to chomp the leaves. When swiss chard plants are small, cabbageworms feed primarily on the undersides of the developing leaves. If there are only a few worms, they can be easily hand picked. For more detailed solutions see the file Dealing With Cabbage Worms
Pale or Yellow Spots, Leaves Distorted Usually Means Aphids
Found throughout the United States, several types of aphids attack Swiss Chard. Soft-bodied, pear-shaped sucking insects about the size of the head of a pin, they suck juices from tender new shoots. Usually green or black, they may also be brown, pink, yellow or red. Aphids retard or distort growth, causing the leaves to turn yellow or brown, wilt under bright sunlight, or sometimes curl and pucker. Pick or pinch off infested leaves and stem tips throw them in the trash. For more information see the files on Controlling Aphids
Little Holes Develop On The Leaves
Flea beetles make numerous little holes in plant foliage and they can destroy small plants rapidly. If the leaves of your swiss chard plants look perforated by pin holes, you have flea beetles. Flea beetles are 1/10 inch long, shiny and black, and may have yellow or white markings. They are very active and jump like fleas when disturbed. For more information see the file on Controlling Flea Beetles
White or Brown Tunnels in Leaves Means Leafminers
White or brown tunnels or blotches on leaves are signs that your chard has leafminers. The leaves may turn yellow and blotchy and look blistered or curled. Leafminers are small black flies, usually with yellow stripes. The tiny yellowish larvae feed between the upper and lower surfaces of leaves, causing the tunnels or blotches to appear. Remove the infested leaves before the larvae mature. For more information see the file on Controlling Leafminers.
White Downy Substance On Leaves Is Downy Mildew
Chard infected with downy mildew will have yellowish or light green areas on the upper surfaces of older leaves. Seedlings develop purplish lesions on the leaves and stems, which become covered with white downy fungus. Plants die very rapidly after contracting downy mildew. If you catch the infection early, apply a copper-based fungicide to diseased and surround plants every 7 to 10 days until harvest. Remove and destroy any plants with a serious infection. For more information see the file on Controlling Fungal Disease