What Is Wrong With My Asian Greens?

Are there any small, round reddish brown spots with white to grey centers on the upper surface of the leaves?

Are there any small translucent spots on leaves, spots later turn black?

Are the roots enlarged and clublike, plants are stunted with yellowish leaves that wilt during the day?

Are the seedlings dying and the stems are girdled or rotted at soil line?

Do the leaves have pale areas on upper surfaces and "downy" patches underneath?

Do the leaves have large, ragged holes in them?

Are the leaves curled and yellow?

Are there large or small holes in leaves, damage may be extensive?

Have the leaves been tunneled?

These symptoms indicate Alternaria leaf spot. Warm, wet conditions favor this fungal disease. Spray infected plants with copper and/or sulfur to prevent further disease development. Plant only pathogen-free seed from a reputable nursery.

Bacterial leaf spot causes circular translucent spots scattered over the leaf surface between the veins. These spots turn brownish-black and may spread to form large patches of dead tissue. To prevent the spread of this disease, avoid working around wet plants. Remove and destroy affected parts. Spray Bordeaux mix on remaining plants.

Enlarged and clublike roots are most likely caused by fungal disease - Club root. Remove and destroy any infected plants. Applying lime to the soil can reduce fungus sporulation.

If your seedlings are falling over and the stems are girdled or rotted at the soil line, the most likely cause is a damping-off disease. Remove and destroy all infected plants. To prevent damping-off let the soil surface dry between waterings, thin seedlings to avoid overcrowding and do not add nitrogen fertilizers until plants have developed leaves.

Pale areas on upper surfaces of the leaves and "downy" patches underneath are caused by Downy mildew. This fungus spreads quickly during cool, wet nights and warm, humid days. Leaves will wilt and die. Remove and destroy all affected plant parts and encourage good air circulation around plants by thining them. Water plants early in the morning to make sure they dry before nightfall.

Large, ragged holes in the leaves are caused by slugs and snails. Slugs and snails feed on the plant leaves usually at night. To control slugs and snails use diatomaceous earth around your plants. You can also handpick them during the night or use shallow dishes filled with beer as a trap.

Distorted, curled leaves are caused by aphids. These tiny insects cluster under leaves and on growing tips where they feed on plant sap. Leaves, stems, and buds get distorted, and later leaves and flowers drop from the plant. You can control them by washing them off the plant with water spray. Insecticidal soap should be used with severe infestations.

Cabbage looper is a pale green caterpillar with white lines running down either side of their body. Looper populations are usually held in check by natural enemies, but if they do become problematic larvae can be hand-picked from the plants. The application of BTK will effectively kill younger larvae.

Leafminers are known pests on Asian greens. These tiny pale green fly larvae feed between the upper and lower surfaces of the leaves. Prune off and destroy all infested leaves. Remove debris in fall because it might contain overwintering leafminers. Introducing parasitic wasps is a very effective method of controlling leafminers.

If there are tiny holes in leaves they are caused by Flea beetles. These tiny, black, brown, or bronze beetles hop when disturbed. Larvae are small and white, feed mostly on the undersides of leaves. Prevent problems by covering young plants with row cover. Control severe infestations by spraying or dusting plants with pyrethrin.