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Garlic, Elephant Ear Garlic - Diseases, Pests and Problems

Basic Information

Problem: White Rot
Affected Area: The disease affects the roots

Description: White fluffy material appears on the stem of the plant at the base of the bulb and moves upward and inward. This can occur in specific isolated sections of a field or in large areas.

Control: Avoid planting in fields where this has been present in the past. Destroy infected plants and treat the soil with fumigants. Using fungicides has also been useful. The fungi cannot live under certain conditions including high summer heat or large amounts of water. Flooding a field while it is hot outside has proven effective in controlling the disease.

Problem: Botrytis Leaf Blight
Affected Area: The disease affects the leaves

Description: White spots surrounded by light green appear on the leaves. Under moist conditions the fungi will spread and the leaves will die and become dry.

Control: Fungicides should be applied in the early stages of the plants when only a few leaves are present. Spacing plants about a foot apart to allow for good airflow also helps control the disease. Crop rotation also helps in control.

Problem: Downy Mildew
Affected Area: The disease affects the leaves

Description: Leaves may have slightly lighter patches in the early stages that turn to brown as the disease gets worse. Parts affected will eventually fold over and die. When it affects the stalks it weakens the plant and the plant cannot hold the weight and it falls over.

Control: Crop rotation is a good way of controlling this disease. The use of appropriate fungicides also helps control the disease. Allowing the field to have proper drainage can help in keeping the mildew from forming.

Problem: Cladosporium Leaf Blotch
Affected Area: The disease affects the leaves

Description: Brown sores appear the length of the plant leaves. Mostly happens later in the plant life after the bulb has formed.

Control: To control the disease make sure to plow the area very well. The best way to control the disease is to apply fungicides late in the season when the disease usually affects the plants.

Problem: Cercospora Leaf Spot
Affected Area: The disease affects the leaves

Description: White spots appear on the leaves more at the tips than at the base. The tips of the leaves often turn brown and start to die. This can eventually kill the whole leaf.

Control: Plant good seeds in well-drained ground. Crop rotation as well as the use of fungicides will also help control the disease.

Problem: Purple Blotch
Affected Area: The disease affects the leaf and stalks

Description: Sores appear on the leaves and stalks of the plants that have white centers. As it gets worse the sores will get bigger and turn purple with a yellow streak going up and down the leaf or stalk. This can cause the plants to start to die. It also affects the bulbs during harvest. The outer scales turn yellow and then red.

Control: Long crop rotations, good drainage, and larger spacing of the plants are recommended to control the disease. The use of appropriate fungicides is also recommended.

Problem: Twister
Affected Area: The disease affects the leaves

Description: Symptoms include the leaves curling and twisting while getting whiter. The plants may die and the bulbs rot easier while still growing or after harvest while in storage.

Control: The appropriate use of fungicides is recommended to control the disease.

Problem: Black Mold
Affected Area: The disease affects the bulbs

Description: The top of the bulb begins to turn black and the scales develop black sores. In the late stages of the disease the entire shell of the bulb can turn black and the bulb will shrivel.

Control: The use of fungicides is used to control the disease. Fungicides can be applied to the bulbs before and after planting and while the plants are growing. After harvest is it recommended that the bulbs be stored in cool conditions.

Problem: Blue Mold
Affected Area: The disease affects the bulb

Description: Soft yellow or purple spots develop on the scales. A blue/green mold can start to grow on theses spots. The bulbs continue to get soggy and eventually the entire bulb can rot.

Control: Make sure that all other diseases in the field are being controlled to eliminate the possibility for infection of the disease. Bruising should be avoided and the bulbs should be stored in cool temperatures. Fungicide use is also recommended.

Problem: Onion Root Maggots
Affected Area: Root

Description: Small white worms about 1/3" long. Large, winged adult flies are brown or gray, 1/4" long with a humpback appearance. Maggots burrow into onion bulbs destroying the crop. Damage is more serious in wet years.

Control: When needed, foliage can be sprayed with *malathion or diazinon when flies appear, about the time forsythia blooms. * Place Diazinon granules in furrow at planting time. Destroy culls immediately after harvest. * Pesticide use and recommendations for various areas are constantly changing. Check with your County agent for current recommendations.

Problem: Thrips
Affected Area: Leaf

Description: Thrips are tiny (1/25" long), slender insects, hard to see and often hide in the angles of the leaves (bulb). They feed on underside of leaves turning them a silvery color.

Control: Thrip damage generally does not merit control. * Diazinon or pyrethrum-rotenone combination. * Pesticide use and recommendations for various areas are constantly changing. Check with your County agent for current recommendations.

Problem: Cutworms
Affected Area: Leaf

Description: Plants chewed off just above ground level. Cutworms are caterpillars that are up to 1 1/2" long and mottled or striped green, brown or gray. When they are disturbed, they roll up in a coil. They usually position themselves at the moisture line in the soil moving up and down according to the water content. If the soil surface is dry, they will be found a couple of inches below the surface where the moisture begins. When newly watered, they will be at the surface.

Control: Put cardboard collar around new transplants to extend 1" to 2" above and below soil level.

Problem: Pink root
Affected Area: Bulb

Description: Roots rot and take on a pink color. Yields can be severely reduced.

Control: Plant in non-infested soil. Soil can be sterilized with Vapam before planting if problem is severe. Rotate planting location.

Problem: Neck Rot
Affected Area: Bulb

Description: Water-soaked spots appear in neck area, turning yellow. Gray mold brows between bulb scales and bulb deteriorates. Usually appears just before harvest.

Control: Avoid using excessive nitrogen fertilizer and allow tops to mature well before harvest. Avoid injury to bulbs at harvest and dry before placing in storage.

Garlic, Elephant Ear Garlic


Plant garlic flat side down