Cotton

Cotton Seedling Pests Associated with Poor Stand Establishment

Weak stand establishment may be caused by insects or plant pathogens, or by unfavorable weather or soil temperature at planting. If your cotton stand is weak, look for the pests pictured on this page, which are the primary pests responsible for stand reduction. For insect pests, you will often need to dig into the soil around damaged areas to find the insect causing damage.

Each name links to more information on identification and management.

Click on photos to enlarge

Seedling diseases
Seedlings affected by soilborne fungi.
Damping-off: Pythium spp.
Identification tip: Look for water-soaked lesions on the roots or hypocotyl of infected seedlings. Lesions may collapse and turn light brown. Girdled plants often die. Pythium may rot seeds and seedlings before germination or emergence through the soil.

Rhizoctonia solani causes dark lesions near the soil line..
Soreshin: Rhizoctonia solani
Identification tip: The main symptom of soreshin is oval- to irregularly-shaped, reddish-brown, sunken lesions on the hypocotyl. Girdled plants often die.

Seedling damaged by black root rot.
Black root rot: Thielaviopsis basicola
Identification tip: Black root rot is characterized by a dark brown to black discoloration and reduced diameter of the taproot of infected seedlings. As the plant ages, healthy tissue replaces decayed tissue, but affected plants may be stunted.
Insects
Variegated cutworm, Peridroma saucia, larva.
Cutworms
Identification tip: Cutworms are various colors, hide during the day, curl up into a C-shape when disturbed, and chew through seedling stems near the soil line.
Seedcorn maggot larva.
Seedcorn maggot
Identification tip: Seedcorn maggots feed on seeds and underground parts of germinating seedlings. They may be found inside damaged seeds or in the soil nearby.
Sugarbeet wireworm larvae.
Wireworms
Identification tip: Wireworms are seed and root feeders. Search for them in the soil where stands are spotty. They resemble mealworms and are slender, elongate, yellowish to brown with smooth, tough skin. They have six short legs close together near the head, and the tip of the abdomen bears a flattened plate with a pair of short hooks.
Beet armyworm larva.
Beet armyworm
Identification tip: Beet armyworm larvae are 1 inch (25 mm) long when fully grown. They are dull green with wavy, light-colored stripes running down the back and a broader pale stripe along each side. They usually have a dark spot on each side of the body above the second true leg.
Adult false chinch bug, Nysius raphanus.
False chinch bug individuals do little damage, but large migrations can severely injure or kill young plants in a few hours. Identification tip: False chinch bugs are about 0.12 inch (3 mm) long, narrow bodied and gray-brown. Immature bugs have inconspicuous red markings on the body. False chinch bugs often hide under plants or clods during the heat of the day. Don't confuse them with bigeyed bugs, which are wider with flatter heads.
Darkling beetle adult.
Darkling beetles are usually not a problem. Identification tip: Darkling beetle adults range from 0.12 to 0.25 inch (3-6 mm) long and are about half as wide as they are long. They are dirty black to rusty brown in color, but this may be obscured by dust or a thin layer of soil. Larvae look very similar to wireworms.

Statewide IPM Program, Agriculture and Natural Resources, University of California
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Agriculture and Natural Resources, University of California

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