Corn, Popcorn

Seeds rot before emergence or young seedlings collapse, producing thin stands and sudden losses in flats or garden rows.

Favored By

Cold or waterlogged soil, contaminated mix or containers, poor drainage, deep sowing, dense seedlings, low light, and overwatering.

What It Looks Like

Pre-emergence seeds become soft and brown; emerged seedlings develop a water-soaked or pinched stem at the soil line and topple.

Prevention

Use sterile seed-starting mix and clean containers; sow at the proper depth; provide warmth, drainage, light, and airflow; avoid crowding and overwatering.

Management

Discard affected seedlings and nearby mix; reduce watering; improve light and airflow. Fungicides have limited value after collapse and must be specifically labeled.

For Corn, Popcorn: Reviewed Research Library baseline; local occurrence and treatment timing vary.

The pathogen girdles stems at the soil line and rots crowns and roots, causing sudden wilt and plant collapse across a wide host range.

Favored By

Hot, humid weather, moist soil, dense mulch or debris against stems, poor airflow, and repeated susceptible crops.

What It Looks Like

White fanlike fungal growth at the stem base and nearby soil, followed by numerous mustard-seed-like tan to brown sclerotia.

Prevention

Rotate with nonhosts such as corn or other grasses; improve drainage; keep mulch away from crowns; remove debris; avoid moving contaminated soil.

Management

Remove plants plus surrounding soil before sclerotia spread; deep burial may help in tilled areas; soil solarization can reduce survival in hot regions.

For Corn, Popcorn: Reviewed Research Library baseline; local occurrence and treatment timing vary.

Galls replace kernels or form on leaves, stalks, and tassels; severe infections reduce ear quality and yield.

Favored By

Warm dry periods followed by rain, hail or cultivation wounds, excess nitrogen, young rapidly growing tissue, and susceptible sweet corn.

What It Looks Like

Silvery white swollen galls enlarge and become gray, then rupture to release masses of black powdery spores.

Prevention

Plant resistant hybrids; maintain balanced fertility; avoid injuring plants; rotate and remove crop debris where smut is repeatedly severe.

Management

Remove galls before they rupture and discard them; no effective curative treatment exists, and home-garden fungicide applications are not recommended.

For Corn, Popcorn: Reviewed Research Library baseline; local occurrence and treatment timing vary.

Sap-feeding colonies distort tender growth, cause yellowing and sticky honeydew, and may transmit plant viruses.

Favored By

Soft new growth, excess nitrogen, sheltered plants, and warm moderate weather.

What It Looks Like

Tiny (about 1/16–1/8 in), soft, pear-shaped insects; green, black, yellow, gray, or pink; two tailpipe-like cornicles.

Prevention

Avoid excess nitrogen; inspect leaf undersides; conserve lady beetles, lacewings, hoverflies, and parasitoid wasps; control ants that protect aphids.

Management

Knock off with water; prune badly infested tips; use insecticidal soap or horticultural oil with thorough contact coverage. Repeat only as label directs.

For Corn, Popcorn: Reviewed Research Library baseline; local occurrence and treatment timing vary.

Mites remove cell contents, causing pale stippling, bronzing, leaf drop, and fine webbing during heavy infestations.

Favored By

Hot, dry, dusty conditions; drought-stressed plants; excess nitrogen; loss of predatory mites from broad-spectrum sprays.

What It Looks Like

Minute, eight-legged mites, yellow-green to reddish, usually with two dark body spots; eggs are round; fine webbing may be visible.

Prevention

Reduce dust; water plants adequately; inspect leaf undersides; avoid unnecessary broad-spectrum insecticides; isolate infested transplants.

Management

Hose leaf undersides; remove badly infested leaves; use insecticidal soap or horticultural oil. Ensure contact and repeat per label because eggs survive.

For Corn, Popcorn: Reviewed Research Library baseline; local occurrence and treatment timing vary.

Adults chew numerous small shot holes in leaves; seedlings can be stunted or killed. Some larvae feed on roots.

Favored By

Warm sunny weather, young seedlings, nearby weeds or crop residue, and repeated planting of susceptible crops.

What It Looks Like

Tiny (about 1/16–1/8 in), shiny dark or striped beetles with enlarged hind legs that jump when disturbed.

Prevention

Use row cover immediately after planting; remove weeds and residues; rotate crops; plant vigorous transplants or delay planting where practical.

Management

Remove cover at flowering when pollination is needed; use labeled kaolin clay or insecticides only when feeding threatens establishment.

For Corn, Popcorn: Reviewed Research Library baseline; local occurrence and treatment timing vary.

Night-feeding caterpillars sever seedlings at soil level; climbing species also feed on foliage and fruit.

Favored By

Weedy ground, plant residue, green manure, and recently converted sod; small transplants are most vulnerable.

What It Looks Like

Smooth, stout, gray, brown, green, or black caterpillars, often striped or spotted; curl into a C when disturbed.

Prevention

Remove weeds and residue before planting; till before planting and in fall; use compost rather than fresh green manure; place collars around transplants.

Management

Search soil near damaged plants at dusk and handpick; treat small larvae with a labeled biological or insecticide only when damage is active.

For Corn, Popcorn: Reviewed Research Library baseline; local occurrence and treatment timing vary.

Larvae feed in corn ear tips and bore into tomato, pepper, bean, and other fruit, contaminating produce.

Favored By

Warm weather, late plantings, continuous flowering hosts, and moth migration from southern areas.

What It Looks Like

Variable green, tan, pink, or brown caterpillar with stripes and tiny dark spines; adult moth is tan with a dark spot.

Prevention

Plant early where appropriate; use tight-husked corn cultivars; remove damaged fruit; monitor moth flights and eggs; conserve natural enemies.

Management

Handpick from tomatoes and peppers; use Bt or spinosad on small exposed larvae where labeled; treatments are ineffective after larvae enter ears or fruit.

For Corn, Popcorn: Reviewed Research Library baseline; local occurrence and treatment timing vary.

Adults and nymphs pierce fruit and vegetables, causing dimpling, corky spots, discoloration, and malformed produce.

Favored By

Warm seasons, wooded edges, diverse fruiting hosts, and nearby overwintering structures.

What It Looks Like

Shield-shaped mottled brown bug about 5/8 in; alternating light-dark marks on abdomen edge and white bands on antennae.

Prevention

Remove weeds and alternate hosts near production where practical; use fine netting; seal buildings to reduce overwintering; conserve egg parasitoids.

Management

Handpick or knock into soapy water; use traps for monitoring rather than control; apply labeled insecticides only when repeated feeding threatens crops.

For Corn, Popcorn: Reviewed Research Library baseline; local occurrence and treatment timing vary.

Larvae chew seeds, roots, and underground stems or tubers, causing poor stands and holes in potatoes and root crops.

Favored By

Recently converted sod or weedy ground, cool moist soil, and high organic matter.

What It Looks Like

Slender, hard-bodied, shiny yellow to brown larvae with three pairs of small legs; adults are click beetles.

Prevention

Avoid planting susceptible crops immediately after sod; till to expose larvae; control grassy weeds; use bait stations before planting to assess risk.

Management

Trap with buried potato or carrot pieces and remove larvae; rotate to less susceptible crops; rescue treatments after planting are generally ineffective.

For Corn, Popcorn: Reviewed Research Library baseline; local occurrence and treatment timing vary.