Potatoes, Sweet

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.

Vascular infection causes gradual yellowing, wilt, stunting, and dieback in many vegetables, berries, and ornamentals.

Favored By

Cool to moderate soil, susceptible hosts, infested soil, repeated planting of host crops, and plant stress.

What It Looks Like

Lower leaves yellow from margins inward, often in V-shaped areas; plants wilt gradually and stem vascular tissue may show light brown streaking.

Prevention

Choose resistant cultivars; rotate with nonhosts or grasses; control susceptible weeds; avoid moving soil; maintain balanced fertility and irrigation.

Management

Remove infected plants; no cure exists. Soil solarization may reduce inoculum in hot climates; replant with resistant or nonhost crops.

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.

Roots, crowns, stems, leaves, and fruit may rot; plants wilt suddenly and whole beds can collapse after saturated conditions.

Favored By

Warm wet weather, poorly drained or flooded soil, standing water, contaminated irrigation water, and repeated susceptible vegetables.

What It Looks Like

Dark water-soaked crown or stem lesions, brown rotted roots, sudden wilt, leaf blight, and firm water-soaked fruit rot sometimes covered with white growth.

Prevention

Use raised beds and well-drained sites; prevent runoff into beds; use drip irrigation; rotate; sanitize equipment; choose resistant cultivars where available.

Management

Remove infected plants and fruit; improve drainage immediately; avoid moving wet soil. Crop-labeled fungicides must be used preventively and resistance-managed.

Wounded vegetables and storage organs rapidly become watery, foul-smelling, and unmarketable in the garden or after harvest.

Favored By

Warm wet conditions, wounds, insect injury, contaminated tools or wash water, poor ventilation, and warm storage.

What It Looks Like

Tissue becomes soft, water-soaked, cream to tan, and collapses into a wet mass; outer skin may remain briefly intact and odor is often strong.

Prevention

Prevent wounds; control insects; harvest in dry weather; sanitize tools and containers; cool produce quickly; provide drainage and ventilation.

Management

Remove rotting produce and contaminated debris; disinfect containers; do not store damaged vegetables with sound produce. No spray cures established soft rot.

Systemic viruses stunt plants, distort leaves and fruit, reduce yield, and persist for the plant's life.

Favored By

Aphids or other vectors, infected transplants or seed for some viruses, nearby weeds, continuous host plants, and mechanical sap transmission.

What It Looks Like

Light- and dark-green mosaic, yellow mottling, rings, shoestring or curled leaves, stunting, and bumpy or color-broken fruit; symptoms vary by virus and crop.

Prevention

Use virus-free seed and transplants; plant resistant cultivars; control weeds; use reflective mulch where practical; sanitize hands and tools.

Management

Remove symptomatic plants promptly; manage vectors early but recognize insecticides may not stop rapidly transmitted viruses. No treatment cures an infected plant.

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.

Adults and nymphs suck sap, yellow leaves, reduce vigor, and excrete honeydew that supports sooty mold.

Favored By

Warm protected sites, greenhouses, dense foliage, weeds, and heavily fertilized tender growth.

What It Looks Like

Adults are tiny white, mothlike insects that flutter when disturbed; nymphs are flat, oval scales on leaf undersides.

Prevention

Inspect transplants; remove infested leaves and weeds; use screens in protected growing; avoid broad-spectrum insecticides that kill natural enemies.

Management

Use yellow sticky cards for monitoring; vacuum adults on small plantings; apply insecticidal soap or horticultural oil to leaf undersides.

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.

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.

Adults feed on many crops and flowers and may transmit bacterial wilt; larvae (southern corn rootworms) attack roots.

Favored By

Warm regions, abundant weeds, corn or cucurbits, and successive host crops.

What It Looks Like

About 1/4 in, yellow-green beetle with 12 black spots; dark head and long antennae.

Prevention

Use row cover on young cucurbits; rotate crops; control weeds; remove residue; plant robust transplants.

Management

Handpick or vacuum; monitor flowers and seedlings; use labeled insecticides only when feeding is severe, protecting pollinators from exposure.

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.

Microscopic roundworms induce root galls, restricting water and nutrient uptake and causing stunting, yellowing, and midday wilt.

Favored By

Warm sandy soil, susceptible crops, contaminated transplants or soil, and repeated host crops.

What It Looks Like

Microscopic; diagnosis relies on swollen knots or galls on roots, often with a weak uneven crop canopy.

Prevention

Use clean transplants; grow resistant cultivars; rotate with poor hosts; solarize soil in hot climates; add organic matter and clean tools.

Management

Remove heavily infested roots; use resistant crops and rotation over multiple seasons; soil-applied products are limited and must be labeled for home gardens.

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.

Browse foliage, buds, flowers, and fruit; damage often occurs high above the ground with ragged torn stems.

Favored By

High deer density, drought or winter food shortage, gardens near woods, and unfenced plantings.

What It Looks Like

Large hoofed mammal; cloven tracks and pellet droppings; browsing can reach roughly 6 ft.

Prevention

Install an 8-ft deer fence or properly designed electric fence; use cages and netting; choose less-preferred plants while recognizing none are deer-proof.

Management

Exclude first; rotate repellents labeled for edible crops and reapply after rain; protect young trees with guards. Follow local wildlife laws.

Clip seedlings and tender stems, browse leafy greens and beans, and gnaw bark in winter.

Favored By

Dense cover, brush piles, fence gaps, drought, and abundant tender vegetation.

What It Looks Like

Small mammal with long ears and short white tail; leaves round pellets and clean, angled cuts close to the ground.

Prevention

Use 1-in poultry mesh at least 2 ft high with bottom buried 3–6 in; remove nearby cover; use trunk guards.

Management

Exclude and protect individual beds; use repellents labeled for edible crops; trapping or lethal control is regulated and should follow local law.

Gnaw roots, crowns, bulbs, and bark and create surface runways, sometimes killing young trees and perennials.

Favored By

Dense grass, heavy mulch against trunks, snow cover, weeds, and protected groundcover.

What It Looks Like

Stocky mouse-like rodent with short tail and small ears; narrow surface runways and gnaw marks are common.

Prevention

Mow and remove weeds; keep mulch back from trunks; use 1/4-in hardware-cloth guards buried several inches; reduce dense cover.

Management

Use properly placed snap traps inside protected boxes where legal; repair habitat conditions; rodenticides carry risks and must follow label and local rules.