Planning reference

Late Blight vs Early Blight

Separate urgent tomato and potato late blight from slower early blight before composting debris, saving tubers, spraying, or leaving suspect plants in place.

Problem diagnostic

Late Blight vs Early Blight cockpit

Start with symptom speed, cool wet weather, stems, fruit, potatoes, local alerts, lower-leaf bullseye rings, and removal timing before composting or saving plants.

Fast water-soaked late blight is urgent; early blight is slower lower-leaf management.
  1. 1 Late blight clues Fast water-soaked lesions, white underside fuzz, stem or fruit infection, and collapse.
  2. 2 Early blight clues Slower bullseye rings on older lower leaves with yellow halos and splash history.
  3. 3 Urgency proof Check speed, weather, stems, fruit, potatoes, local alerts, and removal timing.
Urgency check
Speed/stemsfast collapse and white fuzz versus lower-leaf rings
Weather
Cool/wetcool wet weather raises late blight urgency
Scope
Whole plantstems, fruit, potatoes, and alerts change removal timing

What each nightshade disease signal means

Late blight
Late blight affects tomato and potato during cool wet weather and can move fast through leaves, stems, fruit, and potato tubers when foliage stays wet.
Early blight
Early blight usually starts more slowly on older lower tomato or potato leaves as brown spots with yellowing and target-like concentric rings.
Water-soaked blotches and white fuzz
Late blight lesions often look water-soaked, greasy, gray-green, or dark brown, and humid weather can produce white fuzzy growth on leaf undersides or infected stems.
Bull's-eye rings on older lower leaves
Early blight points more toward older lower leaves, yellow halos, bull's-eye rings, stem lesions, and dark leathery fruit spots near the stem end.
Rapid removal, dry foliage, and local outbreak checks
Late blight is urgent because infected plants and cull piles can spread spores quickly; early blight still needs dry foliage, rotation, mulch, and cleanup, but the removal threshold differs.

Tomato and potato blight workflow

Separate urgent outbreaks from routine leaf spots
Do not treat every tomato or potato blight the same way; check whether lesions are water-soaked, greasy, rapidly expanding, fuzzy white underneath, spreading to stems, fruit, or tubers, following cool wet weather, or instead starting as older lower-leaf bull's-eye spots before composting debris, spraying, saving seed potatoes, or leaving suspect plants in place.
Check weather and speed
Late blight risk rises during cool, wet, humid periods and can collapse plants quickly; early blight usually builds from lower foliage and crop debris pressure.
Look beyond leaves
Inspect stems, tomato fruit, potato tubers, volunteers, and cull piles because late blight management depends on removing infected plant material from the garden.
Keep foliage dry
Water at the base, improve spacing, stake or cage plants, mulch against splash, and avoid overhead irrigation that leaves nightshade foliage wet.
Use local diagnosis before saving plants or tubers
When late blight is suspected, use extension diagnostic guidance and local outbreak reports before composting plants, saving seed potatoes, or relying on protective sprays.

Use these paths

Source basis