Impatiens Necrotic Spot
Impatiens necrotic spot virus (INSV)
4 host plants · Viral
Last updated
This profile contains verified disease data from extension databases. Regional field notes and expert review are in progress.
Impatiens Necrotic Spot can show up on landscape plants, producing visible damage that ranges from leaf spots and discoloration to branch dieback depending on severity. Early detection gives you the best management options.
Start with sanitation: remove and dispose of affected material as you find it. Thin dense growth to improve air circulation, and redirect irrigation away from foliage. If the condition persists despite cultural adjustments, your local Extension office can help identify the pathogen and recommend targeted treatments.
Quick Reference
Management
Ornamental and vegetable seedlings in propagation are highly vulnerable to thrips-borne infection. Young, tender foliage is more susceptible than mature leaves. Plants remain vulnerable throughout the growing season when thrips are active. Greenhouse and nursery environments with high thrips populations present year-round vulnerability. Field crops and landscapes are vulnerable during warm months when thrips populations peak.
Symptoms appear 5-21 days post-infection, depending on host and environmental conditions. Initial symptoms include necrotic spots on leaves (often with a surrounding halo resembling 'chicken pox'), downward leaf curling, leaf tip dieback, and stem necrosis. Infected leaves may drop prematurely. Younger, actively growing tissues are affected first. Cool to moderate temperatures enhance symptom visibility; severe heat may mask symptoms. Not all host species show visible symptoms even when infected.
Cultural Controls
- Use virus-tested, thrips-free planting material. Inspect incoming plant material for thrips before incorporating into propagation areas. Scout plants regularly for thrips and INSV symptoms. Remove and destroy infected plants immediately and completely. Clean greenhouse and propagation area structures and tools. Control weeds that serve as alternative hosts. Increase plant spacing to reduce thrips movement between plants. Maintain sanitation to prevent thrips habitat. Resistant cultivars are available for some host species. Source: PNW Plant Disease Management Handbook; Wikipedia