Iris Yellow Spot

Iris yellow spot virus (IYSV)

1 host plant · Viral

Last updated

Data Maturity Baseline

This profile contains verified disease data from extension databases. Regional field notes and expert review are in progress.

Iris Yellow 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

Agent Type
viral
Causal Agent
Iris yellow spot virus (IYSV)
Host Plants
1
Favorable Conditions
Initial symptoms appear 7-14 days post-infection on young leaves as small, el...

Management

Vulnerability Window

Young, newly emerging leaves are most susceptible to infection. Iris plants are vulnerable from shoot emergence through the entire growing season when thrips are active. Bulb crops are vulnerable during foliage growth and early bulb development stages. Warm-season vulnerability peaks when thrips populations are highest. Seedlings and young transplants show more severe symptoms than established plants.

What Triggers Infection

Initial symptoms appear 7-14 days post-infection on young leaves as small, elongated yellow spots or streaks. Spots may coalesce into larger lesions. Affected foliage may develop a bleached or chlorotic appearance. Leaves become distorted and necrotic tissue may develop. Cool temperatures enhance symptom visibility. In some iris cultivars, symptoms are subtle or latent even in infected plants.

Cultural Controls

  • Use virus-free, thrips-free bulbs and transplants from reliable sources. Inspect incoming bulbs and plants for thrips before planting. Scout crops regularly for thrips and IYSV symptoms. Remove and destroy infected plants immediately. Control thrips to prevent virus transmission. Manage weeds that serve as thrips hosts. Maintain adequate plant spacing. Clean equipment and tools between fields. Rotate away from susceptible crops. Source: PNW Plant Disease Management Handbook

Host Plants (1)

Allium Tapertip Onion