Potato stems cut open, showing discolored streaks inside from Verticillium wilt
Photo: Scot Nelson, Flickr (CC0)

How to spot it

Yellow V-shaped patches at the edges of lower leaves, wilting in the afternoon, and tan to brown streaks inside the lower stem. Worst after cool springs.

What it does

Plants weaken and yield less, and berry canes and young fruit trees can die. The fungus lives in the soil for years.

What to do now

  • Pull and throw away sick annual plants.
  • Water and feed perennials well to help them grow through it.

Keep it away next time

  • Grow resistant varieties ("V" on tomato tags).
  • Don't plant tomatoes, potatoes, eggplant, peppers, or strawberries where any of them had it, for 4 years or more.
  • Heat the soil under clear plastic in summer (solarizing) to cut the fungus down.

Plants it affects

Not sure? Your county extension office can identify it from a photo or sample, often for free.