White Fungus Under Crabapple: Fungicide Strategy for Replanting Success

Jim has a crabapple with white fungus underneath. Snapdragons, petunias, and black-eyed Susans all die there. He suspects the fungus.

Start With Fungus Control

Since the fungus is visible and plants fail consistently, treat it first. Take a sample to an independent garden center for ID and product recommendation.

Effective Fungicide Classes

Look for products containing:

• PCNB (quintozene)
• Myclobutanil (Eagle)
• Thiophanate-methyl (Cleary's 3336)
• Triadimefon (Bayleton)

You may need multiple applications over a year. Rotate chemistries to prevent resistance.

Other Possible Causes

Crabapples also cast dense shade, compete for water, and may have allelopathic effects. But the fungus is the most direct, treatable suspect.

Next step: Get a positive ID, then treat systematically.