Growing plants can be very humbling. I usually consider hosta to be a low-maintenance and carefree crop. However, there are a few issues that can arise on occasion. Take a look at these hosta:  

The 2026 version of GrowerTalks' Insect, Miticide & Fungicide Guide is now available. This resource has become a grower’s favorite feature and tool they use throughout the entire year. I invite you to download your very own FREE copy of the 2026 Insecticide, Miticide & Fungicide Guide.  

 

The newest edition contains tons of content, including chemical class charts, an extensive insecticide/miticide table and numerous articles from several of the industry’s top experts. Curious, but not quite ready to hit the download link above? How about I give you a glimpse of what’s inside the guide? 

• Building Better Fungicide Programs: Balanced Plant Protection Solutions  
• Building Better Insecticide Programs: Basic Rotations + Functional Glow Up 

• Chemical Class Chart for Greenhouse Nursery Fungicides
• 2026 Insecticides and Miticides for Managing Insect and Mite Pests of Greenhouse Grown Horticultural Crops—Raymond A. Cloyd, Department of Entomology Kansas State University 

• Guarding Against Fusarium: Best Practices for Growers—David James Norman, Ph. D., University of Florida Mid Florida Research and Education Center 
• Dedication, Passion & Innovation: What drives Casey Marshall and Tom Dodd Nurseries 
• The IPM Decision Tree: Basic Rotations to Build On; add functional groups that work for your operation—Jennifer Browning PCA, BASF Senior Technical Specialist 
• Field Guide to Thrips in Ornamentals: A Focus on Thrips parvispinus—Zee Ahmed, Ph.D., Clemson University 
• Use of Rice Hulls and Preemergence Herbicides for Improving Container Nursery Weed Control—Chris Marble, Ph. D., University of Florida Mid Florida Research and Education Center 
• Rotate & Re-Apply: Preemergent Herbicides for Nursery Weed Control—Chris Marble, Ph. D., University of Florida Mid Florida Research and Education Center 

• Who are Connecticut’s Specialist Bees—Tracy Zarillo MS., Connecticut Agricultural Experiment Station 
• Soil Microbial Allies in Managed Systems—Mia Maltz, PhD., Assistant Professor, University of Connecticut  
• Knockout Natives—Sam Hoadley, Mt. Cuba Center Botanic Garden  
• Seeing Nature—Andrew Brand, MS., Coastal Maine Botanical Garden  
• Native Landscape Plants with Local Roots—Jessica Lubell-Brand, PhD., Professor, University of Connecticut  

Unless you're a plant pathologist, I think we all agree that the hosta in this week's challenge look pretty bad, but do you know why they look this way? The answer is wet leaves. Foliar leaf spot diseases will only occur when the leaves are wet for long durations.

There are a number of ways this can happen—early morning irrigations, watering multiple times each day, watering during cloudy conditions, extended periods of rain and even dew events. In most cases, I find it’s a combination of watering too early in the day in conjuction with watering during cloudy conditions.