- Carrot Growing Guide | Fundamentals of Bed Preparation, Spacing, Weeding & Watering - Part 1
- Carrot Growing Guide | Season Extension to Lengthen Your Carrot Harvest - Part 2
- Carrot Growing Guide | Carrot Harvesting, Handling & Storage - Part 3
- Carrot Growing Guide | Common Carrot Pests & Diseases - Part 4
- Colored Carrot Varieties | Visual Comparison Chart (PDF)
- Carrots | Key Growing Information
- Early, Main Crop & Storage Carrot Varieties | Photo Comparison Chart (PDF)
- Pelleted Carrots | Key Growing Information
- Classic Storage Crops | Post-Harvest Handling & Storage Guidelines
- Winter Growing Guide | Part 6: Recommended Crops & Varieties
- Choosing Carrots: A Guide to Varieties You Will Dig
- Webinar Slide Deck | Choosing Carrots: A Guide to Varieties You Will Dig | PDF
- Webinar Slide Deck | Flower Seed Starting Fundamentals | PDF
Common Carrot Pests & Diseases to Watch For
Prevention Is Key
Your best protection is simply following Best-Practices for Carrot Culture; good culture keeps you ahead of most disease. And because roots injured by tools or insects often pick up secondary infections, scout regularly so you can act before a problem spreads.
Even so, carrots can still be hit by a number of pathogens. This article doesn't cover them all, but it's worth knowing the ones you're most likely to meet.
Before choosing a treatment, get an accurate diagnosis. Your local Cooperative Extension office, state agricultural university or department of agriculture has specialists who can help identify the problem and recommend how to manage it.
Here's a look at the most common carrot pests and diseases.
Carrot Diseases
Several foliar blights can cut carrot yield and quality. The most common are:
Alternaria blight (Alternaria dauci)
What it looks like: dark brown to black spots with yellow halos along the leaf edges, starting on the oldest leaves.
Infected leaflets often curl, dry out and die, and the leaf stalks can become infected later on. Early, severe infection can keep roots from reaching full size.
To lower the risk and slow the spread:
- Grow varieties with some resistance.
- Keep leaves dry by watering in the morning or using drip irrigation.
- Plant at the right density and avoid crowding the rows.
- Don't overdo nitrogen; too much leafy growth reduces airflow through the tops.
Carrots with Alternaria blight resistance
Cercospora blight (Cercospora carotae)
What it looks like: small dark spots with yellow edges, first on the younger leaves and stems.
See Alternaria for ways to reduce problems.
Carrot Pests
Carrot Rust Fly (Psila rosae)
Like many pests, carrot rust fly isn't a problem everywhere; it is most common in cool temperate regions. The larvae tunnel into the roots and make them unsellable.
The most effective controls are:
- A 3–5-year rotation away from all carrot-family (Apiaceae) crops, placing them as far as possible from last year's planting. (The family also includes parsnip, celery, parsley, dill, chervil, fennel and cilantro.)
- Row cover to keep the flies out. Put it on as soon as the seedlings emerge and bury the edges so it seals.
Wire Worms (Elateridae, Click Beetle Family)
Wireworms, the larvae of click beetles, bore holes into carrot roots and can ruin them for sale.
The best ways to reduce wireworm damage:
- Rotate with crops they don't feed on.
- Don't plant carrots where sod was recently turned under.
- Plow in fall so birds and other predators can get at the wireworms.
Prevention & Early Identification
Whatever you grow and wherever you farm, good practices and routine scouting are the foundation of healthy crops, and that holds for carrots too.
If you think a pest or disease is getting started, contact your regional Cooperative Extension office or department of agriculture promptly. Their specialists can help you identify carrot pests and pathogens correctly and choose the best local management options so the problem doesn't keep coming back.
