Jalapeño Pests & Diseases
How to identify and treat common problems including aphids, blossom end rot, bacterial leaf spot, and more.
Quick Answer
The most common jalapeño issues are aphids (treat with insecticidal soap), blossom end rot (caused by inconsistent watering, not a disease), and bacterial leaf spot (prevent with crop rotation and copper fungicide).
Common Pests
Aphids: Small soft-bodied insects that cluster on new growth. Spray with a strong stream of water or insecticidal soap. Ladybugs are a natural predator.
Hornworms: Large green caterpillars that can defoliate plants quickly. Hand-pick or use Bt (Bacillus thuringiensis).
Flea beetles: Tiny jumping beetles that leave small holes in leaves. Use row covers or neem oil.
Spider mites: Tiny red or brown mites that cause stippled, yellowing leaves. Increase humidity and use insecticidal soap.
Common Diseases
Blossom end rot: Dark, sunken spots on the bottom of fruit. Caused by calcium deficiency due to inconsistent watering. Maintain even moisture and mulch well.
Bacterial leaf spot: Dark, water-soaked spots on leaves. Prevent with crop rotation, avoid overhead watering, and apply copper fungicide preventatively.
Phytophthora blight: Wilting, dark stem lesions. Ensure good drainage and avoid waterlogged soil. Remove infected plants immediately.
Important Distinction
Prevention Strategies
Rotate crops yearly — don't plant peppers where nightshades grew the previous year. Water at the base of plants, not overhead. Space plants properly for air circulation. Remove plant debris at the end of the season. Inspect plants weekly for early signs of problems.
Prevention First