Collard Greens Troubles: Yellow Leaves, Holes & Pest Control

Identifying the Problems

Three weeks after planting, your collards show yellowing lower leaves with holes—classic signs of two distinct issues:

1. Cutworms & Caterpillars

Night-feeding cutworms chew stems at soil level; cabbage loopers and imported cabbageworms riddle leaves with holes. Sevin dust helps but must be reapplied after rain and may not reach pests hiding in leaf folds.

2. Fungal Disease (Likely Downy Mildew or Alternaria)

Yellowing lower leaves with fuzzy undersides suggest downy mildew; concentric rings indicate Alternaria leaf spot. Both thrive in cool, damp conditions.

Integrated Management Strategy

• Sanitation: Remove and destroy severely damaged leaves.
• Physical barriers: Lay cardboard or plastic collars around stems to deter cutworms.
• Hand-picking: Inspect plants at night with a flashlight; drop pests into soapy water.
• Fungicide: If yellowing spreads, apply copper fungicide or neem oil weekly.
• Watering: Water at base in morning; avoid wetting foliage.
• Spacing & airflow: Thin to 18–24 inches for better circulation.

Fertilizer & Soil

Collards are heavy feeders. Side-dress with nitrogen-rich fertilizer (blood meal, fish emulsion) every 3–4 weeks. Maintain soil pH 6.0–6.5.