Pecan Phylloxera: Timing Sprays for Gall Prevention

Pest Biology

Pecan phylloxera (Phylloxera devastatrix)—tiny aphid-like insects—overwinter as eggs in dead females on branches. In spring, they hatch and feed on new growth, inducing hollow galls on leaves and stems. Severe infestations cause nut drop.

Critical Spray Window

1. First spray: Bud swell (buds swollen, green tip visible) — typically late Feb to March in TX.
2. Second spray: 2 weeks later — catches migrants laying eggs.
3. Optional third: 1 week after second — for extended hatch.

Recommended Materials

• Carbaryl (Sevin) or Malathion — both labeled for pecan phylloxera.
• Add fungicide: Chlorothalonil (Daconil) or thiophanate-methyl (Topsin M) for pecan scab prevention.
• Follow label rates for pecans.

Practical Limitation

Home sprayers reach ~20 ft. Once tree exceeds this, professional application or systemic soil drench (imidacloprid) may be needed—but systemics don't control phylloxera well. Accept some galls on tall trees; they rarely kill mature pecans.

Mark your calendar: bud swell = spray #1. Missing this window guarantees galls.