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Locust Tree Caterpillar Infestation and Care

A mature locust in southwestern Nebraska had 1-inch green worms (likely clouded sulphur or silver-spotted skipper caterpillars) two years ago, followed by sparse foliage and dead branches. Control caterpillars with Bt (Bacillus thuringiensis) applied when small larvae appear. Fertilize with 10-10-10 at 1 lb per inch of trunk diameter in early spring to boost vigor and foliage production. Populations vary yearly; infestation may not recur.

Treatment & Prevention

Spray Bt at first sign of caterpillars.
Fertilize annually in early spring.
Monitor for recurring infestations.

Trees: Locust Tree Bark Splitting and Dead Branches: Heat, Drought, and Proper Pruning; Pruning Mature Locust Trees: Timing, Fertilizing, and Realistic Expectations; Oak Tree Bark Sloughing with Gray Fungus After Drought: Hypoxylon Canker—Tree Must Be Removed; Sap Oozing from Apricot Tree: Borer Insect Activity; Propagating Pink Dogwood: Suckers vs. Cuttings; Diagnosing a Century-Old Apple Tree's Decline; Reviving a Struggling Weeping Cherry: Fertilize and Monitor; Preventing Mesquite Pod Production: Florel Growth Regulator; Why Grass Won't Grow After Tree Removal: Dealing with Decaying Roots; Shademaster Locust: Pros, Cons, and Alternative Fast Shade Trees

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