What's eating my black walnut 'sparks 147'?

Black walnut 'Sparks 147' shares the full Juglans nigra pest profile: walnut caterpillar is the most destructive foliage pest; walnut husk maggot ruins nut quality; black walnut curculio is the key nut-boring beetle. Squirrels compete heavily for the crop. All Juglans nigra cultivars face the same core threats regardless of selection.

Gregarious black, hairy caterpillars strip foliage branch by branch in midsummer; severe outbreaks defoliate entire trees. Remove egg masses in early summer. Prune out and destroy caterpillar clusters. Apply Bt spray to young larvae. Destroy caterpillars congregating on the trunk during moulting.

Maggots cause black, rotting husks; kernels are stained, reduced in quality, and sometimes inedible. Remove fallen nuts immediately. Apply spinosad at first adult emergence in late July–August. Yellow sticky traps help time sprays accurately.

Larvae inside developing nuts cause premature nut drop; hollow or partially consumed kernels found at harvest. Sanitation — destroy fallen nuts without delay to break the soil pupation cycle. Insecticide at nut set targets adults before oviposition.

Harvest and cache nuts weeks before full maturity, often taking the majority of the crop on young or smaller trees. Smooth metal tree-trunk bands prevent climbing. Harvest promptly once husks begin to loosen. Netting is impractical on large trees.