Saltmarsh caterpillars and other woolly worms are commonly found in soybean. Larvae feed only on leaves and occasionally cause enough defoliation to justify treatment. The feeding damage is similar to that of other defoliating caterpillars. Eggs are laid in a mass, usually on leaves, and the small, light-colored and somewhat hairy larvae may be found clustered together after hatching. Larger larvae of the saltmarsh caterpillars are hairy and vary considerably in color, although they tend to be white, yellowish, or cream colored when an outbreak occurs. The larvae have four pairs of prolegs and grow to a length exceeding 2 inches.
Management options
| Insecticide (Trade Names) for SALTMARSH CATERPILLAR | Lb Active Ingredient per Acre | Amount Formulation per Acre | Performance Rating |
|---|---|---|---|
| bifenthrin (Brigade 2E, Discipline 2E, Fanfare 2E) | 0.063 - 0.10 | 4 - 6.4 oz | 6 |
| chlorantraniliprole, bifenthrin (Elevest) | See label | 4.8 - 9.6 oz | 9 |
| chlorantraniliprole, λ-cyhalothrin (Besiege) | See label | 6 - 8 oz | 9 |
| esfenvalerate (Asana XL 0.66E) | 0.015 - 0.03 | 2.9 - 5.8 oz | 6 |
| methoxyfenozide (Intrepid 2) | 0.063 - 0.125 | 4 - 8 oz | 8 |
| novaluron (Diamond 0.83E) | 0.039 - 0.052 | 6 - 9 oz | 8 |
| permethrin (Arctic 3.2, Pounce 3.2) | 0.05 - 0.1 | 2 - 4 oz | 6 |
| spinetoram (Radiant SC 1) | 0.016 - 0.031 | 2 - 4 oz | 9 |
| spinetoram, methoxyfenozide (Intrepid Edge) | See label | 4 - 6.4 oz | 9 |
| spinosad (Blackhawk 36% WDG) | 0.039 - 0.05 | 1.7 - 2.2 oz | 9 |
| β-cyfluthrin (Baythroid XL 1) | 0.013 - 0.022 | 1.6 - 2.8 oz | 6 |
| γ-cyhalothrin (Declare 1.25) | 0.0075 - 0.0125 | 0.77 - 1.28 oz | 6 |
| λ-cyhalothrin (Warrior II 2.08) | 0.015 - 0.025 | 0.96 - 1.6 oz | 6 |
| Z-cypermethrin (Mustang Maxx 0.8E) | 0.0175 - 0.025 | 2.8 - 4 oz | 6 |
- A naturally occurring fungus that attacks saltmarsh caterpillars will sometimes quickly reduce infestation levels.