Identifying and Controlling Lettuce Pests in Seattle Gardens

As a new gardener in Seattle, I'm delighted with my butter lettuce growth thanks to abundant spring rain. However, small holes (about 1/8 inch) have appeared on the leaves without the slime trails typical of slugs. What's causing this damage and how can I stop it organically?

Likely Culprits

The damage suggests flea beetles, whiteflies, or aphids—all flying insects. Fortunately, treatment options are similar for all three.

Organic Control Methods

• Botanical Sprays: Pyrethrin and rotenone (plant extracts) are non-toxic to humans/pets and can be used up to harvest. Available separately or combined.
• Homemade Solutions: Insecticidal soap (1 tbsp dish soap + 1 tbsp lemon ammonia per gallon water) destroys insect digestive tracts. Garlic/pepper spray: blend 2 garlic bulbs + 2 hot peppers with water, strain, dilute 1 cup concentrate per gallon. Add molasses for extra potency.
• Oil Sprays (Dormant Oils): Organic, fast-breaking sprays that suffocate eggs and adults. Available at garden centers or Gardens Alive.

Slug-Specific Strategies

If slugs are the issue, try Escar-Go (organic, rain-resistant) from Gardens Alive. For larger areas, spray soil with ammonia solution (1 tbsp each ammonia and dish soap per gallon) early mornings twice weekly. Coffee grounds also deter slugs—studies show 80% reduction and kill juveniles.