Lady beetle

Delphastus catalinae

Adults of this small predatory beetle (less than 2 mm in length) have shiny black forewings covering the abdomen, a rounded body, and a tan or black head. This species is a specialized predator of whiteflies and both adults and larvae will feed on the two main whitefly species found in greenhouses: sweet potato whitefly (B. tabaci) and greenhouse whitefly (T. vaporariorum).

Adult Delphastus catalinae require high numbers of whitefly eggs (approximately 100—150 per day) for reproduction. For this reason, D. catalinae is especially useful for addressing whitefly ‘hotspots’.  In such cases, Delphastus catalinae can serve as a ‘back-up’ for the parasitic Encarsia formosa and Eretmocerus eremicus wasps, since it tends to avoid consuming whiteflies containing older wasp larvae or pupae. Note, however, that recently parasitized hosts (which will contain wasp eggs or very young larvae) may still be at risk of predation.

The eggs of D. catalinae are Iaid in whitefly colonies on the undersides of leaves, and at 28°C the life-cycle (egg to adult) is completed in approximately 21 days. The optimal temperatures for population growth are between 25 to 28°C (77—82°F). The Iower limit for development is estimated to be approximately 10°C (50°F), but development and activity would be very slow at this temperature.

When monitoring for D. catalinae, pay particular attention to the underside of leaves in areas of high whitefly density. Keep in mind that the mature larvae tend to move further down the plant when they are ready to pupate.