As a critical component to the sustainability of both transitioning and organic citrus orchards it is important to understand the impact of foliar dust deposits on the survival of insectary reared Aphytis melinus and Metaphycus helvolus used respectively for the biological control of California red scale and black scale. The effects of both ambient dust and dust generated by orchard operations such as harvesting, weed control or tillage of annual cover crops need to be determined to assist both organic citrus growers and conventional citrus growers in their conversion to sustainable or organic orchard systems.

Viability of these two key parasite species (Aphytis and Metaphycus) was measured after exposure to foliage grown under a variety of orchard conditions generating varying levels of foliar dust deposits in both organic and in transitioning conventional orchards.