How to Manage Pests:
Pest Management and Identification
Scientific name: Aphytis melinus and other Aphytis species
DESCRIPTION Life Cycle
Aphytis melinus is an important parasite of several species of armored scales including California red scale, latania scale, San Jose scale, and oleander scale. Several other closely related (and difficult to distinguish) Aphytis species attack various armored scales in California. Aphytis feeds on and oviposits in immature scales, preferring virgin adult female scales. Adult Aphytis are tiny wasps, measuring approximately 2 mm (1/16 in) long, are yellow and have short knobby antennae. Aphytis melinus adults can be confused with the adult male California red scale; however, the male scale has long antennae, a dark band around its back, and only one pair of wings.
The female Aphytis deposits a single egg beneath the scale cover and upon hatching, the Aphytis larva feeds on the scale. Because its feeding is external to the scale body, Aphytis is considered an ectoparasite. After reaching adulthood, the tiny adult wasp chews a small round hole in the scale cover and leaves. In citrus, the round hole distinguishes scales parasitized by this species from ones parasitized by Comperiella bifasciata, which leaves a larger, more irregularly shaped exit hole. If a parasitized scale cover is flipped over, the dead scale will be flat and dehydrated, and the parasite's cast skin and fecal pellets will be evident.
A. melinus are commercially available and often used in citrus groves for California red scale control. One reason for its effectiveness as a natural enemy is that A. melinus has two or three generations for each scale generation. Ant control is also important where Aphytis are present because ants will disrupt the ability of the parasites to oviposit. Aphytis are sensitive to many pesticides and it is important to check for pesticide residues before releasing the parasites. Be sure to consider secondary effects of a pesticide before using them in any crop where Aphytis is present.