Natural Enemies Gallery

Whitefly Cales Parasitoid

Hosts or Prey

Woolly whitefly and certain other whiteflies

Identification

The easiest way to recognize that C. noacki or related parasitic wasps are present is a change in the appearance of immature whiteflies. Parasitization by C. noacki causes second instar woolly whiteflies to become crusty, puffy, yellowish mummies. The appearance change is because the wasp can be visible through the host covering and its presence inside causes a pigmentation change in the whitefly covering.

When the parasitoid matures and emerges as an adult, it leaves a round hole typically in the second instar of the mummified whiteflies it killed. When not parasitized and an adult whitefly emerges from its covering, it does so from a the fourth instar (pupa) and the host covering is more pale to whitish with a T-shaped or irregular slit. If fourth instar woolly whiteflies are mummified or contain a round hole, the cause is another species of parasitic wasp, most commonly Amitus spiniferus.

The adult C. noacki is a dark yellow wasp with blackish eyes. It is about 1/32 inch (0.8 mm) long. Males are somewhat smaller and darker. Eggs, larvae, and pupae occur inside the host, but the wasp larva or pupa can be visible through the host covering.

Life Cycle

Cales noacki develops through four life stages: egg, larva, pupa, and adult. Adult females oviposit in first and second instar whiteflies and prefer second instars. After hatching from an egg the larvae develop through three increasingly larger instars as they feed inside whitefly nymphs.

An adult female parasitizes about 40 hosts during her lifespan of about 1 week. Egg to reproductive adult development time is about 3 weeks when temperatures average 80ºF. Cales noacki has several generations per year.

Habitat

Woolly whitefly is an exotic species that invaded California from Mexico in the 1960s. It infests a wide range of crops and ornamental plants and was especially a problem on citrus.

Entomologists from the California Department of Food and Agriculture, University of California, and U.S. Department of Agriculture conducted foreign exploration to collect natural enemies of the whitefly as part of a classical biological control program. Researchers collected Cales noacki in Chile. After study under quarantine revealed it feeds only on pest whiteflies, C. noacki was introduced into California in 1970.

Cales noacki in combination with the Amitus spiniferus wasp now provide complete biological control of woolly whitefly. Exceptions are when these natural enemies are disrupted by very cold or hot temperatures or the application of broad-spectrum persistent insecticides.

To improve biological control

  • Control ants because they attack natural enemies of whiteflies and other pests.
  • Grow flowering insectary plants to provide nectar and pollen to feed adult natural enemies.
  • Reduce dustiness that disrupts the activities of natural enemies (e.g., periodically hose off small plants).
  • Avoid the application of broad-spectrum, persistent insecticides for all pests because they are toxic to natural enemies.

For more information see Protecting Natural Enemies and Pollinators and the table of relative toxicities of insecticides and miticides to natural enemies and honey bees for specific crops.

Species

Two Cales species are known from California: C. noacki and C. rosei. Both are parasitoids of whiteflies. Cales noacki parasitizes at least 16 species of whiteflies. In addition to woolly whitefly economically important hosts of C. noacki include bayberry whitefly and greenhouse whitefly.

More Information

Scientific classification:

  • Phylum: Arthropoda
  • Class: Insecta
  • Order: Hymenoptera
  • Family: Aphelinidae
First and second instar woolly whiteflies, <i>Aleurothrixus floccosus</i> (center and left), the young nymphal stages susceptible to oviposition by <i>Cales noacki</i>.
First and second instar woolly whiteflies, Aleurothrixus floccosus (center and left), the young nymphal stages susceptible to oviposition by Cales noacki. Credit: Jack Kelly Clark, UC IPM
Adult female <i>Cales noacki</i> wasp investigating a nymph of woolly whitefly, <i>Aleurothrixus floccosus</i>.
Adult female Cales noacki wasp investigating a nymph of woolly whitefly, Aleurothrixus floccosus. Credit: Jack Kelly Clark, UC IPM
Adult female <i>Cales noacki</i> wasp laying her egg in a nymph of woolly whitefly, <i>Aleurothrixus floccosus</i>.
Adult female Cales noacki wasp laying her egg in a nymph of woolly whitefly, Aleurothrixus floccosus. Credit: Jack Kelly Clark, UC IPM
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