APHID PARASITES FACT SHEET & Release Instructions
Aphid parasites are very effective at searching out scattered populations of aphids, attacking more than 40 different species of aphids. Aphid parasites by themselves don't normally provide total aphid control, but they're very useful for controlling aphids that other aphid-eating insects can't find. Another advantage of aphid parasites is that once they're established in a greenhouse (or indoors on houseplants), they usually keep reproducing for the entire season with no further releases. This makes aphid parasites a very valuable addition to other, more common aphid controls.
Aphid parasites work by laying one of their eggs inside each aphid, and the resulting larvae then consumes the entire body contents. The parasite then spins a cocoon inside the dead aphid, and pupates. The dead, parasitized aphid swells and stiffens into a leathery, brown, mummy-like wrapping. These are referred to as aphid "mummies", and are a sure sign the parasites are working. You can tell when the adult parasite hatches out because it will chew a small round hole in the mummy as it escapes (see drawing). Over her lifetime a single female typically attacks 200-300 aphids. The entire life cycle takes about 3 weeks.
Aphid species controlled by parasites include peach potato aphid, green peach aphid, and other aphid species typically found on peppers, tomatoes, cucumbers, ornamentals and other plants grown indoors or in the greenhouse.
As a preventative treatment, aphid parasites can be used at the rate of 1-2 per square yard of greenhouse space, applied every other week. Preventive releases would be started about the same time of year as aphids typically start showing up in your greenhouse. For existing infestations, use 3 parasites per square yard weekly for at least 3 weeks to get them established. (One release may be adequate for home use.) Another release formula used is 500-2000 parasites per acre of planted material. Parasites arrive as adults, and are ready to be released immediately. Release parasites anywhere near the infested areas, as they fly and spread themselves out from there. For parasite release in larger areas, walk down the aisles or rows, letting the parasites escape from the shipping vials as you walk. The best time to release parasites is early in the aphid season, so you'll get the most benefit from them. Releases are most effective from September to March. Parasites are effective searchers and work well on small, well dispersed populations of aphids.
Aphid parasites are not affected by short day lengths, so they're especially useful during the short days of fall, winter, and spring. (Other aphid controls tend to not be as effective during these periods.) Parasites may not be as effective during later spring and summer, because aphids reproduce very quickly during this time (too fast to be controlled well), and because "hyperparasites" (parasites that attack parasites) are more active during this period. Parasites are attracted to the color yellow, so yellow sticky traps (used for control of certain other insects such as whiteflies) should not be used with aphid parasites.
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