Aphidoletes - The Tiny Titans of Aphid Control
The Best Aphid Predator - Aphidoletes
Which biological control agent can control aphids?
Aphidoletes aphidimyza is a tiny fly, or midge, that consumes all types of aphids in its larval state. Other predators attack aphids like the parasitic wasp Aphidius, the generalist feeder the green lacewing and the predatory mite Anystis, but Aphidoletes has extra benefits as an aphid predator.
Aphidoletes can fly. This tiny titan has wings and can zip in and out of plants, under leaves and in tight places that are impossible for humans to spot, but where aphids may be hiding. Upon release the females will seek out and find aphid colonies where they lay their eggs.
Size doesn't matter. The larvae of Aphidoletes don't discriminate between small or large aphids as do some species of Aphidius, but has been shown to eat over 60 species of aphids. All aphids are on the menu! Aphidoletes will also eat other pests, such as whiteflies and psyllid if aphids are not present.
What does Aphidoletes look like?
When you receive this predator it arrives in a tray, a bottle or in blister packs in its pupal state. This is the life stage where the larvae are changing into the adult midge. As the midges hatch out, they will mate and the females lay their eggs near aphids which they can detect by sense of smell. An interesting note is that Aphidoletes utilizes spider webs for mating, so keep those webs in the greenhouse.
Adults are delicate flies, only 2-3 mm long, with long slender legs and antenna that are curled backwards over their body. The eggs are orange ovals, usually occuring in groups of 6 or more. Larvae are tiny orange maggots, less than 3mm, with tapered heads. They often attach to an aphids leg and suck the juices out. The aphid becomes paralyzed then shrivels up.
How do I apply Aphidoletes?
Tray - Leave the tray with Aphidoletes closed, at room temperature, until many of the flies/midges have emerged from their pupal state. Then open the container and leave in the center of the aphid infested area.
Bottle - Open the lid and leave in the center of the aphid infested area. Protect from direct sunlight. Aphidoletes will emerge and start to establish in the area.
Blister Pack - Open the backs and hang in aphid infested areas. Aphidoletes will emerge and work their magic.
Research shows that early releases in greenhouses will keep aphids from getting out of control. Releasing every two weeks is recommended.
Preventive Rate - .05/ft² or 50 for 1,000 ft²
Rate with aphids present- .1/ ft² or 100 for 1,000 ft²
Where can I find Aphidoletes after I release it?
These predators are so tiny that they are quite difficult to spot. Look for tiny orange eggs and larvae near aphids, often on the undersides of leaves. You may only see the shriveled up carcasses of dead aphids or notice a reduction in aphid pressure. Check out the spider webs in the area for any Aphidoletes just hanging around.
Why should I use biological control?
- Unlike chemicals, when using insects there are no restrictions about re-entry (REI) so it's business as usual, with no waiting between applications.
- Using insects is better for the environment than spraying toxic chemicals that kill both good and bad insects.
- Biocontrols do the work for you, finding pests before they are seen by workers.
- There is no need for expensive application equipment or PPE.
- Safe to use, not exposing people/animals to harmful chemicals
- Pests do not build resistance to predators eating them, as they do to chemicals.
- Some biological controls will create self-sustaining populations in the greenhouse/crops.
When is the best time to start aphid control?
Similar to the saying 'the best time to plant a tree is yesterday', early intervention is best with aphid control. Most biological control agents, including Aphidoletes, are more efficient when used preventatively. This means, start releasing the aphid midge early in the season, early in the crop cycle and/or at the very first sign of aphids in the crop.
Temperature and light will be the determining factor. Aphidoletes are most active between 68 to 78°F. Aphidoletes respond to cool temperature and shortening day lengths (less than 16 hours) by entering diapause. Therefore, in most greenhouses they are only active from March to September unless supplemental lighting is used. Research shows that leaving on one 60-watt bulb all night will prevent diapause in more than half of the larvae within a 20yd diameter circle, if night temperatures are above 60ºF.
What if I have questions?
There are several steps when using Aphidoletes. Take time to read through all the technical information and call the experts at Sound Horticulture with any questions, we are happy to help guide you through this process. (360) 656-6680
The secret of getting ahead is getting started. - Mark Twain
Further Resources
Aphidoletes Tech Sheet - Sound Horticulture
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