Aphid Biocontrol: Time to Plan
Friday, 18 December 2009 11:05
It is time to plan aphid management if you will be using biological control agents. See the message posted January 29, 2009 for more details.
Ornamental plants are susceptible to many aphid species such as green peach, melon, potato and foxglove. Managing aphids using biological control agents is a bit complicated because parasitic wasps are not general feeders and they parasitize specific aphid species. Some suppliers primarily recommend several parasitic wasps, banker plants and a predatory midge to manage the various aphid species. Other suppliers also recommend using predatory lacewings.
Place orders for banker plants about 6 weeks prior to expected aphid infestations. Banker plants with Aphidius colemanii should be started 3 weeks prior to seeding or sticking cuttings in propagation houses as a preventative measure for green peach and black melon aphids. Since cereal aphids used in this banker-system attack monocots, they should not be used in greenhouses containing lilies or grasses. The first Aphidius colemanii banker plants containing the grass feeding aphid species need to be transplanted into larger pots (10”) upon arrival. A week later, the parasitic wasps, Aphidius colemani should be ordered and immediately released on the banker plants. If aphids are observed in the crops, they should be identified and additional biological control agents selected for that species.
If aphid populations increase and more control is needed, Aphidoletes aphidimyza can be introduced weekly for 3 weeks in hot spots to supplement the parasites. Aphidoletes aphidimyza is a generalist predator that feeds on many different species of aphids. They arrive as midges and adults and adults fly out of the tubes upon opening. The midges and other stages are evenly sprinkled upon the leaves of the crop. If using predatory midges, placing the pots in trays with moist sand will help provide pupation sites for them. (The predatory midges pupate in the soil).The parasitic wasps Aphelinus abdominalis and Aphidus ervi are used for potato and foxglove aphids They are released weekly for at least 3 weeks or until aphids are controlled. Yellow sticky cards should continue to be used to monitor aphid predators and new growth should be inspected for aphid populations.
Work with your supplier for rates. Guidelines are available in the 2011-2012 New England Greenhouse Floriculture Guide (ordering info)
Photos: Banker plants with aphids, Close up, Starter cage
New link 11/11 Aphid Banker Plant System for Greenhouse IPM, Step by Step (UVM, Biobest)
Sources for Banker Plants: IPM laboratories , Biobest
Tina Smith, University of Massachusetts
Leanne Pundt, University of Connecticut
