What we learned about aphids: It’s a circle of life thing. Let they be prey.
Notes from Amy Bryant:
Have any of you seen the aphid infestation on the peas (bed 2)? I have sprayed them off with a heavy stream of water several times, put two rounds of ladybugs on them and sprayed with mix of water and soap. After trying all of this, I contacted Dr. Joe Novak and here is his response (see below). Very interesting…
Today I saw parasitic wasps and lacewings and ladybug larvae so I think we are in good shape!!!
Best,
Amy B.
====================================================Hello Amy and Wendy,
I had a meeting on Stella Link a few blocks from the garden this morning and so I stopped by to check on the peas with aphids. The aphids seem to be very healthy! Southern peas are a magnate for aphids. This, in turn, draws many beneficial insects to them and to the garden. In addition to the aphids there were larvae of syrphid flies, aphis lions (young lacewings), and lady bugs. I did not see any parasitic wasps or aphids that have been affected by them, but I am sure that they will be along shortly. The lady bug larvae that I saw were very young, small and black, shaped like those in the image reference below, but very young and small. I have also attached a video that shows the tiny wasps parasitizing aphids. Notice how the parasitized aphids look, tan puffy shells, and watch for this on the peas. Once the parasitic wasps move in it only takes them a week or so to clean out the aphid population, so keep an eye out for them.
( http://video.nationalgeographic.com/video/wasp_parasitic )
I think the reason you have such a heavy infestation of aphids is that the peas have been given too much nitrogen. In general, peas need little or no fertilizer as they can fix nitrogen naturally via bacteria in nodules on their roots. I have noticed that plants that have too much nitrogen are also more susceptible to heavy infestation of aphids. In the future tell the gardeners that peas need half or less of the fertilizer given to other crops. ( If you had planted green beans, they would need a little more since they do not fix nitrogen.)
At this time what may be the best thing to do is to observe the plants and notice where you have good predation by lady bugs and parasitization by the wasps. Do not treat these areas to allow the beneficial insects to build up. Us an insecticidal soap solution on areas of aphids that are not being parasitized or predated to bring the aphid number down.
Joe Novak