Another saga : pecan tree aphids ... (long)
Late last summer/early fall my pecan tree had a horrible infestation of aphids. One problem with aphids is the sticky honey dew they exude which covers leaves, furniture, walks, and drifts even beyond the canopy of the tree. A black mold then grows on it making every thing look like soot has settled. The odd thing is I don't remember ever having aphids before. The pecan tree was very small when we moved here, but has benefited from the water and fertilization of the lawn and is now a medium size tree.
Why after all this time did the aphids come in such high numbers? And then early this summer it starts again ... sigh. I looked on-line and saw various insecticides recommended, but I rarely use killer chemicals and besides I couldn't get them up into the canopy of the tree even if I wanted to.
Natural controls include lady bugs (would they go up there if I bought and released them?) lacewings, spiders and other insects including wasps. Wasps!
Then I remembered Malcolm Beck's account of a pecan tree farmer who had never had a webworm problem until the owner's nephew spent the summer and for entertainment knocked down all the paper wasp nests with his sling shot. The next year the farmer had a huge outbreak of webworms and realized that the wasps had been keeping webworms under control. Caterpillers are the number one food that wasps feed their larva.
In the spring of 2011 I planted lots of butterfly larva plants. I went all out. And to give the butterfly larva the best chance of survival I started knocking down paper wasp nests. I felt kind of bad about it, but I didn't use insecticides and kill them. I just knocked the nest down when they first started building. I left just one or two for old time's sake. You see, I called them my pet wasps.
Paper wasps are non agressive by nature. They were all over my greenhouse/tool shed, but I was rarely stung and then it was only a pin prick. I could reach right next to them and they just watched. But even if I accidently bumped the nest they just gave me a tiny little warning buzz and a bounce off my arm. Wasps are not called the geniuses of the insect world for nothing. Because I was in and out of the shed all the time they were used to me and recognized me as harmless. Now when Bob bumped a nest he got stung so I usually got any tools he needed because I didn't want to hear about how I should get rid of the wasps.
Even so 2011 was going to be my raising butterfly year. But because of the drought the butterflies never came. I saw maybe a total of ten butterflies all last summer and none laid eggs on the plants I'd provided for them.
This year the wasps built a lot of nests and I let them stay. There were a few Gulf frit caterpillars on the passion vine, but only a few, and nothing showed up on anything else. However, the wasp larva have to eat something and their nests looked to be full of larva.
So guess what? The aphid outbreak seems to be over as quick as it started. As usual I can see wasps drifing around high up in the canopy of the pecan tree. I always thought they were taking care of the webworms before they got big enough to make a web but now it seems they were also taking aphids for their larva to eat. That's my take on it anyway.
The paper wasps are staying :-)