This last week was very busy for our Integrated Pest Management (IPM) program.
My sister (and greenhouse business partner) built a home for grass aphids on Thursday. It always feels a bit strange to protect the aphids, but we use them as food for keeping colemani wasps in the greenhouse. This is a lot cheaper than buying more wasps, so it works out quite well.
We screen off a growing bucket with whitefly screen and grow barley grass inside it. Then we introduce grass aphids (which we purchase) into the barley. Every couple of weeks we take out some of the aphid-infested grass and put it into the greenhouse as a banker plant. Then we introduce colemani wasps into the aphid colony.
This works well because colemani wasps will lay their eggs in the grass aphids, killing them and raising new wasps. The grass aphids are not able to eat non-grass vegetation so they stay put. Any new green peach aphids (a very common aphid pest in greenhouses) will have a waiting colony of wasps ready to kill them.
As long as we can keep the wasps out of the protected aphid colony we are producing a decent food source and hopefully a steady production of colemani wasps.