Paul Stamets tells the story about a USDA agent inspecting his mushroom “caves” observing that there were lots of flies. Composted horse manure is a favored bedding material. He advised Paul that “XXX” is approved for mushrooms since it breaks down after three days. Paul replied that it does break down in sunlight. Word has it that the agent turned white. Don’t know whether he wrote that label.
There has been discussion of using pyrethrin to control spider mite, thrips, and white fly. Beware. Timing of application before harvest is an issue about which I could find nothing when it comes to edible (smokeable) blossoms. Many people aren’t aware that while pyrethrin, a natural compound obtained from chrysanthemums, among other plants, is approved for use in organic gardening, pyrethrum is not. Nor are any pyrethroids which are synthetic analogs of pryrethrin. I’d like to use pyrethrin in my greenhouse where both white fly and spider mite are sometime visitors, but I need some guidance as to safe application schedules. I suspect that the issue is not as clear cut as it sounds when it comes to vegetables. Vegetables and most leaves have a waxy surface that we wash before consuming them. Buds, not so much.
I think discussion of the breakdown of insecticides when they are used indoors under artificial light also is warranted. Some of the finely tuned light sources may or may not include ultraviolet in their spectra. Pyrethrin attached to carpet dust has been shown to persist for two months or more (presumably indoors under artificial light).