If you have a site, especially a remote site with invasive plants, in particular infested with hard to eradicate invasive plants like veldtgrass or perennial pepperweed, you can't just cut or treat the plants and leave them in the field to rot. You often have to gather them up in trash bags, carry them out of the area, put them in a dumpster or haul them to a landfill. Seems like there should be a better way, right? What if you could treat plant propagative material (seed or vegetative organs like rhizomes or tubers) in the field and leave the refuse there?
Dumpster filled with weeds
Several years ago my colleague Dr. James Stapleton, UC IPM Plant Pathologist at the Kearney Agricultural Center in Parlier, CA developed a method to kill nematodes in potted plant soils. He called this method tent solarization and it was accepted by the CA Department of Food and Agriculture as an alternative to fumigation. Click here (UC Plant Protection Quarterly, July 2001) to see a publication on this method.
A few years later Jim asked me if we should try it for killing weed seed in the field. So a small team of us, Jim, me, Dr. Milt McGiffen, Jr. (Extension Weed Scientist, UC Riverside) and one of his graduate students Kris Weathers (who naturally did most of the work, but she is now Dr. Weathers) tried solar tents in southern California. We set up three tents, one in Lakeside (a warm, sunny inland community in San Diego County), one in Del Mar, (coastal and not sunny), and Riverside (very warm and sunny) during the summer. We put weeds in bags, built the tents and left them for a week to cook. All of the weed seed were mush after a week, even in the Del Mar site which didn't have consistent sunshine.
The process is described in more detail in this PDF (Using Solar Tents to Destroy Plant Propagative Material in Remote Locations) from my website. A journal article on the process is Stapleton, J.J. 2012. Feasibility of solar tents for inactivating weedy plant propagative material. Journal of Pest Science, 85:17-21.
Do we guarantee this method? No, it can fail if the process is not done right, if there is limited sunshine or time, it the outer tent gets torn, or it the seed is really hard to kill. So try it, but at least for the first few times, make sure the seed is really dead before you dump out the bag in the field.
Original source: Invasive Plants in Southern California blog