farmgate: Is That Really A Cactus Growing Along Your Fencerow?
Global warming or not, you may have cactus growing on your Cornbelt farm, and it may become a sticky issue to deal with, literally and figuratively. The pricklypear cactus has become an invasive specie of sorts, making its way from the desert southwest to pastures and fencerows of the Midwest. And you may prefer to wrestle a grizzly bear than a pricklypear.
Pricklypear is difficult to control say Purdue weed specialists Glenn Nice and Bill Johnson, who add that there are many types of pricklypear in New Mexico and California, but the ones in your neighborhood are probably the Eastern pricklypear, brittle pricklypear, twistspine pricklypear, or plains pricklypear. Nice and Johnson say some have become hybrids and identification could be tricky. Their fact sheet has quite a few ideas of what to do and what not to do in an effort to solve your sticky problem.
If you have a pricklypear somewhere it is probably in a pasture or waste area and may be thriving in drier soils. Bees will pollinate them and seeds will be spread by birds and mammals. Advocates for the pricklypear will tell you that it will help with burns, diarrhea, asthma, diabetes and obesity, but you probably will let them have all they want as long as you get rid of it on your place. On your property it is in the wrong place at the wrong time.
Many farmers will have an initial plan to mow it, and then realize the unintended consequence was just the opposite of what they wanted to achieve. Mowing a pricklypear will chop it into many pieces, spread them, and many of them will root and grow into a large patch. Not a good idea.
Nice and Johnson say using a pick and shovel to get roots out of the ground and collect as many of the leaves or cladodes should be your objective. Burning them is an alternative, but depending on the size and the specie, burning may or may not be successful. Research in Texas indicated 68% to 81% mortality from burning, but insects, rodents, and disease all contributed to the demise of some of them. Prescribed burning over several years has also provided some control.
If you uncap some 2, 4-D and plan to control a patch of pricklypear, you will be wasting your time, money, and effort. It is not effective. The herbicide picloram, which is the active ingredient in Tordon, has demonstrated 75% effectiveness in controlling plains pricklypear over a three year period, during the blooming phase. However, picloram is suspect for problems with groundwater and persistence in the soil, and on sandy soil that is a problem.
Johnson and Nice report that triclopyr, which is found in Crossbow and Garlon, had some effectiveness in treating pricklypear in an Australian study, where it is an invasive specie. However, there is no Cornbelt research which corroborates that report. Regarding the Australians, where pricklypear was introduced to produce dye, and eventually infested about 30 million acres, researchers found that a small parasitic insect helped with the control.
Summary:
Throughout history, pricklypear cactus may have been valuable at times, but today it is a pest and in pastures, waste areas, and sandy soils it can be difficult to control. Chemical controls have little effectiveness with single applications, and continued applications over several years may be required. Mowing will only spread the problem, but the only sure solution seems to be digging and burning.
Posted by Stu Ellis on August 5, 2008 12:34 AM to farmgate