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How can I get rid of a weed called sicklepod?


Question How can I get rid of a weed called sicklepod?

Answer Sicklepod is a weed found in both poor and fertile soils. It is a moderate pest in corn, cotton and ornamental nurseries. It can be a serious pest in soybeans, and more non-farmers (homeowners) are being introduced to this weed each year.

Sicklepod is one of those “Dr. Jekyll & Mr. Hyde” weeds. It even has two scientific names - Senna obtusifolia and Cassia obtusifolia. From 4,000 BC until the 1900s (AD or CE depending or your heathen status), sicklepod was used as a medicine (a laxative) and a dye for clothing. Its medicinal qualities were limited, but important nonetheless.

Sicklepod’s hard seeds and aggressive growth habits challenge modern farmers. If left alone, it becomes a competitor that reduces crop yield. Fortunately, farmers have herbicides which offer good control when properly used.

Homeowners and ornamental nurserymen find themselves colonizing farmland each year. Leftover crop pests become landscape pests. Some pests are difficult to control in a landscape scenario, but sicklepod is actually pretty easy to control (for homeowners anyway).

The preferred method of sicklepod elimination is the same for vegetable gardens and landscape beds. Simply wrap your hand around the base of the sicklepod stem, grip firmly and pull upward. You will quickly find this plant has a small tap root. You may also find out why this plant was used as a dye. If the plant already has seed pods, then you need to send the seed pods on a one-way trip to the landfill. If the plant does not have seed pods, then toss it in your compost bin.

Sicklepod growing in your lawn is very easy to control. Simply mow it down with your lawn mower. Having a mature height of 4.5 feet, sicklepod doesn’t like to be maintained at 3 inches or less.

The trick to sicklepod control is not allowing it to set seed. If you can stop seed production, then sicklepod plants will pop up less and less over the next 15 to 20 years.

In the future, farmers may actually grow sicklepod as a crop. This weed’s seeds have two beneficial compounds – galactomannan and anthraquinone. Galactomannans are used as stabilizers in pet and human food.

Anthraquinone is the compound that contaminates soybeans and cotton when sicklepod seed is harvested with these crops. When grown by itself, the anthraquinone can be extracted from the sicklepod seed. This chemical is still used in laxatives and dyes. Anthraquinones are increasingly being used in cosmetics as well as foods and pharmaceuticals.

For more information about sicklepod, check out http://edis.ifas.ufl.edu/FW007 or

http://ipm.ppws.vt.edu/scott/weed_id/casob.htm If you don’t have internet access, then call 910-893-7533 or email me at gpierce@harnett.org

In case you’re wondering, it is the laxative quality that ruins the soybeans and the dye quality that ruins the cotton. Back about 2,000 BC, folks eating the seeds got a couple colors of dye from sicklepod.

Gary L. Pierce

Horticulture Agent

Harnett County

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