2,4-D Resistance Found in Weeds Could Limit the Herbicide’s Future Usefulness

[xchrom]

http://www.sciencedaily.com/releases/2012/08/120816151812.htm

ScienceDaily (Aug. 16, 2012) — Even as crops resistant to 2,4-D herbicide are being developed, populations of weeds are also developing a resistance. A 2,4-D-resistant variety of the waterhemp weed has been found, and its spread could lessen the impact of an herbicide widely used in grassland and crop production. Despite worldwide use of 2,4-D since the 1940s, only 17 weeds were previously known to be resistant to it

The journal Weed Science reports the discovery of 2,4-D-resistant waterhemp by a grower in Nebraska. Although scarce 30 years ago, waterhemp is now a major problem for crop production in the midwestern United States. This is the sixth mechanism-of-action herbicide group to which waterhemp has developed resistance.

After 10 years of treatment with 2,4-D, waterhemp was no longer effectively controlled in a Nebraska native-grass seed production field. The highest doses of 2,4-D that were used in an on-site field study, 33 lb ai/A, were insufficient to control 50 percent of the waterhemp population.

Researchers gathered waterhemp seeds from this field and performed greenhouse testing against a susceptible waterhemp variety. Twenty-eight days after treatment with the herbicide, visual observation and dry weight values showed a 10-fold resistance in the affected sample. Researchers also found a reduced sensitivity to the herbicide dicamba.

[GliderGuider]

1. But ... who could have predicted such a thing????

Oh, wait...

[happyslug]

2. 2,4 D was develop for it does NOT Kill grasses, like Wheat, corn or rye.

http://en.wikipedia.org/wiki/2,4-Dichlorophenoxyacetic_acid

http://www.nytimes.com/2012/04/10/business/energy-environment/epa-denies-request-to-ban-24-d-a-popular-weed-killer.html?_r=1

At the present time, 2,4 D is considered "safe", through some studies indicate it can cause cancer in high dosages.

What is strange is 2.4 D was developed during WWII, Roundup (Glyphosate) was introduced in the 1970s, but this weed, developed resistance to Roundup (Glyphosate) in 2002. over ten years ago:

http://www.plantmanagementnetwork.org/pub/php/news/waterhemp/

More on Roundup (Glyphosate):
http://en.wikipedia.org/wiki/Glyphosate

Now Roundup (Glyphosate) is a universal herbicide, i.e. kill all plants (Exempt those plants with a resistance to the herbicide), 2.4 D was a SELECTIVE herbicide, it killed only broad leaf plants, it was known NOT to harm any of the Grasses (Such an wheat). Thus the older, less effective herbicide, was able to be used for twice as long as Roundup is something to ponder.