Will 2021 be wet or dry in your area? Hedge your bets. Spray annual weeds early for maximum benefit.
The sooner you remove serious weed competition, the better your grass responds. That’s true almost anytime, but it’s especially true when weather turns dry after you spray.
“We see it in trials, we see it in experience,” says Chad Cummings, Ph.D., a Texas-based field scientist with Corteva Agriscience.
The most famous example may be a two-year demonstration in Brazos County, Texas, by David Bade, Ph.D., and Paul Baumann, Ph.D. Bade was an Extension forage specialist and Baumann an Extension weed specialist with what’s now known as Texas A&M AgriLife Extension Service. Both specialists are retired today.
The pair compared early and late-season herbicide applications with shredding and no weed treatment in fertilized and unfertilized coastal bermudagrass pasture. (See table.) Prior to the test, the pasture had not been fertilized or treated for weeds in at least five years.
The demonstration ran over two very different weather years. In the first year, a summer drought reduced all forage responses. The next year, above-normal rainfall boosted all responses.
In both years, the specialists applied the early herbicide treatments in early May to weeds 3 to 6 inches tall. The late applications they sprayed in mid-June on weeds 8 to 12 inches tall. For the shredding plots, they shredded at the same time as the late herbicide treatment.
The specialists used five herbicides at label-recommended rates in the study. Each herbicide provided good control of the weeds on the respective product labels. Yields in the table are an average of the herbicides.
Fertilized plots received two applications of fertilizer, according to soil test: 350 pounds of 19-19-19 in mid-May and 350 pounds of 15-5-10 in mid-July.
Cummings says there’s a lot to learn from the demonstration:
FORAGE RESPONSE TO WEED CONTROL AND FERTILIZER, TEXAS A&m UNIVERSITY SYSTEM TRIALS
|Dry Matter in Pounds/Acre|
|With Fertilizer||Grass lb.||Weed lb.||Grass lb.||Weed lb.|
|Early herbicide and fertilizer||2,142||209||8,323||0|
|Late herbicide and fertilizer||881||333||7,610||1,494|
|Shredding and fertilizer||577||1,078||5,089||2,208|
|No Fertilizer||Grass lb.||Weed lb.||Grass lb.||Weed lb.|
|Early herbicide, no fertilizer||1,330||202||4,987||0|
|Late herbicide, no fertilizer||477||377||4,898||1,266|
|Shredding, no fertilizer||341||761||4,787||998|
|Check, no fertilizer or herbicide||377||1,127||1,385||4,252|
Study by David Bade, Ph.D., and Paul Baumann, Ph.D., Texas A&M AgriLife Extension Service
® Trademark of Corteva Agriscience and its affiliated companies. Under normal field conditions, DuraCor® is nonvolatile. DuraCor has no grazing or haying restrictions for any class of livestock, including lactating dairy cows, horses (including lactating mares) and meat animals prior to slaughter. Label precautions apply to forage treated with DuraCor to manure and urine from animals that have consumed treated forage. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Always read and follow label directions.