New Alfalfas Offer Yield Advantage

New alfalfa varieties outyield the old by about 10%, says Rob Kallenbach, University of Missouri forage specialist.

That's according to alfalfa variety trials at the university's Southwest Research Center.

"There's not a lot of difference in yields, top to bottom, among the new varieties," Kallenbach says. "The old and popular varieties, like Cody and Vernal, are at the bottom of the list."

Since yields of new varieties don't vary much, yield shouldn't get priority when growers choose varieties, points out Kallenbach. Choose varieties from the right dormancy class for your area. Then finalize your selections by picking varieties with resistance to the most troublesome diseases and insects on your farm, he advises.Hopper-Resistant Alfalfas Get New Thresholds Higher economic thresholds for potato leafhopper-resistant alfalfa varieties were recently announced.

An economic threshold is reached when the potential loss from insect damage is equal to the cost of spraying, says Dan Undersander, University of Wisconsin extension forage specialist. Undersander assisted Marlin Rice, Iowa State University entomologist, and Monsanto's Steve Lefko in developing the new thresholds. Growers should note the following when reviewing the thresholds:

* The new thresholds only apply to established stands of resistant varieties with over 50% resistant plants. These are rated "highly resistant" by seed companies.

* Economic thresholds for susceptible varieties and first-year seedings of resistant varieties haven't changed.

Thresholds have been developed for three hay values - $40, $80 and $120/ton. The table shows thresholds for resistant (PLH) and susceptible (Susc.) varieties at the $80/ton hay value. Complete listings of the new thresholds will be available in extension publications this year.