In today’s Almond Matters, brought to you by Valent, controlling fleabane and marestail can be a difficult task and typically requires two separate applications for the most effective management. The weeds have been found to have two biotypes, one that germinates in the fall and one that germinates in the spring.
“Fleabane and marestail have been probably some of the toughest weeds that farmers have to contend with in orchards,” Valent Field Market Research Representative Tino Lopez said. “The most effective way of controlling fleabane and marestail is to get on a program where you take care of both biotypes by splitting your herbicide application.”
Both of the weeds have strong root systems and can develop significant growth over winter without showing any visible signs in orchards. Getting an effective preemergent down is going to be the most successful defense against not just fleabane and marestail, but other weeds as well. “A program that is targeting fleabane and marestail will be a good foundation program for the entire winter weed spectrum that we get this time of year,” Lopez said.
The first application would have ideally come sometime in early fall normally around the beginning of November. Effective control can still be achieved for those who may not have been able to make the first application in time, it just requires a more powerful approach. “If you were not able to get in during the first biotype, you need to make your first application in combination with burndown herbicides and it requires that you go with the hefty rates of these products,” said Lopez, “once this weed has germinated it is not an easy one to control.”
The weeds are both prolific seed producers and leaving them unchecked can cause significant issues later in the season. Lopez noted the importance of also addressing the second bio-type that germinates in spring, which typically means “coming back in late January, early February with a second application, that way you’re targeting both biotypes.”