There are two species of rice weeds that growers will want to be closely monitoring for this year. The perennial aquatic weed marshweed, which was initially found in California in 1977 was found in Glenn and Sutter counties last year. Another perennial aquatic weed, alligatorweed was also found last year in areas of Butte and Sutter counties.
“Marshweed has been around for a while and we talked about it quite a lot maybe 10 years ago or so but at that time it was thought to not be very widespread,” said Whitney Brim-DeForest, Rice Advisor for Sutter, Yuba, Placer and Sacramento Counties. “But we’ve had last year plus this year, now four sightings of it so we want to make sure that people are on the lookout for it.”
While marshweed did not appear to negatively impact yields, it increased the time required for the fields to dry. During harvest last year some of the growers reported that their moisture content was a bit higher than normal. “That I’m assuming is partially due to the fact that some of the weeds were also being pulled up into the harvester,” said Brim-DeForest.
Last year alligatorweed was found for the first time in northern California along the Sutter River and has since expanded out from there. While a group of aquatic scientists is working to address the issue, growers are being encouraged to be on the lookout for the weed.
“There’s a possibility that if somebody had some irrigation connected or was taking equipment or boats back and forth to the river it could spread. So, that’s why we just want everyone to be aware that it’s out there and has been found,” Brim-DeForest noted. “It’s considered highly invasive, so we just want to keep our eyes out for it.”
Growers that believe they may have either of the rice weed species in their fields are encouraged to contact their local PCA’s or farm advisors.