A new alfalfa pest has been identified in Imperial Valley, California as well as Yuma County, Arizona. Area IPM Advisor for the low desert area, Apurba Barman explained that calls about an unidentified pest began to come in sometime in September. Once samples were taken in October, and the larvae were reared, it was a bit of a challenge during the identification process.
“When I looked at the samples, I had no idea what they were because this pest has never been in alfalfa, at least in Imperial Valley or the low desert,” Barman explained. After sending the samples off for testing, “it was confirmed that this is the pest we suspected called ‘alfalfa leaftier.’ And this is entirely new for the entire alfalfa production system in the U.S.”
While the new alfalfa pest has been found in multiple fields, Barman noted that is it not yet a critical concern. However, if the alfalfa leaftier becomes a heavily populated pest in the region it has the potential to significantly compromise quality and overall yield. “This insect can cause serious damage. When they are on the plant, they fold leaves together and hide inside that leaf structure and they keep feeding there on the green material,” said Burnham.
The insect has previously been found in Florida, Hawaii, Mississippi, and San Diego County. Although damage to alfalfa had not previously been reported in earlier discoveries of the pest. Infested fields in the low desert have been treated with insecticide applications which have shown adequate control. Barman said they will be evaluating the efficacy of different materials as they work to better understand how the pest interacts with local growing conditions.
“To deal with a pest you first need to know the pest,” Barman noted. “We’re trying to understand this new pest and also educate ourselves as well as our clientele about the identification and biology, what to look for, and what the natural enemies are.”