Lygus problems were particularly challenging for California cotton growers this season. President and CEO of the California Cotton Ginners and Growers Association, Roger Isom noted that it is the worst year the industry has seen.
“This year they just kept coming and it was unprecedented,” Isom explained. “I surveyed my board and our growers, and I’ve seen reports from three sprays for lygus up to 11 or 12 sprays. I’ve seen costs from $30 an acre to over $300 an acre just to control lygus. So not talking aphid or whitefly or anything else, literally just lygus.”
The lygus problems were not entirely unexpected given the growing conditions this season. “Basically, we had a very long, cool, wet winter functionally and that really builds up their populations in non-crop areas in the hills. Then they can move into the valley and eventually end up in cotton,” said Ian Grettenberger, Assistant Cooperative Extension Specialist at UC Davis. Management of the pest has been further challenged by a lack of effective materials that could have unintended consequences later in the season. Considerations have to be made as it relates to problems with aphids and whitefly.
“If you’re using materials for lygus that are very disruptive of natural enemies, that means that any aphids or whiteflies that are already in the field or that are moving into the field may have a very hospitable place to land,” Grettenberger explained. “They can reproduce very quickly and not have their offspring eaten by natural enemies that are in the field.”
Damage from lygus was the most severe in the western part of the San Joaquin Valley, in areas of Kern, Kings, Fresno, and Merced counties. Isom said lygus problems were still reported further east, but to a lesser extent. The issue has been so bad in some areas this year that some growers abandoned their fields entirely.
“I’ve been told at least three fields – one in Merced County and two in Fresno – were completely abandoned,” Isom noted. “They said, ‘Look, we haven’t even gotten into the aphid and whitefly season or the cost of defoliation and I’m already going to lose money. So, I’m walking away from it.’”
Brian German
Ag News Director / AgNet West