Leaffooted bug can create a host of problems for California almond growers. Their needle-like mouthparts pierce almond shells and damage the kernel. The pests can bring fungal pathogens into almonds, causing disease and rot. Cooperative Extension Specialist based out of the Kearney Agricultural Research and Education Center, Kent Daane said the particular species creating problems in orchards has shifted over the past 30 years.
“We had a species called Leptoglossus clypealis that was the most important one. It’s a native species to this area. Very rarely, but occasionally, we’d get a second species Leptoglossus occidentalis. By the time leaffooted bug became really a center of attention for almond and pistachio, we noticed it was not the same species,” Daane explained. “It was Leptoglossus zonatus. We’re not exactly sure what caused that shift to happen.”
A possible explanation is a substantial increase in almond acreage over that time period. As leaffooted bugs have a propensity to overwinter in pomegranate orchards, the increased pomegranate acreage could also be a factor. While the predominant species may have changed, the problems the pest can create remain the same.
As almonds are especially vulnerable to feeding early in the season, it is the overwintering population that causes the most concern. Monitoring efforts in spring will be critical for management efforts. The pest feeds on a variety of different crops which can make management particularly difficult as it migrates between different food sources.
“In the laboratory, we keep our colonies going by feeding it string beans and peanuts. So, it’s got a super wide host range. They’re seed feeders. But think of all of the different plants with seeds,” said Daane. “Think of years like we’re having right now with a lot of rainfall, and you see all of that vegetation in the springtime. So many good host plants for these insects to feed on while they’re moving between orchards.”
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