What creature is killing palm trees? Spray drones may save countless trees from the South American boll weevil

It’s hard to imagine how different the Los Angeles skyline would look without palm trees dotting the horizon. Unfortunately, many species of palm trees all over Southern California are facing a serious threat. The South American Boll Weevil (see pic of the shiny black devils!) has been steadily migrating north attacked the first tree in San Diego in 2011. Since then, countless palms have already died and property and grounds managers all over Southern California are worried about the unsightly and costly consequences of these weevils attacking their trees.

The South American boll weevil is a shiny black bug (image courtesy of UCR.)

UC Riverside’s (UCR) Center for Invasive Species Research is monitoring the threat and has published information on their website, commenting “palm mortality caused by feeding weevils will be a costly management expense for home and business owners as removing large dead palms is difficult.”

The South American Boll Weevil kills by burrowing into the leaf base and laying eggs (1). When the larvae hatch, they move up into the trunk of the tree, eating the core of the tree which causes it to rot (2). Eventually, the crown dies (3) and will fall if the tree is not removed. (Image courtesy of the LA Times).

Is there anything that we can do? According to UCR, the best way to protect trees is by applying insecticide to the trunk, crown or soil of each palm tree. SprayTech’s spray drones can be used to apply insecticide directly to the top of each tree–no matter how high in the air!– using less insecticide overall, and significantly limiting the exposure to people and animals.

How to identify South American Palm Weevil on your palm trees:
1. New front leaf notching
2. Yellowing fronds
3. Bug debris under the tree
4. Flattening of the fronds on the top of the tree

University California at Riverside Center for Invasive Species
Image of a palm tree infected by South American boll weevils which caused the crown to die, leaving a halo of green fronds around the trunk.