CO-Horts

Posted by Mary Small, Jefferson County Plant Diagnostic Clinic

The Attack of the Flea Beetles

Apple flea beetles on apple

 Our extension research and demonstration garden on the Jefferson County fairgrounds is home to many vegetable and fruit projects, including some espaliered apples.

While checking on spring growth, my colleague and I were horrified to find an enormous crop of shiny apple flea beetles dining, mating and crawling on the leaves. We’ve found them before in the adjacent garden on evening primrose, but have never seen them on the apples.  Interestingly, they are only on the espaliered ones!

In an historic journal from Kansas State Agricultural College (now Kansas State University), the apple flea beetle was noted in orchard trees “in the lower branches only and near the ground." Our affected tree branches are closer to the ground than branches on the nearby upright trees. Maybe there’s something to what the early Kansas researchers reported.  

Flea beetle damage on tomato

Over in the tomato planting, potato/tomato flea beetles are feasting on the plants destined to be a seed source for our seed library project. Although the size of the infestation wasn’t quite as alarming as the apple one, we need these tomatoes to make it past young plant-hood! Volunteer Master Gardeners have been out vacuuming off the little beasts and applying diatomaceous earth. 

I’ve read that 50 or more holes per leaf are needed before there is any adverse effect on plant growth, but really hope they’re gone before getting that far. If management tactics aren’t deemed to be at least moderately successful, we may have to pull out some bigger guns.  But time will tell.