Shining Flea Beetle Asphaera lustrans on a citrus leaf. Photo by FOL
Shining Flea Beetles are a garden pest. Adults feed on foliage of food producing plants while larvae feed on the root system. Asphaera lustrans of the subfamily Alticinae, in the Chrysomelidae genus (for you science nerds) is a small beetle that can also be called "the gator beetle" since it shares colors with the University of Florida's sports teams.
While we call them a garden foe, they are rarely the culprit behind extensive damage to food producing plants.
There are several species of flea beetles and many of them are so similar they are hard to tell apart. So similar, that many times their identification determined by the plant they were found on. Flea beetles share the shame shape. When they do vary, it is by color.
The Shining Flea Beetle I see most commonly in our central Florida garden is the Asphaera lustrans. To my knowledge it a recent addition to Florida gardens. By recent I mean around 20 years. I found an online article claiming that this specific flea beetle came from Texas sometime in the late 90's. Or at least that is when it was first noticed in Florida.
The good news for us food gardeners is that most flea beetles host on ornamental plants. Unfortunately, there are some that will host on sweet potatoes, eggplants, peppers, tomatoes, kale, broccoli, cabbage, and others. All the information I have found on this Shining Flea Beetle and other common Florida flea beetles lead me to believe that none of those species host on edible plants. The Shining Flea Beetle is believe to host on skullcap - a FL native wildflower. Others host on crepe myrtles, primerose, and other ornamentals.
Damage on foliage by adult beetles can resemble a hole punch appearance across leaves. Larvae feeding on foliage have been observed feeding together in clusters. When you look closely at a leaf with damage from clusters of larvae, it looks similar to a honeycomb. Besides leaves, damage can extend to new stems, and even small roots. Damage typically is most detrimental to new plants or transplants whose roots are young and less established. These new plants typically have a more difficult time making a comeback after major defoliation.
Management of flea beetles can usually be best achieved by allowing natural predators to control them for you. Predatory wasps will feed on larvae helping to reduce destruction and reduce the number of would-be reproducing adult beetles. Other common beneficial predators include lacewings and other small insects that eat the eggs laid on the undersides of leaves. In our own garden, our natural predators control flea beetles efficiently with no effort from us.
If allowing the garden's ecosystem to work for itself is not reducing destruction fast enough, mechanical removal by hand is suggested. By removing most of the infestation and allowing some to remain you can still attract natural predators.
Dematiaceous earth and spinosad can be organic additives to the garden for targeting adult flea beetles. Fungal sprays that are effective in beetles will work as well. The University of Florida recommends Spirotrichum as a fungal treatment.
If all seems lost there are some chemical options. We hope you use these as a last result.
Do you have any thoughts about these bugs in the garden? If so, comment below to keep the conversation going!