Dotted paropsine leaf beetle is a newer damaging invasive pest of eucalyptus in Southern California. Like eucalyptus, it came from Australia. Both adult beetles and their larvae eat eucalyptus leaves, preferably new growth. This causes defoliation, and heavy or repeated defoliation can weaken trees, particularly young or already stressed trees, which may eventually lead to decline. Scalloped-edged dead leaves, beetle frass (poop), and larvae fall out of infested trees, making a mess.


While our UCANR experts are working on the best ways to control this pest, right now options are limited. If your trees look like they’re in good shape and you can tolerate the mess, an option is to do nothing. Another option is raking or sweeping up fallen beetles and larvae, which may remove some insects, although it is unlikely to control a heavy infestation. 


If you’re considering an insecticide, you’ll need to consult a licensed pest control professional or a tree-care company with a licensed pesticide applicator (see links below). 


In UCANR studies, pyrethrins or spinosad sprayings killed all larvae feeding on small trees. However, if the tree is large and long-term protection is needed, professionals may apply drenches or injections of systemic insecticides like neonicotinoids. Also note, that soil-applied systemic insecticides require adequate soil moisture for uptake and may be less effective in dry soils, so irrigation will be needed.


This is not a DIY project for the home gardener! These treatments will cost money, plus these specific pesticides may negatively affect beneficial insects and pollinators in your yard.


You may ultimately want to consider replacing eucalyptus trees with a California native tree if the tree is severely damaged or treatment is impractical. Avoid replacing eucalyptus with other Australian imports like red gum (E. camaldulensis), rose gum (E. grandis), sugar gum (E. cladocalyx), and the silver-dollar gum (E. polyanthemos), as the dotted paropsine leaf beetle has been shown to infest them as well.


Here are some links for your reference: