Caterpillars Hit Rhode Island Hard

By ecoRI News staff

Caterpillars at Crawley Preserve in Richmond, R.I. (Jodi Grinnell)

Caterpillars at Crawley Preserve in Richmond, R.I. (Jodi Grinnell)

The Rhode Island Department of Environmental Management (DEM) is advising homeowners that high concentrations of caterpillars observed statewide may cause short-term defoliation of trees during the next few weeks.

Typical damage, most commonly to oaks and other hardwood species, includes small holes in leaves or leaves that have been chewed down to the veins. These conditions are temporary and shouldn’t cause long-term damage to otherwise healthy trees, according to state officials.

By the end of next month, impacted trees should start to re-foliate with the proper care, according to DEM. Watering trees during times of drought is advised for recovery from defoliation. Applying fertilizer isn’t recommended for trees that have been defoliated.

Homeowners may opt to apply insecticides to control caterpillar populations on their property. Products containing the active ingredient “Btk” are recommended and widely available at retail outlets, according to DEM. Many tree-care specialists are also licensed in pesticide application.

At this time, the state has no plans to apply pesticide to control caterpillar populations, as numbers will eventually decline naturally. DEM doesn’t advocate for the widespread use of pesticide in forested areas given its adverse impact to other beneficial insects, such as bees and butterflies.