Every now and then, for reasons known or unknown, some of our native insects go wild and reach astounding numbers, creating some concerns and damage. Earlier this year we met an outbreak of native caterpillars defoliating hundreds of acres of native hardwood trees in Western Maryland. In June of 2021, you may recall a report of thousands of periodical cicadas that appeared on the beaches of the Chesapeake Bay. Well, earlier this month an avid beach comber reported “billions” of robust tiny beetles lining the western shore of the Chesapeake for more than a mile near Calvert Cliffs, MD. Some were dead but many were alive, clinging to beach wrack and each other along the shoreline. These waterlogged insects were Yellow Poplar Weevils (YPW), a native insect that reached outbreak levels in 2025 in nurseries and landscapes here in the DMV. To learn a bit more about this strange event, we spoke to Professor Paula Shrewsbury of the University of Maryland, an expert in the management of pests of ornamental plants. Her comments are excerpts from weekly reports prepared for the Green Industries of the Mid-Atlantic region in 2025 and 2026.

“These types of “wash ups” are often related to winds and water currents, and the weevil’s (YPW) ability to float. Environmental conditions came together this week that resulted in so many weevils on the shoreline. In looking into this, there have been other reports of similar wash up phenomena of YPW in MD and VA over the years.”

“Monday, June 9th, [2025] I was contacted by two nurseries in Frederick County, MD describing extremely high numbers of native yellow poplar weevil (YPW) adults, Odontopus calceatus (Coleoptera: Curculionidae), on magnolias and they were causing significant damage to the newer foliage. This is a new pest to me and as I searched for information, I found reports of YPW in recent days from VA, DC, and OH. This weevil is known to sporadically outbreak. In an article from Penn State Extension on YPW published in 2015, they reported extremely high densities of YPW in PA and the mid-Atlantic and stated that the level of outbreak then had not been seen since 1968.

Host plants of YPW include magnolias, sassafras, tulip tree (yellow poplar) and sweet bay.  YPW’s life cycle consists of one generation per year and YPW activity is reported to occur from mid-late May through mid-July. YPW overwinter as adult weevils in the leaf litter under their host plants. In the spring / early summer as the weather warms, adult weevils emerge and feed on the buds and newer foliage of their hosts with their chewing mouthparts, mate, and lay eggs in the mid-vein on the lower leaf surface. Newly hatched larvae chew into the leaf tissue and feed as leaf miners. Multiple leaf miners can be found in a single leaf. Larvae pupate within the leaf mine.