Update on Invasive Pests

Update on Spotted Wing Drosophila and Brown Marmorated Stink Bug

spotted wing drosophila Male (left) and female (right) spotted wing drosophila. Inset shows the ovipositor (egg-laying structure of the female). 
brown marmorated stink bug
Adult brown marmorated stink bug.

Spotted wing drosophila (SWD) is an invasive insect pest of most fruits grown in Utah. SWD differs from related vinegar flies in that the female has a large, serrated ovipositor that enables them to lay eggs in healthy, developing fruit. Other Drosophila species can deposit eggs only in overripe or damaged fruit. SWD is native to Asia and was first detected in the continental U.S in California in 2008. Since then, SWD has spread to more than 40 states and is causing severe economic damage in several of these states. In Utah, SWD was first confirmed in Davis County during late summer of 2010. SWD has been collected in traps in low numbers every year since, but no damage has been reported.

The Cooperative Agricultural Pest Survey (CAPS) program placed nearly 200 SWD traps in Rich, Cache, Box Elder, Weber, Davis, and Utah counties in 2014. There were five “firsts”: an early season capture and four new county reports. In early June, a single male was caught near a Davis County orchard in a wild habitat that included river hawthorn, serviceberry, wild plum, and other fruits. This was the earliest seasonal capture of SWD in Utah; in previous years, flies were never caught before mid-August. They were not caught again in Davis County until early September. In addition, the CAPS team collected SWD from traps in Rich, Cache, Box Elder, and Utah Counties, the first report for all four locations. So far this year, 31 flies have been caught in Rich County (starting in late September), 12 flies have been caught in Cache County (starting in mid-August), 1 fly has been caught in Box Elder County (in mid-September), 24 flies have been caught in Davis County, and 2 flies have been caught in Utah County (starting in mid-September).

Brown marmorated stink bug (BMSB) is another invasive insect pest that the CAPS team has been monitoring for the past several years. BMSB is a very serious agricultural pest and has an expansive host range, including fruits, vegetables, and woody plants. It is also a nuisance pest because it uses homes and other buildings as overwintering sites. It is native to Asia and was first found in the U.S. in Pennsylvania during the late 1990s. As of April 2014, BMSB has been detected in more than 40 states and is posing agricultural and/or nuisance problems in about half of them (www.stopbmsb.org).

BMSB was first found in Utah in 2012 in residential areas of Salt Lake City and again in 2013, in residential areas of Salt Lake City and Provo. These findings were always late in the season and in very low numbers. The trend continues for 2014, as we have collected just one specimen, from a trap in Salt Lake City near the Liberty Park area in early September.

We will continue to monitor for SWD and BMSB until at least mid-October, and during spring 2015 we will be holding a series of workshops on SWD and BMSB throughout the state. Watch for updates on this fall’s trap captures and information about these workshops on the Utah CAPS website (utahpests.usu.edu/caps). (Note that individual pages have been set up for each pest.) Please report suspect SWD, BMSB, and crop injury to Lori Spears (lori.spears@usu.edu).

Visit these links for more information on SWD and BMSB:

- Lori Spears, USU CAPS Co-Coordinator


The Cooperative Agricultural Pest Survey is a federal program, administered jointly by USDA-APHIS-PPQ and each state, whose purpose is early detection of invasive species that could threaten U.S. agriculture. In Utah, the program is co-coordinated by Lori Spears and Clint Burfitt (Utah Department of Agriculture and Food).