Plant Protection and Quarantine Pest Alert March 2010

Drosophila suzukii (Spotted Wing)

Background

Spotted wing (SWD) was detected in California in the spring of 2009. Additional survey activities have determined that SWD is present in multiple counties within the southern and central portions of that State. Although the species of Drosophila found in California is a non-quarantine pest, it is Figure 1. Male SWD. Figure 2. Female SWD. still important for growers and producers of various fruit and berry crops to be aware of its Description larvae hatch to begin feeding presence in order to control and inside the fruit. In as little as 2 manage the . SWD is a small (2 to 3 mm) days, the fruit begins to collapse SWD is a small fly that with bright red eyes, a pale around the feeding site with primarily affects ripe or ripening brown thorax, and an abdomen “dents” appearing on fruits such fruit of cherry, peach, plum, with black horizontal stripes. as cherries. Thereafter, mold and raspberry, strawberry, apple, The insect resembles common infestation by secondary pests grape, blueberry, and persimmon vinegar in the may contribute to further damage. crops. This insect differs from Drosophila. However, the adult common vinegar flies in the males differ from other native Distribution genus Drosophila because it can Drosophila males in that they impact ripening fruit in the early possess a dark spot along the SWD is present in , , stages of development, while the front edge of the wing near the , Thailand, India, and common fruit fly only damages wingtip. SWD larvae are small, . In recent years, the pest ripe or overripe fruit. white, and cylindrical. Adult was also introduced and became SWD thrives at cooler SWDs are active in warmer established in . The temperatures (68° F) typically climates; their eggs and larvae discovery of SWD in California is experienced during most of the cannot survive at freezing the first incidence ofD. suzukii in early summer and fall—the same temperatures. SWDs have a the continental United States. time at which berry and fruit high reproductive rate, with the crops ripen. This is a significant potential to complete at least 15 Detection concern because, since different generations each year. berry and fruit crops ripen at D. suzukii is trapped easily in different times of the season, Damage “McPhail”-type traps, bell- SWD may move from one shaped traps that are baited with crop to another as the season SWD damage to fruit first torula yeast and borax pellets progresses. Consequently, SWD shows up as near-microscopic dissolved in water. It has also populations can damage several scars in the fruit surface left by been found in a variety of other different varieties of ripening fruit “stinging” (ovipositing) females traps commonly used to detect during a single growing season. laying eggs. Within 1 day, SWD and control Tephritidae fruit minimizing effects on predators, The USDA is an equal opportunity parasitoids, and honeybees. provider and employer. Over time, these materials may need to be reapplied (at Mention of companies or weekly or bi-weekly intervals) commercial products does not imply to ensure that the treatments recommendation or endorsement by remain effective. the U.S. Department of Agriculture over others not mentioned. USDA neither 2. Use good sanitation and guarantees nor warrants the standard of cultural practices to prevent any product mentioned. Product names further SWD spread and are mentioned solely to report factually Figure 3. Damage caused by D. suzukii on on available data and to provide specific cherries. establishment. Infested fruit that remains in the field allows eggs information. flies. Growers and producers of and larvae to develop fully and, cherry, peach, plum, raspberry, consequently, serves as a source This publication reports research strawberry, apple, grape, for increased fly populations. All involving pesticides. All uses of blueberry, and persimmon crops fruit showing damage and signs pesticides must be registered by are encouraged to conduct their of infestation should be removed appropriate State and/or Federal own detection activities and from the field and destroyed, agencies before they can be report their findings to their local either by burial or disposal in a recommended. county extension office. closed container. CAUTION: Pesticides can be injurious Control Measures Implementing the most appro- to humans, domestic , desirable priate control and management plants, and fish or other wildlife--if they The U.S. Department of strategies is critical to the overall are not handled or applied properly. Use Agriculture’s (USDA) elimination of this fly. A single, all pesticides selectively and carefully. and Plant Health Inspection unmanaged field will serve as a Follow recommended practices for Service (APHIS) is currently source of SWD infestation to any the disposal of surplus pesticides and working with its stakeholders to surrounding area. In this regard, pesticide containers. identify all host species for SWD APHIS strongly encourages all and determine the extent of its growers within infested areas to geographical distribution. The participate in SWD control and United States Department following are APHIS’ preliminary management efforts. of Agriculture recommendations for growers Animal and Plant Health regarding the management and To learn more, please contact Inspection Service control of D. suzukii: your local county extension APHIS 81–35–015 office. Contact information for Issued March 2010 1. Apply environmentally safe all cooperative extension offices toxicants (i.e., GF-120 and is available online at www.nifa. other products approved by usda.gov/Extension/. the U.S. Environmental Protection Agency) across production fields and border areas to reduce any current SWD populations while