SWD Update 20 May 2012
|FINAL SWD update BBY 5-20-12ajd.pdf||218.58 KB|
Spotted Wing Drosophila Update
By the Spotted Wing Action Team (SWAT)
May 20, 2012
Crop update - Blackberry Focus
Oregon leads the nation in blackberries, and also produces raspberries, boysenberries, and loganberries. Marionberries, a variety of blackberry, have been grown in and around Marion County since the mid-1950s, and remain the major variety in their production. The blackberry harvest typically starts at the beginning of July with marionberry and ends in mid-August with evergreen varieties. Oregon produced 7300 acres of blackberries (BBY) in 2011 (NASS; www.nass.usda.gov/). Fresh and processed yield, utilized production, and value are listed below:
Drosophila suzukii (SWD) has become the most serious pest in blackberry production. The data presented and summarized below reflects seasonal SWD trap count comparisons between a blackberry crop and wild BBY.
SWD season update
In the past two seasons, SWD populations started to increase in late-July, overlapping with the end of the marionberry harvest. Current trap counts indicate a slightly higher winter survival rate in wild Himalayan blackberries and non-cultivated perimeter areas adjacent to fruit crops than previous years. At this time, traps are primarily catching the overwintering generation. However, egg-laying has begun and was first found in the small black berries of the ornamental evergreen plant, Sweet Box(Sarcoccoca sp.), with 45% infestation. Most traps placed in BBY show slight increases (1-2 flies/trap /week) over previous weeks, now that warmer and dryer conditions arrived.
Why is D. suzukii a threat to blackberry production?
SWD trap numbers are very high during lateseason blackberry harvest, ranging from 200 toseveral 1000 flies/trap/week, so this crop is at greater risk of infestation. Females are able to lay several hundred eggs in healthy, ripe fruit with her saw-like ovipositor as well as in compromised, split, and damaged fruit. These flies have a tolerance for a wide range of climatic conditions, a wide host range, and a high dispersal potential. Increased production costs related to SWD management include monitoring, chemical input, increased labor and fruit inspection, and reduced shelf life.
SWD control in blackberry
Timely Harvest: Harvest fruit when ripe to ensure good quality. Over-ripe fruit on the canes are susceptible to SWD.
Monitoring: Begin immediately at fruit coloring and continue through harvest. Place apple cider vinegar (ACV) traps and the end of and inside plant rows to provide shade. Replace ACV bait weekly and confirm SWD presence. For detailed monitoring information, visit spottedwing.com.
Control: Please consult the PNW pest management handbook for details regarding control of SWD.
Editor: Wei Yang
Contributing authors: Amy J. Dreves, Denny Bruck,
Jana Lee, Joe DeFrancesco, Vaughn Walton
Agriculture, 4-H Youth, Family & Community Development, Forestry, and Extension Sea Grant Programs. Oregon State University, United States Department of Agriculture, and Oregon Counties cooperating. The Extension Service offers its programs and materials equally to all people.