Posts Tagged ‘fruit pests’

Be Sure to Monitor for Spotted Wing Drosophila in Strawberry and Brambles This Year

Friday, March 2nd, 2012

Jerry Brust, IPM Vegetable Specialist, University of Maryland; jbrust@umd.edu

By now everyone should know that the newest invasive pest, the spotted wing drosophila (SWD), is here in the mid-Atlantic. It was found heavily infesting blackberries and raspberries in central Maryland this past summer and fall. Just about everywhere we trapped for it (I am still trapping adults in February in brambles, SWD overwinter as adults) we have found it on the western shore. We know it is on the eastern shore through trapping efforts by the University of Delaware. What we do not know about the eastern shore is how bad SWD infestations might be this coming season. The first crop that may get hit is strawberries. Information from Oregon and Michigan shows that their strawberries are not attacked to any great extent, but we DO NOT know what the fly may do to our strawberry crop. That is why it would be prudent to put SWD traps out and monitor for the adult flies. Males have a spot at the end of their wings (Photo 1), females do not (Photo 2), but the females do have a strong ovipositor they use to saw into non ripe fruit and lay their eggs—which is why they are such a devastating pest.

Most growers we visited did not think they had SWD on their farm and yet we found it everywhere we looked. The damage is often mistaken for early rotting berries or fruit (Photo 3). Early control is essential, if this fly is allowed to build its population through the summer into the early fall it will be very difficult to control and will be present on your farm basically forever. There are several web sites you can use to build your own traps (just Google spotted wing drosophila traps), or you could ask for help from me or your Extension educator about trapping. The key is to use a very common, inexpensive product as bait in the traps – apple cider vinegar. Traps should be placed in the field within the plant canopy, out of the sun if possible, and checked once a week for flies. Some traps should be located near the edge of the strawberry field and others along a woods edge. There will be many fly species in the trap, if you are not sure you have SWD take it to your local Extension educator for identification.

Photo 1. SWD adult male

Photo 2. SWD adult female

Photo 3. SWD damage to blackberries

Spotted Wing Drosophila Verified in Delaware

Friday, March 2nd, 2012

Joanne Whalen, Extension IPM Specialist; jwhalen@udel.edu

We finished our 2011 SWD monitoring activities in late September in a commercial vineyard and we did not detect any SWD adults in our traps. However, traps that were set out near the Milford area from September through December did collect flies which were verified by a USDA identifier in January 2012 as SWD. During the 2011 season, this pest made its way to Virginia, Maryland, Pennsylvania and New Jersey, so it was only a matter of time before their presence was confirmed in Delaware. As you start the season you will need to consider this pest when making management plans.

These flies can infest and cause a great deal of damage to ripening fruit, as opposed to the overripe and fallen fruit that are infested by most other Drosophila species. Females damage fruit by slicing through the skin with their knife-like ovipositor, and inserting eggs that develop into small white larvae. These cuts can also be a pathway for fungal pathogens, leading to greater reductions in fruit quality. Therefore, monitoring for SWD is important to avoid economic loss. This insect is a pest of most berry crops, cherries, grapes and other tree fruits, with a preference for softer-fleshed fruit. In areas where it has been detected, it is has become an important pest of cherries, raspberries, blackberries, blueberries, strawberries, grapes, peaches, and plums.

For more information on monitoring, identification and control of this insect pest, please check the following links:
http://www.ncipmc.org/alerts/drosophila.cfm
http://swd.hort.oregonstate.edu/

Spotted Wing Drosophila Found in Central Maryland

Friday, September 2nd, 2011

Jerry Brust, IPM Vegetable Specialist, University of Maryland; jbrust@umd.edu

A sample of fruit flies was given to me by Bob Rouse, a horticultural consultant, from fruit farms he consults for in Central Maryland; these flies were identified by me and then verified by the USDA as Spotted Wing Drosophila (SWD) Drosophila suzukii, the first find in our state. This is not good, but this pest has been moving steadily east over the last few years. The SWD is a temperate-zone fruit fly; native to Southeast Asia that prefers temperatures of 67-85° F. Adults are small (2-3 mm) flies with red eyes and a pale brown thorax with black stripes on the abdomen. The most distinctive trait of the adult male is a black spot towards the tip of each wing; the female does not have any wing spots (Photo 1). Larvae are tiny (up to 3.5 mm), white, cylindrical maggots that are found feeding in fruit. This pest was first identified in the western U.S. in 2008. In 2009 it was found in California, Florida, Oregon, Utah and Washington. In the last year or so it has been found in the Midwest and Pennsylvania. Long-distance dispersal usually occurs with the movement of infested fruit to new areas.

While it is not unusual to find fruit flies in late summer infesting overripe or decaying fruit these particular fruit flies are considered nuisances, not crop damaging pests. However, the spotted wing drosophila female lays her eggs inside healthy unblemished fruit with her saw-like ovipositor (Photo 1). The adult female can damage fruit when she oviposits while larvae contaminate fruit at harvest, causing it to become soft and unmarketable (Photos 2 and 3). It infests thin-skinned fruit such as grape, cherry, raspberry, blackberry (raspberries and blackberries appear to be very susceptible fruit), blueberry, and strawberry, etc. SWD overwinters in the adult stage and flies become active in spring, mate, and lay eggs in the thin-skinned fruit. Multiple generations develop each year wherever this insect can overwinter. At a constant temperature of about 75°F it takes only 9 days from egg to adult. This rapid developmental rate allows it to quickly develop large populations and inflict severe damage to a crop.

The best thing to do is monitor for this pest if you have small fruit. Monitoring will help time insecticide applications for greatest effectiveness. You can use homemade traps to monitor for SWD. There are several sites that explain how to make the traps:

http://swd.hort.oregonstate.edu/files/webfm/editor/Wine_Grape_SWD_Bulletin_WSU.pdf

http://jenny.tfrec.wsu.edu/opm/gallery.php?pn=165

http://edis.ifas.ufl.edu/in839

or you can buy commercially made traps: http://www.contech-inc.com/
or
http://ipm.wsu.edu/small/pdf/Spring2011MonitorIDControlSWD.pdf

For any of these traps you will need to add 1 or 2 inches of apple cider vinegar to the bottom of the trap with a drop of unscented dishwashing soap to break the surface tension so the flies will drown. Hang the trap in the shade near berries preferably before fruit begins to ripen. Check the trap weekly for small flies with dark spots at the tip of their wings floating in the fluid. These will be male SWD. Put fresh apple cider vinegar and a drop of soap in each week or so. You also should observe your fruit regularly as it begins to ripen. On cherries and blueberries start checking fruit for punctures the female creates when she lays eggs as soon as fruit begins to develop any color. SWD stings are tiny and a hand lens helps. Pull open suspect fruit to see if there are larvae inside. If you find infected fruit you should spray to prevent the damage from increasing. The infestation level can increase quite rapidly if left untreated. Remove and destroy infested fruit as you monitor. Stings are not readily visible on berries so it is difficult to detect an early infestation by monitoring the fruit alone for damage.

Chemical Management: Malathion will control SWD and has a short PHI, but is very toxic to bees and natural enemies. If monitoring indicates a need to spray, the application should be made as soon as possible. In raspberries or strawberries, sprays may need to be repeated to keep SWD populations low during their prolonged fruiting period in summer and fall. Other possible alternatives to Malathion with fewer negative environmental effects are the spinosyns and neonicotinoids. To get satisfactory control with these alternatives two sprays may be required; the second applied 5 to 7 days after the first. Additional sprays may be needed for berries with a prolonged fruiting period. Be sure to check the label before applying any chemical as the specific chemicals that can be used on one fruit can’t always be used on others.

 Photo 1. Male (left hand side) and Female (right hand side) spotted wing drosophila flies

Photo 2. SWD damage in blackberry

Photo 3. SWD oviposition marks on cherry

Spotted Wing Drosophila Confirmed in Virginia

Friday, July 8th, 2011

Joanne Whalen, Extension IPM Specialist; jwhalen@udel.edu

The first reports of the presence of spotted wing drosophila (SWD) were confirmed last week in Virginia. Although we have not found any yet in our limited survey (only one location), it is very likely that it could make it to our area this season. The following link from Virginia provides more information about this important potential new pest. http://www.virginiafruit.ento.vt.edu/SWD.html

 

Potential New Pest of Fruit – Spotted Wing Drosophila

Friday, April 8th, 2011

Joanne Whalen, Extension IPM Specialist; jwhalen@udel.edu

By now, all should be aware of the newest insect pest present in the Mid-Atlantic Region, the Brown Marmorated Stink Bug. However, there is also a potential for another new pest in 2011, the Spotted Wing Drosophila. These flies can infest and cause a great deal of damage to ripening fruit, as opposed to the overripe and fallen fruit that are infested by most other Drosophila species. Females damage fruit by slicing through the skin with their knife-like ovipositor, and inserting eggs that develop into small white larvae. These cuts can also be a pathway for fungal pathogens, leading to greater reductions in fruit quality. Therefore, knowing that it is in the area and how to monitor it is important to avoid economic loss. This insect is a pest of most berry crops, cherries, grapes and other tree fruits, with a preference for softer-fleshed fruit. In areas where it has been detected, it is has become an important pest of cherries, raspberries, blackberries, blueberries, strawberries, grapes, peaches, and plums. So far it has been detected in California in 2008, in Florida and Oregon in 2009, and in Michigan, North Carolina and South Carolina in 2010. Although we do not have the resources to do an extensive monitoring program, we are currently trapping for it in one location in Delaware in 2011.

For more information on monitoring, identification and control of this insect pest, please check the following links:
http://www.ncipmc.org/alerts/drosophila.cfm
http://swd.hort.oregonstate.edu/