In this Blast
SPOTTED WING DROSOPHILA (SWD) - UPDATE
The Massachusetts SWD monitoring network yielded no trap captures this week. The New York monitoring network has reported first catches in 5 counties but with very low numbers. No other New England state has reported any SWD captures yet.
What does this mean? We are still in the very early stages of SWD population build up. Trapping for adult SWD and examination of ripe fruit (salt flotation) is most reliable when done on site at your farm. Growers with susceptible ripening fruit should be prepared to commence their spray programs (conventional or organic) as soon as SWD are confirmed at their location and/or as soon as fruit coloring begins. The danger of starting too early is 'using up' certain materials with limited allowed applications.
An excellent chart developed of labeled materials for controlling SWD developed by Cornell University can be found here
. Remember to use materials from different IRAC groups in sequential spray applications to avoid developing a resistant SWD population.
Also plan on frequent and thorough harvesting of fruit with a minimum of fruit falling to the ground. Harvested fruit to be refrigerated as soon as possible after harvest. Keep your crop canopy open for air movement and light penetration by weeding, mowing, and if necessary using trellising to hold fruit laden branches up from the ground. And don't leave cull fruit out in the open or near the crop.
Growers should go to their state's SWD Information and Recommendation Web Page for specific information for their state. In Massachusetts see: https://extension.umass.edu/fruitadvisor/spotted-wing-drosophila. In New Hampshire see: http://extension.unh.edu/New-and-Invasive-Pests/Spotted-Wing-Drosophila-SWD.
A suggestion for strawberry growers
who also grow brambles and blueberries: after strawberry harvest, make a couple of applications of a strong SWD insecticide to the strawberry field. There is always fruit left in the field which is an ideal breeding ground for SWD. This should help to slow down any SWD problems in the ripening brambles and blueberries. Renovate the field as soon as possible.
The University of Vermont and Cornell University (together with NY State Berry Growers' Assoc.), have looked at the use of exclusion netting for controlling SWD damage, especially for organic farms. You can find more information on their work at:
- UVM - http://www.fruit.cornell.edu/spottedwing/pdfs/swd-insecticides-berries-ny.pdf
- Cornell/NYBGA - http://mysare.sare.org/sare_project/fne14-813/?page=final
Finally, there is some evidence that attracting humming birds to your field can help lower the population of SWD. See http://blogs.cornell.edu/swd1/2014/09/19/hummingbirds/ for more information on how this can work. We have two locations (organic berry farms) where we are testing this method out.
: A. Eaton, UNH, Cornell Ornithology Lab, S. Schloemann, UMass)
STRAWBERY & RASPBERRY
Potato Leafhopper (Empoasca fabae)
Adults and nymphs are small (1/8"), green, bullet shaped insects that live primarily on the underside of the leaves. Adults fly and nymphs tend to move quickly and sideways when disturbed. Potato leafhopper overwinter in regions south of New England but blow up on wind currents and storm fronts every year by mid-June. They feed on a wide range of plants including strawberry and raspberry leaves.
PLH feed on plant sap which causes some direct damage, but the main damage is from a toxin that they emit while feeding that causes distorted plant growth. In strawberries, it causes discoloration and crinkling of the leaf blade. In raspberry it causes shortened internodes on primocane tips and a downward leaf curl or reflexing as well as yellowing and misshapen leaves.
(photo credits: Cornell Berry Diagnostic Tool, Ontario Crop IPM website)
Look for leaf symptoms and stunting and then examine the underside of leaves to determine presence of PLH. New plantings of strawberry and young canes on raspberry are most susceptible and scouting should focus on those areas. While no hard thresholds are known, it is generally thought that an average of 1 or 2 PLH per leaf warrants action.
Avoid planting strawberries or raspberries near other preferred host plants like alfalfa, beans, potatoes. No specific natural enemies are identified, but promoting habitat for generalist natural enemies can help. Also, some cultivars may be more susceptible than others.
See New England Small Fruit Management Guide
for more information on recommended materials and rates. Note pre-harvest intervals for recommended materials.
||Organic OMRI listed (PHI)
| Assail 30SG (1)
Malathion 57EC (1)
Malathion 8F (1)
Sevin XLR Plus (7)
| Aza-Direct (0)
Safer Brand #567 (0)
|Avoid proximity to alfalfa plantings, which provide a major source of potato leafhopper population build-up.
Archived IPM Berry Blasts are available at the UMass Extension Fruitadvisor website.
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