Monitoring for Spotted Wing Drosophila

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Well, this video has been put together by
Michigan State University Extension to be able to show growers and other people interested in monitoring for Spotted Wing Drosophila how to best do that in fruit plantings. Spotted Wing Drosophila has been detected in the united states now for a couple years in the west coast and in the spring of 2010 it was found in the southeast of the country. So we’ve been
monitoring for it in Michigan this summer and in the late part of 2010 it was first detected in Michigan. So now that it’s here it’s
important that people know how best to monitor for it so they can determine
whether or not this insect pests found in the planting because the foundation of
integrated pest management will be people to know whether or not the insect is present and the monitoring traps are a really good tool and they’re a fairly cheap and effective tool for determining whether or not Spotted Wing Drosophila is in the plant. It’s important to keep the trap down
where the flies like to spend their time which is mostly in the fruit zone. So, in raspberries we have it here this time of the year. In a grape canopy it might be up in the trellis. In a cherry canopy it might be up in the tree
and also important if you can to get these in the shade. Flies spend more time in the shade than they do out in the open. So in the fruit zone in the shade is
ideal and for strawberries you may even want to use a smaller
trap like this that can just be placed on the ground and isn’t likely to tip over. So, there’s different designs here that can work, but each of them has the holes, the apple cider vinegar, and the sticky surface inside. So, coming to this trap each week you’d simply want to to open this up. Just take the lid off. You can then take out the insides and we’ve actually put a
little paper clip here that’s got a hot glue
patch on the top to just stick it in place to stop the water getting in, and then that sticky trap can be taken off
and can then be looked at. We don’t have any flies on this example
but you could then look up close with your hand lens to determine whether or not
the flies on there are Spotted Wing Drosophila. And in the next segment we’ll show you some footage of what the native flies look like and what the specific Spotted Wing Drosophila characteristics are on the trap. so here’s a photograph a male Spotted
Wing Drosophila that was taken down a microscope. This show’s really
clearly the color pattern on the wings of the
species: two dark dots on the ends of the- if the wings on the male are really
distinctive and here it shows those two dots. The other thing to look for is
the red eyes and not so easy to see on this photograph
but there’s also two dark bands on the male Spotted
Wing Drosophila’s four legs. So with a good hand lens you can see
that those distinguishing features pretty clearly. Here’s a trap insert that was pulled out
of the trap with Spotted Wing Drosophila from an infested site and you can see
the trap insert here gives you a nice
area for counting the number that you’ve caught. We’ve got
some Spotted Wing Drosophila males here with
the distinctive black dots on the wings and there’s also
some native species here that may have some markings on the wings but
they’re not the distinctive two black dots. So, looking up close with your eyes, or with a hand lens
preferably, you’d be able to distinguish the Spotted Wing Drosophilas from these
native species and also count the number and record that in your monitoring records. The other thing that can be done with
the yellow sticky traps or the traps that you catch Spotted Wing Drosophila with is to
be able to count the number of female flies that are caught. So, this photograph
shows the distinguishing feature a female
Spotted Wing Drosophila. Unfortunately, the female of this species
doesn’t have the two spotted wings so we can’t use wing
coloration as a way to identify her, or separate her from the
native species. Female Spotted Wing Drosophilas have
these two rows have serrated teeth on the ovipositor shown here on the
left and this is what they use to cut their way into the intact fruit. So, to identify these you might need a small little stick to prize out the ovipositor or
hopefully the fly lands in just the right way on the yellow sticky trap and you can look at this, and once
you’ve got your eye trained, especially down a
microscope, you can go through these trap inserts fairly quickly and count
the number of females. Unfortunately, you do need to look at
this structure to be able to identify whether it is Spotted Wing Drosophila. And if you’re not sure we do have access to an online key that’s been developed by an Oregon State Department of Agriculture
and that link will be coming up after this segment so you can see the
the link to the key and see some photographs of this species and others that are similar but don’t have quite the same
dark serrated ovipositor as Spotted Wing Drosophila. So, this trap if it’s been out here for a
little while the apple cider vinegar would be
starting to lose it’s potency. So, we recommend that you take that trap and dispose of the liquid somewhere else, ideally not right
here because you don’t want the flies attracted to the ground around here. Maybe put it in a different container or just carry it out of the planting and dispose of it away from the trap. So, you’d hang this back up again. Take a new insert, take a fresh one of
these, and you might want to use gloves for this.
These are a little bit sticky. Take that new insert and then just hang it inside the trap surface of the trap lid. Hang it right there, set it back inside, and that trap is now recharged. So, you’d have new apple cider vinegar and, if it needs it, a new insert. Another thing about these traps that’s important to know is that if you have, what you think, is the
first detection of this fly, it might be good to carry some
Ziploc bags with you and then that sticky insert could be just put in a ziploc bag, sealed up, and carried back to maybe show your extension agent or to have a look up close with a hand lens or a microscope out in the field so you can look at it carefully. So, that’s how the traps are set for Spotted Wing Drosophila. Another design of the trap that you can
use to monitor for Spotted Wing Drosophila is this shorter trap and this
is a good idea if you’re putting traps out in
strawberry fields because obviously the taller trap would just get knocked
over. So, this one can be placed down in the row near the fruit zone or in the fruit zone and it’s basically the
same design. It’s just a few inches tall, and it has the holes around the edge and it also has the sticky trap inside. So, you put the sticky trap in and if you were changing it over add the cider vinegar. That’s the bait that attracts the flies. And in this trap the sticky doesn’t have to be hung. You can just set it, try to set it inside there. Basically if there’s a
sticky surface in inside the trap, the flies will be caught in it. That’s now the sticky surface. Flies will
come in the hole, attracted to the vinegar, and be caught on the yellow sticky trap.

 

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