[Market-farming] New Raspberry pest-back again with a vengance
Shoemaker, William H
wshoemak at illinois.edu
Wed Aug 15 09:45:19 EDT 2012
IF it is Spotted Wing Drosophila it is pretty susceptible to insecticides. The problem is that you probably have every stage of the insect present; eggs, larvae, pupa and adult. You'll need to spray more than once to get them under control. Because it has a short life cycle, spraying twice 4-5 days apart may be enough, but I suspect another spray may be necessary. But that still doesn't address migration of new adults into your patch from adjacent areas. You may need to spray continuously to address this pest, perhaps putting on new sprays every 5-7 days.
However, looking at this as an opportunity, if you don't spray you'll lose the crop and suffer despair about ever growing it again. Why not turn this into an opportunity to learn what works? If the insect is pretty easy to kill, why not try several choices, focusing on the least threatening insecticides first? You could try Pyganic and Entrust to see how well they control it. These are OMRI approved and have a history of some efficacy on a number of insects. You could alternate sprays of each, which would reduce the risk of resistance development. That's important with an insect like this with a short life cycle. You could throw Neem, or Azidarachtin, into the spray cycle to see if it works, though I'd be a little concerned about the smell. If you're not growing organically, Malathion is effective and shouldn't affect bees. Unfortunately I think Pyganic will affect the bees.
Sorry to hear you're dealing with this again. I'm afraid we all will be before long.
William H. Shoemaker,
Northern Illinois Viticulturist - IGGVA
Illinois Grape Growers and Vinters Association
wshoemak at illinois.edu<mailto:wshoemak at illinois.edu>
From: market-farming-bounces at lists.ibiblio.org [market-farming-bounces at lists.ibiblio.org] on behalf of Marlin & Christine Burkholder [burkholders at glenecofarm.com]
Sent: Tuesday, August 14, 2012 8:45 PM
To: 'Market Farming'
Subject: [Market-farming] New Raspberry pest-back again with a vengance
The new no see-um fruit fly which first made an appearance on our Virginia farm last summer is back again, with a vengeance! I had considered spraying an insecticide as the crop started into bloom in July but backed off when I saw the number and variety of bees and other pollinators on the plants. I opted instead to inspect the plants with a magnifying glass in search of the offending flies to see if I could make a positive identification before bringing in the bombs. I never could see anything that looked like the spotted wing drosophila which I have been suspecting is the culprit.
Now the first flush is ripening and at least 90% of the ripe fruit is mushy soft, crawling with maggots, and unfit to harvest. If there is no way of rescuing the remaining unripe fruit there will be no reason to attempt harvesting any more of the crop. It looks like we can consider the crop a 100% failure. I am considering bombing them immediately and waiting a week or more to begin harvesting. Anything ripe now or going to ripen within the next week or two would be given a goodbye kiss. Does anyone think this has a chance of working? Would insecticide hitting the infested berries still hanging on the vines kill the maggots and help reduce the pest load next year? Would I also need to soak the ground under the plants to get maggots on the fallen berries? When are the berries being infested? At bloom or preripening?
The only professional beekeeper still operating in our county happens to be a next door neighbor. He is struggling with all the new issues confronting beekeeping, including “colony collapse disorder” believed to be caused by environmental poisoning. I do not wish for my activities to contribute to his demise!
Fall red raspberries have in the past been one of our cornerstone income generating crops. Should I attempt a rescue maneuver now or should I write it off this year and plan to go after it early next season?
This thing is hurting us far more than the BMSB invasion that has had everyone stewing for the past two years!
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