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Author Topic: 2 spotted mites  (Read 1077 times)

Mark Griffiths

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2 spotted mites
« on: May 16, 2018, 05:56:09 PM »
hi, every year these appear and infest the greenhouse - specifially targetting the Aquilegias, Silene hookeri, campanulas and various others.

I don't think there is now an insecticide treatment available? I've tried the predatory mite Amblyseius andersoni, but despite having got some a month ago (and another lot today) it doesn't seem to be keeping the other mites under control.

I contacted the vendors and they recommend a new set of sachets every 4 weeks. So that's 8 per month. I thought once you had a population of Amblyseius andersoni they kept going, eating mites and then fungi until the frosts.

Any words of wisdom?
Oxford, UK
http://inspiringplants.blogspot.com - no longer active.

Ali Baba

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Re: 2 spotted mites
« Reply #1 on: May 16, 2018, 06:01:25 PM »
Any reason you didn't try the usual predatory mite Phytoseiulus? It is specific to the two spotted mite, so not useful for other pests unlike the one you used, but I have used it in an unheated polytunnel and it worked very well once established.

Mark Griffiths

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Re: 2 spotted mites
« Reply #2 on: May 16, 2018, 06:14:30 PM »
hi, I think I just found it via search on Amazon.

Actually the vendor did suggest Phytoseiulus - but still said I'd need to top up every 3-4 weeks. Do they last the entire season for you? Have you got them in now - are you in the UK or a warmer climate?
Oxford, UK
http://inspiringplants.blogspot.com - no longer active.

Ali Baba

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Re: 2 spotted mites
« Reply #3 on: May 19, 2018, 11:35:27 AM »
Hi
I don't have the polytunnel now (in the UK), but I used to buy the predators once a year in the spring when mites were first noticed but before numbers had really built up. The first year I had some improvement, enough to avoid using any sprays. The next few years it worked really well. I would think once a year should be enough, as long as you accept that very minor damage is inevitable. You could top up the predator population if the mites seem to be getting out of control again. I was growing fruit and veg though, so a bit of cosmetic damage wasnt that important. What I did notice was after a few years I didn't need to use control every year, maybe there were enough predators around to keep things in balance.

I've been using Amblyseius andersoni to control thrips in my glasshouse this year for the first time. There seem to be less thrips around so far, time will tell!
cheers

GordonT

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Re: 2 spotted mites
« Reply #4 on: May 19, 2018, 01:15:52 PM »
Mark, we used Phytoselius in our unheated polytunnel for a serious outbreak of mites on eggplant. within two weeks, the new growth was coming up clean as a whistle. We were told that in the absence of mites for food, the predators would consume pollen. The problem was eradicated without having to top up the predators over the season (one treatment was enough- the outbreak was so bad that the new growth on the eggplants was stunted and looked silver from the spotting)
Southwestern Nova Scotia,
Zone 6B or above , depending on the year.

Mark Griffiths

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Re: 2 spotted mites
« Reply #5 on: May 19, 2018, 02:27:40 PM »
thanks both - I'm monitoring the situation having added a second batch.
Oxford, UK
http://inspiringplants.blogspot.com - no longer active.

 


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