# Eastern hemlock sprays



## Upidstay (Sep 8, 2010)

I am trying to save some Eastern Hemlock trees in my yard. They had a pretty good Wooly Adelgid infestation, which I mostly cured with an oil spray and imidichloprid. Trees were i tough shape, but have turned around nicely with some good fertilization. Now the Elongate Needle scale has moved in, along with what looks like mite damage. I was going to spray them again, as I know imidichloprid is marginally effective against these two, at best. Is hort oil the weapon of choice, or would M-Pede soap work better? Also, what is a ood time to hit the critters? I was thinking early to mid-fall, which is in about a month here in CT.


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## Urban Forester (Sep 10, 2010)

Treating now is useless. They have already exuded their waxy coating and will be impervious to insect control. Your right about imidicloprid, totally ineffective. Spraying (for HWA) may be knocking down predators, bringing in the scale/mites. I would soil inject Imidicloprid for HWA. Another, less obvious way to increase scale activity is by the use of fast release nitrogen fertilizer. I would discontinue ANY nitrogen (if any is being used) until the scale is controlled. The crawlers should hatch around mid-May, maybe late May where you are. They have a long crawler stage with treatments viable till the end of June. Remember the more you spray, the more mites you may get. So timing will be critical.


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## alanarbor (Sep 13, 2010)

imidicloprid is like viagra for mites.

Hort oil, properly timed will be quite effective on both scale and mites. You'll have to spray several times during the season as mentioned, due to the crawler activity. If the mites are really severe, mixing a miticide such as floramite or hexygon into your oil on one treatment may help.


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## sweetjetskier (Sep 27, 2010)

This year has been really tough in CT as many other states beacuse of drought conditions stressing the trees a ton.

I have always working to improve the cultural conditions of trees to be the long term help.

Are these hemlocks in a sandier soil, what's the soil OM, and Ph ?

A good mulch layer, 2 inches or so does help keep moisture around, but also keeps soil cooler.

If watering deep,soaking as opposed to frequent light waterings is needed.

We have used merit soil injections with a low rate of PHC 11-22-22 srn to help with uptake,with ok results.

If timed correctly hort oil is best,cheapest way to go. May need repeat treatments.

I have added some Avid on occasion for severe mite problems, but usually don't like kill off natural predators.

I may try some K plus Neem, works great and is pretty freindly product,but I haven't used it in a few years.


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