# Hemlock Wooly Adelgid



## Gabby (Apr 26, 2012)

Hi guys, I have been reading a lot on here by searching "Wooly Adelgid" and I hate to start another topic on the subject but I can not seem to find what is the clearest way to treat for Hemlock Wooly Adelgid. I live in a wooded area in south east N.Y. My wooded lot is 20% Eastern Hemlock and Wooly Adelgid is killing so many of the trees. I have cut a lot of the ones that are dead out near my house but would like to treat for this on some of the ones still doing well. Suggestions? Will the state forestry/DEC help with suggestions I wonder? Let me know what you guys think? I would like to save some of the onces close to my house at least. Thanks.


----------



## forestryworks (Apr 26, 2012)

Try this site instead.

Hemlock Woolly Adelgid, Forest Health Protection, USDA Forest Service


----------



## Tree Pig (Apr 26, 2012)

INSECTICIDAL SOAP/HORTICULTURAL OIL. The safest insecticides for controlling HWA are foliar sprays with either horticultural oil or insecticidal soap. These products are not toxic, but kill the insect by smothering it as the spray dries on the pest, making them safe to use around the home. Even if the entire tree is too tall for complete coverage, spraying as much of the tree as can be treated will help at least part of the tree recover. Make these treatments in the fall from August until it gets too cold to spray. These treatments are timed when eggs are not present as this stage is not readily killed by the smothering action of these insecticides. Also, during the growing season, these products may burn foliage. Only spray trees if the material will not drift into open water such as streams or ponds or onto adjacent property. Both of these products are used at a 1-2% solution with the higher rate giving better control. (2% solution = 2.6 ounces of spray material per gallon of water). Once these materials dry, they will no longer control HWA. Therefore there is no residual control. Trees will probably need to be treated yearly. Treating other times of year will result in poorer control and may result in foliage burn. Be sure that the oils especially stay well mixed with the water during application. 

OTHER INSECTICIDES SPRAYED ON THE TREE FOLIAGE. Other insecticides labeled for use in the landscape will last on the foliage to continue killing the insects once the spray has dried. Therefore timing of spray applications is not as critical as they should last long enough on the tree to kill the crawler that hatches from the egg. However, these materials are more toxic and should be used with care near homes. Materials include Merit (imidacloprid), Talstar (bifenthrin), Onyx (also a befenthrin product), Astro (permethrin) and DeltaGuard T&O 5 SC (deltamethrin). Of these, Talstar (bifenthrin) has been the most widely used, providing excellent control any time through the growing season. Control from spraying Talstar has given two and sometimes three years of control. Again, do not spray trees if the material will drift into open water or other property. Spraying any of these materials may result in increased spider mite and hemlock rust mite occurrence. 

SOIL DRENCHES/SOIL INJECTIONS/BARK SPRAYS. In large trees that cannot be completely sprayed, consider soil drenches or soil injections. In this case, the tree roots take up the product and move it into the foliage where the insect is killed. Soil drenches should be applied when there is adequate soil moisture in either the spring or fall so that the tree will take up the product. Do not use in areas near streams or ponds or where the soil is too rocky. The rates of these products are based on the size of the tree trunk or height in the case of a hedge. Most soil drenches are made with an imidacloprid product including Merit 75 WP, Malice 75 WSP, Zenith 75 WSP. Any of these can be purchased by the homeowner where pesticides are sold. Bayer Advance Garden Tree and Shrub Insect Control, an imidacloprid product for homeowners, is more readily available and can be purchased from home improvement stores. There are other imidacloprid products coming on the market. Any may be used as long as they have a landscape label. Imidacloprid products used thus far have all had 75% active ingredient. Another similar product with slightly faster uptake by the tree is Safari 20 SG (dinotefuran). This may be used as soil drench or bark spray.

 TRUNK INJECTIONS. In large trees that are near surface water or where the soil is too rocky for soil injections or drenches, use trunk injections of imidacloprid. With this method, the chemical is put directly into the tree and then taken up into the foliage. It is best to hire a commercial pesticide applicator who has had experience controlling HWA for these treatments. Again these applications are made preferably in the fall or spring when there is adequate soil moisture for the tree to take up the product.


----------



## ATH (Apr 26, 2012)

Soil drench around the base of the tree with imidacloprid (Merit or the generic copies). That is by far the simplest and it is as effective (or very nearly as effective) as other treatments for this particular pest.

Buy it in bulk and you should be spending less than $0.45 per inch of treated diameter for the product. Note, though, that you are limited in the number of trees you can treat based on amount of product per acre that is safe to use.

Meeting The Threat of the Hemlock Woolly Adelgid.


----------



## Gabby (May 9, 2012)

ATH said:


> Soil drench around the base of the tree with imidacloprid (Merit or the generic copies). That is by far the simplest and it is as effective (or very nearly as effective) as other treatments for this particular pest.
> 
> Buy it in bulk and you should be spending less than $0.45 per inch of treated diameter for the product. Note, though, that you are limited in the number of trees you can treat based on amount of product per acre that is safe to use.
> 
> Meeting The Threat of the Hemlock Woolly Adelgid.



ATH, where is a good place to buy in bulk? Thanks.


----------



## ATH (May 9, 2012)

Imidacloprid is a VERY common chemical, so any chemical dealer should have it available. Agricultural or turf chemical suppliers can certainly get it for you. The original "brand" name is Merit (made by Bayer), but there are many generics as it has been off patent for a few years. I use Quali-pro brand - you can check their website for distributors. I buy from Midwest Arborist Supply. Site sponsor Tree Stuff carries it - others may as well...


----------



## Gabby (May 10, 2012)

ATH said:


> Imidacloprid is a VERY common chemical, so any chemical dealer should have it available. Agricultural or turf chemical suppliers can certainly get it for you. The original "brand" name is Merit (made by Bayer), but there are many generics as it has been off patent for a few years. I use Quali-pro brand - you can check their website for distributors. I buy from Midwest Arborist Supply. Site sponsor Tree Stuff carries it - others may as well...



Here is a link to Imidacloprid from Tree Stuff:

Tree Stuff - Quali-Pro Imidacloprid 2F Insecticide

It is $39.95/Qt. from Tree Stuff. Trying to get an idea how far a qt. or a gallon goes, any idea. Is this stuff a concentrate or is it used straight? Thanks for your help.


----------



## ATH (May 10, 2012)

CDMS is a great place to find labels - you can usually find them on manufacturer websites as well. ALl the info you need to know is there. Remember the label IS the law when you are using an insecticide.

It would be easy enough to answer your question about how much to use...but then I'm afraid you would not read the label, and I'm thinking you need to do that...so here it is: Quali-Pro Imidacloprid 2F label.

Would be happy to answer questions about experiences with use...but I'd recommend that you direct product specific questions to the Quali-Pro Sales Rep covering your area, so you aren't just taking important advice from some random guy on the interweb.

I do like the 2F formulation because it is easy to mix in exact amounts. Some of the others (like the WSB), the pouch determines how much you use...but it may be a little cheaper if you know you are using a lot each time you mix it.


----------



## Camdo (Sep 23, 2012)

Has anyone had experience with bark spray method using PentraBark + Imidacloprid on mature Hemlocks (20-30 inch diameter at breast height) for control of HWA? 
Will PentraBark bleach the Hemlock bark? 
Will Imidacloprid alone work as a bark spray on mature hemlock trees?

It seems to me that forever annual soil treatments of Imidacloprid is asking for eventual ground pollution problems. Bark spray seems a much better method, but does it work? 

There must be someone out there who has tried multi-year, annual bark spray on a mature hemlock tree for HWA control. Does it work?


----------

