Picture caption: Field site where Safari was applied in July, 2009 was heavily infested.
SUMMARY: Safari controls balsam woolly adelgid well, and may work well even with incomplete coverage. However, more research is needed.
Safari (dinotefuran) is one of the neonicotinoid insecticides. Their mode of action is similar to the natural insecticide, nicotine. The most commonly used neonicotinoid is Merit (imidacloprid) which many people have used for hemlock woolly adelgid (HWA). Safari, however, is far more water insoluble than Merit, and control of HWA has proven to take weeks instead of months as it does with Merit.
In fact, researchers are now applying Safari in a spray form just to the trunk of the hemlock and getting good control. Now that's quite a systemic if the chemical is moving through the bark and up to the needles.
Jerry Moody, the CEA in Avery County and I tried Safari against balsam woolly adelgid (BWA) 2 years ago, with very good results. Oddly, this material will not control twig aphids. How something is so good against adelgids and won't control aphids, I don't understand. It is also labeled for scale control, though control of elongate hemlock scale has been variable. (I will talk about that more in a future post).
In any case, Jeff VAnce, the CEA in Mitchell County and I decided to try Safari against BWA in a field trial this summer. We mixed Safari at 8 oz/100 gallons and then applied it one of three ways -- with a thorough spray, only hitting the trunks (and using about 1/2 the water and moving twice as fast), or not spraying the tree at all but just hitting the ground. The treatments were made July 1 with a high pressure sprayer.
I never thought it would work. After all, systemics don't work as well against BWA as they do against HWA because BWA is feeding in the bark and not the needles. However, it did work well.
Before anyone gets too excited, remember that we had an awful lot of rain last summer. This may have allowed the chemical to get into the tree better than it would in a normal year. The results are exciting, and we will try it again this year.