The Value of Christmas Trees

"...there is no reason why the joy associated with the Christmas evergreen may not be a means of arousing in the minds of children an appreciation of the beauty and usefulness of trees; and keen appreciation of the beauty and usefulness of trees is a long stop toward the will to plant and care for them (Arthur Sowder, US Forest Service, 1949)."

Thursday, February 9, 2012

Working with Safari

With the help of Doug Hundley, I've been following a field treated for elongate hemlock scale at the end of the summer. The grower used Safari + Wisdom (bifenthrin) in early August with a high pressure sprayer. He was trying to get rid of the white from the male scales as well as controlling Cinara aphids on the trees he was harvesting. But he was also hoping to get both good scale control and twig aphid control in the trees that he was leaving. The Wisdom should supply both the Cinara aphid and twig aphid control. The Safari would supply the scale control.

Doug and I have followed the field ever since. Doug was particularly interested in seeing if the white from the male scale would weather away and become less of a problem. So we went in just 3 weeks after application. At that time, the white was already less noticeable, but I found only 55% scale mortality which is, needless to say, practically no control at all.

In mid November, about 100 days after application, we went back and  observed 80% scale mortality. The white from the males was hardly noticeable, and there were no problems with harvesting the trees. Definitely we were headed in the right direction, but the scale control was still not good enough.

Just last week, however, we looked again -- close to 6 months after application. Now the control was around 95%. Control is finally good. This illustrates just how long Safari takes to work.

I plan on looking again at the field in mid-April. Hopefully we'll find that there was twig aphid control from the Wisdom that was applied. Then in June we'll assess how many scales are moving out onto the new growth. If not many are, perhaps the grower can skip scale control for 2012.

The following are some of the questions I'd like to try and answer in 2012:

  1. If you get good scale control one year, can you skip treating the next year?
  2. Can Safari control scales when applied with a mistblower?
  3. What is the best timing and pesticide combinations to control all of our Fraser fir pests including scale?
  4. Can you control theses pests and still have little impact on our natural enemies of scales?

So stay tuned as we try to nail down how to use Safari and other materials to the best advantage. I also have more control results I plan on posting over the next several days. Be sure to attend the NCCTA meeting in Boone on Thursday, March 1 when Doug and I will be joined with Brad Edwards and Brian Davis to discuss getting the most bang from your pesticide buck.

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