Today was my eight data collection day for 2010 Fir Experiment #1 and the seventh for 2010 Fir Experiment #2. My current plan to to wrap up Experiment 1 next Monday (it will take me weeks to finish processing the plants, but the active part of the experiment will be over) and Experiment 2 the week after that.
When I was examining the plants today I noticed relatively fresh Phytophthora symptoms on some plants. I attribute this to the recent break in the hot and dry weather. I think the brief rain and cooler temperatures we had a few days ago inspired the pathogen to enlarge its territory and go on a killing spree. Since the species of Phytophthora I am looking at cause root rot in firs, it makes sense that the infected plants would show signs of stress on hot sunny days. The root loss they have sustained reduces their ability to take up water. At first this results in wilting or flagging foliage, eventually it will become necrotic.
In the middle foreground of the above picture you see a flagging Fraser fir. Up until this week it had looked healthy, but today it looked ill. This plant was inocululated with both species of Phytophthora, so it has every right to complain.
In Experiment 2 I am seeing deferences between fungicide treatments, which is a good thing. The real test will occur at the end of the experiment when I crunch the numbers and find out if what I am observing is really significant.
Check out this picture, which illustrates differences in effectiveness of a certain fungicide when exposed to different Phytophthora species.
That’s an encouraging sight. Green and brown. Of course I’m sure the chemical company would prefer to see all green.
One thing I’ve learned from running experiments: sometimes results that look clear in the field become inconclusive during statistical analysis. So I’m withholding all my enthusiasm until I see the results from SAS. That should happen by mid-to-late August.