-E. Taylor
Below is a montage video of the setup for our 2010 study examining winter annual weed seed germination and decay over time. Enjoy!
*Closed captioning is available by viewing the video on the YouTube site, and clicking the “CC” icon.
Archive for the ‘Winter Annuals’ Category
Winter Annual Weed Seed Germination and Decay Video
Friday, June 25th, 2010Raise your hand if you’re tired of RAIN
Friday, June 11th, 2010-E. Taylor 
It seems lately that it rains every few days in Michigan. Even small periods of heavy rain cause the fields to be wet for several days afterward. All of this unwanted precipitation has caused several issues for our research such as:
- Poor emergence of sugarbeets (one field required replanting)
- Delayed planting of soybeans a couple weeks ago
- Delayed planting of dry beans the past two weeks at the Saginaw Valley Research and Extension Center and on campus
- Delayed initiation of our winter annual germination and decay study
So what do we do when we are “rained out”? Many times we will make sure all of the needed stakes are prepared, any chemical needed is weighed out and gathered, and the facilities and equipment are maintained at the Agronomy Farm. We also spend some time up in the laboratory processing weed seed and biomass samples, entering data, sewing storage bags for various experiments, and cleaning weed seed for greenhouse experiments.
Perhaps when the weather begins to cooperate there will be more interesting things to blog about 
Just as a reminder our MSU Weed Tour is coming up on June 30th at the Plant Pathology Field Lab. Information on the tour is available on our website.
White Rust on Shepherd’s Purse
Friday, May 14th, 2010-E. Taylor
Healthy (left) and diseased Shepherd's purse (right)
As part of our winter annual weed research project I observe the growth and seed development of several species. This year in my weed plots I have noticed that the Shepherd’s purse (Capsella bursa-pastoris) plants are showing symptoms and signs of disease with curled flower heads and white fungal growth. The disease first appeared about 2 weeks ago and is now on about 50% of the plants. Our resident USDA-ARS sugarbeet pathologist, Dr. Linda Hanson, believes that the responsible pathogen is white rust (Albugo spp.). White rust is not a true rust (Basidiomycete) but a water mold (Oomycete) that affects plants in the mustard family (of which Shepherd’s purse is a member). It prefers cool wet conditions, which we have had a lot of lately. At first when I observed the disease I thought of biocontrol possibilities, but it turns out white rust is an obligate parasite (i.e. needs a live host to grow and develop) so it would be difficult if not impossible to propagate the disease for biocontrol applications. For more information regarding White rust and other oomycetes visit the American Phytopathological Society site.
Purslane speedwell, the mystery weed
Friday, March 26th, 2010-E. Taylor
Purslane speedwell image sent in for identification
When we are out in the field taking weed density counts we come across weeds typical to our area and cropping systems such as common lambsquarters, giant foxtail, velvetleaf, common ragweed, etc. When we come across something uncommon or new we get a little excited about identifying it. One such weed that we encounter periodically is purslane speedwell (or when you’re in the field without a good reference book “Mystery weed”). Recently, we had a blog reader from Kansas ask us to identify a weed from photos that turned out to be purslane speedwell, so I thought I would take the time to tell you what is known about this weed…though it is not very much.
Common names: Purslane speedwell, neckweed
Latin name: Veronica peregrina
Lifecycle: annual (occuring as a winter or summer annual it appears)
Distribution: throughout the U.S., likes moist soils
Purslane speedwell leaf
Botanical description*: Fiberous root system, erect stems which are simple or branched below, leaves are opposite, oblong to oblanceolate (0.5-3 cm long and 1-9mm wide), and are usually irregularly toothed, flowers bloom in a terminal inflorescence with bracts similar to the leaves and each floret has very small white corolla, fruit form as capsules.
Links and sources:
- plants.USDA.gov
- Missouriplants.com
- *University of Washington- The Burke Museum of Natural History and Culture
- Uva, R. H, J. C. Neal, and J. M. DiTomaso. Weeds of the Northeast. Cornell University Press. Ithaca, NY. 1997.
Pennycress as a Weedy Biofuel?
Thursday, October 22nd, 2009-E. Taylor
You may have a potential biofuel source emerging in your field right now and not even know it. According to an article on AgriNews Online (”Producers growing weeds for fuel“) some growers in Illinois are planning on growing field pennycress for biodiesel production. Field pennycress in a winter annual weed, meaning it emerges in the fall and reaches maturity sometime in the spring/early summer, so in Illinois they are thinking about planting the pennycress into corn stubble in September/October and harvesting in early June, hoping to still get in a soybean crop. Pennycress is a member of the mustard family, it begins its life as a rosette and produces flowers and seeds on a bolt. Though pennycress can be confused with other weeds, such as shepherd’s purse, it can be distinguished by the sulfur smell it emits when the leaves are crushed and the rounded capsules which hold the seeds. In the article, they report that the oil content is nearly twice that of soybean. I have studied the lifecycle of field pennycress for the past few years so I had a few thoughts.
- From what I have seen in naturally emerging pennycress plants in Michigan the plants begin to drop mature seed somewhere between the 1st to 3rd week in June. When the dispersal first begins not all of the seeds on the plant are mature, they mature from the bottom up. For us, harvesting pennycress this late in the planting season would potentially be too late for a soybean crop.
- I have found pennycress seeds to be very easy to harvest by hand for use in laboratory and greenhouse experiments, especially compared to other winter annuals such as common chickweed and henbit. The seeds seperate easily from the capsules. Because the seeds sit high above the rosette of the plant I would imagine that with the right setup they would be fairly easy to combine.
- One greenhouse study, published in Weed Technology by Venkatesh et al. in 2000, showed that field pennycress is a potential alternate host for soybean cyst nematode, so this may be an important consideration in some areas.
Who knows where this weed will end up in the grand scheme of biofuels, but it is kind of fun for weed nerds like me to think about. As a side-note, I will be presenting a poster on pennycress entitled “Temporal seed rain and dormancy of field pennycress and common chickweed” at the upcoming NCWSS meeting in Kansas City, MO.
Thanks to Joe Armstrong for sending me the article.
