- Author: Rachael Freeman Long
Why do my alfalfa leaves look spotty??
Common leaf spot (Pseudopeziza medicaginis) has been very common in some alfalfa fields this spring due to our wet weather! Symptoms include small circular, brown-to-black spots on the leaves. As the disease progresses, infected leaves turn yellow and drop. Although the disease does not kill plants, defoliation reduces plant vigor, hay quality, and yield, especially with leaf loss during drying and harvesting.
Common Leaf Spot (Pseudopeziza medicaginis) in alfalfa - symptoms are small (.12 inch) circular brown/black spots on leaves, leaves turn yellow and drop. Brown fruiting bodies (apothecia) can be seen within the spots with a hand...
- Author: Michelle Leinfelder-Miles
- Author: Daniel H Putnam
The annual UC Davis Small Grains and Alfalfa Field Day will take place on Thursday, May 11, 2017 at the Agronomy Field Headquarters (2400 Hutchison Drive, Davis, CA 95616). Registration opens at 7:45am, and lunch is provided between the small grains morning program and alfalfa afternoon program. The event is free and open to the public, and continuing education credits will be available. Directions are as follows:
The field day is located on Hutchison Drive, just west of Davis. Take the Hwy. 113 exit north from I-80, or Hwy. 113 south from Woodland. Exit west on Hutchison Drive. Take a right at the first roundabout, a left at the second roundabout, and the Agronomy Headquarters is about ¼ mile down in a...
- Author: Kathy Keatley Garvey
UC Cooperative Extension entomologist Larry Godfrey, a 26-year member of the UC Davis Department of Entomology and Nematology faculty and widely known for his research on applied insect ecology and integrated pest management (IPM) strategies, died April 18, succumbing to cancer. He was 60.
Dr. Godfrey was internationally acclaimed for his research on rice and cotton. He was heavily involved in developing IPM to maintain the sustainability of California agriculture, seeking “to reduce the ‘footprint' of agriculture on the environment and society, and to advance the science of entomology and applied insect ecology.”
At UC Davis, he...
- Author: Michelle Leinfelder-Miles
A consultant recently brought in some alfalfa plants to get another opinion on why growth was resuming slowly this spring. The field is located in Merced County and is a sandy loam soil. The field is in its fifth year, is glyphosate-tolerant, and has traditionally produced high-quality hay. About 5 acres of a 40-acre field are affected.
There are many reasons why growth may resume slowly this spring. The obvious reason, of course, is that we received a lot of rain this winter. With that rain has come associated problems from cool, anoxic (lack of oxygen) soil conditions. A previous blog article describes things to...
- Author: Rachael Freeman Long
- Author: Daniel H Putnam
Yellow plants equals nitrogen deficits—right? Maybe not!
When we have a very wet winter or spring, alfalfa fields may look yellow with diseased-looking leaves and delayed growth.
As farmers know, yellowing of leaves is a strong indication that nitrogen (N) may be limiting in the crop. Certainly that's true with corn, tomato, or wheat. It may also be the case in alfalfa too – but since alfalfa is a legume, it gets most of its N from biological nitrogen fixation (N2 fixation from bacteria which colonizes the roots, forming nodules), not from the soil. This ability enables alfalfa to grow well even on sandy N-depleted soils. N fertilizers are generally not recommended...