- Author: Rachael Freeman Long
- Author: Steve Orloff
The recent rains were a welcome relief for many parts of our state, but we are still in a serious drought with our reservoirs and snowpack at historical low levels. Ensuring adequate water for crops will be a challenge this year.
In general, perennial crops, such as orchards and vineyards, cannot survive extended periods without irrigation. However, alfalfa is more resilient because it can go into a drought-induced dormancy over the summertime, at least for one year. The tradeoff is that without water there will be little yield, but research has shown that the stand will persist on most soil types and yield will recover the next year once water is applied to the field again.
In most years hay growers...
- Author: Michelle Leinfelder-Miles
At the Alfalfa and Forage Meeting held at the Kearney Agricultural Center in September, we provided a demonstration of the co-existence of Roundup Ready® (RR) and conventional alfalfa hay fields. The demonstration took place between two hay fields – one of them RR and the other conventional – that were in their third year of production and separated only by a one-lane dirt road. The demonstration showed what is meant by “co-existence”; the RR trait has not transferred to the adjacent conventional hay field or to a nearby organic hay field. All of the fields are co-existing in close proximity, and the RR trait is only found in the RR field. We used commercially-available test strips that detect the CP4 EPSPS...
- Author: Rachael Freeman Long
- Author: Larry Godfrey
Mealybugs are common insect pests of many crops including grapes, citrus, ornamental plants, and various other perennial crops. They feed on trunks, stems, leaves, and roots of plants. At times these infestations can be very obvious on plants due to high mealybug densities, the sticky honeydew that they excrete, and the sooty mold that often grows on the honeydew.
The ground mealybug is an important insect pest of alfalfa, primarily in the Sacramento Valley. This mealybug is a member of a group of species that spend their entire lifecycle below ground. This insect is small (about 1/16" long), whitish, and relatively soft-bodied. Ground mealybugs feed on alfalfa roots by sucking out plant juices, which causes stunting and...
- Author: Carol A Frate
It’s not that I am unpatriotic, but in this context “flags” refer to isolated dead alfalfa stems with dead leaves still attached that are surrounded by healthy stems. The “flags” are usually light colored and the tips are often curled over like a shepherd’s crook or staff.
“Flagged” stems can be caused by several pathogens but when they appear in summer, are light tan in color and have the characteristic crook at the top, it is probably because the stem is infected with the fungus Colletotrichum trifolii (Figure 1). The disease this fungus causes is called anthracnose (it has also been called southern anthracnose). The most obvious symptoms...
- Author: Michelle Leinfelder-Miles
I recently received a call from a PCA who had questions about nematodes that infect alfalfa. He had observed stunted crop regrowth after the first cutting and had reason to think that nematodes could be the cause.
There are three nematodes that tend to be the most problematic in alfalfa. Stem nematode (Ditylenchus dipsaci) is a nematode that feeds on above-ground plant parts, unlike most plant-parasitic nematodes that feed on roots. To recap a blog by Rachael Long and Dan Putnam, stem nematode symptoms include stunting, shortened internodes, and even plant death when infections are severe. It is a fairly easy pest to diagnose if...
