- Author: Shannon C. Mueller
I visited a grower recently who noticed his alfalfa wasn’t coming back as quickly after cutting this summer. He had taken plant tissue and soil tests which both indicated that phosphorus was deficient in the field. Since other management practices appeared to be in line, it looked like phosphorus might indeed be the culprit. Now he was trying to decide which phosphorus fertilizer to use, how much to apply, and when to apply it.
A high-analysis phosphorus fertilizer, such as 11-52-0, or liquid 10-34-0 is usually the most economical source of phosphorus, and both of these sources will result in the same yield response per pound of P2O5 applied. I cautioned that if choosing a...
- Author: Steve Orloff
Many growers have good intentions when it comes to controlling weeds in seedling alfalfa but often fields end up being treated beyond the optimum window. Proper application timing is critical for successful weed control in seedling alfalfa. Not only do weeds reduce the nutritional quality of the alfalfa and reduce alfalfa vigor, but weeds in seedling alfalfa can affect stand density potentially resulting in reduced alfalfa yield over the life of the stand. When herbicides are applied late, weed control can be improved somewhat by increasing the herbicide rate, but that is costly and often increases the potential for alfalfa injury.
In order to get the “most bang for your buck”, treat seedling alfalfa...
- Author: Rachael Freeman Long
- Author: Larry Godfrey
- Author: Dan Putnam
The threecornered alfalfa hopper is a green, wedge-shaped insect about the size of a Lygus bug. These leafhopper pests have piercing-sucking mouthparts and feed on the stems of alfalfa plants, often girdling stems at the base of plants. The resulting damage includes wilting and yellowing and eventual dieback of individual stems. Injury is also caused when adult female hoppers insert their eggs into stems, weakening them.
Threecornered alfalfa hoppers can be found year-round, but in the Central Valley, numbers usually peak in late September and October. This year, they’re out in high numbers earlier (late August). In the low desert, there are two population peaks for adults: one in late July/early August and a...
- Author: Vonny M. Barlow
Several insects can reduce alfalfa yields such as the Empoasca leafhopper group (ELH) which feeds on a wide range of plants and is capable of successful reproduction on over 200 plant species in 25 different families. The ELH found in California alfalfa hay is actually made up of a complex of almost identical insects in appearance and behavior that include the Potato leafhopper, Empoasca fabae (Harris), the Garden leafhopper, Empoasca solana DeLong, and the Mexican leafhopper, Empoasca mexara Ross and Moore.
Empoasca leafhoppers are a severe pest of alfalfa in the eastern half of the USA and portions of Canada. Empoasca leafhopper infestations in California are...
- Author: Vonny M. Barlow
Verticillium wilt disease of alfalfa is relatively new to California, having first been found in isolated fields in Humboldt and Monterey counties in 1985. Verticillium wilt is a disease caused by Verticillium albo-atrum alfalfa strain. Verticillium wilt is the most serious disease problem of alfalfa in the north-temperate areas of the United States, Canada, and Europe. In southern California the V. albo-atrum alfalfa strain was found in 28 of 52 fields sampled in Riverside and San Bernardino counties. Verticillium albo-atrum has a limited host range. The most important hosts of this pathogen include hops, alfalfa and cotton.