Notes from Your Extension Agent:

Alfalfa: Many critics of alfalfa claim that the crop has a low value compared with the resources it uses. However, these critics ignore the economic value of alfalfa nationally, which ranks third only to corn and soybeans, despite the fact that alfalfa receives no direct government subsidies and must compete for economic viability with other “high value” crops such as subsidized grains, cotton and specialty crops. Regionally, alfalfa hay dominates the cropping systems in low desert regions of Arizona and California. In Arizona ~250,000 acres of alfalfa hay were harvested in 2012, with an average yield of 8.4 tons/acre (~250% the national average) valued at > $470 million (NASS 2013). The low desert produces about 26% of California’s alfalfa’s one billion dollar hay crop per year.
Alfalfa has many environmental benefits: it is a rich habitat for wildlife, provides an insectary for diverse beneficial insects, improves soil characteristics, fixes atmospheric N2, traps sediments and takes up nitrate pollutants, mitigates water and air pollution, and provides aesthetically pleasing open spaces. Regions with soil and environment depleted by row crop or specialty crop production, like many agricultural areas in the western US, would benefit environmentally and economically by incorporating a perennial legume such as alfalfa into the crop rotation. Alfalfa fields are important contributors to the biodiversity of agricultural systems; they function as insectaries for beneficial insects, many of which are pollinators or natural enemies that play important roles in the low desert agroecosystem. Beneficial insects move from alfalfa fields into other crops, where they play crucial roles in pollination and biological control. Broad-spectrum insecticide use in alfalfa devastates beneficial insect populations, which affects biological control and pollination across the entire agricultural landscape.
The many environmental benefits of alfalfa were the subject of an interesting article in the Western Farm Press this week.

Stink Bugs: Last season, stink bugs were present in many cotton fields across the state. While stink bugs are not unusual guests in our fields, the prominence and widespread distribution of the Brown Stink Bug (Euschistus servus) statewide has not been seen in cotton since 1963. I found a few stink bugs in alfalfa and small grain fields I am checking, and we have received several reports of Brown Stink Bugs in cotton along the Colorado river in Parker and Blythe, where cotton planting dates were ahead of ours in central Arizona. This may be an indicator of the population and species of stink bugs we might find later in central Arizona. As a result, growers and PCAs should be especially vigilant this year looking for populations of stink bugs in cotton. Monitoring alfalfa and grain fields can give an important early indication of the stink bug populations in the region. Fields should be checked visually (don’t rely on a sweep net) for any presence of stink bugs, esp. Brown Stink Bugs.

COTTON:
Reminder: This season, once again, we are conducting a survey for the new race of Fusarium wilt pathogen of cotton, known as Fusarium oxysporum f. sp. vasinfectum race 4 (FOV 4 ). It has become problematic in the San Joaquin Valley of California. It is an early season disease of cotton. Fusarium wilt disease has never been problematic in Arizona, but a survey was initiated last year to find any races of FOV that might be detectible in Arizona cotton, particularly FOV 4. The survey will be conducted from March-June 2013 with the cooperation of growers who submit samples from suspect cotton.

Mary Olsen and team have developed an app on “Differentiating diseases of young cotton” for the FOV4 survey that can be used as a guide to distinguish diseases that occur on cotton in the early stages and before flowering. This app was done with the funding from the ACIA. The app is a mobile web site temporarily. Once connected, it will stay as an “app” on your smart phone.
It is at this web site: http://apps.cals.arizona.edu/cottondiseases/

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