Diseases in new crops
Crop production trends on the Prairies have moved to diversification and increased production of exotic herbs, spices, essential oils and medicinal plants. Along with these new crops can come diseases that have rarely, if ever, been seen on the Prairies before.
“The plant pathology team at Crop Diversification Centre – South are discovering new diseases and documenting their incidence on the Prairies,” said Kan Fa Chang, plant pathologist with Alberta Agriculture at the centre in Brooks, Alta.
“Plant pathologists spend part of their time looking at diseased plants, isolating the pathogens believed to be responsible, then introducing the pathogen to a healthy plant like the one the disease was originally found on in order to prove it is the true cause of the problem.”
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They also search for controls, whether chemical, biological or cultural, for diseases. The pathology group works with many of the horticultural and specialty crops in the province.
New diseases have been found at the centre. In August 1996, Chang reported sclerotinia stem rot on a crop called stevia for the first time. Stevia, an annual plant that comes from Paraguay, is used as a low calorie sweetener in Southeast Asia and South America. It is 100-300 times sweeter than regular sugar.
The stem rot disease had not been described on the Prairies before.
“The second host that the stem rot was found on was purple coneflower (echinacea),” Chang said.
Echinacea is a perennial herb grown for medicinal purposes. The disease was found in research plots at the centre in 1996. In the spring of 1997, stem rot occurred in echinacea fields at Vernon, B.C.
Chang, along with Sheau-Fang Hwang, from the Alberta Research Council in Vegreville, has done extensive work studying the yellows diseases of caraway, calendula, echinacea, monarda and valerian.
Yellows diseases are caused by microorganisms called phytoplasmas. These are smaller than bacteria, but larger than viruses and are responsible for over 200 diseases in a variety of plants. The best known yellows disease is aster yellows, which attacks vegetables such as carrots.
These organisms survive and reproduce in plant tissue, and are transmitted by insects, like leafhoppers, which feed on the water tubes in the stem of the plant.
“Management of yellows includes focusing on both the pathogen and the vector,” Chang said. “This includes monitoring for leafhoppers and controlling their numbers when they begin to increase. Producers should also control perennial weeds and avoid planting susceptible crops close to fields of other susceptible crops.”
– Alberta Agriculture
Making farming profitable
A member of a farmer-run research group is convinced that a yield monitor and a global positioning system unit can save him money.
“Last year’s soil tests indicated my fields were deficient in micro-nutrients, but I elected to apply these micro-nutrients in test strips only,” said Vince Walker, of the Northeast Agriculture Research Foundation.
Walker grows wheat, barley, canola, peas, flax and some pedigreed seed on 3,000 acres near Star City, Sask.
“But I monitored the yield and found no response to these micro-nutrients. So I definitely saved money and will probably continue doing test strips with fertilizer,” he said.
“But the most important benefit last year was when I applied Tilt to a 120-acre field of Harrington barley, leaving three five-acre strips without Tilt. The monitor indicated a significant yield reduction – more than 10 bushels an acre – on the untreated barley. Last year was drier than normal and I would have expected no response to Tilt. So I have safely concluded that, if you grow Harrington barley in northeast Saskatchewan, you have to apply Tilt.”
Walker is a founding member of the Northeast Agriculture Research Foundation, formed in 1996. The members wanted to establish a farmer-driven program for field-scale research, he said. The goal is to determine whether precision farming is economical in northeast Saskatchewan.
“The foundation has 25 members, with seven having combines mounted with yield monitors and GPS units,” said Roy Button, a soils and crops agrologist with Saskatchewan Agriculture in Tisdale. He has worked with the foundation since its inception.
“Some of the trials conducted in 1997 included fungicide trials on canola and cereals. Three treated and three untreated strips in each field were tested for yield responses from Tilt on barley and wheat, and from fungicides on canola for sclerotinia control. Small plots were also established in the same fields to determine whether similar data could be obtained from small-plot results.”
Button said excellent crop growth in early July led to strong potential for disease. However, dry conditions during the remainder of July resulted in very low levels of disease and no response from fungicide spraying on canola was detected. On the other hand, yield increases of about 15 bushels per acre on Harrington barley sprayed with Tilt were detected on both the small plots and the monitored field strips.
“The farmers with monitors and GPS units have found that yield maps show large variation of yields within fields,” said Button.
“By using these maps over two or three years, plus doing some field scouting and maybe soil analysis, farmers think there is a reasonably good potential to vary the level of inputs and improve economic returns.”
The Northeast Agriculture Research Foundation has planned a number of projects for the upcoming season.
“To determine whether precision technology is going to be effective, the bulk of the work will be done on fields owned by farmers with yield monitors and GPS units to monitor the actual field variation,” said Button.
– Saskatchewan Agriculture
Annual ryegrass pasture
Annual crops can be a valuable part of the regular farm or ranch forage program. Historically, cereal crops have been used as the primary source of annual pasture, but in the past few years, annual ryegrass has received a lot of attention as an alternative source of annual pasture.
“In 1997, a number of on-farm demonstrations were conducted in southern Alberta to evaluate the potential for this grass for summer grazing and as a source of stockpiled fall grazing,” said Gordon Hutton, a forage specialist with Alberta Agriculture.
“The results from these projects indicate that annual ryegrass can provide high quality forage from early summer through to November.”
Trials also indicated stocking rates and cattle live weight gains per acre are dependent on seasonal moisture.
Annual ryegrass is a shallow-rooted grass that is best suited to irrigation or areas that receive 254 to 356 millimetres of rainfall though the growing season.
“Under good moisture conditions, live weight gains obtained in 1997 ranged from 440 pounds per acre for summer pasture to an estimated 100 lb. per acre when used as stockpiled fall pasture,” said Hutton.
“Due to the high forage quality, this pasture program is well suited for use with yearlings or weaned calves.”
Costs of seeding this crop range from $45 to $70 per acre.
Further information on the results of the ryegrass on-farm projects is available by contacting Hutton at 403-948-8502.
– Alberta Agriculture
