Project Objectives

Results

Depots were buried, dug up and analyzed each year from most of the commercial field sites. The sclerotia from the depots were tested for colonization of C. minitans and the number of sclerotia that were colonized from each treatment was recorded. The first complete set of depots was exhumed in December 2008, approximately one month after application and incorporation, to determine how much colonization activity by the C. minitans had occurred since Contans applications. Results from these assessments showed positive results for Co-operator 6’s untreated check and Co-operator 8’s 2 kg/ha treatment. The presence of colonized sclerotia in the untreated checks is likely due to naturally occurring C. minitans in the soil, as this fungus is native to Alberta soils. The second complete set of depots was removed in the spring of 2009 and assessed by Dr. Howard’s lab. Analysis of these depots proved difficult as many of the sclerotial bodies had deteriorated and/or broken in several parts. Positive identification of C. minitans was complicated by the presence of other colonizing fungi, such as Rhizopus, Mucor and Trichoderma. Irrigated soils are very biologically active, and a wide variety of microflora and microfauna contribute to the breakdown of organic matter, such as sclerotia. Coniothyrium incidence on sclerotia in untreated and treated fields and ranged from 0 to 100% (Table 1). The highest positive results were from Co-operator 4 and 5’s fields.  

The results from the depots in 2010 were inconclusive for co-operators 4, 7, 8, and 9. However, the results from Co-operators 1, 5, and 11 showed a higher percentage of Coniothyrium-colonized sclerotia in the Contans treatments compared to the untreated checks. It is uncertain what caused this difference, as co-operators from both groups made spring applications at similar times, and a variety of incorporation methods were seen among all fields.  

Depot results from 2011 were inconclusive for co-operators 3, 4, 9, and 11. Co-operator 5 had a positive result in the 4 kg/ha treatment, with a much higher colonization rate than in the check and 2 kg/ha treatments. Co-operator 6 also had a high colonization rate in the 4 kg/ha treatment, but the check also had a high rate of Coniothyrium recovery.  

Table 1: Depots results for commercial field-scale sites and SARA demonstration site 

Disease assessment and seed yield 

In 2009, disease pressure was high such that percent incidence in the untreated checks and Contans treatments were close to 100% at all sites, with the exception of Co-operator 6’s canola. Two applications of Lance at Co-operator 5’s bean field was the most effective treatment where disease incidence was reduced from 88 to 28%, severity from 1.9 to 0.65, and yield increased 67% from 2315 to 3439 kg/ha compared to the untreated check. The Contans treatments did not reduce disease incidence when used in combination with Lance at any of the trial locations, and the severity increased at all locations.  

Crop yields increased at three locations for the Contans treatment. Co-operator 6’s canola yield increased 10% from 3369 to 3706 kg/ha and Co-operator 5’s beans increased 17% from 2315 to 2709 kg/ha. Co-operator 5’s Serenade + Contans treatment marginally increased yield compared to the untreated check by 111 lb/ac (4.7%), the Contans only treatment by 394 lb/ac (17.0%), and the Contans + Lance treatment by 784 lb/ac (33.9%). However, the Lance x2 treatment had the greatest efficacy, with a yield increase of 1124 lb/ac (48.6%) over the untreated check. Co-operator 9’s Contans applications also had higher yields than the untreated check, with yield increases ranging from 60 lb/ac (4.1%) for the Contans only treatment to 712 lb/ac (49.5%) for the Contans + Lance treatment. 

Overall disease incidence ratings in 2010 were lower than in 2009, with average incidence across all 

fields dropping from 85% to 40%. The only exception was in Co-operator 5’s bean field, which had a 98% 

disease incidence for both treatments. The most positive result came in Co-operator 1’s canola field, where the 2 kg/ha Contans + Proline treatment showed a significant reduction in disease severity from the Proline only treatment. The disease incidence also decreased from 21% in the Proline only treatment to 6% in the Contans + Proline treatment. The disease pressure was very low in this field; however, the reduction in incidence was encouraging. 

In 2011, the disease rating and yield data showed positive impacts for both Contans and Serenade applications. At co-operator 6 field, yield increased by 7% for the 2 kg/ha treatment and by 11% for the 4 kg/ha treatment. Co-operator 11 had a higher mean disease rating in the Contans + Lance portion of the field than in the Lance only portion of the field, with ratings of 1.85 and 1.48, respectively. The yield was not significantly different at ~3.4% higher in the Contans + Lance treatment. Mean disease rating and incidence were not significantly different between the Lance and Lance x2 treatments, but these were significantly higher than the check, Serenade, and ½ rate Serenade + Lance treatments. There was no significant difference in disease rating between the untreated check, the Serenade only, and the ½ rate Serenade + Lance treatments. However, the Serenade treatment did yield 173 lb/ac (6.3%) higher than the check treatment, the largest difference among all the treatments in that field. However, the field was quite variable, so this difference may be due to inherent variability more than the treatment itself.  

Figure 3:  The comparison of treatment yield vs untreated check or a standard application of Lance acting as control treatment

A partial budget approach to economic evaluation of fungicide choices by adding the costs of treatments, including the change in fungicide costs, relative to an untreated base or standard check application (Lance; Figure 3), and added revenues arising from the treatment, including change in yield, relative to a check or base treatment, multiplied by an average price per lb.  These evaluations showed that the biological application could not provide positive economic returns when the disease pressure was high, such as in 2009. In 2010 and 2011, positive economic returns were obtained for five treatments – including Serenade (twice), and Contans 2 kg/ha + Lance (once) and Contans 4 kg/ha + Lance (twice).