| Title |
Investigators | Department | Objectives | Approach Keywords | Progress Reports | Impact Statements | Publications | |
Project * COL00665 | |
| Title | *Improve Potato Yield and Quality through Suppression of Disease |
| Investigator(s) | Davidson, RD; |
| Department | Horticulture and Landscape Architecture |
| Objectives | 1. To evaluate new technology and crop-care products as tools for disease suppression. 2. To develope multi-component control strategies for specific potato diseases that cause measurable economic losses in Colorado. |
| Approach | 1. Chemical control agents, cultural practices, soil amendments, crop rotation and varietal resistance will be evaluated. Elucidation of the basic biology of Spongospora as it relates to disease onset will also be a component of this project. Work on powdery scab done at CSU will focus foremost on meeting the needs of Colorado's potato industry. This project will also be a component of national effort. 2. Season-long foliar fungicide programs for control of early blight will be conducted annually. Cost-to-benefit will be calculated based on disease control and yield. Fungicides for control of seed piece decay, Rhizoctonia , silver scurf, and pink rot will be evaluated in on-station trials. 3. On-farm demonstrations will examine the impact field incorporated compost on the potential for reducing the use of synthetic fertilizers and fungicides by improving nutrient retention in the root zone and the health and diversity of the soil's biomass; the potential for improving water utilization and thereby reducing water and power use in center-pivot irrigation systems; and crop yields and costs of production for potato, barley, and alfalfa . |
| Keywords | Potato, Potato diseases, Cultivar development |
| Progress Reports | |
| 2001 | Fungal diseases of potato continue to be key yield and quality limiting factors in the 2001 cropping season in Colorado. Weather monitoring for disease forecasting was utilized to predict onset of early blight and late blight. No late blight occurred in 2001. Season long fungicide trials were conducted with 23 programs. In trials and across the industry blight suppression was enhanced by 70 to 80 percent by use of Azoxystrobin over conventional fungicide programs. Powdery scab incidence was high in 2001. Efficacy trials showed that fluazinam can suppress disease by 85 percent and will likely be adopted by the industry to some degree in 2002. Rhizoctonia was suppressed in trials by seed treatments and at planting treatments of flutolanil by 60 to 70 percent. Commercial use of flutolanil will likely be widespread in 2002. The potato pathology project provided support to the potato breeding program through screening advanced clones for resistance to powdery scab in replicated on-farm trials. |
| 2002 | For potato, fungal diseases continued to be key yield and quality limiting factors in the 2002 Colorado crop. Weather monitoring for disease forecasting was utilized to predict onset of early blight and late blight. No late blight occurred in 2002. Thirty-four season long fungicide programs were evaluated for control of early blight. In trials and across the industry early blight suppression was enhanced by 70 to 80% with azoxystrobin over traditional fungicide programs. Powdery scab incidence increased again in 2002. Efficacy trials showed that fluazinam and azoxystrobin can suppress disease by 80%. These chemical controls may be adopted by the industry in 2003. Rhizoctonia black scurf was suppressed by 90% in trials where ozoxystrobin was applied at planting. Commercial use of azoxystrobin will be widespread in 2003. The potato pathology project provided support to the potato breeding program through screening advanced clones for resistance to powdery scab in replicated trials. |
| 2003 | Disorders caused by fungi and nematodes are ranked by growers as central yield and quality-limiting factors for potato production in Colorado. Disease forecasting is utilized each season to predict the onset of early blight and late blight in order to optimize fungicide applications. A wide spectrum of 73 fungicide treatments for control of foliar and soil-borne pathogens of potato were evaluated in 2003. We have shown that powdery scab can be effectively controlled with a combination of fluazinam and mancozeb applied at planting. Cultivars tolerant to powdery scab have also been identified in our trials. Chemical treatments combined with cultivar resistance can suppress powdery scab to economically acceptable levels. Red and yellow potatoes account for about 10 percent of Colorado potato production, valued at some $15,000,000. Without controls for powdery scab, production of red and yellow potatoes will soon not be possible. For the first time, biology of the root-knot nematode in the San Luis Valley is being elucidated. With this new information, precisely timed applications of Vydate can provide economical control of nematodes. As a result of our work close to 10 percent of the potato acreage in the San Luis Valley is now treated with Vydate, allowing high value land to remain in potato production. |
| 2004 | Plant pathogens are ranked by farmers as the number one yield and quality-limiting factor for potato production in Colorado. Disease forecasting is used to predict the onset of early blight and late blight and to optimize fungicide application. 58 fungicide treatments for control of foliar or soil-borne pathogens of potato were evaluated in 2004. For the third year , we have established that powdery scab can be effectively controlled with a combination of fluazinam and mancozeb applied at planting. Several cultivars tolerant to powdery scab have also been identified in our trials. Without controls for powdery scab, production of red and yellow potatoes would soon not be possible in the San Luis Valley. Red and yellow potatoes now account for about 10 percent of Colorado potato production, valued at some $20 million. For the first time, biology of the root knot nematode in the San Luis Valley is being elucidated. With this new information, precisely timed applications of nematicides are providing economical control of nematodes. As a result of our work, close to 15 percent of the potato acreage in the San Luis Valley is now effectively treated for root-knot nematode, allowing high value land to remain in potato production. |
| 2005 | Plant pathogens and the disease problems caused by these organisms continue to threaten potato crops in Colorado by reducing yield and quality. Growers have acknowledged that these issues represent the greatest threat to their profitability under current conditions. Use of disease forecasting to predict the onset of early blight and late blight epidemics has been very useful to producers to help in both timing of their fungicide applications and in deciding which chemistries to use. 30 fungicide treatments were screened in 2005 for effectiveness against both foliar and soil borne fungi of potato. As previously seen, fluazinam applied at planting was quite effective in reducing severity and incidence of powdery scab tuber lesions accounting for a significantly higher percentage of marketable tubers over the controls or other treatments. Additionally, as part of a national effort, 36 cultivars were screened for tolerance to powdery scab. Several cultivars show promise in this aspect and may provide management options for disease control that currently do not exist. This becomes more critical each year as growers are increasingly having a difficult time producing highly susceptible red and yellow skinned cultivars in the San Luis Valley. These cultivars account for over 10% of their total production and will be increasing in importance as the beneficial health attributes of potatoes become more public. The biology of the root knot nematode continues to be elucidated in the San Luis Valley. Coupled with this better understanding of the nematode's life cycle and population increases are the use of very effective, economical nematicide programs to aid in management of the pest and the associated tuber problems. Also, research into effectiveness of green manure cover crops under San Luis Valley conditions has resulted in producers improving overall soil health. Under these programs, up to 25% of the potato acreage is now following some sort of management program to effectively control nematodes allowing maximum yield and quality to be obtained from high value land while using limited water resources. |
| 2006 | Plant diseases and disorders caused by viruses, fungi, and nematodes are ranked by growers as key components related to yield decline and quality issues in storage. These problems limit the potential of a grower's potato crop and often add unnecessary expenses to their operational budgets. To manage early blight and late blight, disease forecasting is utilized to predict onset and maximize fungicide effectiveness. These last two years growers have been informed of several different fungicide programs with cost analysis of the different regimes available. Efforts have been made to utilize rotations of different classes of chemicals with appropriate rates. Also, late season applications of fungicides have been made to help control early blight tuber decay. In 2005 and 2006, twenty fungicide regimes were evaluated for timing of application and disease incidence. Also, during this time frame treatment of the crop using Omega, a fungicide for control of powdery scab, was elucidated under SLV conditions. This fungicide was found to be very effective in reducing levels of powdery scab on susceptible cultivars and will be instrumental in helping to control this problem as part of an inclusive management program. This disease is beginning to limit the quality of many susceptible specialty cultivars being produced in Colorado. |
| Impact | |
| 2001 | This research project is applied in nature. Practical and tangible disease management technology will be designed for direct adaptation by potato growers to solve existing problems . The technology will reduce losses due to disease, thereby enhancing the economic disposition of the Colorado potato grower. Input costs should be reduced and the quality of the crop increased. |
| 2002 | This research project is applied in nature. Practical and tangible disease management technology will be designed for direct adaptation by potato growers to solve existing problems . The technology will reduce losses due to disease, thereby enhancing the economic disposition of the Colorado potato grower. Input costs should be reduced and the quality of the crop increased. |
| 2003 | For potato blights alone, more than 90 percent of the potato acreage in the San Luis Valley is currently treated with new classes of fungicides based on efficacy data and application recommendations from this project. Early blight is now managed by two or three fungicide applications per season compared to four or five applications in the past. Likewise, no unnecessary fungicides are applied to prevent late blight as a result of accurate disease forecasting and inoculum exclusion. This precision use of fungicides on potato translates into a savings of $123 to $185/ha ($50 to $75 per acre). In 2003, 27,743 ha (68,500 acres) of potatoes were grown in the San Luis Valley. |
| 2004 | Up to 90 percent of the potato acreage in the San Luis Valley is now treated with new classes of fungicides based on efficacy data and application recommendations developed through this project. Early blight can now be effectively managed by one or two fungicide applications per season compared to three or four applications in the past. Likewise, no unnecessary fungicides are applied to prevent late blight as a result of accurate disease forecasting and inoculum exclusion. For potato production in the San Luis Valley, precision use of fungicides translated into an overall savings of about $5 million in 2004. |
| 2005 | Over 90% of the potato producers in the San Luis Valley now follow a management program for control of fungal and nematode diseases. Growers are very aware of the primary disease and pest issues facing production and have been very receptive to utilizing control and management strategies developed in this program. For example, most growers now use no more than two or three effective fungicides to fully control foliar early blight and manage pathogen resistance . This precise and appropriate use of fungicides translates into a savings of over $5 million each year. Additionally, use of effective management strategies to control soil borne problems has improved the overall yields and quality of the potato in the San Luis Valley making growers more competitive and profitable. |
| 2006 | Over 90% of the potato acreage in the San Luis Valley is now treated with new classes of fungicides based upon efficacy data and application recommendations developed by this project. Additionally, several new chemistries have been screened for effectiveness to control foliar early blight and powdery scab. Growers have been able to reduce their fungicide applications because of use of an accurate forecasting model. Omega fungicide is in the process of having a label change to allow for its use as an in-furrow treatment to control powdery scab. 24,301 ha (60,000 a) of potatoes were grown in the San Luis Valley in 2006. The precision use of fungicides has translated into a savings of $120 to $180/ha for potato producers helping them remain profitable during very tight economic times. |
| Publications | |
| 2001 |
Zink, R.T. and Davidson, R.D., 2001. "2000 Research Report, Extension Potato Disease Control Project". San Luis Valley Research Center; Center, CO. 49 pages. Zink, R.T. and Davidson, R.D., 2001. "Research Progress Report for 2000, SLV Research Center Committee and the Colorado Potato Administrative Committee (Area II)". San Luis Valley Research Center; Center, CO. 52 pages. |
| 2002 |
Zink, R.T. and Davidson, R.D. 2002. 2001 Research Report, Extension Potato Disease Control Project. 55 pages. Zink, R.T. and Davidson, R.D. 2002. Research Progress Report for 2001, SLV Research Center Committee and the Colorado Potato Administrative Committee (Area II). 48 pages. |
| 2003 |
Zink, R.T. and Davidson, R.D., 2003. 2002 Research Report, Extension Potato Disease Control Project. 60 pages. Zink, R.T. and Davidson, R.D., 2003. Research Progress Report for 2002, SLV Research Center Committee and the Colorado Potato Administrative Committee (Area II). 60 pages. Zink, R.T., 2003. Pomme de terre, Information for Colorado Potato Growers. vol. 9, no. 1; February 2003. 8 pages. |
| 2004 |
Zink, R.T. and Davidson, R.D., 2004. 2003 Research Report, Extension Potato Disease Control Project. 72 pages. Zink, R.T. and Davidson, R.D., 2004. Comprehensive Potato Research Progress for 2003, Potato Disease Management. SLV Research Center Committee, Colorado Potato Administrative Committee (Area II). 85 pages. (unpub.) Zink, R.T., 2004. Pomme de Terre, Reports from the San Luis Valley Research Center. vol. 10, no. 1; April 2004. 8 pages. Zink, R.T., 2004. Pomme de Terre, Reports from the San Luis Valley Research Center. vol. 10, no. 1; January 2004. 8 pages. Zink, R.T., R.D. Davidson and A. Houser. 2003. Control Strategies for Powdery Scab of Potato. Amer J Potato Res 81:95-96. |
| 2005 |
Davidson, R.D., Zink, R.T., and Houser, A. 2005. Reports for the CPAC Research Committee; Potato Disease Control Project. 65 pages. Ingham, R.E. and Zink, R.T. 2005. Biology and management of columbia root knot nematodes in the San Luis Valley. Pomme de Terre; Vol. 11 #1: 1-8. |
| 2006 |
Davidson, R.D., R.T. Zink and A. Houser. 2005. Comprehensive Potato Research Progress Report for 2005. CPAC Research Subcommittee. 52 pp. |