| Problem Code: |
Resis
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| Requesting State(s): |
Cochran,Kimberly (TX) ; Heck,Daniel (NY) ; Woodhall,James (ID)
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| Potential Products: |
MycoV-43TM Pro-Leaf; PHC25279
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| PCR Reason for Need: |
Resistance has developed in many of the fungicides in several regions throughout the US including New York, Michigan, Idaho and Eastern Oregon. Severe losses occurred in the last two states (collectively known as the Treasure Valley) in 2023 which also resulted in secondary bacterial bulb rots.As Stemphyllium has only occurred since 2019 in Idaho and Eastern Oregon there is limited trial data for cultural and chemical control. Presently Pristine and Luna fungicides. The Treasure Valley of Idaho and Eastern Oregon is the leading onion producing area in the US accounting for up to 30% in yield. Typically the dry and warm climate is conducive to onion production but since 2020 there have been outbreaks of Stemphyllium leaf blight (SLB). In 2020 this outbreak infected the leaf tips and caused defoliation resulting in yield losses. In 2023, infection occurred later closer to harvest, this resulted in onion leaves dying effectively ‘standing up’. This enabled secondary bacterial rots to establish in the bulbs resulting in significant quality losses and lack of storability. Control of SLB is typically through chemical control, notably using Pristine and Cabrio– which are used routinely for Botrytis anyway. However, resistance to these products have been observed in the Treasure Valley and elsewhere (New York and Michigan) for SLB. SLB is a relatively new issue to the Treasure Valley, therefore there is limited trial data investigating both cultural and chemical control options. With fungicide resistance present in the key chemical options, field trials for cultural control as well as alternative fungicides with a view to resistance management is required. [ID: 8/24/DS]
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| PCR Details: |
Requester would like to test products only.
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| Study Goals: |
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| Comments |
HQ suggests exploring the following options: 1) PHC 25279 (PDHP25279) and 2) MycoV43 (a natural product extract from an estuarine bacterium) [HQ: 8/24/DS]. Prothioconazole has also demonstrated very good results. Preliminary data available on PDMR reports. Most of FRAC 7 and 11 products are not effective to manage this disease. Most labeled FRAC 3 have shown decrease in efficacy [NY: 7/25 AA].
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| Study Accomplishments: |
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