Treatment of seed potatoes with prochloraz for simultaneous control of silver scurf and black dot on progeny tubers

Denner, F. D. N.; Millard, C. P.; Geldenhuys, A.; Wehner, F. C.

doi:10.1007/bf02358247

Cited by 23 publications

(19 citation statements)

References 15 publications

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“…However, a significant yield increase, when compared with a nonfungicide treated control, only occurred 1 of 3 years when azoxystrobin was applied multiple times to foliage during the growing season (Nitzan et al 2005). In furrow applications at planting had no measurable effect on black dot severity and seed treatments have not been effective when soil borne inoculum is present (Denner et al 1997;Read and Hide 1995).…”

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confidence: 93%

Response of Colletotrichum Coccodes to Selected Fungicides Using a Plant Inoculation Assay and Efficacy of Azoxystrobin Applied by Chemigation

2011

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A plant inoculation assay was developed and used to evaluate fungicide efficacy and application timing for reduction of infection of potato stems by Colletotrichum coccodes. Incidence of infected stems treated with azoxystrobin, pyraclostrobin, fluoxastrobin, and mandipropamid + difenoconazole was significantly less than the non-treated control plants when fungicides were applied prior to inoculation. However, fungicide application after inoculation did not significantly reduce infection. Chlorothalonil and mancozeb were not effective in preventing infection by C. coccodes. Additionally, early season fungicide applications by center pivot chemigation in commercial potato fields were evaluated as a potential black dot management tactic. Below-ground stems sampled from replicated plots in commercial fields where azoxystrobin was applied by chemigation at 50 and 67 days after planting (DAP) had significantly less stem surface area covered with sclerotia at 79 DAP than the non-treated control in two of 2 years. However, the effect was not observed both years at a subsequent collection at 102 DAP and only one of 2 years at 140 DAP. Latent infections were detected in non-symptomatic plants collected from the field.Resumen Se desarrolló y utilizó un ensayo de inoculación de plantas para evaluar la eficacia y tiempo de aplicación de fungicida para la reducción de la infección en tallos de papa por Colletotrichum coccodes. La incidencia de tallos infectados tratados con azoxystrobin, pyraclostrobin, fluoxastrobin y mandipropamid + difenoconazole, fue significativamente menor que las plantas testigo no tratadas cuando se aplicaron los fungicidas antes de la inoculación. No obstante, la aplicación del fungicida después de la inoculación no redujo significativamente la infección. Clorotalonil y mancozeb no fueron efectivos en prevenir la infección por C. coccodes. Adicionalmente, se evaluaron aplicaciones de fungicidas al principio del ciclo de cultivo por quimirrigación de pivote central en campos comerciales de papa, como táctica potencial de manejo de la mancha negra. Los tallos subterráneos muestreados de lotes con repeticiones en campos comerciales donde se aplicó azoxistrobin por quimirrigación a 50 y 67 días después de la siembra (DAP), tuvieron significativamente menos área superficial del tallo cubierta con esclerocios a 79 DAP, que los testigos no tratados en dos años. No obstante, no se observó el efecto en ambos años en una colecta posterior a 102 DAP, y solo en uno de los dos años a 140 DAP. Se detectaron infecciones latentes en plantas asintomáticas colectadas en el campo.

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confidence: 93%

Response of Colletotrichum Coccodes to Selected Fungicides Using a Plant Inoculation Assay and Efficacy of Azoxystrobin Applied by Chemigation

2011

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“…In contrast, the application at planting (0 DAP) had little black dot efficacy when evaluated by any of the disease assessment methods and did not positively affect tuber yield. Previously, seed-tuber treatments were also found not to be effective against black dot even when soil inoculum was low or absent (Denner et al 1997;Read and Hide 1995a). The in-furrow application at planting is similar to a seed treatment by partially coating the seed piece and additionally treats the surrounding soil.…”

Section: Discussionmentioning

confidence: 95%

“…Transmission of C. coccodes from seed tubers to progeny tubers was reduced when infected seed tubers were treated with prochloraz and planted in virgin soils but not in infested soil (Denner et al 1997(Denner et al , 1998. In a second study black dot was reduced early in the season when severely infected seed was treated with imazalil but the disease was not reduced on progeny tubers (Read and Hide 1995a).…”

Section: Introductionmentioning

confidence: 95%

Effectiveness of Early-season, Single Applications of Azoxystrobin for the Control of Potato Black Dot as Evaluated by Three Assessment Methods

Cummings

Johnson

2008

Am. J. Pot Res

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Timing of azoxystrobin application for control of potato black dot was evaluated at two to four discrete times during early growth stages of potato from planting to just before row closure in trials from 2003 through 2006. Application timings consisted of a single application of azoxystrobin made either at planting, 34, 43, or 60-62 days after planting. Black dot severity was evaluated on aboveand below-ground stems using three assessment methods. Incidence of infected progeny tubers and yield were also determined. Application at 60-62 days after planting was the most efficacious timing when black dot was evaluated as frequency of detecting Colletotrichum coccodes from 0.5 cm stem sections taken from near the plant crown in 2 of 3 years, as distance of sclerotium expansion on stems in 1 of 2 years, and as sclerotium density on stems 2 of 3 years. Black dot severity was not reduced as evaluated by any of the assessment methods when application of azoxystrobin was made at planting. Below-ground stems had more disease than the above-ground stems as measured by frequency of detection of C. coccodes near the crown 2 of 4 years, distance of sclerotium expansion on stems 2 of 2 years and sclerotium density on stems 3 of 3 years. Disease severity between above-and below-ground stem segments were highly correlated for all disease assessment methods and years except for frequency of detection of C. coccodes from crown tissue in 2005. There were no statistical interactions for any of the disease severity assessment methods between above-and below-ground stem segments with azoxystrobin timing. The sclerotia assessment on above-ground stem segments at end of season was an efficient measure of black dot. Incidence of infected progeny tubers was significantly reduced compared to the non-treated control when application was made at 62 days after planting in 1 of 3 years and at 34 and 43 days after planting in 2 of 4 years. There was not a significant difference in yield between any of the application times and the non-treated control in any year.

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“…Storing different seed lots with a common air source can lead to contamination of a clean seed source by an infected seed source (Secor and Gudmestad 1999). Third, treating seed can limit spread of H. solani from seed pieces to daughter tubers (Denner et al 1997;Errampalli et al 2001;Frazier et al 1998;Geary et al 2007;Hall and Hide 1994;Hide et al 1988;Miller et al 2004; and Peretz-Alon 2004). Effective fungicides cited in these articles that are used today in North America include fludioxonil, thiophanate-methyl+mancozeb, and azoxystrobin.…”

Section: Discussionmentioning

confidence: 96%

Effect of Post-Harvest Fungicides and Disinfestants on the Suppression of Silver Scurf on Potatoes in Storage

et al. 2011

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Silver scurf of potato, caused by Helminthosporium solani, can be a serious problem of potato tubers sold for table stock. The fungus originates primarily on seed and infects the periderm of daughter tubers, causing unsightly blemishes that reduce tuber quality. Secondary spread occurs in potato storage facilities when spores produced on infected tubers are moved through the air system. Depending on storage conditions and time, even a low initial disease incidence can result in significant losses through quality reductions. In the past, thiabendazole has been the most effective post harvest treatment in controlling this disease, but the development of fungicide resistance has made this product unreliable. Because of the lack of consistent alternatives, studies were conducted from 2001 to 2003 to examine the efficacy of various products in suppressing silver scurf incidence and severity when applied to tubers following harvest and prior to storage.Daughter tubers from a seed lot with high incidence of silver scurf symptoms were grown and then harvested 1 month after vine kill. After harvest, tubers were treated with a post-harvest application of various products, stored, and then evaluated for disease incidence and severity each year at two locations (Washington or Oregon and Idaho) and at two time periods (2 or 3 months and 6 months following storage). When treated tubers were stored from the fall of 2002 to spring of 2003, potassium sorbate and B. subtilis reduced disease severity after 6 months in storage at location 1, while azoxystrobin reduced incidence after 6 months in location 2. During the 2003-2004 storage season, azoxystrobin reduced silver scurf at both locations after 2 months of storage. Most products currently labeled for post-harvest silver scurf management were ineffective. While not currently registered, azoxystrobin used as a post-harvest, pre-storage treatment may be a significant method for commercial potato growers to suppress silver scurf in potato storage.Resumen La mancha plateada de la papa, causada por Helminthosporium solani, puede ser un problema serio de tubérculos de papa para el mercado en fresco. El hongo se origina primeramente en la semilla e infecta el peridermo de los tubérculos hijos, causando manchados desagradables que reducen la calidad del tubérculo. La dispersión secundaria se presenta en las instalaciones de almacenamiento de papa cuando las esporas producidas en tubér-culos infectados se mueven a través del sistema de aire. Dependiendo de las condiciones de almacenamiento y del tiempo, aún una incidencia baja inicial de la enfermedad puede resultar en pérdidas significativas por reducción de la calidad. En el pasado, el thiabendazole ha sido el tratamiento más efectivo de postcosecha en el control de esta enfermedad, pero el desarrollo de resistencia a fungicidas ha hecho no confiable a este producto. Debido

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Treatment of seed potatoes with prochloraz for simultaneous control of silver scurf and black dot on progeny tubers

Cited by 23 publications

References 15 publications

Response of Colletotrichum Coccodes to Selected Fungicides Using a Plant Inoculation Assay and Efficacy of Azoxystrobin Applied by Chemigation

Response of Colletotrichum Coccodes to Selected Fungicides Using a Plant Inoculation Assay and Efficacy of Azoxystrobin Applied by Chemigation

Effectiveness of Early-season, Single Applications of Azoxystrobin for the Control of Potato Black Dot as Evaluated by Three Assessment Methods

Effect of Post-Harvest Fungicides and Disinfestants on the Suppression of Silver Scurf on Potatoes in Storage

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