The effect of seed-and soilborne inoculum ofColletotrichum coccodes on the incidence of black dot on potatoes

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

doi:10.1007/bf02360261

Cited by 29 publications

(37 citation statements)

References 10 publications

(16 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Multiple disease foci that coalesce over the course of the growing season could overwhelm the effect of a single source of inoculum from the seed-piece. Soilborne inoculum has resulted in more disease than tuberborne inoculum (Denner et al 1998;Nitzan et al 2008;Read and Hide 1988). Multiple sites of infection would account for the increased disease from soilborne inoculum.…”

Section: Discussionmentioning

confidence: 97%

See 1 more Smart Citation

Colonization of Potato Roots and Stolons by Colletotrichum coccodes from Tuberborne Inoculum

Ingram

Johnson

2010

Am. J. Pot Res

View full text Add to dashboard Cite

The rate of colonization by Colletotrichum coccodes was quantified on roots and stolons of the potato cultivar Russet Burbank. Greenhouse grown plants arising from seed-tubers infected with C. coccodes were observed. The distance that C. coccodes colonized potato roots was measured from the seed tuber to the distal edge of microsclerotial development along the roots starting at 21 days after plant emergence and continued at 14 day intervals until crop death. Visual assessment of disease progress was confirmed by isolation from diseased and non-diseased tissues onto nutrient agar. Expansion of C. coccodes foci along the roots in two independent trials resulted in a linear growth model of 1 mm/day (Trial 1 P<0.011, R 2 =0.84; Trial 2 P<0.007, R 2 =0.87). Colonization radiated from the seedtuber to form compact foci of infected tissue that was rotationally symmetrical; no secondary foci were observed. The results suggested that C. coccodes expanded linearly from an inoculum source and that for multiple disease foci to develop on a root system, multiple primary infections must occur from sclerotia in the soil.Resumen Se cuantificó el nivel de colonización por Colletotrichum coccodes en raíces y estolones del cultivar Russet Burbank de papa. Se observaron las plantas cultivadas en el invernadero que emergieron de la semilla tubérculo infectada con C. coccodes. Se midió la distancia en que C. coccodes colonizó a las raíces de papa desde el tubérculo semilla a la orilla distal del desarrollo del microesclerocio a lo largo de las raíces, empezando 21 días después de la emergencia de la planta y continuando a intervalos de 14 días hasta la muerte del cultivo. Se confirmó el análisis visual del progreso de la enfermedad mediante el aislamiento de los tejidos enfermos y sanos a agar nutritivo. La expansión del foci de C. coccodes a lo largo de la raíz en dos ensayos independientes dio como resultado un modelo de crecimiento lineal de 1 mm/día (ensayo 1, P<0.011, R 2 =0.84; Trial 2 P<0.007, R 2 =0.87). La colonización fue radial desde la semilla tubérculo para formar foci compactos de tejido infectado que fue rotacionalmente simétrico; no se observaron foci secundarios. Los resultados sugieren que C. coccodes se expandió linealmente desde una fuente de inoculo y que para que se desarrollen múltiples foci de la enfermedad en un sistema radical, se deben presentar infecciones múltiples primarias de los esclerocios en el suelo.

show abstract

Section: Discussionmentioning

confidence: 97%

“…Potato plants become infected from soilborne microsclerotia and from infected seed-tubers (Barkdoll and Davis 1992;Denner et al 1998;Dickson 1926;Johnson et al 1997;Tsror et al 1999). Soilborne inoculum has been recognized as being more aggressive than tuberborne inoculum (Nitzan et al 2008).…”

Section: Introductionmentioning

confidence: 96%

Colonization of Potato Roots and Stolons by Colletotrichum coccodes from Tuberborne Inoculum

Ingram

Johnson

2010

Am. J. Pot Res

View full text Add to dashboard Cite

show abstract

“…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

View full text Add to dashboard Cite

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.

show abstract

“…C. coccodes can survive for long periods in soil on plant debris or as free microsclerotia in the absence of a susceptible host (Blakeman & Hornby, 1966) and treatment therefore has to be directed at eliminating or reducing inoculum in soil. Several soil fumigants have been screened for this purpose (Stevenson et al, 1976: Read & Hide, 1995, but only methyl bromide provided effective control (Slusarski, 1989;Denner et al, 1998). However, the cost of fumigation is prohibitive and furthermore methyl bromide is to be phased out in the foreseeable future (Anon., 1994).…”

Section: Introductionmentioning

confidence: 97%

Effect of soil solarisation and mouldboard ploughing on black dot of potato, caused byColletotrichum coccodes

2000

Self Cite

View full text Add to dashboard Cite

SummaryPreplant soil solarisation and mouldboard ploughing to a depth of 30 and 60 cm respectively were evaluated in two field experiments for the control of Colletotrichum coccodes causing black dot of potato. Solarisation reduced disease incidence by 45% when tarping was done for eight weeks and temperatures reached 56 ~ in the top 5 cm of soil. With a six week tarping period and lower maximum temperature (50 ~ the reduction in disease was a nori-significant 25%. Mouldboard ploughing to a depth of 30 cm reduced black dot by 34% and was twice as effective as ploughing to a depth of 60 cm.

show abstract

The effect of seed-and soilborne inoculum ofColletotrichum coccodes on the incidence of black dot on potatoes

Cited by 29 publications

References 10 publications

Colonization of Potato Roots and Stolons by Colletotrichum coccodes from Tuberborne Inoculum

Colonization of Potato Roots and Stolons by Colletotrichum coccodes from Tuberborne Inoculum

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

Effect of soil solarisation and mouldboard ploughing on black dot of potato, caused byColletotrichum coccodes

Contact Info

Product

Resources

About