Spatial dispersion and binomial sequential sampling plan for<i>Cercospora carotae</i>on carrots

Boivin, Guy; Kushalappa, Ajjamada C.; Brodeur, Luc

doi:10.1080/07060669009501029

Cited by 13 publications

(11 citation statements)

References 10 publications

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“…A CIE value of 4 could be accumulated with only one long wet period. Nonetheless, even at 100% disease incidence level, only 1.2% leaf area was diseased (Boivin et al 1990). Yield loss for Alternaria blight only occurred at disease severity of > 20% at harvest time (Gillespie and Sutton 1979).…”

Section: Discussionmentioning

confidence: 99%

“…Delaying fungicide application until a 50% disease incidence threshold is reached has saved up to 40% of the amount of fungicides used in Québec, compared to the décision method based on conventional calendar spray (Boivin et al 1990). In the présent study, CIE 18 was the best threshold for timing the first fungicide application because fewer fungicide applications were required and there was no significant loss in yield, even though disease severity (PAUDPC) in this treatment was higher than in other treatments.…”

Section: Discussionmentioning

confidence: 99%

“…The conventional method served hère as a check. A control treatment without any fungicide application was not included because our objective was to find a method équivalent to using the 50% disease incidence threshold, which provided good control of blight under commercial conditions (Boivin et al 1990). Also, an untreated control treatment would hâve increased interplot interférence.…”

Section: Discussionmentioning

confidence: 99%

“…First, fungicide applications are initiated when plants reach 10-15 cm in height (CPVQ 1987); however, some sprays may not be needed when the weather is not conducive for disease development. In the second method, fungicide applications are initiated when disease incidence reaches thresholds of 80 or 100% of plants with at least one lésion ontheintermediate(middle) leaf for early carrots and 50% for late carrots (Boivin and Sauriol 1984;Boivin et al 1990). In this latter method, an integrated pest management program (IPM) developed for the muck soil régions of Montréal is used.…”

Section: Introductionmentioning

confidence: 99%

“…A study on the effect of interrupted wet periods showed that infection was significantly reduced when the initial wet period was <12 h and when the dry period interruption was >12 h (Carisse and Kushalappa 1992). A forecasting model was developed using the data of Carisse and 92 Kushalappa (1990Kushalappa ( , 1992 to décide when to apply the first fungicide treatment against Cercospora blight (Carisse et al 1993). The model uses values for the cumulative infection équivalence (CIE), from crop émergence until the current day.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of decision methods to initiate fungicide applications against cercospora blight of carrot

Abraham¹,

Kushalappa²,

Carisse³

et al. 2005

phyto

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In 1991 and 1992, two thresholds of a forecasting model were compared with two other decision methods for effectiveness in timing the first fungicide application against Cercospora blight of carrot induced by Cercospora carotae. The first fungicide application was made when : 1) the plants reached 15 cm in height (conventional method); 2) the intermediate (middle) leaves of 50% of the plants were diseased (50% disease incidence threshold method); 3) the cumulative infection equivalence (CE) was 14 (forecasting model CE 14); and 4) the CE was 18 (forecasting model CE 18). In all four treatments, subsequent applications of fungicide were made at 10-d intervals when there was no rain, and at 7-d intervals when there was rain. The CE was calculated based on duration of leaf wetness and temperature during the wet period, corrected for high humidity and interrupted wet periods, and was cumulative starting at crop emergence. For thresholds of CE 14 and CE 18, no yield losses were observed and the total number of fungicide applications needed was lower compared to conventional and 50% disease incidence threshold methods. In a separate study, the CE thresholds were related to the percentage of commercial fields that reached disease incidence thresholds of 50, 80 and 100% to establish low risk (CE 11-15) and high risk (CE 16-20) thresholds. The forecasting of low and high risk CE thresholds were too late for 3 and 19% of the commercial fields because those fields had more than 50 and 80% of the plants diseased, respectively.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Comparison of decision methods to initiate fungicide applications against cercospora blight of carrot

Abraham¹,

Kushalappa²,

Carisse³

et al. 2005

phyto

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Relationship between the incidences of ear and spikelet infection of Fusarium ear blight in wheat

Parry

Edwards

et al. 2004

European Journal of Plant Pathology

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There is a urgent need to develop a rational strategy for managing Fusarium ear blight in order to reduce current reliance on routine fungicide applications, based on an objective assessment of disease risks. One of important components for such a management strategy is a fast, easy, accurate and reliable method for disease assessment. The relationship between incidence of Fusarium ear blight ear infection and number of spikelets infected on an ear (or incidence of spikelet infection) were investigated during three seasons and in four countries in order to derive a simple relationship for predicting disease at the spikelet level using ear incidence. More than half of the data sets of the number of infected spikelets on an ear could not be fitted satisfactorily by a Poisson distribution. Three two-parameter discrete distributions (negative binominal, Neyman type A and Polya-Aeppli) provided a significantly better fit than the Poisson distribution, indicating a degree of aggregation of number of infected spikelets on an ear. Taylor's power-law satisfactorily described the observed variance-mean relationship for the number of infected spikelets on an ear; this relationship was generally consistent over years and countries. A robust relationship between incidence of ear infection and average number of infected spikelets per ear was obtained assuming a fixed variancemean relationship and a negative binomial distribution for the number of infected spikelets. A relationship between incidences of spikelet and ear infection was also obtained based on the complementary log-log or logit transformation of ear and spikelet infection incidence. These models appeared to be consistent over years and countries and thus may be used in making practical disease management decisions involving fungicide applications.

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An IPM Program for Managing Fungal Leaf Blight Diseases of Carrot in New York

et al. 2007

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Fungal leaf blight diseases caused by Cercospora carotae and Alternaria dauci occur annually on processing carrot in New York, with growers applying up to eight fungicide sprays to manage these diseases. An integrated pest management (IPM) program involving the use of a 25% disease incidence threshold to prompt the first fungicide application and timing subsequent sprays by monitoring for increases in disease severity and weather forecasts in conjunction with a 10- to 14-day spray interval was evaluated in grower fields in 1997 and 1998. The IPM plots, compared with the grower plots, required two to six fewer fungicide applications but showed no yield reduction. From 1999 to 2004, the IPM program was validated and the effect of crop rotation and carrot cultivar susceptibility also were assessed. Carrot plants growing in fields with 2-year or longer crop rotation intervals reached the 25% disease incidence threshold later in the season and required fewer fungicide applications. The less-susceptible carrot cultivars also reached the 25% disease incidence threshold later, required fewer fungicide applications, and were less severely diseased than more susceptible cultivars. Validation of the IPM program in New York showed that both fungal leaf blights can be managed effectively using a 25% incidence threshold to prompt the first fungicide spray and making the subsequent fungicide applications based on increases in disease severity, weather forecasts, and a 10- to 14-day spray interval.

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Spatial dispersion and binomial sequential sampling plan forCercospora carotaeon carrots

Cited by 13 publications

References 10 publications

Comparison of decision methods to initiate fungicide applications against cercospora blight of carrot

Comparison of decision methods to initiate fungicide applications against cercospora blight of carrot

Relationship between the incidences of ear and spikelet infection of Fusarium ear blight in wheat

An IPM Program for Managing Fungal Leaf Blight Diseases of Carrot in New York

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