Impact of commercial foliage trimming on disease suppression and yield of processing carrots in Nova Scotia, Canada

2013 ◽  
Vol 93 (6) ◽  
pp. 1155-1163
Author(s):  
G. E. McIsaac ◽  
K. R. Sanderson ◽  
R. D. Peters ◽  
D. J. Garbary ◽  
S. A. E. Fillmore
Keyword(s):  
Nova Scotia ◽  
Prince Edward Island ◽  
Disease Suppression ◽  
Disease Development ◽  
Marketable Yield ◽  
Production Region ◽  
Growing Seasons ◽  
Alternaria Dauci ◽  
Side Trimming ◽  
Cercospora Carotae

McIsaac, G., Sanderson, K. R., Peters, R. D., Garbary, D. J. and Fillmore, S. A. E. 2013. Impact of commercial foliage trimming on disease suppression and yield of processing carrots in Nova Scotia, Canada. Can. J. Plant Sci. 93: 1155–1163. Carrot side-trimming opens the carrot canopy, permitting greater sunlight penetration and airflow. This reduces moisture build-up and creates unfavorable conditions for the development of common carrot pathogens such as Sclerotinia sclerotiorum (Lib.) de Bary. This study was carried out during the 2008 and 2009 growing seasons and was the first to examine the effects of foliage trimming on disease development in the processing carrot production region of Nova Scotia, Canada. Research focused on the effects of foliage trimming on disease suppression and yield using a commercial-sized trimmer in processing slicer carrots over consecutive growing seasons. This study was also the first to look at the effect of trimming on the suppression of Alternaria dauci (J.G. Kühn) J.W. Groves & Skolko and Cercospora carotae (Pass.), two economically important carrot pathogens causing leaf blight diseases in this region of Canada. Plots were established in commercial fields throughout Colchester County, Nova Scotia. Each field had a trimmed and an untrimmed section. All plots were assessed for disease presence at the time of trimming and again at harvest. Foliage trimming was found to have no significant (P=0.05) effect on biological and marketable yield and generated anecdotal reports of ease of crop maintenance and harvest. The severity of diseases caused by Alternaria, Cercospora and Sclerotinia varied among cultivars and significant cultivar×trimming interactions were noted in some cases. Foliage trimming is becoming standard practice in the carrot industry as several commercial carrot producers in North America have adapted the technology to suit their production needs after the prototype foliage trimmer was designed, built, and demonstrated by researchers at Agriculture and Agri-Food Canada, Charlottetown, Prince Edward Island.

scholarly journals Nitrogen and Fungicide Applications for the Management of Fungal Blights of Carrot

HortScience ◽  
2014 ◽  
Vol 49 (5) ◽  
pp. 608-614
Author(s):  
Catarina Saude ◽  
Mary Ruth McDonald ◽  
Sean Westerveld
Keyword(s):  
Disease Severity ◽  
Severity Index ◽  
Leaf Blight ◽  
Cercospora Leaf Spot ◽  
Marketable Yield ◽  
Alternaria Dauci ◽  
Leaf Blights ◽  
Mineral Soils ◽  
N Management ◽  
Cercospora Carotae

Alternaria leaf blight (ALB) caused by Alternaria dauci (Kühn) Groves and Skolko and Cercospora leaf spot (CLS) caused by Cercospora carotae (Pass.) Solheim are the major foliar diseases of carrot in Ontario, Canada. In addition to reducing photosynthetic area, the diseases can weaken carrot tops, which can break during mechanical harvesting, reducing harvested yields. Fungicides are commonly used to manage the disease, but there is potential to reduce fungicide applications through nitrogen (N) management. Trials were conducted on mineral soils from 2006 to 2008 to determine the importance of applied N and fungicide applications to control fungal leaf blights of carrot. Three rates of N (0, 110, and 220 kg·ha−1) and 0, 3, or 5 (2006 and 2007) or 6 (2008) fungicide applications were applied. Leaf blight severity was assessed biweekly throughout the season and at harvest. The severity of both ALB and CLS and combined disease severity index at harvest decreased with increasing N and fungicide application. In some cases, disease severity of carrots treated with high N and no fungicides was equivalent to carrots treated with no N and five fungicide sprays. Total and marketable yield increased with increasing number of fungicide sprays in 2006 and 2007, but N application did not affect yield. Results suggest that severity of ALB and CLS can be minimized through a combination of N and fungicide applications, but rates of N higher than 110 kg·ha−1 may reduce marketable yield through a decrease in stand and an increase in oversized roots.

scholarly journals Effect of Foliar Trimming and Fungicides on Apothecial Number of Sclerotinia sclerotiorum, Leaf Blight Severity, Yield, and Canopy Microclimate in Carrot

Plant Disease ◽  
2008 ◽  
Vol 92 (1) ◽  
pp. 132-136 ◽  
Author(s):  
Mary Ruth McDonald ◽  
Kevin D. Vander Kooi ◽  
Sean M. Westerveld
Keyword(s):  
Relative Humidity ◽  
Sclerotinia Sclerotiorum ◽  
Organic Soil ◽  
Leaf Blight ◽  
Research Station ◽  
Marketable Yield ◽  
Sclerotinia Rot ◽  
Alternaria Dauci ◽  
The University ◽  
Cercospora Carotae

Foliar trimming of the carrot canopy has potential for reducing the severity of Sclerotinia (Sclerotinia sclerotiorum) rot of carrot (Daucus carota subsp. sativus). The effect of trimming the carrot foliage once or twice, with and without fungicide application, was examined on carrot plants grown on organic soil for 3 years at the University of Guelph–Muck Crops Research Station in Ontario, Canada. The number of S. sclerotiorum apothecia, carrot leaf blight (CLB; Alternaria dauci and Cercospora carotae) severity, canopy microclimate, and total and marketable yield were assessed. The number of apothecia of S. sclerotiorum and relative humidity in the canopy were reduced by trimming done at either the first observation of apothecia or at 100 days after seeding (DAS). In both cases, the effects of trimming on canopy microclimate lasted between 2 and 4 weeks. Trimming the canopy twice during the season did not reduce the number of apothecia compared with trimming the canopy once at 100 DAS. Foliar trimming had little effect on CLB severity. This was attributed mainly to the lower requirement of the CLB pathogens for prolonged periods of high relative humidity and leaf wetness compared with S. sclerotiorum. Foliar trimming did not improve the efficacy of fungicide applications for CLB control. Trimming the canopy once or twice had no effect on total or marketable yield. Thus, trimming has potential to improve the management of Sclerotinia rot of carrot, and trimming both at first observation of apothecia and at 100 DAS could reduce apothecia production and relative humidity within the canopy.

CHAETOCNEMA CONCINNA (MARSHAM, 1802), A EUROPEAN FLEA BEETLE INTRODUCED IN NORTH AMERICA (COLEOPTERA: CHRYSOMELIDAE: ALTICINAE)

1990 ◽  
Vol 122 (4) ◽  
pp. 647-650
Author(s):  
Laurent Lesage
Keyword(s):  
Nova Scotia ◽  
North America ◽  
Prince Edward Island ◽  
Host Plants ◽  
Flea Beetle ◽  
Collection Data ◽  
First Time

AbstractChaetocnema concinna (Marsham, 1802), a European flea beetle, is reported for the first time from Canada. Preliminary collection data indicate that it may feed on the same host plants as in Europe. It has been collected to date in Prince Edward Island, Nova Scotia, and Maine.

Efficacy of Different Level of Systemic Fungicides on Management of Rice Blast at Baitadi, Nepal

2020 ◽  
Vol 7 ◽  
pp. 33-42
Author(s):  
Ashok Acharya ◽  
Prabin Ghimire ◽  
Dhurba Raj Joshi ◽  
Kishor Shrestha ◽  
Govinda Sijapati ◽  
...  
Keyword(s):  
Disease Severity ◽  
Rice Blast ◽  
Fungal Pathogens ◽  
Block Design ◽  
Rice Variety ◽  
Disease Suppression ◽  
Systemic Fungicide ◽  
Disease Development ◽  
Systemic Fungicides ◽  
Different Levels

Rice blast (Pyriculariaoryzae Cavara) is one of the most devastating diseases affecting the rice crop in across the world. Systemic fungicides are used for the suppression of blast diseases caused by fungal pathogens. Propiconazole and Carbendazim are commercial chemical control products available in markets for the control of the fungal pathogen. An experiment was conducted to examine the effectiveness of systemic fungicide on suppression of rice blast incidence in farmers' field during wet seasons in 2016. The treatments consisted of the use of different levels of propiconazole and Carbendazim on ‘Rato Basmati’ a landrace rice variety. The experiments were arranged in a randomized complete block design with three replications. The disease was scored according to the standard scale developed by the International Rice Research Institute (IRRI). Disease severity and Area under Disease Progressive curve (AUDPC) was computed based on that scale score. Propiconazole and Carbendazim at different levels reduce disease development than no treatment (control). But its efficacy was not consistent. The magnitude of disease suppression by Propiconazole was high as compared to Carbendazim. The application of propiconazole at the rate of 1.5 ml effectively reduced disease severity and AUDPC at different dates. So propiconazole at the rate of 1.5 ml thrice at weekly intervals is effective to reduce the disease development

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