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Poster: Biology & Disease Mgmt: Chemical Control


Evaluation of fungicide efficacy and cultivar susceptibility for the management of anthracose on celery
M. MCDONALD (1), M. McDonald (1) (1) University of Guelph, Canada

Anthracnose on celery, also called celery leaf curl, is caused by Colletotricum fioriniae. The disease was first identified in Ontario, Canada, in 2011 and has been increasing in severity. Field trials were conducted to determine if there were differences in cultivar susceptibility and to identify effective fungicides. The celery cultivars were: TZ6010, TZ0295, TZ6200, TZ6029, TZ9779, Nero, Sabroso and Plato. Cv. TZ 6200 was used for the fungicide trial. Seedlings were transplanted on 24 June into ‘muck’ soil (organic matter ~70%, pH 6.5) in the Holland Marsh, Ontario. Each replicate consisted of 3 rows, 55 cm apart and 5 m in length. The trials were inoculated on 18 August with a suspension of 1 x 105 conidia ml-1, and harvested on 13 October. The fungicides evaluated were Omega (fluazinam 40.0%), Bravo (chlorothalonil 50%), and Flint (trifloxystrobin 50%). Fungicides were applied on 31 July, 13 August and 8 September, 2015. Disease incidence and marketable yield were assessed. Cultivars Plato, TZ 9779, 6200 and 0295 had high disease incidence (86, 66, 66, and 67%) compared to less susceptible cv.’s Sabroso (24%) and TZ 6010 (27%). Fungicides Flint and Bravo had low disease (34, 45%), compared to the untreated check (83%). Increased disease incidence in September was related to a decrease in the percent of marketable yield by weight (r2 =0.45)