Canadian Plant Disease Survey 2020 Volume 100: Disease Highlights 2019

Abstract

(PHL) provides diagnoses of disorders detected in field crop samples caused by fungi, bacteria, viruses and plant parasitic nematodes, and insect pests of agricultural crops grown in British Columbia. Between January 1 and November 30, 2019, the PHL received 790 samples including Christmas trees, field crops, greenhouse vegetable and floriculture crops, forest nursery seedlings, herbaceous and woody ornamentals, small fruits, tree fruits, nuts and speciality crops for diagnosis. No significantly new, or unusually high level of any disease was detected in the samples. METHODS: The BCAGRI's Plant Health Laboratory provides diagnoses for disorders detected in field crop samples caused by fungi, bacteria, viruses and plant parasitic nematodes, and insect pests of agricultural crops grown in British Columbia. Samples were submitted to the laboratory by ministry staff, growers, agri-businesses, municipalities and Master Gardeners. Diagnoses were accomplished by visual and microscopic examination, culturing onto microbial media, biochemical identification of bacteria using BIOLOG® and serological testing of viruses, fungi and bacteria with micro-well and membrane-based enzyme linked immuno-sorbent assay (ELISA). Molecular techniques (polymerase chain reactions (PCR) (conventional and/or real time) were used for some species-specific diagnoses. General primer PCRs (for fungi and bacteria) were followed by sequencing to identify the organism involved. Some specimens were referred to other laboratories for identification or confirmation of the diagnosis. RESULTS AND COMMENTS: Overall in 2019, British Columbia had mild winter weather conditions in January followed by a severe cold snap in February. Spring was wet as is normal for BC and was followed by a short, dry summer. The wet weather in the spring supported bacterial blights on woody ornamentals, tree fruits and berry crops. Fire blight incidence was higher than usually seen in tree fruit and woody ornamental crops. Summaries of disorders detected in field crop samples/disorders and their causal/ associated agents diagnosed on crop samples submitted to the laboratory are presented in the following Tables 1 to 13 organized by crop category. Diagnoses not listed include: abiotic disorders detected in field crop samples due to nutritional stress, pH imbalance, water stress, drought stress, adverse growing conditions, genetic abnormalities, environmental and chemical stresses including herbicides, fruit abortion due to lack of pollination, insect-related injury and damage where no conclusive causal factor was identified.

Current and Future Pathotyping Platforms for Plasmodiophora brassicae in Canada

“…Nonetheless, P. brassicae has continued to spread and is considered to be one of the most significant problems facing canola growers. Clubroot is now endemic to much of central Alberta [1], with more than 3000 confirmed field infestations [8] and the disease having been identified in 44 of the 66 counties or municipal districts where canola is grown [9]. Epidemiological models had predicted that clubroot could spread beyond Alberta throughout the Canadian Prairies, and since then the disease has been confirmed…”