Resources for growers

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Important insect pests in canola in Western Canada include flea beetles, lepidopteran larvae (i.e. diamondback moth, Bertha armyworm, cutworms, and alfalfa loopers), and aster leafhoppers. Examples of the damage associated with insect feeding from some of these pests have been included in the extension card. While feeding activity from aster leafhoppers does not result in significant damage to canola and other plant species, it can lead to the infection with a bacterial plant pathogen (known as phytoplasmas). The strain of phytoplasma that affects canola and other crops in Western Canada is Candidatus Phytoplasma asteris (Group 16SrI) or Aster Yellows phytoplasma (AYp). Common symptoms of phytoplasma infection include altered pigmentation in plant leaves (yellowing or redenning), abnormal development of floral parts (presence of green petals, bladder-like pods, etc.), and excessive branching. More information about levels of infection and symptoms in several annual crops (canola, barley, wheat) and non-crop plant species (dandelion, sowthistle) can be found in this publication (Open Access).

This figure is from a publication in Phytofrontiers (Open Access). In this study, I examined possible differences in the levels of phytoplasma and symptoms across various plant species. Three plant species (Arabidopsis thaliana, canola, and barley) were characterized by high levels of infection, but the symptoms differed among them. While Arabidopsis thaliana and canola were characterized by yellowing during the early stages of the infection, this was not the case for barley. Symptoms in barley plants were observed in the late stages of the infection (yellowing) and were similar to symptoms associated with other biotic and abiotic stresses.