Fungi

Fungi and fungi-like organisms inflict huge yield losses globally despite the abundant use of fungicides. Plant pathogenic fungi cause disease symptoms on all plant parts (seed, seedling, leaves, fruits, and root). Symptoms may include spots and blights on leaves, stems, and fruit, rots of tubers, cankers, damping off, seedling and plant diebacks, galls, and wilts. Their early detection in infected plant tissue will ensure taking preventative measures.

Fungal disease diagnosis at the Plant Health lab consists of classical approaches based on visual disease symptoms, hyphal and spore morphology, shape and size of conidia and other fruiting structures. Fungal infections are often systemic, and plant tissue is surface sterilized followed by incubation either on sterile filter paper under humid conditions or incubated on selective media for their successful isolation and identification. In some cases, molecular methods such as PCR and DNA sequencing are used to resolve the causal species.

Fungal Submission Guidelines

Depending on the crop or the symptom area, there are specific sampling instructions. Please contact our Field Plant Pathologist for details, but below are some general guidelines:

• Briefly describe the problem/symptoms on the sample submission form.
• Sample must be representative of the symptoms observed in the field.
• Select samples that are still alive with visible symptoms. Dead or dying tissue should not be sampled.
• Plants should be dug (not pulled) so the entire root system remains intact.
• Be sure to collect the sample prior to pesticide application. Pesticides may interfere with diagnosis.
• Wrap the plant/plant parts in a paper towel and enclose it in a plastic bag so that the sample does not dry out. Be sure to shake off any excess soil from the roots or send them in a separate plastic bag.
• Specimen must be fresh. If a sample cannot be mailed immediately, keep it refrigerated or in a cool area out of sunlight.
• Shipping samples immediately after sampling is the best option. Otherwise, samples can be stored briefly at 4-10°C until they can be shipped. DO NOT freeze samples or expose them to heat.
• Pack the sample securely in the Styrofoam/cardboard box and mail it or drop off.
• If possible, choose the fastest method to mail out the sample. Mail early in the week to avoid weekend delays.
• Please include completed submission form(s) for each sample.
• Please contact the Perennia Plant Health Lab at planthealth@Perennia.ca to notify us of incoming samples

Drop off or Mail to:
Perennia Food & Agriculture
28 Aberdeen Street, Unit 6
Kentville, Nova Scotia B4N 2N1
877-710-5210

Figure 1: Anthracnose (Colletotrichum acutatum) (fungal) of strawberry sample submission with diseased root tissue and healthy plant tissue.

Figure 2: Plant sample cutting diagram. Position 1 indicates where a leaf tissue sample should be taken (try and include at least four leaves). Position 2 indicates where a stem tissue sample should be taken (make sure to include both healthy and diseased tissue). Position 3 indicates where a root tissue sample should be taken.