I spent all day Saturday at VanDusen Botanical Gardens reviewing some common disease problems of trees, flowers and shrubs, which many of us have in the garden.
Plant pathologist Andrea Buonassisi reviewed the basics of plant diseases and helped us bone up on our diagnosing skills.
If you have a plant that looks abnormal, it is generally a good indication that something is wrong.
The first step is to identify the host plant. Second, look for symptoms and signs. Consider it evidence and spend some time gathering your information.
Symptoms can include - but are not limited to - blight, blotch, brittle, callus, cankers, yellowing, curling, die back, leaf drop, and leaf spots.
Signs are the evidence - the actual presence of the disease agent on the plant. Do you see fuzzy fungal growth or shiny, slimy bacterial oozing? Let's hope not.
After identifying the host and realizing you have a problem, the next step is management.
Master gardeners and gardeners in the know like to use I.P.M or Integrated Pest Management skills whenever possible when we talk about disease.
Try to resist the urge to run out and buy a quick fix. The plant is diseased for a reason and it is much more beneficial to take a complete look at your environment and growing conditions first.
I know it sounds easy but prevention is the number one thing you can do to eradicate disease in your gardens. This includes planting the right plant in the right location and giving it the optimum growing conditions.
Factors like temperature, light, water, soil and ph, and nutrients can really affect a plants health and if these basic conditions aren't met the plant becomes stressed and more apt to become sick or diseased.
There are two categories of plant disease: environmental disease and infectious disease. Some common examples of environmental disease are winter damage, high temperature and dry wind damage, pollution, low iron and nitrogen and cedar flagging and conifer needle drop.
Infectious diseases are diseases that occur over a long time. Think about an infectious plant disease triangle.
You have the host plant, the pathogen (fungus or bacteria), and the environment. If you break the triangle, you can generally stop the disease.
Nematodes are a common pest of perennials. Raspberry and strawberry plants are very prone to nematodes and you can see their damage in the form of root rot and verticillium wilt. To avoid this, make sure the berries are in well-drained soil - they will not tolerate wet roots.
Also, do not plant in areas that raspberries have died in or where tomatoes, peppers or eggplants have grown.
Plant viruses include mosaics, abnormal growth issues, ringspot and vein banding. A plant virus can often look like a nutritional problem.
To help you accurately diagnose your plant's disease, check out a great manual called - Home and Garden Pest Management guide of British Columbia.
This user-friendly book is a wealth of knowledge in helping to keep your garden healthy.
