Perhaps the most common source of plant problems will be in the form of plant pathogens that cause diseases. In the vast majority of cases plant diseases cannot be readily cured, rather they must be prevented. In order to prevent these problems from occurring we need to better understand the source of the problems, anticipate them, and take proactive action.
There are thousands of plant diseases and most of them will be the result of pathogenic fungus, bacteria, or viruses. These pathogens may be present at any point in the plant’s life cycle. An easily overlooked point at which pathogens can occur is in the seed stage. Seeds can pick up pathogens when they are still growing on the mother plant, when it was harvested, and even at planting. To avoid seed-borne pathogens it’s best to acquire certified disease-free seeds, keep them safely stored, and plant into soil with minimal pathogen contamination. When planting a certain kind of crop consider whether or not the prior crop was diseased and if it was related to the new crop being planted. Plant residue from prior growing seasons can facilitate transmission to the new crop, so remove as much residue as possible, solarize the soil, and plant high quality seeds. In addition to that, plant unrelated crops the next season that are less likely to share the same diseases. As a plant is growing it’s important to closely monitor for diseases or anticipate them. It is strongly encouraged to also use seed varieties that are recommended by the University of Florida. A list of specific varieties can be found in UF’s Florida Vegetable Gardening Guide.
Ultimately for a pathogen to occur you need a susceptible host, which is a plant that can get a disease, a suitable environment, and the presence of the pathogen. If one of these three are missing from the equation, a disease will not occur. With that information we can choose non-susceptible plant varieties or use pesticides to prevent problems before they occur or very early before the crop has been damaged.
As a plant is growing pathogens can be spread in a wide variety of ways such as rain or irrigation droplets, insects, or human activity (ex. pruning). Splatter onto soil will readily cover leaf surfaces and allow for fungal or bacterial pathogens infect the plant host. If given the choice between overhead irrigation and drip irrigation it’s far better to use drip irrigation. Insects are an extremely common way plant pathogens can be spread. They are especially known for spreading viruses and bacteria. In order to prevent the spread of these pathogens, using non-susceptible plant varieties can greatly help or use the appropriate insecticide if necessary. For perennial plants, human activity can also spread pathogens from plant to plant by pruning with contaminated tools. Simply clean the tools between using on new plants and after use such as with a dilute bleach solution.
By taking the time to plan ahead and responding quickly, most plant pathogens can be stopped before they become a problem.