Whether you are growing your first tomatoes or consider yourself a professional grower, plant diseases can hit you unexpectedly. The most common problems in gardens and orchards are usually fungal diseases. It is confirmed that fungal pathogens are responsible for 85 per cent of all plant diseases. Fungal pathogens wait in the soil and infiltrate new plants and even stay overnight in pruning shears until they have a chance to attack.
Once active, fungal diseases exploit weak spots in plants, making them more prone to other diseases and insect damage. Protecting your garden with experienced growing practices and effective fungus treatment will help you maintain the beauty of your plants and the abundance of your harvest.
Know your enemy To learn about the various ways fungal pathogens work, keep the following fungal diseases in mind:
- Black spot: Dark spots on the top of the leaves indicate the effect of a disease known as black spot. These spots never affect the underside of the leaves and expand until the leaf turns yellow with black spots. Like many fungal diseases, black spots need water on the plant surface, either in droplets or as a film of water, in order to reproduce and spread. Plants too close to each other, wet conditions, and overhead watering all contribute to the development of black spot disease.
- Rust: This fungal disease does get its name from the rust-orange sores that form on the underside of leaves. The fungus grows and spreads, and the surface of the upper leaves becomes discoloured, and, over time, the leaves of the plant fall off. The cool and humid climate, as well as the wet foliage, promote the spread of this disease, which is also transmitted with the help of wind, water and insects that transmit it unconsciously.
- Gray mould: Flower buds and petals that used to be beautiful and vigorous fall off and rot, taking on a velvety grey mould appearance. The pathogens are responsible for this wind-borne disease strike during the cool, humid days of spring and fall. High humidity, poor air circulation, and excessive closeness between plants create ideal conditions for the spread of grey mould.
- Powdery mildew: The formation of a white powdery coating on the leaves, new shoots, and other parts of the plant often indicate the presence of powdery mildew. Unlike various fungal diseases, powdery mildew does not need plenty of water to grow or spread as it remains active even in hot, dry weather. High humidity and poor air circulation encourage the spread of this wind-borne disease capable of attacking succulent new shoots.
Use cultivation to your advantage
As part of the adhering to the principles of comprehensive pest control, an effective challenge against fungal diseases involves creating a balance between proper cultivation of plants and an adequate response when necessary. Putting these measures into practice helps protect and limit the vulnerability of your garden:
Improve air circulation and then increase light penetration in and around plants through judicious pruning and adequate spacing between plants. One method to achieve this is by reducing the density of plants or by changing the environment around them. Prune infected plant parts immediately and dispose of debris, do not use to compost. Always cut through healthy tissue so that no residue of the disease remains on the plant.
Sterilize pruning utensils by cleaning them well with a common household disinfectant. When you suspect disease, clean them before and after each cut as well-intentioned pruning could spread the problem.
Fight fungal diseases right out of the box.
The crucial component of a good protection plan is a fungicide with a proven effect that prevents diseases from being activated and provides the immediate treatment. The fungicide GardenTech Daconil with chlorothalonil as the active ingredient provides great protection against a wide range of fungal pathogens and simplifies the control of fungal diseases in your garden.
Prevention is the key to protection, especially on susceptible plants or plants that have had fungal problems in the past. For example, most rose bushes are often vulnerable to black spots and other fungal diseases. The University of California State Comprehensive Pest Control Program recommends using chlorothalonil-based fungicides, such as Daconil fungicide, to protect healthy rose tissue and prevent grey mould and black spots.
When used as a preventive and active treatment, Daconil fungicide can prevent, control or stop more than 65 types of fungal diseases in flowering plants, vegetables, shrubs, fruit and shade trees. Follow the descriptions on the label for the type of plant you are treating and the disease you think the plant has. For example, for ornamental plants such as roses and azaleas, use Daconil as a preventative before the disease is observed, as recommended by the North Carolina State University Plant Pathology Extension Department and the department Cooperative Extension Program at Clemson University.
4Hollyhocks are famous for their vulnerability to rust, so protect them from when the plants are small. For flowering annuals, such as cinia, which are prone to powdery mildew, apply the treatment by observing the first symptom of the disease.