Dealing With Plant Diseases
Prevention Is Better Than Cure
Good cultivation is as much a part of fighting diseases as recognizing and treating them, and with few fungicides now available to the amateur, preventative measures are essential.
Plants require a ready supply of nutrients and water to sustain healthy growth, so add plenty of organic matter to the soil to release nutrients and help retain moisture. Additional watering may also be needed, particularly in hot weather. It is important not to forget plants under cover and in containers, which rely on regular watering and feeding to sustain them. Damp conditions and poor air circulation can encourage fungal problems, such as damping-off of seedlings, so use free-draining potting mix and provide good ventilation when sowing indoors.
A neat garden also helps to keep diseases at bay. Ensure that sources of infection, such as dead leaves, harvested plants and nearby weeds, are removed at the first opportunity. Burn or discard any diseased material; don't compost it because infection could spread.
Although not easy in a small garden, it is advisable to practice crop rotation, where related groups of crops are grown together and moved to a new bed each year, helping to prevent the buildup of diseases in the soil. Where diseases are known to be a problem, try growing resistant varieties. Be aware that plants brought into your garden can introduce disease, so check any purchases or gifts carefully before planting.
Deficiency, Not Disease
Signs of nutrient deficiency, such as yellowing leaves and blossom end rot on tomatoes and peppers, are often mistaken for diseases. Learn to recognize these disorders, so that you can act quickly and minimize their effects. Sometimes the remedy is as simple as improving the water supply; other problems may need fertilizer added to the soil.
Text copyright 2007 Royal Horticultural Society