Non Chemical Methods Plant Diseases

Resistant plants. With some plant problems the easiest way is to avoid planting cultivars that are more disease susceptible. Red tip photinia has become a high maintenance plant because of a foliar leaf disease. Why attempt to grow it? With fruits and vegetables there is a greater availability of resistant cultivars than with ornamentals. Tomato cultivars have been available for years that are resistant to nematodes and some fungal wilts. Some pear cultivars are resistant to fireblight.

Right plant -right place approach will help reduce problems with many ornamental plants. Boxwoods and dogwoods prefer light shade. Azaleas and daphne need good drainage. Before planting be honest with your self about what will grow in the space you need to plant. Does it have the right amount of sun, drainage, or soil conditions for you chosen plant to survive? Chose plants that are adapted to the environmental conditions that you have.

Crop rotation can break the disease cycle for many vegetables and flowers. By altering crops from one year to the next, the amount of disease inoculum is reduced. Pansies and vinca share some of the same diseases. To plant them as alternating crops is asking for problems.

Recommended planting and harvest time should be followed closely. Planting when the soil is cold and wet, can cause okra seeds to rot in the ground. Late plantings of squash are very likely to suffer from powdery mildew. Wait to plant pansies until the soil temperature has cooled in the fall. Vinca should not be planted until the soil has warmed in the spring.

Removing plant debris in the fall will reduce future plant disease populations. Debris serve the disease as an excellent home for the disease to overwinter. Rotten peaches left under the tree can cause brown rot fungus to be worse the following year. Removing the mulch containing fallen leaves will help control black spot on roses. Plant debris should be destroyed or at least removed from the site. Composting may not be a good idea unless you do a thorough job of turning the pile so it reaches a high temperature.

Removing the infected plant will help control the spread to other plants. Remove infected plants immediately.

Weeds can harbor diseases and insects that spread diseases. Remove weeds while they are young. You should mow or destroy weeds from ditch banks and other near by areas.

Soil improvements is a time proven method to reduce plant stress and decrease soil born disease by improving soil drainage. Good soil produces good healthy plants which are more resistant to insects, diseases and environmental stresses.

Cultivating flower beds and the vegetable garden will expose soil insects and disease organisms to the weather and birds.

Mulching can reduce plant diseases by preventing splashing of inoculum from the soil onto the plant. Mulching will also enhance the overall health and vigor of most plants.

Soil solarization is a new approach to heat treating the soil. Clear plastic mulch is laid over the soil in mid summer for one month. The soil temperature builds up and kills many soil borne fungi, nematodes and weed seeds.

Soil testing will reveal pH and nutritional problems that can reduce growth and lead to plant stress. Proper spacing of plants will improve air circulation and help the foliage dry quickly. This will reduce the likelihood of many fungus disease that thrive under moist conditions.

Consumer Horticulture | Quick Reference