By Barbara Perry Lawton
In recent years, gardeners have become wiser to the dangers of many pesticides and have learned better, more conservative ways of dealing with weeds, pests and diseases. Although, unfortunately, pesticide-based plant care still predominates in much of our lawn and garden management, the spread of information on IPM (integrated pest management) and PHC (plant health care) is helping reduce the usage of often dangerous chemicals.
We should learn to live with a tolerable amount of diseases and pests. We can’t – and shouldn’t – get rid of every destructive bug. I strongly believe that our goals in home gardening should be to be pesticide-free, not pest-free.
Integrated Pest Management
Although IPM was originally developed for agriculture and commercial pest control, the concept should be applied to even the smallest of gardens. Quite simply, IPM consists of the following sensible steps:
- Identify the pest and use knowledge of its biology and natural enemies to control.
- Monitor pest populations through careful observation.
- Note the extent of any injury to plants.
- Establish a tolerable threshold of injury.
- Use cultural, biological and mechanical methods to control unacceptable levels of pest populations with selected use of least toxic pesticides such as insecticidal soaps and horticultural oils only as a last resort.
- Keep records, noting the results of the control strategies.
The following specific techniques for controlling pests are conservative and will help ensure a healthy environment:
- Handpick or squash pests as soon as you notice them.
- Spray destructive insects off plants with a hard fine spray of cold water.
- Introduce natural predators that will consume pests.
- Use parasitic insects that kill specific pests by living on or in them.
- Use microbial organisms to make pests sick.
- Rotate crops.
- Use disease-resistant varieties.
- Keep a clean and tidy garden.
- Destroy diseased plants.
- Maintain healthy fertile soil that has abundant microbial life.
Plant Health Care Programs
A newer and more encompassing gardening philosophy is called Plant Health Care (PHC). Roger Funk of the Davey Tree Company articulated this concept in the 1980s. He and other horticultural experts had been thinking, “we shouldn’t concentrate on managing pests when really what we want is healthy plants.”
PHC calls for addressing the entire garden and keeping a larger view as you plan and care for plants. In essence PHC is as follows: Identify and inventory your garden plants. Make regular health inspections. List your plants’ special needs. Finally, incorporate IPM in any pest control effort.
The fact is that healthy plants get few diseases and are bothered by few pests. When plants are stressed by the wrong amounts of nutrients, water and sunlight, by excessive heat or cold, or by other environmental factors, they will be more susceptible to pests and diseases.
Other Ways to Prevent Pest and Disease Problems
Cleanliness and sanitation practices constitute the first step in preventing harmful insects and diseases. Diseased plants, including those infected with such things as scab, brown rot, powdery mildew, shot hole fungus or peach leaf curl should be hauled off, not used as mulch or cold compost. Examine plants, bulbs, corms and tubers before buying, making sure that they are healthy, firm and unbruised.
Whenever possible buy disease – and insect -resistant varieties. The more vigorous a plant is, the less susceptible it is to pests and diseases. Over-fertilizing plants tends to make them weak. Remember these easy prevention tips:
- Disinfect tools contaminated by diseased plants.
- Keep foliage dry – don’t let moist foliage go into night.
- Grow varieties suited to your area.
- Do not overcrowd plants.
- Rotate crops and ornamental annuals.
- Identify pests and learn their life cycles.
- Remove dead and diseased plant parts from the garden.
- Never let your plants want for sufficient water or nutrients and keep an eagle eye out for marauding pests.
Many experts consider ultrafine horticultural oils the most effective controls available for controlling harmful insects and mites. Even these wonderful solutions to garden problems should only be used when needed. Never apply it during droughty hot spells. During cold snaps, the oil may not flow well. As always, read directions carefully and apply as indicated.
Barbara Perry Lawton is a writer, author, speaker and photographer. She has served as manager of publications for Missouri Botanical Garden and as weekly garden columnist for the St Louis Post-Dispatch. The author of a number of gardening and natural history books, and contributor to many periodicals, she has earned regional and national honors for her writing and photography. Barbara is also a Master Gardener and volunteers at the Missouri Botanical Garden in St Louis MO.