Seattle Public Utilities Mami Hara, General Manager/CEO

IPM Questions and Answers

Why Use IPM?

Integrated Pest Management protects the natural enemies that help keep pests in check. It avoids unnecessary chemical use that may endanger human health and the environment. This approach has gained acceptance worldwide and is now mandated by many governmental agencies. IPM represents the future for the landscaping industry because it is the best long term solution to pest management and plant health, and because customers want it.

Demand for IPM services is increasing as concern over pesticides grows. Companies that provide IPM services are increasing their market share. When a client hires an IPM practitioner, they receive expertise, careful monitoring, and labor-intensive cultural practices instead of just chemicals.

Why calendar-based, broad spectrum sprays don't work

Some people think of timed sprays as "booster shots" for the garden, that keep plants invulnerable to problems. But these calendar sprays are generally ineffective. Why?

Pests are not the primary problem. Over 2/3 of plant difficulties result from soil conditions, watering practices, nutrient imbalance, heat, freezing, or other cultural problems. Sprays are wasted on these problems. Broad-spectrum chemicals also damage the beneficial soil life and insect predators that keep plants healthy.

Even if some pests are present, treatment may not be needed. Most plants can tolerate some damage and just "grow out of it." Using sprays unnecessarily wastes time, money, and materials, but its primary problem is the disruption of a natural garden ecosystem. Learning when and how to manage garden problems requires more effort and attention than simply spraying by a schedule.

Disease organisms, weeds and insects grow with light, temperature, and moisture, not by watching the calendar. Timing of application is essential, because plants are more vulnerable at certain stages than others to pests, and pests are more easily controlled during certain life stages by natural predators, cultural practices, or treatment. Using non-chemical controls, or as a last resort the least-toxic product with the least non-target impact, protects people, pets, wildlife, and the beneficial bugs and soil organisms too.

Fertilizers and IPM: avoid fertilizer/herbicide mixtures

Most woody plants like trees and shrubs can get the nutrients they need from the soil, with regular additions of compost and mulch. Annuals and lawns, and some perennials, may need additional nutrients. Base all fertilizer programs on regular soil testing and plant need. More is not better – it wastes product, pollutes our streams, and can damage soil and plant health.

Avoid “weed & feed” fertilizer/herbicide mixtures: they aren’t timed right for plant needs and they spread herbicide unnecessarily all over the landscape. Use cultural and mechanical weed controls or spot spray if necessary. Also avoid fertilizer/insecticide and mulch/herbicide products. When choosing fertilizers look for natural organic or slow-release products that feed plants longer and are less likely to wash off into streams and lakes.

More questions?

See fact sheets, resources and ask the experts your questions at our IPM home page.