Ken Brennen, Extension Master Gardener in Anoka County, June 25, 2014.
“What can I spray it with?” That question often pops up when gardeners first see a pest or disease problem. As Master Gardeners we promote the concept of Integrated Pest Management (IPM), hoping you will not get to the point of asking that question. The basic IPM concept, that prevention is better than cure, can be illustrated in terms of your own health. As a sensible person you'd rather live a healthy lifestyle than constantly take strong expensive medicines with potentially disastrous side effects just to stay alive. You understand that disease germs are all around us but by staying healthy you can keep them at bay. And if they do get you, the result will probably be something you can cure at home.
The same should apply to your garden. If you keep your plants fit and healthy from the day you get them, your need for drastic treatments should be minimal. You may never need those chemicals with nasty side effects that ripple through the environment and kill the pollinators and beneficial insects (and perhaps birds) that are partners in growing a healthy garden.
IPM starts with putting a plant in the right place. That means the right soil, sun exposure, spacing for air circulation, and freedom from competition (read tree roots and weeds here). To grow up healthy, a plant requires the right food (fertilizer) and water, in the right amounts at the right time. This may require you to get some cultural information about your plants, but it is all readily available from your University of Minnesota Extension and the associated Anoka County Master Gardeners.
The next to the last step in IPM is to monitor your garden closely, preferably every day. Just as with your own health, the garden's health will be easier to restore if you catch problems early.
If you spot something starting up, the IPM response is to identify it and find the least destructive way to control it. We use the word “control” rather than “eliminate” because you would have to treat the entire world to truly eradicate a pest. You just want to control the problem in your garden patch to the point where you can live with it and keep it from spreading. It's very much like having a cold - no drastic measures required beyond a reasonable self-care.
Most common problems can be identified with help from your Anoka County Master Gardeners at http://www.extension.umn.edu/garden/master-gardener/ask/ or the University of Minnesota Extension website http://www.extension.umn.edu/garden/. A cure may be as simple as hosing off those bugs with water, cutting off some infected leaves, draping some fine mesh over your plants, or adding mulch to prevent weeds. In these days of increasing human and environmental health concerns, it's better to keep the chemicals as a last resort. And if you do find it necessary to use them, remember to read, understand, and follow instruction on the label. In the USA the label is the law.