On the Bee Thankful Farm in Deerfield, the heirloom tomatoes are protected from aphids and tomato horn worms by diatomaceous earth – an organically-approved powder of the finely-crushed shells of tiny organisms called diatoms – and by natural predators like ladybug larvae and wasps. Against fungus, they’re sprayed with organic fungicides like potassium bicarbonate.

But every tomato seedling was planted in a hole with a mixture of water and (non-organic) Miracle-Gro, and non-organic fungicides are a possible last resort if their organic counterparts can’t keep the plants alive and producing.

Clearly, Bee Thankful isn’t an organic farm. However, it also isn’t a farm where synthetic chemicals are dumped on every pest or leaf-spot.

Instead, Bee Thankful practices Integrated Pest Management, or IPM. The goal of IPM is to keep both expense and environmental impact to a minimum, while maintaining acceptable product quality. This means that a farmer following IPM only uses pesticides, herbicides or fungicides when levels of pest damage or weed competition become unacceptable, keeping pollution and product prices to a minimum.

When a pesticide, even an organic one, is used at the first sight of a pest, it can do more harm than good; the pesticide may kill the pest’s natural predators, and the cost of the pesticide might be more than the cost of letting the pest do its damage.  Also, overuse of pesticides and herbicides breed resistant strains of pests and weeds, as seen recently with Roundup.

If pest or weed control become necessary, the IPM farmer first uses the mildest methods possible, like trapping pests or pulling weeds by hand. If this is not effective enough, the farmer then uses the next mildest methods, like introducing a pest’s natural enemy, or using a species-specific, minimally toxic pesticide or herbicide. The strongest, most toxic chemicals – including those that are organically approved – are only used if the farmer finds them absolutely necessary.

Preventative measures are also an important part of IPM. Crop rotation keeps a particular crop’s pests and diseases from accumulating in one spot, and giving young plants a nutritional boost with a concentrated fertilizer increases those plants’ chances of outcompeting weeds and surviving pest-damage without later intervention.

The principles of IPM aren’t limited to agriculture; they can also be applied to gardens, and even to homes. IPM is usually also a part of organic farming; an organic farmer just limits him- or herself to organically-approved substances.

But no matter where it is used, IPM requires enough knowledge about pests and weeds to know how – and when – to deal with them. Fortunately, the viability of IPM is recognized by most state universities, which endorse it and offer classes and information for local farmers and community members. The University of New Hampshire Cooperative Extension’s Integrated Pest Management program conducts research, monitors pests and weather, publishes manuals and newsletters, and conducts grower meetings to help NH farmers and residents save money and do less damage to the environment.

Unfortunately, funding for IPM regional centers, like the one that supports UNH’s program, is not included in the 2011 federal budget. As a result, the centers will not be able to support as much research or help as many farms and other businesses adopt IPM practices through grants.

But for now, the tomato plants on the Bee Thankful Farm will be monitored for diseases and pests, damage will be assessed, and the most economical and environmentally-friendly methods will be used to make sure that the fruit is plentiful and delicious. And hopefully, there will be more farmers, gardeners, and homeowners practicing Integrated Pest Management next year.