Measuring Pesticide Use

Is pesticide use going up, staying about the same, or declining?

This seemingly simple question requires careful thinking and a lot of data.

One might choose to focus on one or more of the following pesticide use metrics:

• The pounds of pesticides applied in an area in a crop cycle (usually a calendar year).
• The number of different pesticide active ingredients required to bring a crop to harvest.
• The number of different applications necessary to grow a crop, taking into account that many pesticides are sprayed more than once on the same field in a year.

But, measuring pesticide use by just pounds applied can be misleading. In fact, any  single, individual way to measure pesticide use will sometimes be misleading.

That’s because some pesticides are applied at high rates per acre — 1 or more pounds, and even up to and over 100 pounds per acre.  Yet other pesticides that do largely the same thing, and sometimes work equally well or better, might be applied at a much lower rate per acre — say 0.1 pound.

Switching from a pesticide applied at 2 pounds per acre to an equally effective pesticide applied at 0.1 pound should be 20-times better, right? Well, sometimes, but not always. Why?

Because pesticides control their intended targets in a myriad of ways. Some, very toxic chemicals effectively kill or otherwise control pests at very low doses. Others are not nearly so potent, or have a hard time sticking on or getting into the target pest, so more must be applied to ensure an effective dose comes into contact with the intended target. Environmental factors like rainfall, temperature, and soil type can alter how stable pesticides are once applied on a crop. Stable products remain active and effective for a longer period of time and can deliver more cost-effective control than pesticides that break down quickly in the enviroment.

And then there is the public health consequences of pesticide use.  Many pesticides target pests where they are metabolically or developmentally vulnerable. Some pesticides work via a mode of action with no counterpart in mammals, while other pesticides pose human risks via the same mechanism through which they kill or control pests.

Why Measure Pesticide Use?

There are three major reasons to measure and track changes in pesticide use.

First, pesticides cost money. Farmers have to carefully scout pest levels in their fields, to know what problems they face and to decide which pesticides (if any) to apply, when, and how. Rising pesticide use usually means rising costs and shrinking profit margins.

If incrementally rising pesticide use is not stabilized, a farm will become economically — and perhaps environmentally — unsustainable.

Second, scientists and regulators working to understand and manage pesticide risks in the environment and among exposed people need up-to-date and accurate information on how much pesticide is being applied, where, and how.

Such pesticide use information is vital input data in the pesticide risk assessment and regulatory processes.

Third, pesticide use has a myriad of impacts on biodiversity, water quality, pollinators, endangered species, food chains, genetic evolution, and competition among species and within ecosystems. It plays an often ignored role in climate change. So citizens and scientists, policy-makers and pundits, all have a need to understand whether and how, and how rapidly, pesticide use is altering the world around us.

Solid and accurate pesticide use data is essential if we are to understand — and more effectively manage — how these chemicals impact life on earth, and the earth itself. HHRA is here to help fill this need.