Putting Pesticides In Their Place

By Richard Freeman

Pesticide use in the Cannabis industry has received some bad press lately.  In Colorado, producers have recalled several large batches of edibles over the last year due to pesticide contamination. In 2015, consumers in the same state sued a producer for selling organically-labeled products tainted with pesticides. Denver health officials quarantined 60,000 plants from the same producer, and Colorado’s governor has promised a robust regulatory response.  Change is coming.

Of course, farmers have used pesticides in one form or another for well over a century – on food, tobacco, and non-consumables like hemp. That use has sewn controversy for decades, so the basic arguments are well known.  Proponents assert that pesticide use can and does increase production and avert risk of disaster.  The underlying assumption is that the products are safe if used correctly (strictly within guidelines of the label).

Opponents assert that residual pesticides pose health risks to consumers. The case is especially poignant with Cannabis farming, since pesticide companies have yet to test pesticides in marijuana and CBD Cannabis production. (Federal prohibition has thwarted such testing.)  Opponents also assert that through unintended contamination, pesticide use affects people, pets and wildlife, reduces biodiversity of non-target organisms, and ultimately selects for pesticide-resistant pest strains.  From this perspective, unintended contamination is common, and farmers routinely use pesticides outside the label guidelines. (By definition, applying pesticides on Cannabis will violate labels until the Environmental Protection Agency updates them to include use with marijuana and CDB cultivation.)

Aside from their differences, however, both sides will agree that if farmers do use pesticides, they should use them sensibly, effectively and efficiently.  In this regard, any pesticide use should be part of a larger, comprehensive Integrated Pest Management (IPM) strategy.

IPM is a pest management framework that emphasizes maximizing net value (profit) – the spread between expected benefits (income) and expected costs.  When considering pesticide use – or any other cultural practice – the farmer compares the expected costs from pest-induced damage to the expected management costs for labor, equipment and materials – in addition to the risk of decreased product value due to pesticide contamination.  The farmer avoids cultural practices that don’t show a return.

IPM includes a large set of cultural practices – of which pesticide application is only one.  These practices fall into four groups. Environmental/ecological practices create a low-risk growing environment that’s healthy for plants and isn’t vulnerable to pest outbreaks.  Monitoring is key to catching problems early, before serious infection or infestation.  Indirect controls involved adjusting growing environments (lighting, atmosphere and soil) to thwart pests.  Direct controls follow or accompany indirect controls.  Direct controls include mechanical, biological and chemical controls.

In IPM, chemical controls function as a direct control of last resort.  They vary significantly in mode of action and toxicity from product to product, and the intensity and scale of their use depends upon the growth stage of the crop and the type and scope of the pest problem.

IPM offers several benefits to commercial Cannabis cultivation, small-scale as well as large-scale.  Aside from maximizing value, the farmer routinizes pest management, thereby avoiding crisis responses (which are expensive).  Budgeting and scheduling become more reliable and costs are more predictable.

Equally important, IPM benefits the consumer and minimizes costs borne by people and critters who might suffer the effects of pesticide exposure, and farmers get mimimal exposure, as well.  It’s a win-win scenario. The farmer benefits in many ways, and society and the environment benefits.  And, well-designed IPM puts a much better face on our industry than headlines featuring pesticide-caused calamities.