Are You Ready for California’s Pesticide Regulations?

Columns - Hort How-To

Lessons and tips to help growers comply with state laws.

Aphid feeding on a cannabis plant
Photo by Mel Frank

Pesticide regulations matter a great deal to any agricultural market. And they’re an even bigger deal for California cannabis cultivators, who now-thanks to the California Department of Pesticide Regulation’s (CDPR) list of pesticides allowed for use on cannabis crops (see page 78)-have clear guidelines for how to deal with pests legally.

This is great news. Even better is the fact that effective pest management programs can be built from this small list of pesticides, and cannabis producers in The Golden State have no excuse for ever testing positive for illegal pesticide residuals.

California’s obsession with pesticides and the rules it has in place today are the result of a long history of pesticide misuse in the state, whether that misuse has stemmed from blatant negligence or a misunderstanding of state regulations.

California cultivators attempting to become pesticide compliant may feel as if they are straight-jacketed at times. When the legal stuff doesn’t seem to be working, thoughts may start creeping into their heads like, “What are the chances I will get caught?”-but that question never needs to be asked if the available pesticides are wielded in concert with other controls. (More on this later.)

Regularly scouting for pests is important for any IPM program. If pests are spotted before they spread too far, pest control using approved products will be more manageable.
Photo by Blue Rose Designs

Become an Expert at Mitigating Pests and Using Pesticides

It is important to note that cannabis is merely a subtopic within the state’s pesticide regulation-and cultivators must ensure they’re compliant with all the rules, not just the cannabis-related rules. Fortunately, the CDPR’s website contains resources to help cultivators determine if their grows are compliant.

California law allows for a property operator to make his or her own decisions about pesticide use. If the operator is comfortable and successful in managing pests, there is no need to call in additional help. Therefore, it benefits the grower to learn everything he or she can about pesticides and the local rules that apply to them. If more support is needed, growers should engage pesticide experts.

Here are two educational resources of which all growers should be aware. It’s also a good idea for every grower to make his or her staff aware of this information, too. The more people know about pesticides, the better.

When pesticide issues extend beyond a grower’s comfort zone and outside advice is needed, the grower should know that anyone consulting on pesticide use on California crops for compensation must be certified by the state. In California, only professionals who pass a rigorous certification checklist become Pest Control Advisors (PCA). Calling a PCA for any pesticide concerns will ensure that everyone is compliant with the law and that you get the best advice money can buy.

Non-PCA consultants can still design pesticide-decision processes, education and tools; they just can’t direct their usage. In California, be careful what information you buy from whom, and never try to sneak something past the regulators.

The following tips can help guide California growers as they think about their pest-management plans.

1. Know the Pesticide Pool

The pesticides California allows on cannabis are botanical, microbiological or naturally sourced products. The list is dominated by botanical oils and 20-plus ingredients that growers can choose from. Growers are not permitted to use any product that contains active ingredients not contained on the list.

2. Read the Label and Follow the Instructions: It’s Simple

There are two key aspects to pesticide labels: effectiveness and safety. Labels are the first and last word on what pests the product addresses, and the conditions and application rates at which the product is most effective. California’s allowed pesticide list contains examples of pests targeted by each active ingredient. All growers also should carefully read product labels to ensure they are aware of all pests a product can target.

In terms of safety, labels define usage levels and practices that are safe for applicators, workers, consumers, wildlife and the environment.

Ensuring label instructions are followed is the hardest part. The consequences of a pesticide screw-up are high. Investors may sleep easier knowing that you have two people read the label, agree on what it says and ensure the instructions are followed to the letter. If that sounds like overkill, just wait until the next pesticide dosage mistake.

3. Comply, comply, comply

Pesticide compliance starts by ensuring that non-approved pesticides are not in the grow. As simple as that sounds, the negative impact of compliance failures suggests that a practice should be established where the operations manager is responsible for vetting all proposed pesticides against the list before a purchase order is approved.

We say “practice” because plans, procedures and policies don’t make things happen. Practice does. Embrace and develop a culture of compliance practices that reinforce proper handling, and it will perpetuate itself. The alternative is found in the experiences of every grower in legalized states who has failed pesticide testing.

Compliance almost always involves documentation. With pesticides, that includes logging which plants are sprayed when, by whom and with what pesticides. Qualified applicators and pesticide logs may or may not be required by the state, but county agriculture commissioners may ask for that information. Perform your due diligence and determine what rules you need to follow and what reporting is required.


4. Use Everything at Your Disposal

Given any list of pesticides, growers still must consider if and when to use them. If they elect not to use a certain pesticide, they need to consider what can be used in its place. Oils are great for mite control in the vegetative stage, but they are not so great on flower buds. Some mites target ingredients, so adding biological predators is the last piece of the flower mite-management puzzle.


Daily scouting for and spot treatment of powdery mildew may be labor intensive, but it can determine whether a crop goes into the flower, extract or proverbial waste bucket.

California has many growing climates, some in locations where botrytis is found. In these locales, the question isn’t if botrytis will appear, but when. This motivates growers in these locales to keep a sharp eye out for signs of bud-destroying botrytis and to set harvest as soon as possible after any signs of botrytis are discovered. If the definition of a pesticide is something that prevents losses, labor is a very effective pesticide.

5. Stay on Top of Things

It only takes a moment for an operation to be contaminated. California growers (and all growers) should understand that pesticide regulation is extremely serious and that failure to comply can shut down an operation. Properly documented procedures and constant oversight are necessary to prevent pesticide contamination. Failure isn’t an option.

Kerrie & Kurt Badertscher are co-owners of Otoké Horticulture, LLC and authors of “Cannabis for Capitalists.”