1. Regulatory Mold and Yeast Testing Impact on the Cultivation of Cannabis by Kurt Badertscher Otoké Horticulture
Passing the test has proven to be tough during advisory beta testing of the Colorado Department of Public Health and Environment’s testing of cannabis for bacterial and mold/yeast contamination. Testing is done at the end of a lengthy and costly process so growers are well advised to learn where these contaminants are coming from, how they are spreading and accumulating and hopefully how to control them. Failure to be able to control levels during cultivation could drive growers to expensive post harvest processing with heat or irradiation to meet the current limits.
Culturing and monitoring airborne bacteria, mold and yeasts gives growers feedback on the contamination inside an operation over time and is the first step in understanding how molds and yeasts accumulate and spread inside this crop which can direct strategies for controlling those levels proactively.
Method: Industry standard sampler system, commercial microbiology lab1.
Data Summary2: Process improvement across 2 years based on aerosol contaminant measurements
Comments:
The level of the most virulent human pathogens like A. fumigatus are generally in line with outdoor levels suggesting these pathogens are present, but apparently only accumulating in rather than reproducing in the facility.
Remaining high count pathogens are considered particulate issues, not usually considered a risk to human health according to our reading of the Center for Disease Control database.
Next testing will relate these now low airborne levels to the ultra high levels reported from official mold and yeast testing. That data was not made available for this poster.
Further research into better quantifying the pubic health exposure posed by molds and yeasts would be prudent, timely and truly in the best interests of the public. 1 2
Initial testing identifies high levels of Penicillium and Beauvaria bassiana isolated to a pesticide used in the operation.
High worker exposure rates remediated except for Penicillium
Penicillium source identified, process and airflow changes reduced overall levels
Further overall low levels with Penicillium continuing to be an issue 1 2 3 4 3 4
Multiple bars for a pathogen indicates it was found in multiple locations in the operation. Note scale changes between charts
1 – Anderson Sampler and EM Lab P&K microbiological laboratory Data from and used with permission of a licensed cannabis production facility. Company name withheld by request

2. Pesticide-free Rhizosphere Protection – Bug Bags
by Kurt Badertscher Otoké Horticulture
Some states have approved the use of some pesticides for use on cannabis based mostly on their being on the list of 25b minimal risk pesticides which are exempt from tolerance requirements, registration with the EPA or both. But approval does not equate to effectiveness.
At the end of 2015, root aphids had proven especially resistant to all pesticides approved for use on cannabis and beneficial predator suppliers did not have an answer either.
Integrated Pest Management teaches growers to use a variety of tools to control pests. With pesticides and beneficials removed from the toolkit, good old exclusion is one way of addressing the problem.
Placing plant containers inside a bag that can be sealed around the stalk of the plant creates a smaller portal of entry to protect such as spraying Tanglefoot® or other sticky substance on the stalk to capture any aphids that may attempt to enter the small opening around the stalk. The bag color allows scouts to see aphids making the trek toward the opening.
Fabric for the Bug Blocker product was identified by placing aphid infested plants inside a bag. The root ball was dosed with an Azadirachtin pesticide which does not kill the aphids but does irritate them to where they attempt to get away. The photo of the aphid shows a very early instar exiting a test bag made of loose weaved cotton muslin. Tighter weaves were specified and the final product is impervious to aphids, allows water to drain freely and air to be exchanged.
Works with drip, hand and ebb and flow, home and at scale