Landscape SA Featured Article – Vol 98 | Feb 2021
In this article on cannabis, the seventh in a series published by Landscape SA, Cilo Cybin Pharmaceutical explains its pest control method. Karyn Richards spoke to cultivation director Alasdair Walton.
Natural or biological control is the use of living organisms to control pest populations in plants in order to avoid unwanted pathogens. This method does not rely on the use of manmade chemicals and also poses no threat to human health, crop production or beneficial organisms. Biological control uses other organisms to control unwanted insects, mites and weeds.
In requires an active human management role and can be an important component of integrated pest management (IPM). Walton explains that an infestation of thrips was discovered on a few of their cannabis plants, despite the fact that they are grown in a strictly controlled, sterile environment. He says the thrips may have entered their premises from someone coming in from elsewhere, but the specific cause has not been identified.
The humid conditions of the growing room could have helped the pests to proliferate but this is not a cause in itself. Fortunately, the infestation has been confined to one growing block and only 27 plants were infected. Thrips are tiny, fringe-winged insects that suck plant sap and can be a serious threat when present in large numbers. With asymmetrical mouthparts, different species feed on plants and leaves by puncturing and sucking up the contents. The insects lay eggs in plant tissue and manifest as yellowish, speckled dots on the tops and undersides of leaves.
Cilo Cybin used a product manufactured by Koppert Biological Systems, a company with extensive knowledge of micro-organisms, bio stimulants and pheromones designed to improve plant resilience. The product is supplied by Bio Leaf Technologies.
In conjunction with this, Neem oil was also used, having been diluted and sprayed onto the cannabis leaves. It is a naturally occurring pesticide found in the seeds of the Neem tree. Yellow to brown in colour, the oil has a bitter taste and a garlic/ sulphur-type smell. It consists of a mixture of components that reduce insect feeding and act as an insect repellent.
Azadirachtin is the most active component of Neem oil and interferes with the insects’ hormone and nervous system, making it more difficult for them to grow and lay eggs. Once treated, the cannabis plants improve within 7-10 days but Walton says the leaves continue to be inspected because the plants have lower immunity and can be re-infected.
At the time of infection, the plants were approximately two weeks into flower and six weeks old from propagation. Other pathogens that can affect cannabis plants include spider mite, white fly and powdery mildew. These can occur individually or all at once, and in the latter case, plants have to be destroyed and incinerated.
Text by Karyn Richards. Photos courtesy of Cilo Cybin Pharmaceutical.