State regulations in Colorado and Washington only allow pesticides in cannabis gardens similar to those permitted for organic farms. Treatments of soapy water and neem oil work, but most gardeners find them hard to rely on. Nobody wants nasty chemical pesticides in their herb, so what functional alternative do they have? Predatory insects, but you have to know how to use them.
One great predatory insect any cannabis gardener can use on their crop is the green lacewing. This “broad spectrum” predator works great against thrips, whiteflies, mealybugs and, of course, the dreaded aphids and spider mites. Other sources may tell you to use predatory mites to fight spider mites, but one way or another, your buds will still be covered in mites, and who wants that?!
To use green lacewings properly, one must understand their lifecycle, but don’t worry, you don’t need a PhD in entomology, or a hippie-esque understanding of Mother Nature.
Quite simply, green lacewing larvae feed on pest insects like aphids or spider mites. Lacewing adults cease to be predatory and feed on nectar, pollen or honeydew. Growers with sever infestations can order green lacewing larvae. You will most likely have to order them online, and make sure to carefully follow the instructions that come with these little guys. Larvae will immediately start to eat your pests.
Alternatively, a gardener could order green lacewing adults. Adults don’t eat any pests, but they come pregnant and ready to lay eggs, which hatch into larvae and begin to eat your aphids, mites and even each other.
For effective and lasting pest management, the gardener needs a way to keep the population of green lacewings around so they continue to devour the pests as they return. If not, the lacewings will die off. If even one spider mite female is left over, it could lay eggs and produce up to 1,000,000 spider mites; so, it’s important to keep your predators around!
Green lacewings adults feed on pollen, nectar or honeydew. If you provide them with a source of food, they will continue to reproduce and should stick around your garden—indoor or outdoor. All this requires is that you plant a few flowers in your garden. Outdoor growers should plant native wildflowers to provide pollen and nectar for your lacewings, and the flowers will also attract other native beneficial insects to your garden to provide more broad spectrum pest-fighting action.
Indoor growers, on the other hand, can plant whatever flower meets their fancy, as long as the flower matches your lighting schedule. If you put a flower that normally blooms in the fall into your vegetative room, it will vegetate and stop making flowers. If you plant a flower that normally blooms in the spring in your flowering room, it will also stop flowering. You need flowers! Put spring-flowering plants in the vegetative room and keep them there; put fall-flowering plants in the flowering room and keep them there. You can buy seeds and germinate them to save money, and maybe a few mature plants to provide some immediate food for the lacewings.
Remember to have fun with this little experiment. Researchers from the Xerces Society for Insect Conservation have done some serious science into pest management using native insects coupled with native wildflowers and grasses, but their techniques will only work outdoors.
Don’t miss our previous Grow Hack: How to Harvest for Regeneration