Whiteflies will hide underneath your cannabis leaves much as the spider mite and can be just as detrimental. They are teeny tiny and spread diseases as they munch on one plant then move to another. Worse, they traverse afar and spread plant diseases in exponential proportions. To check for whiteflies, all you need do is shake your plant. If you see a swarm of what looks like white dust with wings once disturbed, you have discovered one of the most damaging bugs to your cannabis crop.
Whiteflies feed on the leaves and stems of plants, including cannabis. They excrete honeydew, much as the aphid and also spread diseases. They are one of the most damaging pests to food crops. Since marijuana is consumed or used by humans, it falls under this category when considering harmful pests. Whiteflies are immune to pesticides which makes them an even formidable foe. They appear in masses making them hard to control. The best most effective control method for repelling the whitefly is prevention.
A natural way to prevent the onslaught of whiteflies is via companion planting. By planting zinnia within your cannabis plants, in addition to the aforementioned marigolds, you will send whiteflies to someone else's yard of whom may not be as bug conscious as you. (And that might be a good thing, actually!)
Zinnias are colorful and attract natural predators of the whitefly when incorporated into your garden or Mary Jane plantation. They attract hummingbirds (majestic tiny little miracles!), predatory wasps and flies, all of which feast on whiteflies. Minty scented plants such as hummingbird bush, pineapple sage and bee balm serve the same purpose as they naturally disguise the scent of surrounding plants that attract whiteflies.
If these preventative measures still result in the appearance of whiteflies, all is not lost! There are other ways to fight the whitefly. Spraying your plants with the same garlic oil concoction used to combat aphids works on these nasty little insects also.
Another natural solution to ridding your cannabis of whiteflies is to make a simple oil spray by mixing two tablespoons vegetable oil with one gallon water. Pour into a spray bottle and spray the plants thoroughly, paying attention to the undersides of the leaves. Spray your plants twice per week until you no longer see them. Or just ask your local gardening centre for a spray to get rid of white flies.