Prevention and control of the Whitefly
Basil aroma repels the White-Fly
As in most pests and diseases that may affect the different strains of marijuana, prevention is basic to reduce the chances of possible attacks and infections. We can rotate our plants with others, thus creating an association of beneficial plants: growing Marigolds, Chinese Carnations or Basil will help to prevent the appearance of whiteflies because its smell repels them. We must check the underside of the leaves regularly looking for adults or larvae, and use an organic insecticide like potassium soap or Neem oil every few days. The use of sticky traps, in which adult insects will be sticked, will make things more difficult for them.
If we already have an affected crop we can use different ecological remedies to combat the plague: Rotenone and Pyrethrins (commonly used in organic farming as an alternative to chemicals) work well, and their use can be alternated with other insecticides such as infusions of Tansy or wormwood.
Macrolophus Caliginosus, natural predator of the White-Fly
If these remedies don’t work – or if we don’t want to use them for any reason – we can combat the White-Fly with different natural predators. Some of the most effective ones are:
Cales Noacki: Small wasp that parasites whitefly larvae. Very effective, although it isn’t commercialized on the market.
Encarsia Formosa: especially effective in greenhouses. Small fly of just 1mm of black colour with transparent wings. As the Cales Noacki, it lays its eggs (parasites) in White-fly larvae. It reaches its maximum predatory efficiency at a temperature of 25-27ºC and 50-60% relative humidity, using 10 predators per m2.
Macrolophus Caliginosus: useful also to combat other pests like spider mites. They attack Whiteflies in all their stages, preferring eggs and larvae.
As a last resort, and always avoiding their use for the sake of our environment, we can use chemicals to eradicate a Whitefly pest. These treatments will be especially effective against the larvae, which tend to be more sensitive to these substances. It should be noted that Whiteflies have a great capacity to develop defenses against these products, so we should alternate the use of several active principles to get maximum effectiveness. We should always choose insecticides respectful with the natural enemies of the plague that we are going to treat, limiting their use to the most and always as last resource, since a biological crop is always better.
As active substances against the White-fly, and among others, we find Butocarboxim, Buprofezin, Imidalclopid, etc.
We hope to have helped you in the fight against this annoying pest, remember that preseverance in prevention and hygiene are the keys to prevent the emergence of any pest or disease in your plants. We wish you happy and prosperous crops!