Very few things are as frustrating for cannabis growers as seeing the grow they’ve devoted so much time and effort to go down the drain. Cannabis plants face a wide variety of risks during their life, the most devastating of all being definitely the plagues. Spider mites, for instance, are 0.3 inch long arachnids very much feared for the extensive damage they can cause to a range of crops, despite their small size. To prevent them from derailing our grow, there’s a range of effective preventive and reactive strategies we could follow.
Growing cannabis is a time-consuming process that requires patience and effort if great results are to be obtained. However, the path is full of obstacles that could jeopardize the safety of your plants, one of the most disturbing being the attack of a plague. Red mites can easily throw a wrench in your crop. If you really want to learn how to identify and combat them, make sure to keep on reading!
A much-feared mite
Most commonly known as spider mites, red mites (Tetranychus urticae) are one of the worst nightmares of cannabis growers and farmers in general. These tiny 4-legged arachnids can only be spotted with the help of a magnifying glass or a microscope. Females are red, with a rounded abdomen, while men are more pointed, with bright colors closer to pink. The reason why they make such scary enemies is their incredible reproductive potential and their devastating effects.
Besides, they're invisible to the naked eye. At best, we'll be able to see some small red dots that seem to move a little, but they're hardly noticeable. With an average size of 0.3 inches, females tend to be slightly bigger. That's why good monitoring is as critical to the early detection of the plague as having some knowledge on the signs of a spider mite infection.
Eating and suffocating is their thing
Spider mites are phytophagous mites; in other words, they feed on plant sap. But they're also highly polyphagous, meaning they're attracted to an array of plant species, including marijuana. If you happen to find like a white stippling, it will most certainly be the injury caused by the sucking out of the leaf's contents. Sometimes, these little spots could be black or yellow. A single spider mite is said to be able to bite over 30,000 times per day, which amounts to more than 1 million bites in just a month.
Another reason why they're actually so dangerous is for their tendency to spin protective silk webs with the sole objective of creating the perfect environment for them to thrive. The problem is that this webbing suffocates cannabis plants. Plants gradually turn yellow, dry out, and eventually die off.
So if you've noticed any similar changes in your plants, you should start working to get rid of them as quickly as possible. But remember: prevention is better than cure.
A good defense is the best offense
If no spider mites have still attacked your beloved plants, it may be time to take measures in order to keep them away for good. One of the best ways of doing it is with the help of other tiny allies, especially if you're an outdoor grower:
- Ladybugs, for example, are incredibly effective. To raise an army of ladybugs you can either buy them online or collect/attract a few wild specimens. Besides mites and aphids, they eat pollen, so if any nearby plants have flowers (fennel, dill, coriander or carrots are their favorite picks), they'll be happy to help you.
- Another predatory mite used against this pest is the one known as Phytoseiulus persimilis: these true killers continuously look for spider mites to suck out their body fluids. Although they eat spider mites in all their stages, they seem to have a special liking for the eggs. Adults can eat up to 7 spider mites and around 20 larvae and eggs in a single day.
- Cleanliness will also help you them at bay, especially in indoor grow spaces. Every time you introduce a new plant into your grow, say clones or fully-grown plants, make sure they're not bringing in any pests from outside. Disinfect your clothes and your skin/hair if you've been working with other plants too for the very same reason.
- Besides clean, your cultivation area must have a good airflow for spider mites thrive in stale air. An extra air circulation could be a great deterrent. Don't forget to buy some quality filters to stop any mite trying to get inside.
- And last but not least, keep an eye on the room's temperature and humidity levels. At temperatures higher than 80ºF, they reproduce at light speed.
You may also consider using an insecticide as a preventive measure. The market is packed with organic preventive insecticides to effectively ward off spider mites. If preventive action fails, don't worry. There's plenty you can still do:
- Ecotenona is a biological acaricide made from tropical plant root extracts that effectively combats aphids and whiteflies. It must be applied on the leaves so it can penetrate the nervous system of the spider mite. Neem oil, potassium soap, and pyrethrum oil are also very good choices.
- A less aggressive solution, but maybe a less effective one as well, would be the use of water. Spider mites, by nature, love hot and dry environments. Excess moisture can destroy the eggs and hamper their reproductive cycle. To give them a really hard time, make sure the grow room's relative humidity is always around 55-60%.
- Outdoors, rain will turn into your greatest ally. If you're growing indoors, instead, you can artificially humidify the environment. For doing so, you need to use a water-filled backpack sprayer (better if the water is cold). If you opt for this alternative, make sure you spray the underside of leaves for good, because that's where these mites usually hide out and start webbing.
Never forget the saying "better safe than sorry", though. Examine closely your plants on a regular basis in order to identify any signs revealing the presence of spider mites. Early detection is critical to the protection of your cannabis plants.