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What insects are friendly for cannabis grow?

The trick is to know your enemies from your friends and to keep allies nearby. Friendly forces like ladybugs and assassin bugs are generalist predators. Recruit them to feed on some of the most common invasive pests like aphids, thrips, and whiteflies.

Cannabis growers are predisposed to react to the discovery of bugs and insects in the grow-op with extreme prejudice. However, some insects in the cannabis garden can be the most effective form of front-line defence. In fact, some animals can also be great four-legged weed warriors, too.


An Assassin bug is small and flat with a long, moveable snout that can be folded up underneath its body. Its most characteristic feature is its red eyes. The most commonly found type is brown-black with light flecks on the cases of the wings. The females are about 3 mm in size and the males are a little smaller.

There are many species of bug, but the one most interesting to us is the assassin bug. Assassin bugs are in turn also dividable into a great many species, the one most interesting to us being the one called Orius.

When thinking of applying Orius you have to bear in mind that the assassin bug is sensitive to various chemical plant protection agents. So for example, you should not apply Nomolt (teflubenzuron) or Admire (imidacloprid) if you don’t want to devastate your Orius population.


The body of the lacewing is slender and elongated, and its colour is green to yellow-green. Lacewings look a little like mosquitoes, but the wings are much larger, and rounder and show their fine veins clearly. In rest, the wings are folded away on its back like a canopy, while in flight they glisten with a pearly sheen. It is certainly not a quick or agile flyer and it can easily be snatched out of the air. All four of its wings have the same shape and can move independently of each other. Lacewings are vulnerable; the wings are easily damaged, whereupon they will no longer be able to fly to the plants it feeds on.


Lacewings come in many species and sizes, the other well-known one being the Brown lacewing (Micromus variegatus), which is less common. The Green lacewing is found all over the world, with the exception of Australia and Antarctica.

It is handy that this lacewing eats enormous quantities of aphids, especially when they are larvae. The imago (adult) mainly feeds on the secretions of aphids (honeydew) and pollen. Females also eat the odd aphid, especially when they are pregnant with eggs. Aphids are the exclusive food of the larvae, which are veritable eating machines and look a little like the larvae of ladybirds.

The aphids are not actually eaten but sucked dry, as are red spider mites and whitefly, two other plant pests. In greenhouse horticulture especially, lacewings are used en masse to clean up aphid infestations. A single larva can gobble up to 50 aphids a day.


The eggs are laid in between aphid colonies and are on long stalks. These stalks are designed to keep the eggs clear of ants, which enjoy the honeydew secreted by the aphids, which they protect. The larva is broad and caterpillar-like and has a brown, irregular colour, three pairs of little legs and long, pincer-like mandibles (jaws).

Some species of lacewing larvae camouflage themselves with bits of plant or dead aphid in order to hide from ants. When after some time the larvae pupates a web is spun amongst the vegetation. There are two generations a year, and in the winter the imago hibernates, often in houses. During this resting period, the lacewing turns brown, but in the spring it turns green again.


The ladybird is a brightly coloured beetle, usually red or yellow with black spots. They have an oval, almost round shape. A large part of the head and thorax are covered by the neck shield, and its back end is covered by two wing cases (the hard main wings). Ladybirds congregate with other ladybirds. If they are endangered, they usually fall stock-still and refuse to move at all. They can also excrete a yellow fluid that tastes and smells very bitter. This fluid is not poisonous, but gives a good impression of being so.


The ladybird is a welcome partner in the agricultural world. The reason for this is evident: they’re aphid guzzlers. A ladybird can eat up to 500 aphids in a day. What’s more, they are in no hurry to move on so long as there are still aphids to be eaten (unless you chase them away). If you see a ladybird, just leave it in peace! Take note, however, that the ‘Lemon ladybird’ is not looked on so positively. This is a yellow variant with black spots. This doesn’t eat aphids but mildew. Even though mildew is a cannabis pest, the lemon ladybird is not much help; in fact, it’s a carrier and spreader of the disease.


Although they’re very desirable, it should be noted that the ladybird is a protected species in Belgium. People are therefore not allowed to catch them, kill them, collect them, sell them, transport them, imprison or disturb them. In other words, you can’t do anything with or to them. The above information, therefore, is only to be acted upon in countries where the ladybird is not a protected species.

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