Use pyrethrin products when the sun goes down! Save the bees!
(thrip leaf damage pics by theMallacht)
Can be used both as a topical spray, and can also be used directly at the roots. Spinosad is an organic insecticide made from the fermentation of a specific soil bacteria (actinomycete Saccharopolyspora spinosa) and kills thrips via ingestion or contact by affecting the insect nervous system. Spinosad can be a good choice for organic and outdoor growers, because it is very toxic to thrips, but is less toxic to many beneficial insects.
With soaps, coverage is very important as it does not stay on your plant for long, so follow-up applications may be necessary. Although this is considered safe, avoid getting any on your buds!
Pyrethrin based insecticides are not very toxic for humans and degrade quickly, which is why they’re commonly recommended for vegetable gardens. You will need a mister (also called a “One-Hand Pressure Sprayer”) to spray all the leaves evenly.
Neem Oil will leave an unpleasant taste/smell on buds when used to treat flowering plants, so don’t let this stuff get near your buds! There’s also some evidence Neem oil may be harmful to humans so use with care! That being said, Neem oil is an all-natural remedy that is very effective against many different types of bugs and mold. You will need a mister (also called a “One-Hand Pressure Sprayer”) to spray all the leaves evenly since neem oil and water can separate easily.
Pyrethrin products break down quickly, over the course of just a day or two. The major problem with them is they are very toxic to bees. Although cannabis plants generally don’t attract a lot of bees, please use this as a last resort, and also try to use it right after the sun goes down because bees sleep at night. This lets it start to break down before they wake up.
In their “nymph” (juvenile) form, thrips appear pale, fat and almost wormy from afar
They can appear with or without wings, depending on their stage of life
If you see tiny, wormy little bugs, dark winged insects or bronzed discoloration on the leaves, you may have thrips. Learn how to get rid of them!
As we already mentioned, thrips are a group of small insects (1-2mm in length) formed by several species which attack a large number of plants and cultivars. They are actually the smallest flying insects found around the world. The most common species found on cannabis plants is Frankliniella Occidentalis, which can be found almost anywhere and is also primary vector of a large number of plant viruses. If environmental conditions are optimal, they can produce up to 11-12 generations per year..
Thrips have two pairs of wings and are normally whitish/yellowish (adults are a little darker). They are found on the underside of the leaves, where they pierce the plant tissues to suck sap and lay their eggs. Their sucking action is easily visible at naked eye, since they leave silver-yeallow stains on the surface of the leaves (a little bit larger than those left by spider mites). Oftenly, these stains are the first visible symptoms of a thrip infestation on our plants. In the event that the population of thrips reaches a considerable number, we’ll also observe tiny black dots on the leaves, which are their droppings.
Despite it is not the worst pest for marijuana, thrips must be carefully identified and treated through a number of prevention and management measures, especially if we live in an area where these insects are commonly found.
Thrip and marijuana
We can also find thrip nets (as we can find mosquito nets) which are put on the air intake/outtake and thus prevent thrips from entering our grow room. This type of nets are mainly used by indoor/greenhouse farmers.
In the event that – depite our prevention measures – we find thrips in our grow room we can use any organic insecticide (they work great gainst thrips) every 2-3 days and until we see no signs of activity on our plants. Potassium soap and pyrethrins (chrysantemum extract) are excellent options. They’re even more effective when used together. If these products are not enough, we can use chemical insecticides like Confidor (Bayer), although we’ll only use this type of products as a last resort due their impact on the environment (and the grower himself).
Another option, much safer than chemical products, are biological control agents: we can find several natural predators of thrips oftenly used by farmers to prevent/eradicate an infestation of thrips. Ambliselius cucumeris and Ambliselius degenerans are normally very effective, as well as the Orius laeviatae bedbug. Remember that this type of pest control is much more effective in indoor grow rooms and greenhouses than outside.
Finally, and as happens often with pests and diseases, some cannabis varieties are more resistant to thrips than others, so using the most resistant individuals will ensure healthy crops free from insects.
Next we’ll tell you what are thrips, how they reproduce and what should we do to avoid an infestation of these tiny insects on our marijuana plants. At the end of this post, you’ll also see a spectacular video of a thrip eating spores of powdery mildew on a cannabis leaf.
How to treat thrips on cannabis plants While thrips (insects of the Thysanoptera order) are not usually a serious thread for our crops, thay can be a pain in the neck if not identified and