Effective against many pests, Spinosad is particularly good at controlling and thrips due to it killing both the adults and larvae. The mode of action is that it attacks the nervous system of the thrips what leads to paralysis and death.
Thrips have the ability to build up a resistance to pesticides due to their short generation time, high fecundity, and a haplodiploid breeding system. Due to tight controls within the UK, not many pesticides are available to the home grower. There are many brands that contain the same active ingredient. Mostly these contain pyrethrums or maybe cypermethrin what is a systemic pyrethroid. The trouble with this is lots of people use them in their gardens and the thrips quickly build up a resistance. This has already happened to Spinosad within some areas of the USA as Spinosad has been approved there since 1993. This is what makes Spinosad perfect for us UK growers as it’s not available to the general public unless you really search for it so it’s still great for wiping out thrips as well as other pests within the UK.
Spinosad is a great choice for the indoor cannabis grower for the following reasons.
• Has a long residual effectiveness of 5 – 7 days when applied correctly
• Is effective against many pests but won’t harm many predatory mites
• Has a very low toxicity to mammals
• Can be applied up to three days before harvest
NOTES:
- You should only use Spinosad a maximum of three applications when controlling thrips as they can and will build up a resistance to it. One to two applications should be more than enough but heavy infestations should be controlled by rotating between pyrethins or something light like S&B Plant invigorator or Canna Cure. A ten week break should be taken after applying more than twice.
- Spinosad should be applied just before lights out.. It will hang about for a while as long as it's not exposed to high levels of light while suspended in water.
I can’t recommend an off-the-shelf brand atm as it’s not really available like that in the UK but you can grab a bottle of Conserve SC on ebay for about £18 or there is another guy selling it in smaller doses but what he’s selling is Spinosad suspended in acetone. This is normally used as flea spray but he also sells it as a pesticide. His is fine to use too but you should bare this in mind if you’re mixing the Spinosad with other products. From what I’ve read, the acetone shouldn’t cause any issues with other products like Bacillus Subtilis but I’ve not the knowledge or the equipment to know for sure. I’ve been using it and it seems fine and the thrips are all dead.
I hope this helps someone out because thrips are out in force this year and I had massive problems killing them. My usual routine of pyrethrins and cleaning up the infested leaves didn’t even really make a dent. They were swimming in the stuff, laughing at my futile attempts to kill em. Spinosad wiped them out real quick :D
Ebay link: https://www.ebay.co.uk/itm/264835996328