swim Posted November 18, 2019 Hi all, I bought a dual-action insecticide/fungicide mixture containing myclobutanil as fungicide and tau-fluvalinate as the pesticide. I read about this tau-fluvalinate and it turns out that it is a pyrethroid insecticide, meaning it is a different molecule but structurally similar to pyrethrin. I read here that pyrethrin burns cacti but couldn't find info on tau-fluvalinate. Anyone had their cacti burn after using this chemical? Cheers *I went systemic to treat some nasty rot caused by mold possibly due to the long time a cutting spent in postage. I noticed the woody tissue in the vascular bundle was somewhat affected even though the rest of the section looked pretty healthy: This is the vascular bundle after my first cut (notice the darkened woody tissue) And this the vascular bundle after my second cut Do you think this is a legit cause of concern or should I just sulfur it and let it dry ? I heard the remaining fungus can move up through the woody tissue so I would like to make it 100% clean. Share this post Link to post Share on other sites
Evil Genius Posted November 18, 2019 (edited) Hey mate, it looks perfectly fine now. Leave it as it is. If you keep it at a not too cold place with low air humidity and lots of fresh air it should be alright. If not post it again. About the pesticide. Haven't used it before, but definitely possible it causes burns. Don't ever use pesticides in direct sunlight. Also make sure to follow the dosage recommendations religiously. Bye EG Edited November 18, 2019 by Evil Genius 1 Share this post Link to post Share on other sites
swim Posted November 18, 2019 Thanks EG, I am aware of the magnifying glass-effect of the sprayed pesticides/fungicides and avoid it alltogether. I sprayed a small trich to test the effects of tau-fluvalinate and will post again to share the results. As far as I understand certain chemicals (like pyrethrin) can trigger a reaction that results in breakdown of cactus tissue into brown or black mush. My plants spontaneously develop these patches of black blisters with exudates very similar to what people report after chemical applications. Makes me wonder if all cases of "rots" are really due to infections or cacti are just exposed to chemicals that disagree with their tissues. Share this post Link to post Share on other sites
swim Posted November 26, 2019 (edited) * Tested out fluvalinate on a small bridgesii a week ago and to my observation it did not affect the plant. Today I sprayed a pup and a fresh tip growth on the same plant to see if newly growing tissue is sensitive. Pachanoi, bridgesii or peruvianus did not react to this pesticide pup or adult. I haven't tried it on a fresh cut section or very small seedlings, but it looks safe otherwise. Edited December 21, 2019 by swim Share this post Link to post Share on other sites