I’m trying Alocasias again after finding this method with Sphagnum & leca. However, when I got home from the plant store with my newly bought Alocasia cuprea, I found out that it had thrips. I thoroughly showered the plant and removed all the soil (microwaved for later re-use) and repotted with the new method. I couldn’t find any more thrips after that, but to be safe I wanted to try a mild insecticide.
A retired botanist in the comments under this video recommended a 200 mL leaf spray using 13 drops of lavender essential oil, 19 drops of lemongrass essential oil and 5-7 mL rubbing oil (to emulsify). I don’t have lemongrass oil, but I do have lavender and a few other somewhat insecticidal oils. Also, instead of rubbing alcohol I have bio-ethanol which I think should work similarly well as an emulsifier and contact killer for some pests.
So I’m trying this leaf spray:
- 32 drops of essential oil (~0.8%):
- 15 drops lavender (somewhat effective against thrips as well as mites)
- 9 drops rosemary (mostly effective against spider mites)
- 5 drops tea tree (antifungal, effective against spider mites)
- 3 drops lemon (somewhat effective against thrips)
- 6 mL 95% bio-ethanol (~3%)
- 2 drops of mild dish soap
- distilled water to 200 mL
It does smell nice, although I know it’s not very healthy to inhale so I spray somewhere with good ventilation that I know nobody will be in for a while. Also citrus oils can cause phototoxicity so I should only spray in the evening.
Let’s see if the plant survives the repotting and leaf spraying, and if the pests stay away so it can graduate from quarantine.