can I save my cholla? scale problem

[warnersf]

seemed to happen overnight, my roughly three foot tall cholla is covered with a white and purplish coating, I'm assuming its scale. should I try and save it or remove to hopefully prevent spreading?

[Steve Johnson]

Not scale -- see this:

https://cactiguide.com/cactipests/#cochineal

That purplish coating definitely indicates cochineal insects. The systemic mentioned in the linked article is typically Imidacloprid. I give my potted cacti Imidacloprid soil soaks as a preventative every spring, and I capture the runoff so that I can take it to a home hazardous waste facility for disposal. If your cholla is growing in the ground, unfortunately I'd have to recommend against using Imidacloprid.

[abhikjha]

Thanks Steve! Sorry @warnersf for hijacking your thread a bit! I just bought Imidacloprid

(https://www.amazon.in/dp/B07RBW24YW/ref ... 8V7H1E3EC4)

My growing season is all year round, so I will use it probably before the rainy season as damp and wet weather may invite lots of pests. Currently I don't know for what reasons, few ants are roaming around my pots, especially on flowering ones.

Thus I have three questions:
1. The company is advising to use 1ml in 1L water. This dilution sounds fine to you?
2. Do they work against ants?
3. Can it be used as foliar spray?

[Steve Johnson]

Thanks Steve! Sorry @warnersf for hijacking your thread a bit! I just bought Imidacloprid

(https://www.amazon.in/dp/B07RBW24YW/ref ... 8V7H1E3EC4)

My growing season is all year round, so I will use it probably before the rainy season as damp and wet weather may invite lots of pests. Currently I don't know for what reasons, few ants are roaming around my pots, especially on flowering ones.

Thus I have three questions:
1. The company is advising to use 1ml in 1L water. This dilution sounds fine to you?
2. Do they work against ants?
3. Can it be used as foliar spray?

I did the math with your 17.8% Imidacloprid, and 1 ml per L should be okay, although 1.3 ml is better for soil soaks. However, I don't know if you can be that precise about it. Haven't a clue if Imidacloprid works against ants. And yes, it can be used as a foliar spray.