Systemic Fungicides - How often do you rotate ?

[ksriramkumar]

Hi,

How often do you rotate systemic fungicides. I have 2 formulations (carbendazim and thiophanate methyl) and as of now use one after the other after a gap of 3 weeks. I have heard from some of my friends that they use one formulation for 3 consecutive times and then shift to another for another 3 weeks and come back to first formulation. what do you do?

[78Terp]

I have not used any.

[Catt Mandu]

I guess "use at random" comes closest to describing how I use any fungicide of other disease/pest control (or more accurately, use when needed, adjust culture to improve conditions for the plants, then stop using the control when it is not needed).

[catttan]

I am with Catt Mandu on this.

[raybark]

I agree, a fungicide is like any other pesticide, and preventive treatment is to be avoided.

[Cjcorner]

I use one until it no longer is effective. I still end up with several bottles and every so often may throw something different in to shake things up.

[Carolla]

I haven't used one yet on my orchids. I tend to be very conservative in chemical usage - maybe because I grew up in the 60's and 70's and the hippie influence stuck!! lol

[stateless]

I'm with Carol on this, I'll use them if necessary, last time I sprayed was well over a month and a half, for fungus I use either a systemic or a topical and combined them at times for an overall measure, also use an Ortho rose pesticide and fungus

[plucker]

I use biological control and don't need fungicides. I let the good fungus eat the bad stuff and reap the rewards with increased growth.

[hulsey]

I only use Captan or Thiram powder when needed, like when there is a black spot. I use it straight and undiluted, the powder into the black spot, very effective in drying the bad stuff out, and stops any spreading. So basically I only use chemicals when required, and it's not often. No spraying, just concentrated application on the trouble spot, no air pollution.

Except for the occasional use of Physan to disinfect mounts. I could actually use hydrogen peroxide or alcohol, but physan is cheaper in the long run, at least in my area.

I echo the sentiments of others here who would rather make the plants stronger and more resistant to disease, as it should be.