Banrot in Aus
 

Hi, I'm getting a harsh lesson in Orchid hygiene after owning a greenhouse for 6 months with a large percentage of plants suffering Fungus from my overuse of a humidifier in Summer (my non greenhouse climate is normally 10-30% humidity).

I've seen a lot of comments regarding Cleary's 3336 use which isn't available in Aus, I understand the active ingredient (Thiophanate-methyl) is also present in Banrot which can be found in a few places here, and that its use in conjunction with Mancozeb will cover most scenarios.

The issue is the cheapest in can be purchased for is $330 which is more than I can spend right now (I've just spent $400 on Confidor tablets and spray for mealybugs).

I also have the Yates suite (Anti-Rot, Mancozeb, Liquid Copper and Rose spot gun) and Hyclor/Alganox (a Physan equivalent) which is working to an extent, but keep hearing most effective treatments generally have restricted availability through regulation.

Does anyone with experience have knowledge of a cheaper alternative here in Aus before I spend another $300 to get me out of this hole :(

Thank you

Fred ----- one good one is yates anti-rot phosacid. Cheap as chips, from bunnings. Cheap ----- but good.

OOPS ---- just noticed you have that one already.

Cleary's/thiomyl is probably not essential. If gentle air-flow can be kept up in the growing area, then hardly any need (or no need) for cleary's.

You have a decent collection in the kit already too :)

Thanks for that, I will stick with Phosacid as the systemic remedy. I recommend Hyclor from Bunnings ($7) it seems to be getting things in the right direction, Yates mancozeb has had a bad effect on a few of plants so will put that to the back for a bit.

On another not Eco oil has killed almost every plant I've applied it to remedy mites, so unsure what I'm doing wrong there :(

Most welcome Fred. Watch out for the oily type substances, like eco-oil etc. If it gets very bright and sunny, the oily stuff on the leaves can do some leave scorching or something - something maybe to do with localised heating effects - or the heat can't get away from the region ----- maybe.

Fred ---- what sort of orchids had issues with the mancozeb? I sprayed mancozeb on pretty much all my orchids - catts, dends, onc, everything ----- without issues. Just asking - so that if it does have bad effects on something, then at least I got heads-up on it.

See if you can get azoxystrobin. It’s sold as Heritage here in the US. It’s a good wide spectrum systemic fungicide.
My greenhouse stays in the 80% range all summer with the evaporative cooler and fogger going. I don’t have much trouble with fungus, but it may be due to the complete volume of the greenhouse being exchanged in less than a minute! Two circulating fans run 24/7.
Also, plants are dry by nightfall from the latent heat of the day.

Are you sure you are having rot problems? What was your humidity range last summer? Sunburn and blackening of new growths can be caused by overheating and underwatering. Many people confuse the look of sunburn and underwatering with fungus attack.

Thanks for the replies, I wish it was the heat, I encountered a couple of 44c days in Dec but can combat that with shadecloth and evap coolers. It's what I can't see that's tripped me up in what's now Winter here. The black spots tend to have yellow circles which spread.

Southpark - Mancozeb only affected a couple of plants - a Lycaste which I'm trying to save and a Rodriguezia which developed a black spots then yellowing, I think the plants may have been to sick so this took out the fungus which in turn impacted/browned the plant. I think it's more the white residue over all the plants which worries me and makes me think they can't transpire.

I'll look into azoxystrobin which seems to sell here as Amistar for farmers here. Thanks

Many Lycaste are winter dormant and drop all their leaves. As they're naturally dying they often get all kinds of ugly spots and patches.