Timing of topical and systemic fungicide use

[orchidhope]

If I apply a topical fungicide which I have on hand to my orchids how soon is it ok to apply a systemic fungicide which is on order to be delivered in a couple of weeks.

Thank you for any insight into their simultaneous use.

[estación seca]

I would suggest looking up the monthly growing recommendations at Motes Orchids in Homestead.

[Keysguy]

I guess the question I would ask is "why are you applying either"?

Do you have a fungus issue you are trying to resolve or are you just applying prophylactically?

I grow in the Keys and am not there with my plants all summer. 5 or 6 years ago, when I returned in Oct. I noticed the stems of several vandas covered in what looked like a black powder. I got the issue resolved and from that point to now I spray all my orchids with a solid application of Captan before I leave them for the summer and have had zero re-occurrence since I started doing that.

The fungus appears and particularly propagates in hot, humid and stagnant conditions. I am right off the open water so usually the "stagnant" part is not an issue for me with the constant trade winds and it may be that one particular summer was just not very windy and the fungus got started. I'm not there to constantly monitor so do I really need to do this annual application or not? I dunno, it seems to work but maybe the airflow has just improved.

I digress but understanding why you think you need to apply a fungicide is important to answering your question.

[orchidhope]

Keysguy,

Thank you for your probative question in order that you might provide a more meaningful answer.

Purchased my first ever ONLINE orchid Pot. Chief 'Sweet Orange' and my first post on this board was whether it was diseased and if I should ask for my money back as it had a black sheath at the base of a new shoot, where it emerged from a pseudobulb, plus it had a black spot with beige center and I was concerned it was diseased. Quarantined it, and watched it because although I have had orchids for some time, this is the first time I have ample time to attend to them to do them justice so am learning all I can about them. I also added a photo in that post that showed two green nubbins emerging from the new shoot which I would take as new active growing roots. Louis a senior member said he thought my photos showed a normal plant and the spot was just a scabbed over portion, which I have since researched and would presume he is correct on the scabbed over spot.



Interestingly, I have an old, old heavily overgrown Cattleya from 2001 which has been out in our direct sun and seasonal rains receiving no treatments or nourishment and it has SIX new shoots emerging and every one of them has this black sheath at its base, so I too am hoping the plant I received is still healthy and normal or my old one is quite tough.

I have come to think the chemical companies have put the black rot fear out there so that we purchase more chemicals and I overacted upon seeing ANY black on my new purchase.

If needed, I had read a topical fungicide will interact with anything it contacts where a systemic fungicide will provide future protection and it is a good idea to plan to protect orchids from future disease. I have a topical on hand now and a systemic ordered to be here in possibly 2 weeks hence the timing question on using them back to back.

I've got a fertilizing routine down pretty good but am quite lacking in protecting them or treating abnormalities other than with 3% hydrogen peroxide and cinnamon.

So appreciate your taking your time to respond since you are in the Keys. I now keep my orchids on an open air covered porch protected from direct sunlight by two layers of shade cloth as a good bit of sun shines on the exposure every afternoon so they only get dappled sunlight. Have a couple small fans moving air through them as well.

Trying to do my best and enjoying it immensely but a long ways to go before I feel competent in my understanding of their proper needs.

[Keysguy]

Gottcha.
Sounds like you've got things under control.

I just went and read your other post regarding your Cattleya. I think you are fine as well. Catts are tougher than you think. Especially growing them in the Keys because our environment is very similar to where most of them naturally occur. They seem to bounce right back no matter how much abuse they might be subjected to.

Just keep an eye on it. Regarding water, mine are in a shade house and get watered for 15 minutes every fourth day PLUS every drop of rain that naturally occurs. That means they get a lot of water during the summer growing season and not so much from fall to spring. If you are only watering once a week, I think you could stand to up that some but NOT if it's potted in a lot of sphagnum. Hard to tell from your pics but a Catt in the Keys wants to be either in a basket with loose coarse media (or none at all) or a pot with loose coarse media. They can drown and suffocate in sphagnum.

If it's in sphagnum and never gets any water other than what you provide, then once a week is probably OK but that can create other issues like it's tough to get super dried sphag to absorb any water at all after awhile. You're beter off in the Keys letting the Catt go "au natural" in the yard. Rainwater is their friend.

Whereabouts exactly in the Keys are you?