Preventing and Treating Fungal and Bacterial Issues in Orchids

Well after my last Blog post hurricane Ian decided to come and hit Florida. Before we talk about orchids, my thoughts and prayers are with those on the west coast that had the devastating brunt of this. We're running a donation sale where 10% of all our proceeds on sales from 10/1 to 10/7 are being donated to help those who need it most. 

Normally in Florida start to get our drier weather in September but this year it was the exact opposite. August was dry and September was wet, and I mean really wet. Add to that the amount of rain we got from Ian and you are talking weeks and weeks of almost nonstop rain. This rain was even at the worst time, night time, and did not allow our orchids to dry out. 

This much rain daily and at night is a recipe for fungal and bacterial issues like black rot or brown/soft rot. Root rot is also a problem in all our potted plants during times like this. So how do we help prevent these issues and treat them when they arise?

Basic Culture:

First lets talk culture and simply ways of growing that can help.

Spacing and air movement are crucial. Your orchids should not be bunched up and right next to each other. Now I know how this happened. You started with one orchid and now you have 100+ and no room to put them. Welcome to the club! Still it's best to keep all you orchids a minimum of 6" apart but preferably 12". This helps the air movement between them so they dry out faster and if the do contract and any issues it lessens the likelihood of spread. If you can have a covered grow area with a fan that is ideal but not always possible for most hobbyists.

Your watering schedule should always be in the morning. Do not water in the afternoon or evening. I know we went over this is the basic culture post but still it should be said here. If you're getting rain, stop watering!

Inspect your orchids daily. I like to do this in the morning with a cup of coffee. It's the best way to start a day imo! At the first signs of any issue separate the orchid in question and treat it.

Preventative Treatments

So you've set up your environment the best you can. Now what? Preventative treatments are key. In my previous post Fertilizer and Treatment Recommendations I have links to all the treatments I use and recommend.

As always follow all manufacturer guidelines and dosage requirements, spray downwind, and wear any necessary protective gear.

Physan 20 and Zeritol HC are both algicides, fungicides, and bactericides. Both are great to spray on your orchids when they are wet from a long multiday or nightly rain. I prefer Physan but Zeritol is an excellent choice for those who want to use a more homeopathic or natural treatment. These can be used often and whenever you need. Physan can damage open flowers and developing buds but a healthy plant will bloom again so it's sometimes a sacrifice I'm willing to make. Remember to not use the same sprayer for Phsyan and Zertiol that you use for anything else.

The last preventative treatment is The Cocktail:

“The Cocktail”. This is a preventative measure to keep all your orchids healthy and safe.

What is it? It’s a mixture that treats and prevents thrips/bugs and funguses and works both topically and systemically.

When should you use it? Use it for your outdoor plants only, every six to eight weeks. Use a pump sprayer, not the Ortho Dial-n-Spray.

All ratios are per gallon.

• Orthene ½ TSP -Orthene Turf Tree & Ornamental Spray is a broad spectrum systemic insecticide that controls many different species of both sucking and chewing insect pests

• Banrot 2 lbs or Thiomyl ½ TSP - These are systemic broad spectrum systemic fungicides (40% Wettable Powder) effective in controlling damping off root and stem rot diseases caused by Pythium, Phytophthora, Rhizoctonia, Fusarium & Thielaviopsis.

• Spreader Sticker 1 TSP - Increases residual activity of sprays by preventing wash-off

• Southern Ag Dithane M-45 or Protect DF 1 TBS - A topical treatment for leafspots, rust, botrytis, anthracnose, early and late blights, and downy mildew

The day or several days, depending on the orchid, prior to applying The Cocktail I recommended to not water. This ensures your plants are thirsty and absorb as much of the mixture as possible, part of the mixture is systemic. Apply it twice back to back just until you get run off from the roots. Do not water or use Physan for 24 hours after to avoid rising off the products.

Now what?

Well, the best laid plans of mice and men and all. Even with doing all the right steps you can and will still have problems. So you found an issue on your orchid. First what is it? I'll do a future post on common problems but for now the Staugor Orchid Society Pests and Diseases pdf is a great start.

For most of these problems, with a sterile tool cut off the infected area at least one inch past it or one bulb back. Treat the cut with a paste made from Banrot and Dithane. If you do not have these spray it down with Physan or Zeritol. Then dry the orchid out for several days. Keep it away from the rest of your collection and monitor it closely. If you see any spread or residual issues try again but know when to call it quits. I love all my orchids but I see so many people trying to save plants that are putting the rest of their collection at risk. I will simply not do that but that is a personal choice.

Feel free to message or email me with any questions. If you have pictures of the orchid in question please send them. 

Happy growing!