Phalaenopsis New Leaf Yellowed

[MarthaMD]

Hi All - this is my first post! I became the proud new owner of two different orchid plants given as gifts a few months ago. One is a Phalaenopsis which was doing beautifully until the past week. It flowered and the new leaf came out and looked perfect, until a few days ago when I noticed it was yellowing right at the crown. I do not think it had standing water within the crown at any time because I am careful when I water and it is protected from rain. It is outdoors right now and lately it has been in the high 80's to 90's. I water it a couple of times a week, give or take, when I feel the moss is dry.

Today when I inspected the plant I noticed numerous small gray insects on the plant. I do not know if these are mites or something else. They are visible to the naked eye and are on the leaves and stem and air roots. I have never noticed them before but I must concede I also wasn't looking that closely before because the plant was doing well as far as I could tell. When I took pictures of the leaves, I noticed the underside of the leaf is a dark purple color.

I took pictures to the best of my abilities so I will post them as well. Oh and I want to apologize about the bug spray in the first photo - I PROMISE that wasn't for the plant but rather for a large wasp nest in my outdoor storage closet! I just happened to set it there unthinking before I took the photo! Thank you for any and all advice - I am admittedly a hopeless newbie

[WhiteRabbit]

Hi Martha! I let some other people advise about your Phal - but I wanted to welcome you! I'm sure some other members will be able to help you

[RosieC]

Welcome to Orchid Board Martha.

The leaf looks to me like it's rotted, but that would normally be due to water in the crown which you have said is unlikely.

It's difficult to know what the bugs are. I had aphids on one of mine recently but there are a lot of other things it could be and I don't know much about bugs.

The red colouring in the first two pics look normal to me.

[Eyebabe]

Unfortunately, to me, it looks like crown rot which usually results in losing the orchid plant.
I would not give up yet though.
Bugs in the media imply it needs to be replaced and I would do that. I would in the process of repotting, cut off all the old rotted roots and any inflorescence/spikes.
I would also treat with 10% bleach solution or Physan 20 as an overall anti-fungal/anti-bacterial. If you have mosquito bits put some in the media as the usual "bugs" crawling in the media as you described are fungus gnat larva...however, you can do this later if necessary. Mosquito bits are a pretty common home and garden product; Physan 20 is a bit harder to find.
Watch it closely and if the crown continues to soften and that lead leaf "melts away" pitch the plant.
Also, keep it away from your other orchids while you wait...
Good luck

[camille1585]

I pretty much agree with all the above. The purple is usually normal expecially on young leaves, and the yellowing sure looks like crown rot. Sometimes despite being careful about not getting water in the crown it just happens that the one time there's a little bit in there (especially on a cool night) is the time you'll get issues.

One thing that does help stop the progression of crown rot is to pour a bit of hydrogen peroxide (it should be the 3-6% one) into the crown. Usually it'll fizzle a bit as it decomposes into O2 and H2O, and after a few minutes you can clean it out. It's a strong oxidizer, so helps disinfect and kill the rot. I would repeat it once a day for a few days, and then keep an eye on the plant. If you see the next top leaf start to yellow from the base outwards, then that's not good news.