What Might be Causing this Bud Blast/Flower Drop?

[vlhart]

Hello!

This Brother Sara Gold phal appears to be in some kind of distress. The flower you see has only been open for two days. As you can see in the backlit photo, the leaves of this phal are extremely thin, almost see-through. It had somewhat thin leaves when I bought it 2 years ago. In the spring/summer of 2015 it had a big growth spurt and grew 4 thin leaves and lots of roots very quickly (but no flowers). I did notice that during that summer, it seemed to be oozing sap from the leaves quite a lot but there was no sign of pests then.

This summer it grew one new leaf but all the leaves seemed to be getting thinner and duller (losing the sheen). I had a big thrips problem last summer in a different room in the apartment and found some in this plant, then in the fall I saw a few black/grey tiny mites in this plant and some others nearby but I no longer see that many. I treated it mostly by wiping the leaves clean, or submerging the leaves in water (carefully to avoid water in the crown) and trying to knock pests off.

It lost two leaves last week (one pictured here) before the first bud opened and another appears to be going leathery. Any thoughts on what might be happening? I'd like to save the other two buds if possible.

It's in a SE facing window that does get into the 60s at night, high 70s-low 80s during the day. It's possible that it had some cold damage as the leaves were touching the window at one point? The roots seem to be in great shape.

Thanks for any advice!

[url=https://flic.kr/p/RH5nvL]

[jkofferdahl]

To me your plant looks quite dry. How often do you water it, and how humid is the growing area? Phals have to store water in their leaves since they lack pseudobulbs, so it's natural that a dirth of water would thin the leaves.

However, your mention of seeing insects on your plants does lead to another possibility, though I think watering is a major player. When you treat for them, don't worry about getting liquid in the crown of the plant, just make sure that the liquid is air temperature or slightly higher. Though it's usually discussed that getting water in Phal crowns will almost instantly lead to rot and ruin, in reality it's not that likely at all. Cool water is the culprit. Also, if you keep the air moving around your Phals then such problems are even more significantly reduced. If you have bugs, kill them, then worry about the plant.

[Leafmite]

I have found my Phals do best when I soak the roots until they turn green. If they do not turn green quickly, I soak them longer and then water more often.

If you have non-orchids, it is important to get rid of any insect issues. They will keep re-infesting the orchids.

Unfortunately, many of the more powerful pesticides (Malathion, Sevin, etc) are not recommended for indoor use. If the plants do not produce fruit or edible leaves, you can use a granular systemic for roses. Just be certain to water very well so the roots of the plants are not burned and use a saucer to catch the water (and make certain pets and children do not have access to the saucer). These should not be used if you plan to use any part of the plant in your diet.

For the plants that do produce edible fruit or leaves, I have been experimenting with used coffee grounds. They need to be applied once a month but the experimental group has been clean for the past two years. It is also safe to use Neem oil and diatomaceous earth indoors with the edible plants and your orchids. That is what I have been using on the edible plants that have not been getting coffee grounds as well as the orchids (as they have not remained clean of pests).

Good luck!

[jkofferdahl]

For insects I am a user, and big proponent, of Diatomaceous Earth. Every couple of weeks I dust my plants with it and it takes out any and all little nasties. Plus, it's pretty safe.

[Dollythehun]

I've also found Bonide "Mite X" which is a botanical control for mites, thrips and aphids. But, I agree your plant looks parched.

[vlhart]

Thanks for all the responses! I typically water this one once a week, with a minute under the faucet, and then mist it everyday/other day until water begins to drain through. The roots always green up immediately. It also lives next to a humidifier I run every other day that keeps things around 50-60% humidity. On off days it's very dry - 10-15% humidity (New York radiators). I did recently cut back on watering however because I was beginning to think I was overwatering and I read somewhere that I should reduce watering in the winter (however with the dry heat in the apartment, perhaps I should water the same all year round.)

I'll give it a good soak in the morning.

[Cym Ladye]

You might want to check the component of diatomaceous earth. Some reports claim it may be carcinogenic primarily if inhaled.

[estación seca]

Yes, diatomaceous earth is dangerous when inhaled. It may be carcinogenic and it definitely can cause silicosis (miner's lung) if inhaled over time. Many other things we use have dust that is just as dangerous, including vermiculite, perlite, pumice, sphagnum moss and peat moss. It is best to make sure these things are wet when working with them, or wear a mask.

[dounoharm]

hi! I see a couple issues here...first is water...the media and roots seem extremely dry! i think you need to soak your plant a bit longer. maybe every 6 days or so. you might benefit by placing your plant on a plate of moist gravel. it seems your apartment is very dry inside, which happens in the winter....
containers like your brass one are very pretty, but could be dangerous if you pot sits flat on the bottom of it. I like to put corks in my containers, or you could use large pebbles or even marbles. that will provide a little more breathing space for your plant.
dry air, and a dry plant are the perfect storm for bugs. they will take over if you don't keep them in check! rather than spritzing with water, use a insecticidal soap, and get the underside of the leaves and the roots too...another option is to bag your plants, pot and all, and spray with a systemic every month or so....do it in a garage if you can.
you mentioned soaking...it is save to dunk the whole plant, just make sure the crown is dry afterwards....it is too tedious to do it another way, lol....I have left mine in a bucket for days sometimes....of course unpotted!
remember, orchids 'breathe' from stomata in the UNDERSIDE of the leaves, so always keep check on whats happening there....good luck!