Orchid Culture Questions and Answers
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Questions and Answers from 2015
by Sue Bottom, from the St. Augustine Orchid Society Newsletter
Email us with any orchid question, if we can't answer it we'll find someone who c
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Crusty Bumps on Leaves
 

Crusty Bumps on Leaves
Q. I have something going on with a couple of my orchids. The sap on the leaves is sticky and clear and there are also crusty bumps on the leaves.
A. That is armored scale. If you have just a few plants, you can wipe it off with a Q tip soaked in isopropyl alcohol. You'll have to watch the plant carefully for the next few weeks to make sure you have found and removed all the scale. There are a lot of chemical sprays and drenches that can also be used. (Dec-15)


Keikis on Dying Mother Phal
Keikis on Dying Mother Phal
 

Keikis on Dying Mother Phal
Q. I have a phalaenopsis orchid that appears to be dying. The leaves are wrinkled and turning yellow and there is no root system. However it has sprouted three keikis perhaps in a last ditch attempt to 'save' itself. What can I do to keep the mother orchid alive long enough to re-pot and keep the keikis?
A. I think your root system is compromised. Check to see if the plant is very wobbly in the pot. You can probably bring the plant back to life if you repot it and nurse it back to health, but you will have to make a decision about whether or not to cut the spike with keikis off because that is consuming resources that the plant could otherwise use for growing new roots. The keikis will probably not survive on their own because roots have not yet formed, though you can see the swelling at the base of the keiki that will be a new root. I have heard of people who place the spike with keikis in a vase with water and the keikis have continued to grow, though this is the exception rather than the rule. Best for the mother is to remove the spike and repot, using a small pot and New Zealand long fibered sphagnum moss. The sphagnum encourages root growth. If you canít bring yourself to cut the spike, maybe theyíll all pull through the repotting experience. (Dec-15)


Top Leaves Yellowing on Phal

 

Top Leaves Yellowing on Phal
Q. This phalaenopsis is not having a good day. It has been healthy for years. It just finished flowering, and the very center of the plant was a bit yellow. so I cut off the flower spike. Then BAM it's totally yellowed and dying, can it be saved?
A. Iím afraid your plant has crown rot. The growing heart at the center of the plant has died for some reason, often it is caused by water standing in the crown of the plant. That little side shoot above the green leaf may be a flower spike, but Iím hoping it is a basal keiki, a new plant trying to grow to replace the mother plant. The best thing you can do now is remove those yellow leaves, pour hydrogen peroxide all over the plant to kill any bacteria (the crown rot is caused by bacteria), and then watch that new basal keiki. Once it starts to form roots that will sustain the plant , you can think about separating mother from pup and potting it up. (Dec-15)


White Spheres on Long Filaments
 

White Spheres on Long Filaments
Q. There are some strange white spheres on long filaments on this Brassavola nodosa. What are they?
A. Those are lacewing eggs. According to Planet Natural "the common green lacewing (Chrysoperla rufilabris) is a widely used beneficial insect which naturally controls many different pests. Actually, most species of the adult lacewing do not kill other insects but subsist on pollen, sweet nectar, etc. It is their offspring or lacewing larvae that do the job. The adult lacewing lays her eggs on the foliage, each on top of hair-like filaments. After a few days the eggs hatch and a tiny larva emerges which is also known as the ďaphid lionĒ because of its voracious appetite... Besides aphids, they feed on just about any soft-bodied pest they can ďgrab,Ē including citrus mealybugs, cottony cushion scale, spider mites, thrips, caterpillars, insect eggs, etc." (Nov-15)


To Pot or Not Repot My Phal
 

To Pot or Not Repot My Phal
Q. I wonder what's best to do once an orchid begins to look like a palm tree at the bottom? I find that terrarium bark, available in any pet store, is sterile and of the right consistency to do a good job when repotting.
A. That is a really nicely grown phal, it has 8 beautiful green leaves and it doesn't get much better than that! The potting mix looks like it's getting a bit old so it probably should be refreshed, but you don't want to disrupt the bloom cycle by repotting. You'll have to check to see how wobbly the plant is in the pot. If it's not wobbly, leave it be until after it is done blooming. If it's very wobbly in the pot you'll have a decision to make, best for the plant to be repotted but not best for this year's blooms. You may be able to repot without disrupting the roots too much if you water wash the mix away from the roots and then just drop new mix into the pot or drop the roots as is into a slightly larger pot and backfill with fresh mix. You'll have to trust your instincts! (Nov-15)


Leaf Spotting on Oncidium Alliance Plant

Leaf Spotting on Oncidium Alliance Plant


 

Leaf Spotting on Oncidium Alliance Plant
Q. Can you tell me what this is on the leaves of my Degarmoara (Dgmra.) Memoria Jay Yamada? How can it be treated?
A. Get some copper and spray all the leaves, just move any dendrobiums away from the area you are going to spray because they don't like copper. More important is figuring out how the bacterial/fungal infection occurred, too much leaf wetness? not enough air movement? Look at your growing area and see which ones seem to have the leaf spotting and which ones don't. Perhaps there is something different in the environmental conditions that can be changed going forward. Make a note to yourself to spray plans preventatively next year, perhaps monthly in August and September to protect the plants from infection. The best kept secret is that fungicides work as a protective armor from infection, very few of them can actually cure an infection once it is inside the plant. At that point, the best you can hope for is keeping it from spreading. (Nov-15)


Cattleya Turning Brown from the Roots
Cattleya Turning Brown from the Roots
 

Cattleya Turning Brown from the Roots

Q. My Cattleya has started turning brown from the roots upwards. Yesterday it seemed that only two were affected today it has spread. What is wrong with it? I only water once a week. My other orchid is fine. Is it dying?

A. That is the evil black rot, the bane of the Florida cattleya grower during our hot humid summers. Black rot is caused by one of the water molds, it is very fast moving and very deadly. Are the pseudo bulbs soft, watery and smelly? I think the rot has traveled too fast and too far for you to save the plant. I stopped repotting cattleyas in the hot humid months of July and August because inevitably some of the transplants would get rot. Letting the plants go to a hard dry in July and August can also help prevent infections. If you catch it quick enough you can cut out the infected tissue and pour some peroxide or better yet one of the specialty chemicals through the plant and keep it on the dry side. (Oct-15)


Phal Leaves Look Dehydrated
Phal Leaves Look Dehydrated
 

Phal Leaves Look Dehydrated

Q. Iím trying to revive a phalaenopsis for a friend. It was in old, decomposed potting mix and most of the roots were rotten. I trimmed off at least 3/4 of the roots, put it in new mix (bark, lava rock, perlite) and in a new clay pot. It lost all the original adult leaves, which I expected, but now it is continuing to lose leaves. Each one goes through the same process, the surface of the leaf looks withered, then it droops, and then dies. There is no evidence of lesions, spotting, etc. I have the plant on my table in the pool cage where it gets indirect light. I have been watering it every 3-4 days and I make sure the mix is dry before rewatering. I use filtered water, also fertilizer and epsom salts every 3 weeks or so. It had a small new leaf when I got it. That leaf has grown and it has a second new leaf. It is regrowing roots and has beautiful healthy green root tips. I suspect it is getting too much or too little water, but I don't know which.
A. You are making all the right moves. Your plant is just recovering from the transplant shock and returning to health, regrowing roots and beautiful green root tips. Sometimes bark is hard to hydrate when you first use it so you have to water a little more frequently than you otherwise would, and a shot of seaweed/kelp or any of the root stimulators will encourage root growth after repotting, but the fact is the plant looks like it is returning to health and starting to grow again. Weíll have a second growth spurt in the fall after the temperature and humidity mediate so you have another 6 or 8 weeks of growing before it will start thinking about blooming. It looks great and is recovering very nicely. Keep up the good work! (Oct-15)


Strange Growth on Dendrobium
 

Strange Growth on Dendrobium?

Q. We bought this orchid last March and after all the flowers fell off it started this slightly amazing growth pattern. What is happening?

A. It looks like twins! Looks likek this soft cane dendrobium has produced two keikis for you. You can gently twist or cut the new plantlets from the mother plant cause the roots are long enough to sustain the plant. In fact, theyíre so long you may have to soften them up so youíll be able to get them into the small pot dendrobiums seem to love. Wet the roots a couple of times over the course of an hour or so and situate them in a small pot, you can even plant both keikis together in the same pot for twice the fun! (Oct-15)


Sobralia macrantha
 

What Orchid is This?

Q. Can you identify this orchid?

A. Our best guess is Sobralia macrantha. Itís beautiful. (Sep-15)


Cattleya in Sheath with New Growth
Cattleya in Sheath with New Growth
 

Cattleya in Sheath with New Growth
Q. My cattleya has grown a new pseudobulb and sheath for the last few months, though I don't see any trace of a bud in the sheath. Now I notice that another old pseudobulb has sprouted a second pseudobulb. Does this mean that the first one is not going to develop a flower, or can there be two flowering pseudobulbs at the same time? I thought that cattleyas only send out one pseudobulb at a time.
A. Your plant looks great! Some cattleyas bloom from a green sheath, which just means the flower bud emerges from the sheath soon after it forms, and some bloom from a dried sheath, which just means the orchid takes a rest after it forms the sheath and the flower bud will start growing a few months after the sheath forms. It looks to me like a flower will be produced from that healthy growth, so just be patient unless the sheath starts to turn a sickly yellow or brown in which case you may have to slit it so the bud will not rot from inside due to condensation from day night temperature changes.
The new growth also looks good, it wants to produce a new lead that will also hopefully bloom. Orchids can send out more than one pseudobulb at a time and bloom from many pseudobulbs at one time. Some tend to grow along a line like an iris, some branch and form multiple leads. You would think that the multiple pseudobulbs that bloom simultaneously would be forming at about the same time, but you'll just have to wait. Keep doing whatever you're doing, and hope you'll get blooms from both at the same time! (Sep-15)


Sobralia macrantha
 

Yellow Spots on Leaves?

Q. What should I do about the yellow spots on the leaves?

A. Whenever you see yellow chlorotic spotting on leaves, turn the leaf over and look at the undersurface. If you see a patch of scale you have your answer. Then you'll have to look for signs of scale on other parts of the plant, particularly on the pseudobulbs under the papery sheath, in leaf axils, etc. You can spray the entire plant with isopropyl alcohol though you'll have to retreat weekly for several weeks. Check out the orchid pests page for other home remedies as well as insecticides that are effective on scale. (Sep-15)


Yellow Phalaenopsis Flower Fades
 

New Phalaenopsis Flower is Much Yellower than Older Flowers
Q. I have had this orchid for a few months now. It's really healthy and hasn't lost any flowers. It recently started to bud again and all the new flowers are a darker yellow when they open than the original flowers. Why?
A. The early yellow phal hybrids were notorious for opening one color yellow and then fading over a week or three to a much paler color. Perhaps that is what is happening although it seems to be a pretty extreme difference in flower color. The other side of the coin is that it usually takes a flower 3 days or so to develop its full flower color. (Aug-15)


Bacterial Damage on Phal Leaf
Bacterial Damage on Phal Leaf
Bacterial Damage on Dendrobium Leaf
 

Phal and Dendrobium Leaves Damaged when Forming
Q. I am attaching pictures of some of my phalaenopsis that shows new leaves that are badly damaged. I have several phals that showed the same markings as soon as the new leaves appeared. What's strange is that the leaves of the 4 different plants affected are the newest one and all about the same size. I am growing the orchids on my covered patio and don't have kids or pets. I repotted the plants about a month ago so could it be that I damaged the roots during that process? Is that the result of spider mites? I didn't see any mites or webbing. I have tried spraying insecticidal soap and alcohol without results. May I also show you pictures of my dendrobiums that were doing fine and just last week the leaves started to yellow in places and the back of some have indentations that appear whitish.
A. I donít think it has anything to do with the repotting, root damage or spider mites. The new tender leaves were damaged somehow while they were forming and the scars simply enlarged as the leaves got larger. Weíve ruled out mechanical damage. I suspect the problem was you had rainwater or condensation pooling in the crown of the phalaenopsis and the emerging leaves from the dendrobium cane, and bacteria invade the water and cause the rot. You can do a number of things, peel the sheath down, blow the water out with a can of compressed air, keep hydrogen peroxide handy and spray or drip a few drops in, etc. Walgreenís sells a real handy sprayer with hydrogen peroxide that you can refill. (Aug-15)


Catasetum has Keiki and No Roots
 

Catasetum Has Keiki and No Roots
Q. This catasetum keiki has grown out of the top of the pseudobulb and the longest root is about 2 in long. I'm thinking it is time to plant this but how? Some folks have told me to plant the whole pseudobulb about 1/2 way in the media and let the new roots find their way down to the media. But I'm concerned that way will rot the whole pseudobulb. Should I try to remove the keiki from the old pseudobulb and plant it? Do I discard the old pseudobulb or let it just sit and hope it grows more keikis even though it has no roots?
A. You can do either thing with the catasetum. One option would be to lay it horizontally halfway buried in a shallow bed of sphagnum, but of course the keiki would then be facing in the wrong direction. Is the pseudobulb hard throughout or is it soft at the base? If itís soft at the base, it is probably starting to decline in which case I would probably cut the pseudobulb about 2 nodes down and plant the keiki with the attached pseudobulb (which is still feeding it) vertically into your potting mix and let it develop into your future plant. Then you could try for more keikis by laying the remaining piece of the pseudobulb horizontally and hoping that more keikis sprout up from the nodes. The underlying question would be what happened to the roots on the big fat pseudobulb? I think I might see a slight yellowing at the base of the bulb so Iím guessing it might be declining in which case Iíd perform the surgery to give the little guy the best chance for survival. (Jul-15)


Phal Leaves Yellowing at Base
Phal Leaves Yellowing at Base
 

Phal Leaves Yellowing at Base
Q. I got this as a gift and realized a week ago that it was not doing well. It seemed over watered and I have left it in relatively dark area. Just got rid of all the potting material, cut away some rotten roots, and took some pictures. Do you think it can survive?
A. I think that orchid is a goner. It looks like it has crown rot, where the growing heart of the plant is invaded by bacteria and killed. See how the leaves yellowed from the base up and how the central part of the plant is not firm? Itís possible a new side shoot could develop, and if you want to try, cut off the flower spikes and see what develops but itís only a 5 or 10% chance and you might just read it its last rites. (Jul-15)


Pimply Looking Buds
 

Pimply Bumps on Orchid Buds
Q. Here's a picture of the buds on my cattleya, they are pitiful. They look pimply. What could it be?
A. It's hard to tell from the pic. If the bumps are raised and they look like tiny warts when they open, it's edema, which is caused by watering late in the day when the nights turn cool. It sort of looks like something has been munching on the bud from the pic though, so the usual suspects would be either slugs/snails or thrips. You can lay a piece of apple or potato out on top of the pot and go out with a flashlight before bed and see if you have attracted slugs/snails to the bait, in which cause you'll have to start spreading slug/snail killer around. If it's thrips, get ready for a war because they are really tough to get rid of. (Jul-15)


My New Phalaenopsis
My New Phalaenopsis

 

My New Phalaenopsis
Q. For my half century birthday recently I received an incredible orchid with 38 flowers either in bud or bloom! Sitting in my air conditioned office in full sun in a small pot it seems most happy. However, it has a growing patch of leaf that is shriveling and looks very life threatening. I would prefer a home type treatment rather than powerful chemicals if at all possible.
A. I think you have a few things going on. That one leaf looks like the beginning of sunburn, shield the plant from direct midday sun. They are shade loving understory plants and canít take midday sun, even insides. Be careful not to water until the sphagnum moss approaches dryness. Donít water on a set schedule, water when the potting mix is drying out. When the plant is done blooming, find someone to help you repot it, either at a local orchid society or nursery. That mix looks like itís served its purpose and is ready to be refreshed. (Jul-15)


Raised White Streak on Phal Leaf
Raised White Streak on Phal Leaf
 

Raised White Streak on Phal Leaf
Q. Have you ever seen this? I've not been able to find any pictures on any site with this raised line/vein. This orchid is very healthy, fast growing, large leaves, and it blooms often. Have you ever seen this?
A. That is one healthy and happy looking phalaenopsis. I think that raised streak is just a weird mutation that happened as the leaf was growing and expanding rapidly. I don't think it's anything to worry about, you're doing a great job. (Jun-15)


Vandas Don't Bloom
 

Vandas Don't Bloom
Q. I have had two vanda plants for three years. They are very healthy but they don't flower. What could be the problem?
A. If they're not flowering, they're not getting enough light. They look nice and healthy and they're growing well. But they're growing next to flowering phalaenopsis that like perhaps a third as much light as vandas. Move them slowly into brighter light so you don't sunburn them. (Jun-15)


Does Sticky Substance Mean Mealybugs
 

Does Sticky Substance Mean Mealybugs
Q. I purchased a new Den from a nursery on Saturday. I have repotted it with fresh media and inspected it for any pest issues, Today I was inspecting it again and saw a glistening sticky substance on a single leaf under a bloom. I rubbed around the bloom stem and it was sticky. I do not see any sign of mealy bugs crawling around.
A. That sticky substance is plant sap, sometimes called "honeydew" and sometimes a vigorously growing plant simply exudes the plant sap. Other times a sucking insect like scale or mealybugs might pierce the leaf and cause the plant sap to be exuded. If you have inspected and find no signs of pests and your plant looks healthy and happy, just kick back and enjoy the flowers! (Jun-15)


Lower Leaves Droopy on Phal

 

Lower Leaves Droopy on Phal
Q. Several of my phals have lower leaf loss, starting with droopy leaves which then become yellow and die. They are starting to make new leaves at the top of the plant and have bloomed beautifully this season so I think they are otherwise healthy. This one has 3 of the lower leaves that are droopy. I let them totally dry out before watering and they could be getting too dry.
A. That phal is in lava rock isnít it? You should probably be watering every 2nd or 3rd day. The roots look find so my guess is that you need to increase your watering frequency. Iím not sure but that your leaf yellowing is from too much sun, they shouldnít get direct light between around 11 am and 2 pm, maybe you should move it to a shadier location or closer to the house. They yellowing appears to be on the higher points of the leaf where you would first see the sign of sunburn, so you may not be so bright to cause sunburn but bright enough to cause chlorophyll damage. Your plants are gonna be fine, just a little fine tuning. (Jun-15)


Paph's Pouch Dried Up

 

Paph's Pouch Dried Up
Q. I have a recently bloomed Paph. Petula's Glory that's bottom cup dried out. This happened overnight and I don't know why, what can I do for this not to happen?
A. Water must have gotten into the pouch. If water gets into the pounch, it starts to rot greatly reducing the flower life. You have to be careful when watering or misting to not get water into the pouch. In nature, the dorsal sepal often leans over the pouch to prevent rainwater from accumulating in the pouch. (May-15)


Bought Orchid on Ebay
 

Bought Orchid on Ebay
Q. I just bought this plant on Ebay and it arrived with discoloration on one of the leaves. One is sunken and goes completely through. I sent a picture to the seller on Ebay and he says the plant is fine. Can you identify the problem?
A. There are good orchid vendors on Ebay, but perhaps you should strike that vendor from your list for future purchases. The brown and black parts look like heat damage or sunburn. Pull it out of the pot and cut off the back ugly pseudobulbs, water blast it with the hose end sprayer set on flat to remove any papery sheaths and any scale that may be hiding underneath. Pour hydrogen peroxide over the above ground part of the plant to kill any bacteria. Put it in fresh mix and pour a drench of imidacloprid through it just in case there is lingering scale. Then wait for it to grow new leads and gather strength. (May-15)


Chlorophyll Damage from Too Intense Light
 

Chlorophyll Damage from Too Intense Light
Q. Do you have any idea of what is causing the yellowing of the older leaves on this cattleya? The division of the same plant immediately adjacent to it does not have this symptom.
A. That yellowing is very different from the leaf yellowing youíd get if an older leaf were dying. The yellow marks are on the highest points of the leaf, which would suggest that itís increasingly bright light that isnít bright enough to sunburn but is bright enough to damage chlorophyll. Thereís not much you can do but wait for the plant to grow new leads and leaves. (May-15)


Before and After Pictures of Prosthecea radiata
Before and After Pictures of Prosthecea radiata

 

Before and After Pictures of Prosthecea radiata
Q. I have read that Dithane M-45 (1.5 tbsp/gal) can be mixed with Thiomyl (1.5 tsp/gal) to treat possible Fusarium on my Prosthechea. Do you have any suggestions for what to do with my plant?
A. Thiomyl is actually repackaged Cleary's 3336 (thiophanate methyl) and it will work on fusarium although whether it can actually fix a fusarium infection is questionable. I don't believe Dithane will do anything to fusarium, it is for leaf spotting fungi. When I look at your huge prosthechea, I see rhizoctonia rather than fusarium. It may be time for surgery and a thorough drench with Thiomyl which is labeled for both fusarium and rhizoctonia. Our Miami friend sent a before and after picture, finding a lot of new roots and growths in the process, great job! (May-15)


Vandas Losing Lower Leaves

 

Vandas Losing Lower Leaves
Q. I'm having some accelerated lower leaf loss with one of my vandas. It has produced 3 to 4 new leaves since November and it even has 4 big healthy new roots. However, since the end of winter, it has started having yellowing of the lower leaves, and has lost 4 to 5 leaves. It is hanging with my other orchids, getting lots of sunlight and good air movement.
A. I would say the lower leaf loss is due to the cooler weather rather than anything you have or haven't done. The vandas with a lot of the big two toned sanderiana in the background really don't like to go below 60F while the ones with coerulea and tesselata in them are much more cold hearty. They can probably drop below 50F without missing a beat. I'd say it's just the vanda's parentage coupled with the recent cold weather that has caused the leaf yellowing, but it'll probably grow keikis at the base of the plant so it will fill out for you. (Apr-15)


New Growth on Phaius Rots
 

New Growth on Phaius Rots
Q. The Phaius has now done this twice, has new growth that looks good, and then rots off at the base and falls off. I thought maybe I was overwatering, but I only water once per week typically and maybe twice in the summer. They all start with good looking new growths, but then they get a lot of brown spots in the leaves and they never really develop a full sized leaf and pseudobulb.
A. We turned to George Hausermann of EFG Orchids who grows a lot of Phaius, who responded: I would check in the pot and see how the root system looks. Chances are that the roots are rotted and causing a systemic infection, most likely bacterial. Repot the orchid and apply an antibacterial drench. (Apr-15)


Phal Bloom Spike Died in Middle
 

Phal Bloom Spike Died in Middle
Q. I live in Massachusetts and I've had my orchid plant in the window. I'm wondering if it got too cold one night, because half way up the bloom shoot it seems to shriveling up! I also had the plant clip on it, but I didn't think it was too tight. Any ideas of what caused the problem?
A. I bet you are right, the cold probably damaged that tender tissue. What a bummer! Perhaps youíll luck out and itíll throw off another spike, or it will bloom twice as nice next year! (Apr-15)


Something Eating Phalaenopsis Leaves
Something Eating Phalaenopsis Leaves

 

Something Eating Phalaenopsis Leaves
Q. I am forwarding you a photo of damage by some pest on my phalaenopsis. I am in the Bahamas and have never had this problem in 14 years. The buds on the spikes have also been eaten. Can you help?
A. Whoops, somebody stopped by for lunch. If it happened here, Iíd say lubber grasshoppers are likely culprits. Cockroaches, rats, etc. are also possible. Youíll have to think of what kind of fairly large pests might be around some of your other landscape plants to figure out what ate it. I wonder if there are iguanas or other large lizards in your area? Whatever ate those leaves is big though, you can see the mouth marks on the leaves. (Apr-15)


Black Spots on Enc. tampensis

 

Black Spots on Enc. tampensis
Q. Can you help me identify what kind of disease is on underside of these Encyclia tampensis leaves? The spots are not sunken. Otherwise the plant looks very happy and is spiking.
A. That looks like a big happy clump, growing well and throwing off new shoots. It may just be purple pigmentation from the sun caused by the changing sun angle resulting in the plant getting more direct light than earlier in the year. No problems as long as the spots are more purplish than black. (Mar-15)


Brassia Pseudobulb is Browning
 

Brassia Pseudobulb is Browning
Q. I am new to orchids, but my cousins got me to buy a spider orchid. The flowers fell off, the spike turned brown and one of the pseudobulbs is partially brown. Now what?
A. The spider orchid looks like itís been kept too wet. That brown line working its way up the pseudobulb suggests the beginning of rot. Keep it dryish until you see the new roots forming. Also, they donít like to be in too large of pots, and you select your pot size based on your root mass, not the top growth, so you may want to consider potting down a size. (Mar-15)


Thick Leaved Oncidium
 

Thick Leaved Oncidium
Q. We have been raising orchids for 10 years. Our front hall looks like a greenhouse due to a 20 ft x 8 ft dome above it. We recently have become infested with small flies. I have tried various chemical methods but to little avail. I am not sure what kind of flies they are. Any thoughts?
A. The butterfly orchid, a Psychopsis, hates to be repotted and often sulks when its roots are disturbed. They do best in a lava rock or largely inorganic mix in which it can grow for many years without disruption. You will have to flush salts from the pot but you wonít have to worry about a degraded potting mix rotting the roots. The plant wonít like it in the short term, but perhaps you should put it in a smallish pot with mostly inorganic materials and let it recover. (Mar-15)


Black Pitting on Brassavola Leaves
Black Pitting on Brassavola Leaves
 

Black Pitting on Brassavola Leaves
Q. I just purchased a beautiful brassavola orchid, and realized after I returned home that the surface of three of its leaves is covered with deep black pits. I assumed this was from fungal damage and sprayed with thiomyl. I thought perhaps these are old lesions because the orchid seller is quite reputable and I've always bought very healthy plants from him previously. However, I don't know if one can tell the difference between a previously treated problem and an active infection. Would you advise a follow up treatment? Is it better to remove the damaged leaves or keep them on the plant after treatment? Should I keep it isolated from other plants?
A. That looks like bacterial brown spot. Thiomyl is great for fungal infections but won't kill bacteria. I'm guessing that it's old damage, but to be sure, you could spray some hydrogen peroxide on all the leaves (Walgreen's sells peroxide in a handy little spray bottle). As long as the spots don't enlarge or spread to other leaves, the infection is not active. I treat all orchids with a pesticide and fungicide as a precaution before adding plants to the greenhouse rather than practicing isolation where you would wait and watch for a problem to crop up. (Mar-15)


Chlorotic Spotting From Scale

 

Chlorotic Spots on Cattleya Leaf
Q. What are these yellow spots on my cattleya leaf?
A. That sure looks like scale. Look at the underside of the leaf and see if you have white masses under there. You can use a soft toothbrush or Q tip dipped in isopropyl alcohol or put the alcohol in a spray bottle and spray the plant. Walgreens sells isopropyl in a high quality sprayer that you could use to spray the plant top to bottom. For some residual treatment, you could finish up with a drench of one of the Bayer products containing imidacloprid. (Feb-15)


Twisted Leaves On Cymbidium
Twisted Leaves On Cymbidium
 

Leaf Twisting Issue on Cym. Pauwelsii 'Kessander', CCM/AOS
Q1. I live in Massachusetts and have my cymbidium outside from March until mid-November and then it goes upstairs to a small bathroom with southern light. Fearful of losing my one and only, I have always slightly under watered it, thus some curling of leaves and slight splitting. The only issue that I presently have is that some leaves are twisting. Any ideas?
A. This beautiful Cym. Pauwelsii 'Kessander' received a cultural award from the AOS. We turned to resident cymbidium expert Harry McElroy for an answer: How a plant is placed in relation to the sun is important when moving them. It is a good practice to develop a system - like placing the tag on the side of the pot away from the sun. If a plant grows in one place for an extended period the new leaves grow so that the sun strikes the leaves in the most efficient way for photosynthesis. Moving the plant and placing the plant so that the sun is at a different orientation to the plant often causes the leaves to twist to the new sun angle. After becoming aware of this you may automatically call the side of the plant facing the sun "the front" and the part away from the sun the "the back". How much a leaf twists when moved depends on it stage of growth or maturity. Mature leaves twist less than leaves which have more to grow. (Feb-15)


Small Flies in Growing Area
Small Flies in Growing Area
 

Small Flies in Growing Area
Q. We have been raising orchids for 10 years. Our front hall looks like a greenhouse due to a 20 ft x 8 ft dome above it. We recently have become infested with small flies. I have tried various chemical methods but to little avail. I am not sure what kind of flies they are. Any thoughts?
A. Iím guessing fungus gnats. Hereís a link to some informantion on controlling fungus gnats from the University of California. They report that fungus gnats are primarily a nuisance insect that thrives in moist conditions but can cause root damage. You can spray with Bacillus thuringiensis subspecies israelensis, sold as Gnatrol, which is a different product from the traditional Bt. (Feb-15)


Air Plant
 

Air Plant
Q. Can you identify this orchid for me? I believe it is an air plant variety found growing wild in trees in Florida. It was given to a friend of mine as a gift and he would like to know the species.
A. That is a Tillandsia, in the bromeliad family. It may be Tillandsia bulbosa. (Feb-15)


Orchid Too Big for Space

 

Orchid Too Big for Space
Q. My potted dendrobium is blooming beautifully but it is three feet tall! Any way to shorten it without killing it?
A. No, thatís just how those phalaenopsis type dendrobiums grow. Perhaps you would be more interested in the minicattleyas and more miniature growing orchids for your windowsills. Try visiting some of the spring orchid shows to find lots of variety in orchids at a single venue. (Jan-15)


Dark Spots on Back of Phal Flowers
 

Dark Spots on Back of Phal Flowers
Q. I have dark spots on the back of the petals on my phal. They fall off if I rub them with my finger. The stem seems to be leaking sticky sap. It started some 10 days ago, and now I see that it is spreading to the baby plant. The roots and leaves are thick and strong, what next?
A. I think that is soft scale. Get some isopropyl alcohol and a Q tip and wipe all the scale away from top to bottom. Then fill a spray bottle with isopropyl alcohol and spray the plant, top and bottom leaves, in leaf crevices, everywhere they can hide. Youíll probably have to retreat weekly for a couple of weeks. You can also pour some of the Bayer product containing imidacloprid through the pot cause scale can also infest the roots. Thatís a mighty pretty phal! (Jan-15)


Aerial Roots
Aerial Roots
 

Aerial Roots
Q. I accidentally broke a spike of Phalaenopsis that has been blooming for just a week. I am very mad at myself. This pot has a lot of aerial roots. I should repot it as soon as possible but I do not know what to do with the aerial roots, they are very difficult to water. Should I push them into the pot, leave them as is, or cut them off?
A. Thatís a shame about breaking the spike! The aerial roots have acclimated to growing surrounded only by air and they may get smothered growing inside the pot. You can go ahead and transplant, get the roots good and wet for an hour so theyíll be pliable. Cut off the old dead roots and resituate the plant in the pot. If the aerial roots go into the pot fine, if they donít, thatís fine too. You can give the roots a hair cut so theyíll fit without bending and then perhaps theyíll grow new roots acclimated to the potting mix. Then put some peanuts in the bottom of the pot and backfill around the roots and youíre done! (Jan-15)


Toad on Orchid
 

Toad on Orchid
Q. This is my orchids new little friend. He sleeps with my plants all day long. Will he hurt the orchids?
A. I am sure theyíll be very happy together. You probably wonít be surprised to hear how helpful your natural population of anoles and frogs can be. Iíve seen anoles capture and eat cockroaches in my growing area. Youíll often see anoles licking the honeydew off flower buds, eating any thrips or scale that might be in the vicinity. Who know what this toadie might be snacking on at night? (Jan-15)


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