Conventional wisdom

[Hien]

For a while I keep thinking why orchids in natural setting are not in so much trouble as our plants.
This is what I think happens, in the home environment, the insects are not blown away by wind, are never drown in rain storms, never get eaten by other predators etc...
The insects are killing my plants left and right , they will stay hidden in the growing point of the plants, where the leaves are the youngest & most vulnerable. Because they suck the sap out, the leaves collapse on themselves & never open, so it will be harder to get to the insect.
When I decide to do what peoples say not to do[this "no water in the crown" conventional wisdom has been printed so many time in the orchid magazines], I water right into the crown, make sure spray more water so it will stay inside the leaves (after all this is what happens in nature after every rain storm) You will see that the very symetrical damages (when the leaves in the folding state, the insects eat continuously on both sides ) by insects stop, and the leaves have a chance to grow.

 

[paphioboy]

oh, no..! Hien, do you know what caused that? ity: Is it sunburn or..?

 

[Hien]

oh, no..! Hien, do you know what caused that? ity: Is it sunburn or..?

Oh no, it is not sun burn, the browning has a growing direction like a V follow the insects dining trail. I even fold some scotch tape with the sticky side out, and stick it into the leaf growing point, when I pull it out, there are a lot of insects stuck on the tape.
Here is the parvi hybrid photo, you can see the pattern. sunburn does not make this "symetrical ink test" design.
Peoples who grow in greenhouse have fans (that mimic the wind) & using stronger water sprays (like rain), so I think they have less problems than peoples who grow inside the house who only water at the roots zone.

 

[paphioboy]

there are a lot of insects stuck on the tape.

I think they're scales then... My paphs which are plagued by scales sometimes have these markings too...

 

[Candace]

why orchids in natural setting are not in so much trouble as our plants.

I sort of think of the phrase "if a tree falls in a forrest does it make a sound?" in that don't plants surely die or become victims of predation in nature as frequently as they do in 'captivity' if not more often? If we aren't there to see the corpses then the dead don't exist:> I guess I've always believed that there is quite a greater amount of plant death in the wild due to competion for resources, predation etc. than in my lowly g.h. I sure do have my casualties, but still hold to the hope plants have better odds in my care. Maybe I'm deluding myself?

 

[SlipperKing]

I have been taught to really pour on the water, flood the plants! Wash way the dust and dirts that settle out on the leaves. Make the mix "float" a bit before you stop the water. This cleans the leaves and aerates the mix. This action actually makes my organic mix last longer. Keeps it loose with no stagnation. Stagnation = root death. I never give any thought to the time of day either, winter or summer. 4AM, 10AM 2:35PM nor 7:46PM matters, if the plants need water they get it. You can get away with this because of good to great air movement. That is the key. I rarely have rot problems. Heavy watering washes away the critters. Dribble watering washes the critters into the crevices setting yourself up for rot! Plus, slow water movement through the pot does not pull air into the pot which is what the roots need and the critters don't. When I get rot it because I just messed a round with the plant. Repotted it or injuried in some way, like knocking off the bench and allowed a critter access. Memic nature, wind,water and NO repotting! (which of course is not possible) No one will convince me otherwise.

 

[Rick]

I sort of think of the phrase "if a tree falls in a forrest does it make a sound?" in that don't plants surely die or become victims of predation in nature as frequently as they do in 'captivity' if not more often? If we aren't there to see the corpses then the dead don't exist:> I guess I've always believed that there is quite a greater amount of plant death in the wild due to competion for resources, predation etc. than in my lowly g.h. I sure do have my casualties, but still hold to the hope plants have better odds in my care. Maybe I'm deluding myself?

Once plants make it past the seedling stage I think they are pretty stable in the wild, and have low mortality. This is not because of wind or rain blowing away bugs as opposed to a basic dilution factor. The odds of a particular plant being found and devoured by a pest is lower than in a GH because there are so many other choices around it. Also there are predators and parasites for every pest wanting to eat a plant so generally the density of pest species is lower in the wild than in GH conditions. Thirdly just about all plants have some form of natural defense against most pests (whether fungi or bugs) and under GH conditions the plants may not grow those defenses as well. A forth reason is that the pests attacking are orchids are different species from the ones encountered in the wild, and they will not have evolved any natural defense against them.

A general observation of captive monoculture systems is that they are more prone to disease and pest attacks than diverse wild systems, and the reasons are summarized above.

 

[Candace]

Maybe I should just set them free. ;>

 

[orcoholic]

Hien,

I have never seen an insect make such uniform marks on plants unless they happen to chew the edge of a leaf that has not opened yet. Then there are uniform markings on each side of the leaf. The markings on the plants in your pictures look to me to be caused by water sitting in the new leaf as it was developing. Too much humidity could probably cause the problem too.

It seems to me that a plant in the wild would usually be self draining because it grows attached to a tree, or on the side of a cliff, and the water cannot accumulate in the crown.

My suggestion would be to increase your airflow for the problem in the picture. If you have insect problems, treat that as another separate problem and get a good insecticide.

Michael

 

[Hien]

Hien,

I have never seen an insect make such uniform marks on plants unless they happen to chew the edge of a leaf that has not opened yet. Then there are uniform markings on each side of the leaf. The markings on the plants in your pictures look to me to be caused by water sitting in the new leaf as it was developing. Too much humidity could probably cause the problem too.

It seems to me that a plant in the wild would usually be self draining because it grows attached to a tree, or on the side of a cliff, and the water cannot accumulate in the crown.

My suggestion would be to increase your airflow for the problem in the picture. If you have insect problems, treat that as another separate problem and get a good insecticide.

Michael

That is exactly as you said, they chew on the unopened leaves, so they munch both sides at the same time (as if someone hold two donuts close to the two corners of another person's mouth, the recipient of the donut would make a bite on the left, then the next bite on the right), keep going down as the leaf grows, the brown marking is just the result of collapsed/dying cells. Once I start to water in the crown to drown them, there is no more brown

 

[Candace]

Once I start to water in the crown to drown them, there is no more brown

Looks like typical mite damage to me and would also follow that since they hate water(most mites anyway) your spraying would dislodge them. I tend to want to treat with something more potent. And I've lost enough paphs to rotted crowns this season. I was a bit careless with my fans and watering this winter and I'm paying the price now:<

 

[SlipperKing]

One other possiblity would be water setting in the crown when strong (as in direct) sunlight hits the plant. Heating the water up to a dangrous temperature level and cooking the plant. But of course with well shaded plants this doesn't happen. I've also seen this type of damage to plants when an oil base pesticide is use and sunlight heats it up.

Rick H

 

[NYEric]

I think we went thru the watering issue before. What plant in nature isn't exposed to rain, which means water in the crown?! Of course since I'm mostly growing hybrids, there's not a lot natural to their culture. However, they're still plants, i.e. same type of culture. Regarding pests, they had to come in from somewhere. try to find the culprits and isolate them. Spring is a time the mealies and scale start to spread so increase your maintenance. Check inside the crowns, at the bases, and under the leaves at least once a week. Q-tips or paper towel swabs soaked in alcohol will remove the pests. I nipped some good outbreaks in the bud recently. Good luck.

 

[John M]

Hien, that's thrips damage. They hide in the centre of the new, developing leaves and suck the plant juices, causing cell death in a patern just like you've shown. Get rid of them by thoroughly spraying all the plants with Orthene WP at a rate of 1 teaspoon per litre of water. Orthene is systemic and will be absorbed by the plant and poison the thrips the next time they go for a meal! Spray the plants 3 times, 7 days apart and your problem should be solved!

 

[Hien]

Hien, that's thrips damage. They hide in the centre of the new, developing leaves and suck the plant juices, causing cell death in a patern just like you've shown. Get rid of them by thoroughly spraying all the plants with Orthene WP at a rate of 1 teaspoon per litre of water. Orthene is systemic and will be absorbed by the plant and poison the thrips the next time they go for a meal! Spray the plants 3 times, 7 days apart and your problem should be solved!

Thanks for the suggestion

 

[NYEric]

Let us know what happened.

 

[John M]

BTW: This is a good case for isolating new plants and preventatively spraying them before adding them to your collection. I had an infestation of European Greeenhouse Thrips about 15 years ago because I accepted a few gift plants (Paphs), from a co-worker and I just put them into my collection without treating them first. I noticed the funny marks in the leaves and lazily gave the plants a quick inspection and decided that the damage was old and no bugs were present. WRONG! It took a few months for the critters to multiply and infest my entire collection. Then, I lost many valuable Paphs to these nasty bugs while I tried many different environmentally friendly methods of eradications.....none of which worked. Then, I finally went with three treatments of Orthene WP, 7 days apart and the Thrips were gone. 'Haven't had any problem with them since. Good luck.

 

[NYEric]

I find w/ thrips, usually I can catch them on the fly and kill them. Of course I'm intimately familiar w/ my plants so I try not to let things go un-noticed.