oily patches on leaves

[tom499]

Today my parents came home with another orchid for me Its a Miltoniopsis with bulbs close to opening. The medium is coconut shells.The leaves seem rather pale, one is a yellowish colour. Also The under sides of some of the leaves have a oily appearance. they dont seem to be sticky, and a cotton bud isnt picking up much. Is it just past pesticide use or something else? the plant seems quite dry, but i do not want to water it yet till im sure whats up with it.

[kmarch]

Dear Tom,

Hello and welcome to the forum. Miltoniopsis and Miltonia leaves are naturally lighter than other orchids I've grown, also a plant grown in more light than what might be considered ideal usually has lighter leaves. If the one yellow leaf is on an older growth, I'd not worry as it's not uncommon for old growths to lose a leaf occasionally.

The oily substance could possibly be from a treatment wiht insecticide. Neem oil (oil from a particular kind of tree) is a fairly common insecticide, especially among growers who like to avoid chemical applications. Neem oil can leave an oily sheen or droplets on leaves. Here in Australia I use something called Pest Oil which is basically the same idea but uses a like of petrolium oil instead of the neem oil. It too leaves an oily residue on my plants.

I believe it is ok to go ahead and water your Miltoniopsis, you don't want to stress the plant. If the oily deposits bother you, you might consider using a sponge and a very small amount of soapy (like a very mild dish soap) water to wash them off.

Keep us posted on yoru progress and ask more questions if you have them.

Cheers,

-Kevin

[tom499]

then i shall not worry i seem to have one of each type at the moment, so arrangement on my table and water is complex i think im gonna try and concentrate on growing orchids from one country or species. less to think about hehe

Is this neem oil good to have then? i dont have any pesticides or chemicals, just some powdered orchid feed and a pot of cotton buds.

my first orchid got mealy bugs and nearly died, i split it up and stuck it in some orchid compost. its pretty small, but i just didnt think it was ll going to survive

my newer orchids seem to be doing good though. weird, the ones i repot just arent the same afterwards...hehe

[kmarch]

Dear Tom,

Somewhere on this forum is a thread about selecting orchids. Take a look and give it a read. I believe the best way to successfully grow orchids it to know what conditions you have to offer then grow orchids that like those conditions. As you progress you'll see more and more which types do best for you and you can get more of those.

You don't need pesticides unless you have pests. It's a good idea to keep new orchids away form your collection for a few weeks so you can see if they have any bugs. This will prevent infestation on a wider scale should you bring home one with hitchikers.

Mealy bugs are one of the easier bugs to treat (unless one lets them get really bad before acting). They are soft bodied and can be cleaned up with applications of rubbing alcohol with a cotton swab.

Personally, I believe it is not always a good idea to divide plants if they have an infestation (exception: if they are really large and you can get a good size division that is clearly pest free). ou may get other opinions on this but i tend to think plants remain stronger when they are larger and left undivided.

I also look carefully at my plants when I water. This helps me find critters before they get out of control.

Happy Growing!

-Kevin

[fred]

Tom499
I am a little puzzeled with this.

Quote.
my first orchid got mealy bugs and nearly died, i split it up and stuck it in some orchid compost. its pretty small, but i just didnt think it was ll going to survive

Did you split the plant ?
Myself I would treated the plant for Mealy Bugs with white oil.
I hope this helps you

[fred]

Hi Tom499
I thought that you might find this useful.

ORCHID FOOD
In their native habitat, orchids scavenge nutrients from whatever happens to be nearby: decomposing leaves, bird or animal droppings, or minerals borne in rainwater. You can help your orchid to grow faster and bloom sooner by feeding it the right fertilizers. Look for products that contain nitrogen (N), phosphorus (P), and potassium (K), along with trace elements such as iron.

Potassium (K) is mainly responsible for the control of flower, and fruit development. Phosphorous (P) for flower production, and Nitrogen (N) for healthy vegetative growth. The amount of feeding depends on the plant concerned, the time of year and general health of the plant. Investigations have shown that feeding should begin with more Nitrogen just when the new shoots are showing, more Phosphorous and Potassium being necessary towards the end of the season.

THINGS TO CONSIDER: Orchids growing in bark need more nitrogen than either phosphorus or potassium (in proportions of 30-10-10). This is because the bark is decayed by bacteria that use a large amount of nitrogen, leaving very little for the plant. Therefore, the most important step to remember when feeding your orchid is to correctly identify the type of fertilizer you should be using. Beautiful Orchids has five different orchid foods available from our online catalog. Before feeding your orchid, always read and follow the directions carefully

[kmarch]

Hi Fred,

I live in Melbourne here and I've not seen white oil in stores. Am i not looking hard enough? Perhaps not at the right stores?

Is "white oil" a brand name?

Cheers,

-K

P.S. on a different note, what do you use to treat fungus on leaves?

[tom499]

i was young and foolish then i used diluted white spirit in the end, but i think the leaves burned, so i cut off the worst bit and replanted in some fresh compost. got some new growth showing.

ooo also my miltonia is flowering my paph is still going slow, but seems to be making progress. is amazing how small the buds are, and how they grow to such large flowers