Damages on underside of Howeara (Puanani) leaves

[orchid94070]

I bought this Howeara a couple of weeks ago, and it started having some spider-mite like damages, so I sprayed a 1% mixture of neem oil on it and kept it indoors. The damages stabilized. I took it outside (in a shaded area) again, and sprayed a 1% mixture of mineral oil to preempt further "spider mite" damages. Then these patches of damaged leaves just exploded in a day!! What is happening? Please help!! Thanks.

[SouthPark]

Spidermites can damage plants relatively quicky for sure.

The spidermites are definitely just doing their thing - surviving - but since they can and will take-out whole orchids, then they need to be controlled.

Spraying lots of water on the plant's leaves (under and over all parts of leaves, and stem) will definitely drown mites. They generally don't like water or lots of moisture.

But it's important to make sure that air-flow is ok in order to dry the plant and leaves after spraying - to avoid issues with fungus activity on leaves and stem, and crown rot etc.

So if spraying is done - sometimes it's a good idea to tilt the plant over to drain any excess buildup of water in the 'crown' region (where the new leaves grow out from).

One nice option is mancozeb solution - spray onto the whole plant, and let dry. Gentle air-movement in the growing area will help with drying.

Preventative treatment could be to use Azadirachtin - eg. azamax.

The little jeweler's magnifying glasses with LED light can help you see if there are little mites under the leaf etc.

[orchid94070]

Thanks SouthPark for the quick response! I will go ahead and buy the treatments you suggested (and also the magnifying glass!!). I guess my surprise is with the quick flare-up of the damages. I took the plant inside for about a week after I spotted the initial damage, and there was no further damage. When I took the plant outdoors, everything just exploded. Perhaps the air outside is too dry, and the spider mites just latched on.

Do you think that the plant will make it given such extensive damages to the leaves? Is there some special ICU treatment I should give the plant to help it survive the damages? Thanks again!

[SouthPark]

Originally Posted by orchid94070

Do you think that the plant will make it given such extensive damages to the leaves? Is there some special ICU treatment I should give the plant to help it survive the damages? Thanks again!

Most welcome! This plant can certainly make it.

Once whatever it is (assuming mites) is under control - this orchid can definitely keep growing nicely.

It doesn't look like any ICU treatment will be needed here.

I think you were doing the right thing with the neem oil application - as in keeping the orchid in shade. Just watch out for neem oil, because if the oil remains on the leaf ---- patches or layers of it, then I have heard that sunlight shining onto the leaf can lead to leaf issues - as the heat can't leave particular regions fast enough - destroying leaf cells etc.

I haven't used neem oil on my orchids before. So this is a 'just in case' thing.

[estación seca]

Oil is harmful for leaves of most plants, especially those with thin leaves. That's why orchard fruit growers spray horticultural oil only when the trees are dormant. Some neem preparations seem less harmful than others. I would not spray mineral oil on a plant with leaves.

I think what happened to your plant is the things you sprayed got into holes left by the spider mites and killed surrounding tissue. Spider mites are almost everywhere in gardening environments, so it's almost never possible to get rid of them forever. Spraying all surfaces of the plant with a weak solution of dish soap kills adult spider mites, but not their eggs. The treatment is very well tolerated. I use 1 teaspoon/5ml of liquid dish soap in 1 quart/liter of water. Repeat every 4-5 days for 3 treatments to kill bugs emerging from eggs. I don't use any pesticides for spider mites because dish soap works fine.

You can also use 70% isopropyl (rubbing) alcohol but it doesn't seem to be available in the US now.

[orchid94070]

Thank you! I will try the concoction you recommended!

---------- Post added 07-29-2020 at 12:29 AM ---------- Previous post was 07-28-2020 at 11:46 PM ----------

Thank you! I will try the concoction you recommended!

[SouthPark]

The dishwashing liquid method mentioned by ES is a very good method. The solution helps to wet the leaf (along with the mites) more than just water by itself.