Peristylus lacertifer

I am confused by one thing in growing local plants here (Southern Thailand), especially the terrestrials. I have to work very hard to keep the fungus out of my collection. I am spraying weekly during the wet season, varying the fungicide I use, and even then I still get some attacks. Some of these plants are growing in the wild within kilometers of my home.
Talking to other growers I find they are doing the same. Out in the wild you do not see these plants being destroyed by fungus every week. In culture the density of the plants is much higher which creates a better environment for the pathogens, but I am still suprised the fungus is so prevalent in cultivation compared to the wild.
You grow in cultivation and also see the plants in the wild. Do you see fungus destroying plants out in the wild? Do you have fungus problems when you are growing plants in what is basically the same environment as they grow naturally.

1. Do you see fungus destroying terrestrial plants out in the wild?

It is not obvious. I do not know. This is something that you have to follow-up over a period of time.

Some terrestrials are clump forming, others are growing close together. Pollinators and insects carry pathogens between plants in the wild.

2. Do you have fungus problems when you are growing plants in what is basically the same environment as they grow naturally?

I do not have fungus on any terrestrial plant parts above ground. I do not know what is happening below ground but the leaves/spikes are healthy. During the dry season I can check rhizomes/tubers/pseudobulbs.

I do have serious problems with snails, slugs and leaf-eating insects. Some species are attacked while neighbouring species are left alone.

It is less than a year since I have started to take terrestrials from cleared forest areas and from national parks which allow cattle grazing during the rainy/rice growing season. I have replanted these terrestrials in an enclosed area in a teak plantation. The local soil is sand. On the sand I have dumped composted teak leaves mixed with rotting wood/bark. The top layer,the actual planting medium, is finely broken weathered sandstone rock. The build up bed is held together by old logs. This method of planting has been discussed on the "Terrestrial Orchid Forum".

http://forum.terrorchid.org/viewforum.php?f=7

For your info Bruce: large quantities of sphagnum moss were for sale at Chatuchak Market in Bangkok recently. This is the first time that I have seen sphagnum for sale in Thailand. Every Wednesday and Thursday the market is open for plants only.

Peristylus lacertifer is growing in open areas in dry Dipterocarp forests on sandstone and slate soils. Grass species growing on these types of soil allow ground orchids amongst them. Grasses growing on lateritic soils are very dense and will smother most orchids.

"It just suprises me that there seems to be little problem with fungus in the wild, but such a major problem in dense cultivation."

Could it be that you are buying your fungus problem? Each time that you buy plants from a nursery they carry new pathogens. I have never bought plants from a nursery and I have had no fungus problems.

Hey,

that could be white rot fungi, they love living in dead wood but when giving the change they will try to eat anything. Looks similar to something I have had.

Getting rid of the fungi is always hard especially if there is a local source of it. And you have it growing on the ground with tones of dead wood.

I know they love nitrogen and are capable to break down plant matter for carbon. When I needed white rot fungi I just took some dead wood like the one near your orchid and put it on NA agar and it grew like wild fire.

I hope this information helps.

Erkele

"... all the plants get regular treatment."

The products that you have bought are probably fake. Change suppliers and products. Use a new way of thinking about how to get them (e.g via Boots, a pharmacy selling agrochemicals, a hospital, ... If necessary import the fungicides from the two countries to the South of you.