Bugs - Orchid Board

gngrhill · #1 01-30-2015, 11:09 PM

Hi, all. I have been growing orchids now for almost 3 years and have never had insects except for fungus gnats which I control with a mosquito dunk floating in my watering water. Does a terrific job on them. Last week I found what I'm sure was a mealy bug on the bloom stem of one orchid. I hand picked it off and haven't seen another so far. Today I found on a different orchid a lot of small brown bumps which I am thinking might be scale, but never having it before am not sure. I wiped the leaves with alcohol making sure I got them all off. What I would like to know is where do they come from on orchids that have been here for a year or two and none of the others seem to have them ? They must come from somewhere. All the newer orchids seem to be clean. Have not seen any other bugs except these 2 and they have been here, never outside. Any ideas ? Do you think my treatment is ok or do I need to do more ?

billc · #2 01-31-2015, 03:30 AM

Somewhere along the line one of the plants you introduced to your collection must have had some eggs in the potting mix. When conditions are to their liking BOOM! you have bugs. In my experience once you have mealys you're doomed. They must lay the eggs in inaccessible regions of the plant because no matter what you do they almost always come back. Several applications of Neem oil over several weeks will keep them at bay but they will be back. Get yourself some Q-tips and alcohol and prepare for battle when you water.

Bill

gngrhill · #3 01-31-2015, 04:31 PM

Thanks, Bill, even tho I'm not happy with the answer

Orchid Whisperer · #4 01-31-2015, 04:59 PM

Plants shouldn't be doomed, but to get rid of them, you will need a systemic insecticide, used weekly for at least a month.

NYCorchidman · #5 01-31-2015, 05:24 PM

Well, most often these pests hitch hike into your collection via newly bought plants.
Also, even if the plants are grown indoor, the bugs may come in through the window during the warmer months. These bugs are small and can be carried in the air.

Now, I disagree with mealys will always come back.
They come back because you have not treated correctly. I have got rid of them on two plants.
I did toss one badly infested plant since it was just too much to deal with and the plant was not that great anyway.
What I did was
1. It was a dendrobium. I washed down the plants to detach many. It was a bad case, but easy to wash them off the cane. then I picked out any more of them that I found for a few weeks watching daily.
I no longer had mealy bugs ever since.
2. A paphiopedilum venustum. With plants like paphs, you cannot wash the bugs off since the bugs can hide on the plants. I spayed insecticide about two three times with a few days of interval and I have never seen the bugs since. It's been a year. The plant did react rather badly but now it's healthy and in bloom.

---------- Post added at 05:24 PM ---------- Previous post was at 05:22 PM ----------

Quote:

Originally Posted by Orchid Whisperer

Plants shouldn't be doomed, but to get rid of them, you will need a systemic insecticide, used weekly for at least a month.

I thought systemic insecticide is used as a drench and then the effect last for a while?? Why apply weekly for a month?

gngrhill · #6 01-31-2015, 11:46 PM

thanks NYCorchidman for the optimistic outlook. I have not seen anymore since I removed the ones I saw, but I'm keeping a close watch on all the orchids.

ALToronto · #7 02-01-2015, 12:57 AM

I have mealybugs as well, and I've been fighting them with SucraShield (an organic pesticide available from Ray). It is a contact pesticide - to work, the insect must be sprayed directly, and it dessicates soft-bodied bugs. It doesn't work on scale, the only way to get rid of it is to use a systemic and poison the plant itself. Apparently, neonicotinoids work well for scale.

I had scale infestations on only two plants, and I ended up tossing both. The first, a young paph, was too damaged by the time I realized what was happening. The second was a large staghorn fern, and I hated to throw it out, but after several months of wiping the suckers off the leaves, I had damaged the leaves too much, and the fern was no longer attractive.

Orchidbyte · #8 02-01-2015, 08:26 AM

I use a product called Imidacloprid, it comes in many forms. I use a product made by Bayer called fruit,citrus & vegetable insect control, the product is a systemic supposedly safe to use on edible products, I still don't use it on vegetables. I had bad outbreak of scale and mealys a couple of years ago tried alot of different things that either smelled bad and gave me a headache, or just didn't work, I used the Bayer product once a week mixed with plant food and within a month problem solved. Now I use product once every 3 months and have not see any bugs, except those damn bush snails, can't seem to get rid of them no matter what I use.

gngrhill · #9 02-01-2015, 05:12 PM

Thanks, Orchidbyte, for that useful tip. I will try it if they come back again

NYCorchidman · #10 02-02-2015, 05:52 PM

Imidacloprid is one of the most common ingredients used for systemic insecticides.

What is the product name with this chemical that is used for edibles??
I do not get it because plants treated with systemic would contain the chemical inside them and therefore you should not eat them, unless the dosage is very low and do not stay inside the plant tissues for too long.