What to use next in rotation?

[kmccormic]

Hi Folks:

I believe what I have is Thrips. They are teeny tiny, smaller than a mechanical pencil tip. I couldn't get a good look at them even using an Optivisor and flashlight because they are FAST! Dark brown or black, living only in the medium, and possibly winged. How do people get these things to pause long enough to positively ID them anyway? Never could find them on the plants themselves, only ever in the medium if I watered. Never any webs. No red residue on a paper towel if I swiped the undersides of the leaves. I think they came in on 2 plants I'd bought even though I quarantined them for 2 months and they were clearly just repotted when I got them. I couldn't figure out why my plants (new and old) were suddenly dropping leaves or why promising buds just stopped. The new plants went to a mushy bud 2 months in or dropped the spike. I initially thought it might have been due to new home bud blast until I spotted critters in the medium.

So I whipped out my reference by Sue Bottom on what works with which bugs to try to ensure I always used a different mode of action with treatment. I used an Imidocloprid spray on the plants and medium, which seemed to cut them down immensely, then 2 weeks later a malathion spray and drench. Some of the plants didn't seem to like the Malathion, (the Slc really didn't like it, several new shoots turned black overnight even though it was away from any strong light, that was traumatic for me.) It's two weeks later, I haven't seen another pest anywhere, but with egg laying cycles what they are, I don't trust that the next generation isn't just about to hatch, and it only takes 1 fertile female to start the whole cycle over again. I'm trying to decide between Orthene and Bifenthrin as a next step. The plants will be staying indoors for another 2-4 weeks anyway, so phototoxicity shouldn't be an issue.

Orthene is systemic spray and drench, aspects which I like. I have never used either before and I'm nervous about the dosage to use per gallon (I use a quart bottle) which will be safe for orchids in general, and I have a concern about using two systemics so recently. And could you use them together with fertilizer or stick to just plain water? If I use Bifenthrin, what dosage for that?

If I've mis-diagnosed the pest, doesn't Orthene cause an explosion of mites? I'd hate to undo progress if I've determined the wrong pest.

Thoughts? Advice on dosage? All ideas welcome.

[Helene]

I cant help much, I rarely had any problems- but one time I got some bugs with a plant bought from Ikea. I believe it was some sort of trips.

In my country I havent found many things to use- only this one product from Bayer- Calypso spray.
I sprayed the infected plant, leaves and everything, and also the plants in the same window (thats how I learnt to quarantine plants…&#128540.

That took care of things, and didnt hurt or slow down any of the plants. Maybe I was just lucky.
Think it was a brassia hybrid, maybe different in other plants, and sprayed a couple of the phalaenopsis next to it.

Thats all I have tried myself. I'm sure people here will help you more- I dont know what Orthene or Bifentrin is.



My plants survived. But I think it also depends on how badly infected they are. Calypso Spray enters the plant, and those feeding of the plant will die. I sprayed only once. I think it says to spray once more 2 weeks later if there is more bugs.

Sorry to hear about your issue, and hopefully you can save the plants and get good advice from someone more experienced

[tucker85]

I'm not familiar with thrips in media but I've had problems with them on my buds and blooms, especially vandas. They are very small and very fast so your description sounds right. Here, in Florida, Orthene is considered the "go to" insecticide for thrips. Unfortunately Orthene is a nasty, smelly organo-phosphate that's only available in concentrated form which I don't like to have around the house. I've found that I can control thrips with Ortho Rose and Flower or Ortho Flower, Fruit and Vegetable. It's usually available at Home Depot, Lowes or plant nurseries. It's premixed in a spray bottle so it's not as toxic as the concentrated Orthene. I don't know if it can be used as a drench but it is a systemic insecticide so regular spraying with it should work. Of course, if you prefer to use Orthene, it is very effective on thrips. Good luck.

[Ray]

First, I think you've over interpreted "rotation". The recommendation is to do a complete course of treatment (the acephate 97UP I carry recommends three treatments at two-week intervals) with one mode-of-action, then the next time you need an insecticide, use one with a different MOA, not rotate them at each treatment. Also, it's best to check the MOA to know you're changing them, as two different products camp have the same one.

I'm with Tucker, thrips are plant tissue burrowers, not media dwellers. What you're probably seeing are psocids, which apparently do little to harm the plants.

It's Merit (imidicloprid) that has been implicated in mite outbreaks, not Orthene (acephate).

[kmccormic]

Thanks for clarifying Ray. I think if it's just book lice then I will hold off on another round of treatment. I haven't seen any sign of them for two weeks now.