phalaenopsis with white bugs on stems
 

Hi everyone,
I'm new to posting. I moved from Los Angeles, CA To San Diego, CA and my phalaenopsis orchids moved with me. They were doing fine until a neighbor gave me 6 of her orchids. I was wondering what had happened because 3 of them had no leaves left, 1 had 1 leaf left, 1 had 2, and 1 had 2 leaves left. The first one died in a week, and the rest I managed to save. The 2 with no leaves (after much TLC) have 2 new baby leaves growing. Yay!! However, the one with 3 leaves actually managed to grow a spike and bloom. However, now it has all these critters growing on it. I've never had any issues with bugs before and I'm at a loss on what to do with them and I'm worried it's going to spread to the other orchids. Everyone says to make sure that I determine WHAT they are first so that I know how to effectively get rid of them. I looked at the pest chart and they look like mealy bugs?? Please help with identification and also what works best to get rid of them! Thanks for any help!!

Mealy bugs. (I think "Phalaenopsis" is Latin for "mealy bug magnet... :biggrin:) Rubbing alcohol on a q-tip gets the individuals. In a spray bottle you can nail a wider area, then clean up the corpses with a tissue. Then you can follow up with a good systemic insecticide such as Bayer's Advanced 3-in-1 (take them outside to spray, they are safe indoors once they dry) As far as the physical removal with alcohol is concerned, there is no residual effect so you need to be vigilant, kill them as soon as you see them.

Thanks Roberta! I've already removed them with the Q-Tip and alcohol. However, I'm just worried about infestation. How bad can it get? Also, what's the first signs I should look for? Is it the spiderweb type substance or the actual mealybugs? Lastly, should I spray all my orchids and repot them? As you can see I'm getting kind of paranoid.

I have found mealies to be pretty ubiquitous around Phals, and they also go after Paphs. At this point, I think vigilance is important. Especially look at the backs of Phal flowers. The bugs are pretty obvious when they are around, and if you are watchful you can kill them before they do much damage. So just watch... You can spray with the alcohol.. just put a sprayer into the original bottle. It is harmless to plants, flowers and people/pets. (70% isopropyl alcohol, the standard... the 90% stuff is too strong) If you kill them as you find them and it doesn't get worse you're home free... it may take several weeks of treating to get the successive generations. If there is a bigger, more widespread problem developing, you can go for the Bayer's Advanced 3-in-1, but if you can knock them down just by paying attention, so much the better. At this point, observe and see if you have a bigger problem or not... can't predict, you'll know in a week or so of observation.

Use the Bayer 3-in-1 (or another insecticide containing imidacloprid) once a week for one month. Spray all parts of the plant, including roots and potting medium.

Imidacloprid is a systemic insecticide and will help prevent a new infestation free om taking over.

I have some experience with mealybugs, but on Paphs. Manual removal was not a solution in my case..when you see those adults (larger than 1mm), it means they are already in development stage in which they're able to reproduce and, trust me, they can reproduce a lot. They also hide both in hard-to-reach areas (like in between the leaves) as well as in the potting medium (especially in the upper portion of bark mix!)...so by just removing them one by one, the next generation is already maturing with some adults probably reproducing in areas where you don't see them.

I used imidaclopride in water dispersible granules, you can also buy a imidaclopride/thiacloprid solution that's already mixed. I prefer this to sprays because I keep all the plants indoors and the option of simply letting the pot drench in the solution and swabbing the leaves with cotton soaked in the mentioned solution is preferable to spraying it. These insecticides are systemics so they get absorbed in the roots of the plant and transported to the leaves where, once ingested by the mealybugs sucking on sap, they poison them, both adults and young ones. Bonus is that these solutions are a bit sticky (I think they contain some sucrose) so the bugs in the potting medium get coated with them as well, it gets absorbed into their body and kills these hidden nests as well.

I've occasionally had these show up on my Phals too. I just do inspections of all the plants during my weekly waterings and remove any that show up. For my indoor Phals, I usually manage to get rid of them this way in 3 weeks or so.

My outdoor Phals are continuously recolonized, so they're always coming back, but I'd rather perpetually battle the mealy bugs than hurt the frogs that live in their pots.