Mealybugs on Paph. Magic Lantern, pesticide options? - Orchid Board

CROrchid · #1 10-27-2018, 09:04 PM

Hi everyone,

This spring I purchased a Paph. Magic Lantern from an online orchid shop, the plant seemed healthy and well developed. Sometime in the middle of the summer, I noticed a whitish clump on the backside of the leaf (where the tag with the hybrid's description touches the leaf), it was cca 2mm in diameter. At the time I just removed it thinking it was some fiber that got stuck onto the sap. Anyway, moving forward, the plant has been doing very well, it's not a turbo-fast grower like Phals, but one new leaf has completely grown out and another one is currently growing.

Now, a week ago, while watering the plant, I took a look at the backside of the leaf and noticed three small bugs, approximately 1mm in length which seem like long-tailed mealybugs to me (photograph below). I have removed them immediately and started inspecting the plant...that is when I removed some additional 6 or 7 smaller bugs (maybe 0.5mm in length, barely visible) which were hidden in between the leaves and very hard to reach. I have also removed one from the rim of the pot itself. 2 days later I removed an additional tiny one. Now for the last four days, I'm observing the plant everyday and don't see them any more.

Anyway, my plan is to drench the pot in systemic pesticide, then again in two weeks..this should allow the plant to absorb it and poison the sucking mealybugs and newly hatched ones if they are crawling somewhere where I don't see them yet. Afterwards, I'd repot the plant in new media and a new pot (not sure if it's the best time to do this, but the plant is in active growth, I guess it should handle it?). I have on hand imidacloprid in water dispersible granules and thiacloprid in liquid solution, which one would you recommend?

Oh and one more thing, I have two small Paph. malipoense which were close to this plant (on the same saucer), now I have moved them away from the infested plant. I have been checking them extensively, both on the undersides and between the leaves and have not seen any signs of mealybugs, not even the tiniest ones. I have also repotted one of them some two weeks ago, and while I did not inspect the roots too carefully, there seemed to be no obvious signs of them on the roots. Should I be drenching them in pesticide as well or better to wait and see if any bugs show up first (I know imidacloprid is supposed to have low phytoxicity, but these are young plants so I'm a bit worried if they'll handle it the same as a mature one)?

Dollythehun · #2 10-27-2018, 09:29 PM

One problem with the granuals is that they rapidly work their way through the bark and out the bottom of the pot. It's quite effective but, I water lightly when I use it. If your plant is in a terrestrial mix, or moss, it won't be a problem.

Ray · #3 10-28-2018, 09:50 AM

Treat the plant with your water-soluble systemic insecticide THREE times at ONE-WEEK INTERVALS.

Most insecticides only kill adults, and the egg hatching time for mealies is typically 5-10 days, so if you wait two weeks between treatments, it is likely unaffected eggs will hatch, the creatures mature and lay more eggs before your next treatment.

CROrchid · #4 11-12-2018, 05:40 AM

Quote:

Originally Posted by Dollythehun

One problem with the granuals is that they rapidly work their way through the bark and out the bottom of the pot. It's quite effective but, I water lightly when I use it. If your plant is in a terrestrial mix, or moss, it won't be a problem.

Quote:

Originally Posted by Ray

Treat the plant with your water-soluble systemic insecticide THREE times at ONE-WEEK INTERVALS.

Most insecticides only kill adults, and the egg hatching time for mealies is typically 5-10 days, so if you wait two weeks between treatments, it is likely unaffected eggs will hatch, the creatures mature and lay more eggs before your next treatment.

Thank you both, I'm still waiting for insecticides to arrive. I have removed one more mealybug in the meantime and have not seen any since but will treat the plant anyway and repot it later (at least a nice chance to put it in a transparent pot!). By the way, the plant is growing like crazy, it seems the infestation was not bad enough to cause it much harm luckily.

ZoeO · #5 04-20-2019, 04:11 AM

CROrchid, I know this thread hasn't been active in a while, but I have a similar issue to yours. I had a phal with a small mealybug infestation - luckily I caught it pretty quickly, but it was sitting next to two of my favorite paphs. I was wondering if you decided to treat the two paphs that did not show signs of mealybugs? I hope that you were able to save everything and are you pest free now? Hopefully a happy update? I'm absorbing all of the advice on this thread as well as hoping to hear some encouraging news. This is my very first post on this board and unfortunately my first (hopefully last) bout with pests.

CROrchid · #6 04-20-2019, 04:59 AM

Quote:

Originally Posted by ZoeO

CROrchid, I know this thread hasn't been active in a while, but I have a similar issue to yours. I had a phal with a small mealybug infestation - luckily I caught it pretty quickly, but it was sitting next to two of my favorite paphs. I was wondering if you decided to treat the two paphs that did not show signs of mealybugs? I hope that you were able to save everything and are you pest free now? Hopefully a happy update? I'm absorbing all of the advice on this thread as well as hoping to hear some encouraging news. This is my very first post on this board and unfortunately my first (hopefully last) bout with pests.

I have treated only the infested plant (and later another one that I got from another online shop that had the same issue, but that's unrelated) with imidaclopride granules dispersed in water. I let the pot drench in it for half an hour, took a cotton ball, soaked it in same solution and swabbed all the leaves on both sides. Repeated it three times, one week apart, no watering in between...now, almost a year later, no signs of mealybugs ever again. I have not treated the two smaller Paphs near it but decided to observe them...never seen any mealybugs on them, on the underside of the leaves nor in between them.

If you plan on using these synthetic pesticides, always use gloves or they can get partially absorbed through the skin.

ZoeO · #7 04-20-2019, 11:49 PM

Thank you CRorchid for your reply. Sorry I didn't get a chance to reply back sooner. Your update gives me some hope. Often you see members post about pests but not many follow ups or updates about how it went. So I'm glad to hear there's chance I can still do something.

CROrchid · #8 04-24-2019, 07:06 AM

Quote:

Originally Posted by ZoeO

Thank you CRorchid for your reply. Sorry I didn't get a chance to reply back sooner. Your update gives me some hope. Often you see members post about pests but not many follow ups or updates about how it went. So I'm glad to hear there's chance I can still do something.

You're welcome. Mealybugs are easy to kill using systemic insecticides since they get absorbed by the plant and once the bugs suck onto the sap, they ingest the poison and die. From my experience with them, they do not spread too quickly to other plants (in case your other plants are not touching the infested one) unlike spider mites which float from plant to plant just on air current.

A good method for locating them is having a flashlight (can be the one on your phone) pointing to the plant in a completely dark room. Make sure to inspect the both sides of the leafs as well as those tight areas in between them. You'll have to inspect the plant and those which were near it daily to make sure the infestation is gone.