I looked through this for awhile looking to see if anyone else had this problem. My rhodies are looking sad, they have bites in semi circles on the leaves and are very unhealthy looking. These are in the shade under some conifers. My other rhodies are fine where they are more exposed. A friend told me I have root weevils? A beetle type thing that come up at night and eats the leaves and has larvae that eat the roots and stems? Anyone know what this is and what I can do? Someone said Fels Napha soap would help but how do I use that?
Rhodie root weevil
well, I don't know how to use the soap, but I know that the best control for these critters is a two part issue. The soaps, sprays, topical applicants, etc. will only affect the adults (where there are adults, there are larvae already growing as well). There are a couple of sprays that you can get at most garden centers that will say that they are for root weevils. I can't remember the chemical compound that takes care of them, I think that it's orthene. but, the brands will say what they're for. However the: sprays, powders soaps, topical stuff, only affect the adults and does nothing to kill the larvae that eat the roots and later become the adults. the larvae are likely already working on some plants some where. And since the larvae attack the roots, they actually may cause more damage to the health of the plant. The way to kill those buggers is to spray nematodes (sp??), another bug that eates the larvae. Typically, nematodes do their best work in the fall by eating the larvae that will become next springs adults. But, they may be able to be a little helpful this time of year. If it were me, I would spray for the adults now and the spray nematodes this fall. from then on out you may be able to skip the spring sprays and do just nemotodes every year or other year, unless there is and epidemic of sorts. but, that's not often.
This message was edited Apr 14, 2008 10:50 PM
Well I was hoping it was something easy, but assumed not. I was told the soap will kill the larvae, it is supposed to be a drench at the roots. I was hoping someone else used it and it was a miracle cure and one dose would end the problem. But I kinda knew that would not happen.
Thanks for the info.
Well, there's no harm in trying the soap! Go for the soap and let us know how it goes! It doesn't really sound as if you have an "infestation" of sorts, typically one or two plants is not much of a problem, hitting them with the two punch process probably isn't necessary. However, nematodes are really quite easy to do. I didn't get around to spraying them last fall due to surgery and I have two Rhodies (out of many) that they have chewed on several leaves. I don't usually bother with the spray in the spring unless there's serious damage going on. Since there doesn't seem to be a big problem, i'm going to wait until fall and spray nematodes then. Then it'll be at least another year before I do anything about them again. All I do for the nematodes is pick up a box of them in Eugene (or order online), put them in a sprayer with a large nozzle, add the amount of water the directions say, and then .....spray!
The hardest part is catching the right weather: not too hot, not too cold, and within a certain time frame of rain/watering. That's why fall is the best time. Good luck! redchic
ohhh, I forgot something, but you probably already know about the weevils anyhow. Much of the time the larvae are not under the plant that the adults are eating! To figure out for certain where to "soap" them, you actually need to have found the little critters or (and I think this is what's most commonly done) treat under all the plants in the affected area that they like to eat (rhodies!)