Black vine weevils (& strawberry weevils) are omnipresent in this area......I'm not sure they seem to be any more numerous this year than in the past :-)

Control of vine weevils is not as straight forward as one would hope. In addition to there being an almost ideal habitat for them throughout much of the area (if you have 'em, so do your neighbors!!), it requires a properly timed, two-pronged attack to be successful and usually over a couple of growing seasons. And no guarantee they won't show up again in another year or two.

The vast majority of weevil damage is cosmetic. The larvae typically do minimal damage to established plants, although some smaller perennials - heucheras being high on the list - can sustain serious root damage. It is only the adults that feed on the foliage and even that is limited to certain types of plants. Plants that tend to be heavily damaged might be best located away from the front entry or heavily trafficked areas just for aesthetics.

Whether you attempt control or not is up to you. Sometimes tolerance is just the simpliest path:-) If biological controls are used on the larvea, it can get pretty expensive. It is helpful to read up on the life cycle to gain an understanding of how these critters function - all adults are females - and when is the best time in their life cycle to pursue control of both adults and larvae and the most effective methods to accomplish that.

Over my years as a horticultural consultant, I have found that rhododendron sources typically have some of the best info about vine weevils - perhaps because these plants head the list of the garden ornamentals they prefer :-) The attached link offers one of the most complete discussions of control methods I have encountered. Scroll down to "management in the landscape" for the pertinent section.

Here is a link that might be useful: ARS weevil control info

Root weevils have been a plague o' locusts in my yard this year. Way worse than previous years. Ironically enough the rhodies show little damage in my garden. It's the raspberries and roses that get trashed. It's getting pretty bad right now too, leaves reduced to tatters, raspberry fruits spoiled, rose flowers chewed up. And now they're starting on the blueberries, migrating throughout the yard. I'd say it's a particularly bad year for them.

Are you sure root weevils are causing the damage? Adult weevils typically limit their feeding to the leaf margins of some broadleaf evergreen woody ornamentals, like rhodies and azaleas, laurels, salal, bergenia, evergreen viburnums, vaccinium, pieris and even conifers. I have never known (nor I have ever found documentation to support) their feeding on any floral or fruit parts nor on most decidious plants (hydrangeas and hostas can be an exception). Larvae have a different menu preference but nothing above ground :-) Even the strawberry root weevil only affects the roots of the plant, not the fruit.

I'd suspect you are looking at something other than root weevils for the majority of your problems.

Oddly enough, I found a black weevil parked on a nearly ripe blackberry in the yard. But that was the first time in over ten years.

We seem to have outlasted the weevils in this yard, for this year. Very little damage to low rhodie and eucryphia leaves.
We have used nematodes for control in the past, but not recently.

The weevils no doubt have boom and bust years.

Since WSU has multiple publications on root weevils on cane and bush berries I think they'd beg to differ with gardengal on host plant range of root weevils. They describe 7 different species that are considered common pests. And as a long time serious gardener and rosarian I've pretty much eliminated other causes of the damage to the fruits and flowers in my garden.

So yes I'm sure it's root weevils and they show a definite preference for the roses and raspberries over the rhodies. Not that the rhodies are damage-free but it's minor, and it's probably different species of root weevils involved. And the weevils are an order of magnitude worse this year than in previous years. It's making me think twice about moving any of these plants to a new garden, that's for sure.

I too have read all the WSU publications on root weevils and a from a few other sources, like UCDavis. Diagnosing plant problems and recommending treatment is one of my primary professional responsibilities and I have studied this issue in depth. With respect to cane fruits as well as strawberries, any significant plant damage is due to larvae feeding on the roots and/or girdling the canes at ground level, causing wilting or even death. There is no evidence to support or any reference to larvae (or adult weevils, for that matter) feeding on fruits or flowers. And virtually without exception, all remark that damage by adults to foliage is purely cosmetic and insignificant to the health of any of the plants on which they might feed.

I haven't seen as much damage on the rhodies, either, they seem to prefer the hydrangea. I was most worried about all the grubs that must be eating the roots to have produced so many weevils. When I went out at night with a flashlight to find out what was doing all the damage, I could not believe how many weevils there were. Every year it seems like the weather conditions produce a bumper crop of some particular insect, at least it isn't wasps this year! Has anyone tried those nematodes? Do they actually work?

Tough time of year to apply nematodes, the process requires cooler and damper soil than typical summer conditions.

We did use the new dehydrated nematodes this spring for flea beetle control. Just mix with water and sprinkle on soil. Autumn application could get results for 2013.

Nematodes work very well, provided you select the appropriate species and apply them at the right time. Actually, now into September/early October is the best time to utilize beneficial nematodes for larval control. It is the proper time in the life cycle of the weevils as well as affording the ideal soil temperatures for the nematodes to flourish. Applying in late spring or early summer, the soil temperature is too cold or the larvae not present in the proper instar stage. Water the soil well before application and drench the root zone of any suspected host plants.

Control of root weevils is always going to a be a two-pronged attack. You must capture/trap/kill the adults as well as treat for the larvae. Doing one without the other is a waste of time and often money (nematodes are not cheap). And it is not a one time shot method. You must repeat the process for several seasons to get effective control and then periodically thereafter. Root weevils will always be a fact of PNW gardening life. But in the vast majority of cases, the bulk of their damage and effect on plants is only cosmetic.

I've obtained a few pretty well chewed up rhodies over the years doing yard makeovers. Chewed up so bad the customer didn't want them in their 'new' yard.
Rather than throw them away, I just put the rootballs in the pond for a few days. Replanted, trimmed any low lying branches touching the ground, and planted them. The new growth came out with no notches. I did it several times with the same results. The larvae can't handle two days under water, but the rootball can.
Some varieties of rhododendrons are more susceptible to the weevils than others.
Mike

Thanks, Mike, that is info worth knowing!