several months ago i asked in the pest forum if anyone had had any experience with lily beetles - no luck or rather, lucky for all those that have not had their lilies desercrated by these lady bug look-alikes. my understanding is that these evil doers originated in conn. and have made their way throughout new england. two years ago when i had weaned off all bad chemicals, they completely annihilated all my asian and oriental lilies. i tried safers and some other organic products, to no avail. this year i bought some poison whose name eludes me at the moment (not sevin-something new) and i have a few flowers but the foliage is so hacked, the plants look horrible (as i look at the lovely pics posted...). two of my gardening buddies have given up and thrown their lily bulbs away to use the space for other plants. it's really discouraging; they can hit and accomplish a lot of damage before you're aware of their presence. does anyone have any suggestions for combatting these things? they are worse than japanese beetles and i thought they were the scorge of the gardening world. help!
We have a real problem with them in southern England, they attack Fritillaria too. We pick them off and squash them when we find them. There are few chemicals to control them and we only have one parasitic wasp species in England that is a natural predator.
RHS suggest "imidacloprid + methiocarb (Bio Provado Ultimate Bug Killer aerosol) or imidacloprid + sunflower oil (Bio Provado Ultimate Bug Killer concentrate). The larvae are more susceptible to insecticides than the adults." Perhaps there are similar chemicals in the US that contain those ingredients.
imidacloprid in the US is available in Bayer Advanced ____
Here's an excerpt from a post on another gardening forum about one person's experience. There was quite a debate about whether this chemical is harmful to bees, butterfiies and other friendly insects as well as pets. This chemical is also used in flea collars for pets, so as long as they don't have high dose exposure they should be fine. The lady in this post makes a good point about "localized" use of the treatment around the lilies.
"Finally it was either to use chemicals or pull up the lilies. I decided to try some cautious use of chemicals. I located Bayer Advanced Tree and Shrub. It contains imidacloprid. I think it is sold especially as a drench for hemlocks with wooly adelgid. You stir it into water and pour it just on the ground immediately under the lily. It helps to water it in or have rain. I applied it when the first bug appeared and the lilies were only a few inches high, in fact some had not even emerged. After that the damage stopped. Since then I have seen only 4 or 5 beetles and have not seen any grubs on the leaves. It is such a pleasure to be able to enjoy lilies again and I hope that such a localized application will do little harm to anything else."
Information I've read elsewhere suggests turning the soil lightly around your lilies early in spring to expose the larva just beneath the soil.
Hope some of this is helpful and that those darn things don't come west!
We do not have lily beetles this far north, thank goodness. But in the summer issue of Ontario Gardener there is an article about lily beetles that I found interesting. It states that one female can lay up to 450 eggs. Yikes. Also says that you can try insecticides with carbaryl, methoxychlor or rotenone. These pesticides are effective on the young larvae & somewhat on the adults. You must be sure to spray on all the undersides of the leaves.
Has anyone tried Neem oil? I bought some this week to use on an aphid & whitefly infestation as well as tiny black worms. Haven't used it yet, hopefully tomorrow. It is supposed to be mixed in small amounts as it will break down if stored in water for long periods of time.
" When only a small number of plants are infested, one can remove these pests manually. However, when many susceptible plants are attacked, applications of pesticides may be warranted. Neem products have been shown to kill larvae (especially the very young ones) and to deter the adults but applications may need to be administered early in the growing season and then repeated with some regularity (weekly) in order to achieve the desired level of effectiveness. Chemical pesticides are available but be careful to not use these when foraging bees are in the area and visiting flowers."
I saw another post that someone said that when picking off the adult beetles they couldn't stand the idea of squishing them so she threw them in a bucket of olive oil. (?) She found they drowned in it. Supposedly the oil affects them by clogging up their "pores" in their exoskeleton (?) through which they respire. They reported that they started spraying olive oil on the leaves (including undersides) and the soil around the lilies and met with some success had seen nary a beetle in many weeks.
Frankly, I'd be willing to try any and/or all of the suggested treatments. Anything to save my LILIES!!