They just invaded this part of Vermont last summer. I read they only came to New England in the last few years. I also read that Spinosad insecticides kill the larvae; Pyrethroid insecticide kills adults. Do you have any such stuff? They wiped out my Oriental Lilys last year and apparently overwintered because I have picked off several already.
Thank you for your help, K.T.
Red Lily Leaf Beetles, also known as Scarelet Lily Beetles, are a bright red and fast flying leaf beetle that's highly mobile and destructive. Indigenouse to Asia and some parts of Europe, it's thought they made their way here to North America with some plants sometime in the past 50-75 years. Initially discovered in one or two States and Canada, the lily leaf beetle is now found throughout the New England states and is considered to be both invasive and destructive. If you see them on your property a pro active pest management program is strongly suggested to control the population and prevent further growth. Leaf beetles like to live close to good food supplies and once they find your landscaping will no doubt take full advantage of your offerings. Unlike many of our native species which can live without doing severe damage, the lily leaf beetle has a tendency to destroy more than what it leaves for us to enjoy. For this reason they should be managed to the fullest extent or else you'll be risking your gardens bounty.
Like several other invasive pests, Asian leaf beetles over winter and don't die when the cold arrives. Adults seek a good place to hibernate and many times this will be on the outer siding of a structure. Man made buildings – especially any structure which is heated – will provide both shelter and warmth to help them through the long winter. It's during these cold months that leaf beetles will become active inside the home. This is especially true if you keep house plants growing year round. Poorly sealed homes with a lot of open cracks and crevices for leaf beetles to enter living spaces may also see inside activity. Like Asian Ladybugs, Boxelder Bugs, Leaffooted Plant Bugs and Stinkbugs, the red lily leaf beetle will forage inside if conditions are right.This invasion may also occur in early spring when they become active again and are trying to get back outside for the warm summer months. We commonly get reports of problems in the fall and then again in the spring with this pest and if you see them active at either time on your home, it's a good chance your house is becoming a nest site. In early spring the adults which successfully leave will immediately start looking to feed, mate and lay eggs.
The preferred plant or food for lily leaf beetles is the asiatic lily but it's been found to feed upon oriental, easter, tiger and turk cap lilies as well. It will also feed on fritillaria and other plants when they can't find a preferred food supply. The exact list of plants lily leaf beetles are willing to eat is still largely undetermined at this time but it's ever growing. It's also suspected their young will feed on a broader range of plants but this is still undetermined. Anyone who has seen them around their property or found them in their garden knows the extent and damage just a few can do. They eat fast and move rapidly causing damage and weakening plants in their path. Worse yet is how quickly they reproduce.
After coming out of hibernation and mating, females will start to lay eggs. They commonly lay between 250-500 eggs every spring and will typically distribute these on individual leaves of host plants. These plants will be wide spread and could cover several acres. Eggs will be in groups of 10-15 per leaf and only a few leaves per plant will be utilized. Females will then fly away to find another plant and spread out their eggs increasing the odds of survivability for their young. In 1-2 weeks the eggs will hatch larvae which are fierce feeders. Consuming everything in their path as they grow the larvae will mature in less than a month. Once fed out, they'll drop to the ground to pupate. In the soil they'll molt and change to the more commonly seen adult. This molting stage takes 2-3 weeks so by mid summer you'll have a whole new crop of adults adding to the local population. It's believed all adults will simply feed the rest of the summer and into the fall until it gets too cold for them to continue. Since young adults are quite capable of flying, their design lends itself to the rapid spreading of this beetle. Unlike other pests which are limited to just crawling around, the leaf beetle can fly using it's keen sense of smell to locate local food supplies.
At this time there are several products available which work well on lily leaf beetles. We offer both the stronger pesticide formulations which work quickly and last a long time. We also offer organic products which typically take longer to knock out this pest but in the end can provide adequate control. If the problem is on lilies or some other plant that won't be yielding fruits or vegetables, the pesticide formulations will be the preferred product to employ. If you're finding the lily leaf beetles in your vegetable garden, some of the non toxic organic options will be better suited for the treatments required.
The strongest option includes a combination of BIFEN IT and SPREADER STICKER. The Bifen is a synthetic pyrethroid which is both active and long lasting. Odorless and easy to use, Bifen should be sprayed onto any plant where activity is found or suspected. Add the Spreader Sticker to the tank mix to insure you get good coverage on the bottom side of the plant leaves. Leaf Beetles like to hide on the underside of plant leaves and the Bifen won't uniformly cover the plant leaving a lot of spots where beetles can survive. Adding Spreader Sticker to the tank mix will eliminate much if not all of these locations. Treat any plant in the landscape with activity or any you wish to preserve and save from feeding damage. The Bifen can be used pretty much everywhere except vegetable gardens.
If the lily leaf beetles have found their way inside the home, the best product to use in the living space will be the PHANTOM AEROSOL. Low odor and dry to the touch when applied properly, Phantom has proven effective for other winter pests like Asian Ladybugs; another tough Asian import. During applications for this pest it's been learned the Phantom will work on leaf beetles too so treat moldings, baseboards, around windows and electric outlets too where they'll enter living spaces. Treat monthly until the activity subsides but if you wish to stop them for good, you'll need to treat the outside of the home with the liquid Bifen. Doing this in the fall can really help and keep them out but if you find them inside during the winter, use the Phantom. Lastly, be sure to treat in the spring with the Bifen to intercept their spring exodus so you won't have them returning next fall.
The organic products we've found labeled for our common leaf beetles also work well on lily leaf beetles. If you need to treat any plant which will be yielding vegetables or fruit, go with the 3-IN-ONE FIM organic concentrate. Fast acting and effective on any leaf eating beetle, it can safely be sprayed on vegetables with only a 1 day to harvest wait time. It can be used on lillies as well and should be applied weekly when treating a known infestation. Another product we've found to be effective is the BT DUST formulation which uses bacillus thuringiensis as the active. This is definitely a good choice for the larvae though it's unclear if it's working well enough on adults. Lastly, INSECTICIDAL SOAP will also kill both adults and larvae but it's only active when first sprayed. When using soap, expect to treat every few days to keep ahead of the problem as lily leaf beetles will keep appearing from local populations and since soap doesn't provide any residual protection, the new arrivals will be able to thrive on vulnerable plants. If you find adults coming around a day or two following your treatments, consider one of the stronger options to get better and longer lasting protection.
For your benefit, here are direct links to the products listed above:
Spreader Sticker: http://www.bugspray.com/item/spreader_sticker.html
Phantom Aerosol: http://www.bugspray.com/item/phantom_aerosol.html
Insecticidal Soap: http://www.non-toxic-pest-control.com/concentrates/insecticidal-soap