Monday, May 23, 2005

Killing the Red Lily Beetle

I have the dreaded red lily beetle (aka scarlet lily beetle). Yesterday I saw several adult beetles living on the Fritillaria imperialis in my bulb bed, as well as on the Lillium ‘America’ in my long bed, but not (yet) on the shorter Lillium ‘Stargazer’ in the same bed about 15 feet away.

So I sprayed Lillium ‘America’ with Schultz House & Garden Insect Spray (0.02% Pyrethrin) yesterday. The product claims to work on beetles, and today I saw no beetles there, although they were still on the unsprayed F. imperalis. But I have seen reports of very limited effect from this organic pesticide, and it’s close to impossible to spray-cover all parts of this Lily plant, whose leaves are still quite curled up, especially if you want to avoid overspray.

I do not want to use far more toxic pesticides such as imidacloprid. Instead, I have a more radical plan, or experiment, in mind. That is to use fumigation (i.e., gas, within an enclosure). In general, fumigants are considered too dangerous for amateur use. But I would use either cigarette smoke or carbon dioxide to kill the beetles, and I can’t see fearing either gas (well, smoke is more like an aerosol), especially when used outside, and within an enclosure.

Basically, I could upend a container like a trash can – preferably clear – on the plants. This container would have two holes in it, one connected to a hose, the other with a flap or other one-way valve on it. Since smoke (and carbon dioxide) is heavier than air, I will pump smoke into the lower hose, with air to vent out the top until the container is full of smoke. The cigarette will be held within a pipe-like mechanism, surrounded by a glass cylinder, so I can watch the cigarette burn down as I pump air into the mechanism, through the hot cigarette, and into a narrower tube placed on the filter. (I may remove the filter; why reduce the toxins?)

Of course, I do not know if this will work – ideally, kill adults, eggs and larvae. I have read of a high-school science experiment / propaganda, where tobacco smoke is shown to kill flies, which are unharmed by a similar amount of paper smoke. Also, nicotine has long been used as an insecticidal powder, and is in the tobacco plant precisely as a systemic pesticide, as are most plant toxins. It’s just a question of dose and duration, relative to the particular susceptibility of the Lily Beetle.

Provided the beetle infestation survives the pyrethrin – which seems likely – I think I will have to head out to a hardware store, or maybe a head shop, if they still have those, soon.

Whether tobacco works or not, I may also try carbon dioxide. It’s easy to get 10 to 20 oz. tanks of pressurized liquid CO2 for use in “constant air” paint ball guns (they’re rather smaller than the standard propane tank used by plumbers).

I have not been able to find anything concerning horticultural use of tobacco smoke as an insecticidal fumigant. Does anyone have any experience with such methods, or know of any source concerning the same?


The Nature Nut said...

I really feel for you. My Riverwood garden was infested with the Lily Beetle a few years ago, and once they settled in, I could never entirely get rid of them.

My method was to tour each plant twice a day (morning and evening) and kill every beetle I saw. The easiest (and most satisfying) was to grab the little #$%*&^ and squish them between my finger and thumb. I used to destroy hundreds each day.

Since I have built a new house (and garden), I have been reluctant to plant lilies, because the Lily Beetle is present in my new neighbourhood.

Good luck with your method, I'll check back to see if you've posted results of your fight.


P.S. I like your site ... if you would be open to a link exchange, I would be happy to do so.

Jenn said...

Tobacco Mosaic Virus.

Something to think about with the cigarette idea.

Might not be a problem with the plants you are dealing with.

Anonymous said...

I have been heavily infested with the terrrible lily leaf beetle for four years. I have many lilies in my yard and spend a good couple of hours every other day patroling them. I have resently read that neem works as well as Merit, which is suppose to be used in the spring when the bulbs begin to emerge. I plan on trying these items and if they don't work then I plan on pulling all my lilies out and destroying them.


Anonymous said...

I would like to know how you make out battling the Dreaded Lily Beetle. I cannot spray because I keep honeybees and try to spare them any toxics or possible toxics. I have stopped planting lilies and do not like to admit that I removed the lilies that were desiccated (3 summers in a row) by the beetles. It is heartbreaking because I love lilies.

Anonymous said...

Tobacco..In febuary of 1971 I worked for the Miracle Gro company packaging Miracle Gro, Prill, a lawn fertilizer, and small 8-10 oz. cans of Nicotine to be used a a fumigant in greenhouses. Inspired,I soaked cigars in water and sprayed the resulting smelly brown liquid [ which I assumed was laden with nictine], with success, on aphids and white fly. Red Lily Beetle.....I first heard of "the scourge of Cambridge" about 10 years ago. They arrived in my S.E. New Hampshire gardens about 6 years ago with devastating results. I have been using common ground black pepper to repell ants from my strawberry patch and around the perimeter of my home since 1973. With nothing to lose I decided 2 years ago to dust my 50+ lilies with black pepper. I used to have 75+ but could not keep up with hand picking the beetles and larva 3-4 times a day. I have had up to 90% reduction in 4 diffrent locations and 2 trial gardens not dusted are covered with larva, The pepper seems to annoy them. I have found stiff but alive beetles on the soil the day after dusting. I try to dust up under the leaves. The pepper that falls to the ground is helpful as that, as I understand, is where the adults spend the night and the larva drop to pupate Give it a try respond to

Yasi said...

I just pick the beetles and the eggs, first thing in the spring, as soon as it starts to get warm, and then if I am vigilant in May, this knocks back the population and it's not so difficult to keep up with them. I think I'll try making a tobacco tea and spraying the plants with that.

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Anonymous said...

Thanks for the advice here. I've been using tweezers to get the little devils out from between the leaves and that helps catch more of them. I'm going to try the pepper now. If that doesn't help I'll try the nicotine.

They had destroyed the lilies in my backyard so badly that I took them out, washed the bulbs off and placed them in a pot to winter. They just found the ones in my front yard so the war is on.