Years ago, when Organic Farming & Gardening magazine was printed in black and
white, and small enough to stuff into one’s pocketbook or jacket pocket to read
as time allowed, it was always filled with intriguing tips and commentaries for
growing better vegetables and controlling garden pests. I remember reading
about white geraniums being deadly to Japanese beetles. Not growing many
geraniums back then, I filed this piece of information somewhere in the back of
my mind until this past weekend.
While watering some pots of ‘Orange Appeal’ geraniums that I had started from seed
and strategically placed in an old blue, wooden wheelbarrow, I couldn’t help
noticing that there were belly up Japanese beetles nestled in the leaves! On
Saturday I just thought, how curious and flicked them off. A repeat performance
the next day triggered those latent memories and also brought back to mind a
more recent posting from the Agricultural Research Service (ARS).
According to the ARS, the negative effect that geraniums have on Japanese beetles (an
obnoxious pest – at least here in New England) has been known since the 1920’s
but not until recently have scientists started exploring this relationship more
closely. It seems that within a half hour or so of nibbling on either the flowers
or (as I saw) leaves of the geranium (Pelargonium zonale), the beetles become paralyzed for about
24 hours. Had I known they were not dead, I would have finished them off. Under
laboratory conditions, the beetles generally will recover. In the wild,
however, they are often snacked upon by other critters since they don’t have
much of a chance of getting away in their paralyzed state.
An entomologist at the ARS, Chris Ranger, along with a scientist at Rutgers,
is working on developing a botanical insecticide from these paralytic compounds
which hopefully will be available sometime in the near future. Read more about “Geraniums
and Begonias: New Research on Old Garden Favorites” in the March 2010 issue
of Agricultural Research magazine.
Not only are my few pots of geraniums helping to control the Japanese
beetles in my yard but as I hand pick them from my roses, 4 o’clocks, hollyhocks
and dahlias, I also have been noticing that a fair number of beetles have
little white spots on their green thoraxes. These are eggs of the Winsome fly.
The larvae will hatch and burrow into the beetle where it will begin feeding.
This apparently affects the beetle’s behavior and it will bury itself in the
soil where the larvae continues to feed and overwinters in the hollowed beetle
shell. The following year, an adult winsome fly emerges to continue its quest
to find more Japanese beetles to lay eggs on.
But enough of this backyard reality show! It’s summer1 The gardens are
glorious and, if you are looking to travel to the western part of
Massachusetts, do check out the house and grounds at The Mount, Edith Wharton’s
summer home.
Edith Wharton was not only one of America’s greatest writers but
she also designed The Mount and the accompanying landscapes. There are 150
acres filled with mossy woodlands, meadows, tree-lined drives and walkways, her
restored greenhouse and formal gardens. The house which has in large part also been
restored can be toured as well and it is well worth a slow stroll through the
rooms which have many fascinating and little known facts about the life of
Edith Wharton and her great compassion and drive to help others during WWI and
later. Not only was she a great gardener, interior decorator, and writer but
she was also a great humanitarian. Take a step back in time and experience her
world in the early 1900’s.
Good gardening to you!
Dawn
July 28, 2011 at 2:49 am
Edith Wharton’s gardens are lovely. I guess I don’t have enough geraniums because the Japanese beetles are terrible this year.
August 26, 2011 at 6:40 pm
fertiliser…
‘Orange Appeal’ Geraniums Lure Japanese Beetles to their Death (or at least give them a nasty hangover!) « Uconnladybug’s Blog…
February 25, 2012 at 2:24 am
I tried this approach of Japanese Beetle control for the first time last summer though I also put down Grubex on the lawn and planted several catnip plants. i could not believe how little Jap beetle damage I had as opposed to previous years. Plus the Geraniums add plenty of season long color.
July 11, 2012 at 7:16 pm
[…] Geranium flowers can be deadly to the Japanese beetle. A particular amino acid in a geranium flower that causes paralysis of the Japanese beetle is identified in this study, and you can watch the paralysis here. This blogger has had success controlling Japanese beetles with geraniums. […]
August 14, 2015 at 8:42 pm
[…] When I started this little experiment, I only knew that Geraniums were known to repel the Japanese Beetles. They actually don’t repel them, but they do help keep them from eating your plants and there is actually science to back it up! […]