organic, kinda sorta

I sup­pose say­ing that your gar­den­ing meth­ods are mostly organic is like say­ing you’re slightly preg­nant. If you’re a total purist this is a yes/no sort of thing. I try to keep away from most chem­i­cals, but every now and then some­thing pushes me off the wagon.

Mealybugs ugh ugh ughA few days ago I dis­cov­ered that there was a sud­den and mas­sive infes­ta­tion of mealy­bugs on one of my plant­i­ngs of green-eyed glo­riosa daisies, Rud­beckia hirta. In addi­tion to the mealy­bugs, there was a major trail of ants going into the bed.

I’ve posted before about the sym­bi­otic rela­tion­ship some fungi and crit­ters have with ants. Since then I’ve read how another critter–bumblebees–have been increas­ing their depen­dence on the hon­ey­dew pro­duced by suck­ing insects, in this case, aphids. Appar­ently the bum­blee pop­u­la­tion has crashed in Scot­land, likely because of habi­tat loss that has destroyed many of the plants they depend on. To com­pen­sate, the bum­ble­bees have been vis­it­ing plants infested by aphids and feed­ing off the sweet goo the smaller crit­ters pro­duce. The aphid goo, how­ever, lacks the essen­tial pro­teins that plant nec­tar pro­vides the bees, and the bees are suf­fer­ing even more.

In deal­ing with my ant-mealybug prob­lem I didn’t want to use a bunch of poi­sons, partly out of prin­ci­ple, partly out of the fact that the affected plants sit right out­side the kitchen window–not a place I wanted a pile of toxics.

My solu­tion to this prob­lem was two-pronged: try to con­trol the ants that were cul­ti­vat­ing the mealy­bugs, and reduce the num­ber of mealy­bugs on the plants to give them a fight­ing chance.

I’ll start with the mealy­bug con­trol steps because that was the organic part. You can knock down mealy­bug pop­u­la­tions to a cer­tain extent using a strong blast of water. You can also use a non-toxic sub­stance like insec­ti­ci­dal soap. With peo­ple head­ing over to the house this hol­i­day week­end, I opted for the lat­ter approach, hop­ing the con­trol would be quicker and more thor­ough. A thor­ough squirt to cover stems and leaves–top and bottom–has reduced their num­ber con­sid­er­ably. I’ll repeat in a cou­ple of days to try to drop the pop­u­la­tion further.

The ant con­trol part was more dif­fi­cult. Some species can be con­trolled by a mix­ture of borax and sugar left near their trails, but unfor­tu­nately my ants didn’t care for my cook­ing. Dish­wash­ing deter­gent mixed up with water can some­times be poured onto their nests to con­trol many of the ants that come in con­tact with it, but effects don’t last long. Ants dis­like cucum­bers, so you can some­times keep them away by spread­ing cucum­ber peel­ings. But once again, that can have lim­ited effects.

So out came the bar­rier spray that I used once this year to keep them out of the house after every­thing else failed. The hard­scape around the plants got a quick perime­ter line of the stuff, as did a cou­ple spots where the ant line crossed some bricks. A quick touchup a cou­ple days later and so far they seem under control.

So, yes, I did let a few squirts of chem­i­cals into the gar­den, but com­pared to spray­ing the plants all over with some­thing poi­so­nous, this seemed like a rea­son­able compromise.

So is this organic? Not really. But it’s a good way to reduce depen­dence on chem­i­cals by tak­ing a more sys­tem­atic approach to pest control.

July 03 2008 | Categories: gardening • my garden | Tags: • • • | 1 Comment »

ant farm[ers]

So…you think humans are the only crit­ters who farm and gar­den? Think again. From a Sci­ence in Brief col­umn in yesterday’s LA Times comes this about ants:

Study finds ants long­time farmers

Ants took up farm­ing some 50 mil­lion years ago, accord­ing to researchers who traced the ances­try of farmer ants.

An analy­sis of the DNA of farmer ants traced them back to an orig­i­nal ances­tor — a sort of Adam ant, at least for the types that raise their own food, accord­ing to a paper pub­lished in the online edi­tion of Pro­ceed­ings of the National Acad­emy of Sciences.

In the last 25 mil­lion years, ants have devel­oped dif­fer­ent types of farm­ing, includ­ing the well-known leaf-cutter ants. Leaf-cutter ants don’t eat the leaves they col­lect. Instead, they grow fun­gus on the leaves and eat the fungus.

Only four types of ani­mals are known to farm for food — ants, ter­mites, bark bee­tles and, of course, humans. All four cul­ti­vate fungi.

If you have online access to that jour­nal, you can read the full arti­cle at: http://www.pnas.org/cgi/reprint/0711024105v1. There’s no research on whether ants pre­fer to cre­ate for­mal gar­dens or nat­u­ral­is­tic ones, though I’d guess aes­thet­ics aren’t hight on their list of concerns.

To that, I’d also add that some ants are also live­stock farm­ers in that they cul­ti­vate other ani­mals. Aphids and ants have a sym­bi­otic rela­tion­ship, with ants tend­ing aphids to share in the sweet nec­tar they exude. And all last year we had a major ant trail lead­ing from the ground into the grape­fruit tree, where ants and scale insects had set up shop on the skins of the young grape­fruits. It didn’t seem to affect the grape­fruits too much, though we always had to remem­ber to scrub them clean before serv­ing them up. Here’s a link to a related story on ants and scale insects in trop­i­cal cof­fee plan­ta­tions.

March 30 2008 | Categories: gardening • quotes | Tags: • • • | 1 Comment »