This morning I found myself picking pill bugs off my bean seedlings.
I noticed that several of the new sprouts — Kentucky Wonder, Contender, and Scarlet Emperor — had wilted and looked chewed. A few had pill bugs on their tender new leaves, but all had dozens of these tiny crustaceans just beneath the surface of the soil, devouring the seed from which the plant had sprung, as well as the young roots.
Pill bugs are a type of woodlouse, a bug I’ve always regarded as kind of harmless. Typically they come out at night to feed on dead plants, which benefits soil fertility, but apparently they can be a pest in cultivated environments. They breath through gills, and so require moisture, which I have been providing regularly to germinate the bean seeds. The combination of a wet environment and new growth drew the pill bugs out of the nearby leaf litter where they typically dwell.
At least half the beans are a loss, but will be easily replanted — a benefit of having started the warm-season crop early this year. However, starting over sets up the same conditions that caused the problem in the first place.
There are, of course, dozens of chemical options with which I could firebomb the entire planter, but that’s not really the way we roll. Sprinkling the bugs and the area around the new plants with diatomaceous earth is a greener option. D.E. is simply crustacean and algal fossils that have been deposited in marine layers, crushed and pulverized for millions of years, and then mined as a fine powder (I suppose the mining’s not really green). When used as a pesticide, D.E. slips between the segments in a hard-shelled animal’s exoskeleton and has a desiccating effect — in other words, it dehydrates the animal to death.
However, karma-wise, that sets me up for, what, an Australopithecus bone bludgeoning?
I ended up going with a solution that accomplishes two goals: reduce the population of pill bugs to the point where it no longer poses a threat to my bean sprouts (hopefully) and put the dead to good use. I guess third goal that my solution satisfies would be gardening without inputs.
I picked the 50-or-so woodlice from my plants and fed them to the chicks. I wanted to see how they would react to their first non-feed food. And you know, it doesn’t really take a biologist, or an experiment, to know that a bird will eat a bug.
They did. And they were damn happy with their handfuls of hand-picked terrestrial crustaceans.
You might be able to create a small controlled planting box, isolated from your planting beds and then transplant the beans when they have germinated and are strong enough to survive a pest attack. I like the bird solution though. Once they’re big enough they might find a great deal of nutrition from picking through the compost. Just make sure you have your worm bucket covered when you set loose the pullets.
Also give worm castings a try, they take about a month when sprinkled along the base of plants but unlike DE you can get it wet and it won’t kill ladybugs, spiders and other beneficials.
[...] a small garden can be destroyed. Diatomaceous earth can work on them as it does woodlice (see “A roly-poly problem” posted on Mar. 24), but grasshoppers are so mobile I’d have to dust much of the yard and [...]
[...] month or so ago when my first round of beans succumbed to woodlice (see “A roly-poly problem” posted Mar. 24), a friend and former student of mine recommended that I grow beans in pots until [...]