June 26, 2009

The Slug and I

Last Tuesday morning, the Boston Globe reported something I already suspected: that eastern Massachusetts was on track to have its ‘dimmest’ June since record keeping began in 1885. According to the article, Boston and vicinity had, through June 22, received just 32% of the ‘available’ sunshine. In an average June, the region gets 55% of the possible sunshine between dawn and dusk. In June 1971, a record of 77% was set. (Also in that month, the New York Times began publishing the Pentagon Papers. Coincidence?) Until now, only 1903 was dimmer and, with a week of gloomy weather in the forecast, the record seemed certain to fall.

I do not know if we eclipsed the title, but I can state with some certainty that at least one record was set: I have never seen more slugs on my plants than I did in June. The slug population was off the charts.

I have learned that the common garden slug (Arion distinctus) is constantly with us, but usually as eggs. Charmingly, garden slugs are hermaphrodites, so any two slugs can get together, make whoopee, and play rock-scissors-paper for the right to lay a clutch of 15-30 eggs which lay dormant in the soil until it rains.

If you live in New England, you may remember that it rained in June. I can, personally, count on the fingers of one hand the number of hours in June when it did not rain. And, so, with cool temperatures and lots of moisture, the slugs hatched and came out to play. And to eat every plant in sight. By mid-June the slugs were fat, roly-poly things having feasted on the trays of annuals that were purchased in May with the expectation of planting beautiful, colorful containers.

My wife and I began looking for solutions. Being environmentally responsible sorts, we bypassed the Armageddon solutions at out local garden center. These pellets promised to Kill Slugs Fast, but cautioned in the fine print that they would also take with them to animal kingdom heaven ladybugs, earthworms, cats and dogs.

The Internet, that vast repository of wisdom, offered multiple ‘organic’ solutions to our slug problem. The first suggestion was to create a barrier of lava rock around the plants we wanted to protect. This probably works extremely well in Hawaii. It is of minimal utility in Massachusetts. There was also a tip that we could use lint from our clothes dryer as a deterrent. However, to be effective, we would need to add four ounces of vinegar to the final rinse water (I promise I am not making this up). Something called Quack Grass is reported to damage the nerves that slugs use for feeding. There was even a recipe for ‘Quack Grass Cake’ (corn bran, powdered milk, cornstarch, the aforementioned Quack Grass and 16 ounces of beer, beaten to a paste and run through a meat grinder). This seemed a somewhat promising lead until I Googled Quack Grass and got 134,000 hits, almost all of them in Q&A forums on gardening web sites asking, ‘Help! How do I get rid of the stuff?

I decided that what we needed was not a deterrent, but a method of eliminating our garden pests, responsibly. One web site offered a list of predators. Rhode Island Red hens, the site said, are great slug hunters that eat every specimen of Arion distinctus they can get their beaks on. A nice idea, but our neighbors might object. Blackbirds, crows, ducks, jays, owls, robins, seagulls, starlings and thrushes are also known slug eaters. We have successfully encouraged all of the preceding (except seagulls) to visit our yard. But they do not appear to have developed a taste for our slugs. Perhaps they did not read that particular web site and get their dietary marching orders.

A further search yielded the tantalizing fact that there is a predatory nematode that has been demonstrated effective against slugs. Phasmarhabditas hermaphridita (hermaphrodite vs. hermaphrodite!) are being “mass reared” in England but are not yet sufficient in production to be used widely. Like some D-Day armada, they await the time when their numbers swell sufficiently, when they will likely be launched against the garden slugs of Normandy.

We decided it was time to stop reading Internet articles and start practicing Better Living Through Chemistry. Out came the trusty handbooks. Isopropyl alcohol works. Wonderful. It will also kill many of the plants to which it is applied. Next. Wormwood tea works. Great, but we don’t have any wormwood. Next. Ammonia works. It also burns tender leaves. Next. Quassia works. Wonderful. The nearest quassia trees are in Ecuador. Also available from your neighborhood herbalist at prices so staggering you can afford to replant your property when it stops raining. Next.

Iron phosphate. It kills on contact. It’s poisonous to slugs. It won’t harm plants if you use it sparingly. We looked for the downside. There wasn’t one. The slugs ingest the iron phosphate and lose the will to live. Where had this advice been hiding?

It must be that iron phosphate just isn’t glamorous enough. Wormwood tea, lava rock and Rhode Island Reds all have a certain folksy quality that sound authentic. Iron phosphate sounds… industrial. We found some. We applied it. A week later we had far fewer slugs.

We’ve dealt with the stragglers the old-fashioned way: we’ve removed them by hand, then applied shoe leather to slug.

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