Wednesday, September 24, 2008

The Good, the Bad, and the Ugly: Biological Control at the Conservatory

The horticulture staff faces a number of challenges when it comes to keeping the conservatory's plant collections looking their best. One of the most constant is dealing with pest insects attacking the collections. Having so many plants in contained environments, their density and year-round growing seasons create a great opportunity for pest insects to make themselves at home. At the conservatory, we try to choose the most effective and people-friendly (we are open to the public every day) options. The most interesting of which is biological control, or the use of one organism to control the population of another (undesirable) organism. Sure, there are sprays to kill bugs, or even the simple removal of a pest. But introducing predators and parasites to kill pest populations is far more exciting!

Since we grow plants year-round and in such high density, they are much more suceptible to pest attacks. If one plant harbors an insect, chances are the plants nearby eventually will , too. There is no freezing or dormant season,like there is outside, either. We regularly monitor our plant collections, looking for evidence of the unwelcome insects feeding on our plants--this could be something as obvious as spots on leaves or flowers, or something as minute as the perpetrators themselves. We receive shipments of "good" bugs, as often as weekly, and release them in areas where we know we have an issue. The beneficial organisms are often specific to certain pest insects; they are usually predators or parasites that prefer certain species. We can order them from a catalog and recieve them within a week.

Be sure to look around the conservatory and you may see some of our good bugs in action--sometimes there are ladybugs wandering around looking for an aphid snack. This may sound awfully gory, but there is a satisfaction to knowing that the bugs responsible for ruining a stunning flower, or destryong the leaves of a specimen tree, are being devoured by another insect. Or maybe I am just a vindictive gardener....