|Is there a safe, effective way to discourage wasps and hornets on my balcony garden? I am very allergic to their stings, and at any one time can have a half-dozen or more flying in and around my containers.|
|The most common types of "pest" wasps are paper wasps and yellow jackets. (They are both also "beneficial" insects in that they eat many pest insects.) These are types of "social wasps", as opposed to solitary wasps.
Paper wasps are the ones that build those papery, honeycombed nests in barns and under the eaves. If possible, inspect your eaves (if you have them on your balcony) regularly to look for signs that they're starting to build a nest there. If you do see the beginnings of a nest, try to get someone not allergic to spray some water on the nest to scare off the wasps, then use a broom to remove the nest. (Don't do this with an established nest.)
Yellow jackets are much more fearsome--and more aggressive--than paper wasps. These creatures build nests underground, then scout the local area for food sources. The first thing to do, then, is to remove any food sources on your balcony. This includes pet food and garbage cans; don't bring out sugary drinks in open containers (better to get a cup with a lid and built-in straw), and don't leave uncovered food around.
Planet Natural at
offers a botanical wasp & hornet spray you may want to try.
You can also try trapping them: If yellow jackets are the culprits, you could try a "Yellow Jacket Trap", they usually pop up in garden centers in the spring and are available now in many garden catalogs. Although they are marketed as a trap for yellow jackets, I have seen a few other types of wasps in the traps at emptying time.