GREEN SCENE: Big bad bugs

Assassin Beetle, Cicada Killer Wasp, Elephant Beetle and Giant Walking Stick – these are all big bad names for totally harmless insects that co-exist with us on this planet. Whether we like it or not, insects are a part of our world and have been around longer then we have. Their vast numbers are mind-boggling and their importance in the natural food chain is unsurpassed. There are over a million identified living species of insects roaming the planet.

We tend to remember the bad things about bugs, like the plague of locusts (grasshoppers) that rained down on the pharaoh of Egypt when he refused to let Moses’ people go! Or reports of July 26, 1931, when swarms of grasshoppers consumed and destroyed millions of acres of crops in drought-stricken Iowa, Nebraska and South Dakota during the Dust Bowl years.

A simple explanation of an insect plague is when environmental conditions occur that cause a species of insect to suddenly explode. Am I suggesting we are due for an insect plague? The answer is “No!” We have had to fight off large populations of Japanese beetles this year. And Emerald Ash Borer is taking a terrible toll.

The smallest recorded insect, a Feather Winged Beetle, enters the ring at only two-hundreds of an inch long, while the longest is the Giant Walking Stick at over a foot long, both totally harmless insects. The largest beetles are the Titan Beetle from Brazil, the Elephant Beetle from Mexico and, my personal favorite, the Goliath Beetle from countries close to the equator in Africa.

In the Midwest we just have the basic insects. Some sting, some bite, some sing all night long (the cicada) but, for the most part, insects just do their thing. It is only when they inconvenience us that we think “bad bugs” and put them all into the same “bad” category.

This time of year we have “The Good, The Bad and The Ugly Bugs.” The bad is the Cicada Killer Wasp, which appears when it gets hot, starting in July. This solitary wasp digs a hole in the soil in the full hot sun. The wasp hunts down, kills and drags a cicada to the hole and stuffs it in. The wasp then lays an egg on the dead cicada. When the egg hatches it begins feeding on the dead insect. These insects do not sting and are not aggressive unless provoked, such as running them over with a lawn mower on a really hot day. A soaker hose will encourage them to move away.

The “ugly insect” is the Tomato Horn Worm. It is a beautiful green color, which camouflages well on tomato leaves. The adult is a Five-Spotted Hawk moth which lays eggs on your tomato plants. The eggs hatch and the worms eat nonstop until they get as big as a man’s thumb. This worm can consume large portions of a tomato plant in just a few days. The best control is hand-picking and destroying the worms.

The good insect is the alien-looking Praying Mantis. The baby mantis’ are the size of mosquitoes when they hatch from a Styrofoam-like egg sac in the spring. Over 200 insects can emerge from one sac. This majestic insect eats all kinds of aphids, larvae and insect eggs. Like the Tomato Horn Worm it is also a master of camouflage. They are hard to see until mid-summer when these insects get quite large and are easy to spot. They die shortly after they lay the eggs for next year.

Not all insects are bad. So before you grab that can of killer spray ask yourself, “Is this bug really bugging me or my plants? Can I just hand pick and destroy or spray the plant with a hard stream of water? Will it finish its life cycle and just go away?” If the bug is not bugging you, then just let it be.

Margo Hansen is a horticulturalist and the director of programs at the Bickelhaupt Arboretum in Clinton. She is the host of the Great Green Garden show on KROS Radio on Saturday morning.