Preserve and Protect the Good Bugs

By Ralph E. Mitchell

Living in Florida means that we must coexist or at least tolerate a certain amount of insects. Most of the insects that we see or temporarily interact with are harmless to both life and property. Out of the million plus insects we know about, only a small number are actually pests. There are many insects that we depend on for certain essential tasks such as plant pollination and organic matter recycling. There are also many other "beneficial insects" that work for us behind the scenes in our landscapes and gardens by eating the bad bugs. Common beneficial insects that you might find in your garden include lady beetles, lacewings, spined soldier bugs, and tiny wasps.

Lady beetles are everybody's favorite and are generally easy to identify. One common type, the convergent lady beetle, is orange with six small black spots. The larval stage is grey and orange and looks to many like a miniature alligator. Both adult beetles and larvae are voracious predators of aphids as well as scale insects. While releasing large amounts of these beetles to overwhelm an aphid infestation is a common practice, they tend to fly away. Beyond their nature to disperse, they need adequate food to keep them on site and reproducing. As long as the aphid population is sufficient, lady beetles will do their job.

Another type of lady beetle from Australia is called the "Mealybug Destroyer". Like its name suggests, this insect predator specifically feeds on mealybugs. In fact, the literature mentions that each larval "Destroyer" can eat two-hundred and fifty mealybugs as it develops! The larva is covered with a white waxy material that makes it look like a mealy bug. It is this resemblance that may mistakenly identify it as a pest instead of a beneficial. While the Mealybug Destroyer is in Charlotte County, it can sometimes be purchased commercially. Two to five "Destroyers" per infested plant usually do the trick.

Green lacewings are another common and effective beneficial insect. Common throughout Charlotte County, this delicate green insect with golden eyes does not look too menacing, but the larval stage does! Known as "Aphid Lions", the larva are equipped with large mandibles for catching and feeding on aphids. Green lacewings lay eggs at the end of delicate silk stalks and can be purchased through mail order catalogs. Generally, releasing from one to five eggs per square foot of garden offers sufficient pest suppression.

Next on our list of common beneficial insects is a type of true bug. A good example of this insect is the spined soldier bug. It is actually a predatory stink bug that attacks and consumes many soft-bodied insects and their larva. While most stink bugs feed on the fluids sucked from plants, the spined soldier uses its straw-like mouthpiece to pierce and suck fluids from various insect prey. The spined solider can be identified by its pointed, spine-like "shoulders"; plant-feeding stinkbugs have rounded shoulders. Last, but not least are a variety of parasitic wasps. These tiny wasps are parasites, unlike the other insects mentioned in this article which are predators. They lay eggs into the body or the egg of their specific prey. The parasite's eggs hatch and the larval wasp feeds inside its host eventually killing it. In the final stage, the adult wasp emerges from its host. Parasitic wasps tend to attack things such as aphids or whiteflies. An example of this may be found if you carefully examine leaves infested with aphids. "Aphid mummies" which are the swollen empty shell left by a parasitic wasp after finishing feeding and development within its host, are a common and welcome sight . I have also recently seen parasitized whitefly larvae on various plants brought into our office for examination.

While many of the beneficial insects mentioned above can be purchased and released, often the best way to encourage and preserve a population of these organisms is to be able to identify them, use insecticides sparingly, and practice least-toxic pest control methods if necessary in a selective manner - in other words, conservation. For more information on all types of insect topics, please contact our Master Gardeners on the Plant Lifeline at 764-4340 from 1 p.m. to 4 p.m. Mondays, Wednesdays and Fridays. Our office is located at 25550 Harbor View Road, Suite 3 in Port Charlotte. Our other Plant Clinics are available across the county: Demonstration Garden every Thursday from 9 to 11 a.m. Englewood/Charlotte Public Library 9 a.m. to noon every Monday. Mid County Regional Library first Thursday of the month from 1 to 3 p.m.

Don't forget that Florida Yards and Neighborhoods or FYN is a program that our office encourages as it promotes planting the "right plant in the right place", water conservation, common sense pest management, sensible use of fertilizers, composting, etc. that help develop a sustainable landscape. For more information on this important, over-arching program, please contact Audrey Durr at 764-4340. Ralph Mitchell is the county extension director/horticulture agent for the Charlotte County Cooperative Extension Service. You may contact him by e-mail [email protected] You may also contact a volunteer Master Gardener at [email protected]

Resource:

Henn, T., Weinzierl, R. & Koehler, P. G. (2005) Beneficial Insects and Mites. The University of Florida Extension Service, IFAS.