|PHOTO CONTRIBUTED BY HENRY HARTMAN/CREATIVE IMAGES
|PHOTO BY MICHAEL VANDEVEER/VICTORIA COUNTY MASTER GARDENER INTERN
|PHOTO BY HENRY HARTMAN/CREATIVE IMAGES
|COMMON SOUTH TEXAS BENEFICIAL INSECTS AND WHAT THEY PREY UPON
*Ladybug (Lady Beetle)- Aphids, soft-bodied insect larvae, mites
*Praying Mantis (Mantid) - Nearly all insects/arthropods
*Trichograma Wasp - Caterpillars
*Green or Brown Lacewing - Aphids, soft-bodied insect larvae, mites
*Beneficial Nematodes* - Subterranean insect larvae - fire ants, fleas, grubs, gnats
*Spiders** - Flying insects - spiders aren't picky
*Nematodes aren't insects. They're microscopic subterranean worms.
**Spiders aren't insects, either. They're arachnids.
FOR MORE INFORMATION
Search for "Beneficial Insects" at http://vegipm.tamu.edu/indexbyname.html
Click on "Insects by Name" at http://vegipm.tamu.edu/index.cfm for a list and pictures of beneficial insects and pests
Also at this site, they are listed as pests found on certain vegetables along with biological, cultural or chemical controls
|PHOTO BY JOE JANAK/VICTORIA COUNTY EXTENSION AGENT
Various ladybug (beetle) species can be found in garden settings. While the adults do eat aphids and other pests, the larva stage are more beneficial than the adults and are veracious aphid eaters.
|97 percent of insects are
beneficial or harmless
|June 04, 2009
by Michael Vandeveer,
Victoria County Master Gardener Intern
edited by Charla Borchers Leon,
Victoria County Master Gardener
|Did you know that there are more 1 million known species of insects (100,000 in North America) and an estimated 10 million un-described ones? How many of those are harmful vs. beneficial?
Roy Parker, extension entomologist in Corpus Christi, told our Master Gardener classes that only 3 percent of insect species are classified as pests? The other 97 percent are considered either beneficial or harmless.
You may wonder why it seems like 100 percent of the pests end up in your garden every summer. Me, too. What can we do to promote the good guys and minimize the bad guys?
Good or Bad?
First of all, we need to be able to differentiate the good from the bad. Odds are, the bug you're looking at is either neutral or good, but your perspective (what you're trying to grow) has an impact on whether you might consider an insect friend or foe.
For example, the assassin beetle is an avid hunter of caterpillars and other insect larvae. He must be good, right?
Usually, unless you have a butterfly garden, in which case you're trying to promote caterpillars to turn into butterflies. If this is the case, then the assassin beetle is one of the worst things you can run into.
Remember, beauty is in the eye of the beholder; not every beneficial insect is beneficial to every gardener.
Promoting the Good Guys
What can you do to promote beneficial insects in your growing area? The late John Jackman, Texas AgriLife Extension Service entomologist, once said there are several approaches to accomplishing increased populations of good guys in your garden. They are generally divided into three categories:
1. Classical biological control - the importation and establishment of foreign natural enemies.
2. Conservation - the preservation of naturally occurring beneficials.
3. Augmentation - the release of natural enemies to increase their existing population.
Classical Biological Control
Let's dig a little deeper into what each of these mean. Many pests in the United States were imported (usually accidentally) from other parts of the world. They arrived here and had no natural enemies, so they flourished.
Classical, biological control seeks to bring their natural enemies to them to help get their populations back under control. This type of biological control is normally carried out by governmental agencies and requires years of research and study to ensure that the introduced enemy doesn't end up becoming a pest itself.
Some classical, biological controls have successfully been in use for more than 100 years. One of the most recent attempts is to introduce the phorid fly, a natural enemy of the fire ant from South America to help control the fire ant.
Conservation is an approach we can all practice in promoting beneficial insect populations. Learning to identify pests from their predators is an important step in this approach. It involves looking closely at your garden and its inhabitants.
By taking this one step further and monitoring pests and beneficial numbers over several days or weeks, you can utilize a strategy called integrated pest management using cultural, mechanical and biological control techniques with pesticides as a last resort.
A good reference guide or access to the Internet is helpful, too. Judicious use of pesticides, even organic pesticides, is always good advice and especially so in this case.
Many pesticides are indiscriminate in what they kill. They don't know a ladybug from a fruit fly.
Using pesticides only when pest populations become overpowering and beneficials can't keep up control is part of the IPM program.
Also, you can use selective pesticides intended to control only a specific kind of pest, not beneficials, such as insect growth regulators.
Finally, with augmentation you release beneficials into an area where their population is low or nonexistent.
This can either be done as an inoculation (releasing a small amount of beneficials before the pests become a problem, in hopes that any pests that do present themselves are controlled by their introduced enemies) or as an inundation (releasing large amounts of beneficials to attack an existing pest that has already established itself in your garden).
These may work well on occasion, however, Jackman said that the benefit of additional releases may be marginal because many of these predators and parasites already exist in the environment.
Minimizing the Bad
Do you have aphids on your hibiscus blooms? Ladybugs, especially the larva stage, love them. If you don't see any ladybug larva, pupa or adults around consider turning loose a packet of ladybugs on them.
Even if they don't decide to establish themselves in your garden permanently, the entertainment value of watching them devour the aphids is worth every penny.
Many different beneficials can be purchased at several local, organic-friendly garden stores.
In the last couple of years, I've made a conscious effort to stop squishing every spider and wasp I see around my house. And while I can't say I never have any insect pests in my garden, I can say it has gotten dramatically better.
It's always pleasing to see flies and stinkbugs stuck in a spider's web or to see a wasp zeroing in on the caterpillars trying to stake a claim in my tomato plants.
I stopped using fire ant poison four years ago in favor of introducing beneficial nematodes. Now, with about three applications per year (at the first sign of a new fire ant mound), I rarely see them (neither do my neighbors, since the nematodes like to go exploring beyond my fence).
Let/Help Nature Run Its Course
As with many things in life, if we leave Mother Nature to her own devices, she usually has a solution to every problem, although sometimes we have to assist by monitoring and making adjustments. Pesticides can be valuable and necessary tools in fighting pests. But sometimes, the simplest solutions can be right under our noses (or shoes).
|PHOTO BY HENRY HARTMAN /CREATIVE IMAGES
|PHOTO BY HENRY HARTMAN/ CREATIVE IMAGES
Numerous insects are active around this cactus flower. According to entomology statistics, most species of insects are likely beneficial or harmless.
|PHOTO BY JOE JANAK/ VICTORIA COUNTY EXTENSION AGENT
While the adult ladybugs do eat aphids and other pests, the larva stage are more beneficial than the adults. The larva stage of the ladybug is often mistaken for a pest.
|PHOTO CONTRIBUTED BY TEXAS AGRILIFE
Like the larva of the ladybug, the lacewing larva harvests far more aphids as well as thrips, mealybugs and mites than does the adult and is many times mistakenly destroyed.
|PHOTO CONTRIBUTED BY TEXAS AGRILIFE
The green lacewing adult is only about 3/8-inch long and is beneficial to harvest aphids and small pesky insects.
|LUNCH AND LEARN WITH THE MASTERS
Dr. Pattie Dodson Public Health Center
2805 N. Navarro St. in Victoria
Noon-1 p.m., Monday
Free to the public
Master Gardener Ed Gregurek will speak on "Essentials for Building a Trellis, Arbor and Raised Beds"
Presented by Victoria County Master Gardener Association
Bring your lunch and drink.
|The Gardeners' Dirt is written by members of the Victoria County Master Gardener Association, an educational outreach of Texas AgriLife Extension - Victoria County. Mail your questions in care of the Advocate, P.O. Box 1518, Victoria, TX 77901; or email@example.com, or comment on this column at www.VictoriaAdvocate.com.|