More is not necessarily better in fire ant battle

By MANDY SPIKES | Central Texas Edition

April 1, 2004 -- Fire ant control is a problem that many Central Texans face, both on their farmland and around their homes. At the Comanche Farm, Ranch, and Dairy Day, which was held March 25 in Comanche, Bob Whitney discussed this problem and ways to help control the fire ant population.

Whitney stated that he has discussed with farmers and landowners fire ant problems for the past 20 years. Fire ants, which are native to South America, have become well established in South Texas and are being established more around Central Texas.

"There are two kinds of native fire ants. They are the southern fire ant and the tropical fire ant. Fire ants come in many different sizes. There are also two types of colonies. These are monogyne, which are single queen colonies, and polygene, which are multiple queen colonies."

Monogyne colonies have around 40 mounds per acre. With polygene, there are around 250 mounds per acre. Polygene workers are smaller and are less aggressive toward other workers because they are all from the same group.

"When a winged female mates, she begins to establish a new mound. Her wing muscles are absorbed to produce eggs. Initially, she feeds on the eggs. But she will have 800-1000 eggs a day."

The way the mounds are formed, it's really hard to see the number of fire ants in a mound, he said. These mounds can go extremely deep. They will go down to where there is more water, which is the moisture from the soil. Fire ants try to regulate the environment to keep it at a certain temperature. They also want the mound to have access to both food and water.

Whitney gave different control options when dealing with fire ants, all with various advantages and disadvantages. "Quarantines don't work. Both natural and biological options are very successful. There are also physical, mechanical, organic, chemical options, and the eradication process."

The eradication process is very questionable, he explained. "I don't think that it will work. The reason is that the ants infest extensive areas and have multiple colonies. These gives the pesticides many limitations."

Natural and biological control options work, he said, because it's dealing with the weather and predators. "Droughts and winters are hard for fire ants. Newly mated queens can be attacked by such predators as birds and lizards. There are other ants that will compete for food," Whitney said.

Chemical treated options include a method called the two-step method, which Whitney recommends.

"I would rather not do the individual mound treatment because you can't see all the mounds to treat, so it's very difficult," Whitney said.

In the two-step method, a person will broadcast a bait. A bait is a product that fire ants love. These baits have insecticides that contain food and a toxin. This is done two times a year, in the fall and the spring.

"The advantages is that there is no need to find the mounds. It has long lasting control, ranging from 6-12 months. It's the least expensive method and not labor intensive. It has low human toxicity and has few environmental problems."

Disadvantages Whitney gave are: It's slow to work, usually taking a few weeks to many months. For less than ten acres, it's expensive. It works only on active ants, and could harm non-target ants.

The last disadvantage that he gave is that it requires a spreader.

Whitney stated that the keys to good control include: More is not better. Follow the label. Twice a year for control. One to one-and-a-half pounds per acre for bait. No rain for 24 hours after bait is put out. And use fresh product.