Pasture grasses always contend with natural requirements and pests

By MANDY SPIKES | Central Texas Edition

Dr. Allen Knutson, Extension entomologist, shows farmers what he believes is the best defense against fire ant infestation. Knutson states that the two best baits to use in hay fields are Amdro and Extinguish. "I have seen very effective results when you combine both products," he said. - Photo by Mandy Spikes

October 2, 2003 -- When farmers care for the land, they want to achieve the best results that will last the longest time. From growing the best type of grasses for their herds to feed on to protecting their land from pests and insects, the farmer must constantly evaluate what works best for their land.

At the Comanche County Forage Tour, which took place Sept. 25 at Billy Mac Barnes' farm in DeLeon, farmers were given advice on ways to grow their grasses and products to control fire ant infestation. Dr. Tony Provin, Extension soil chemist, discussed the different phosphorus amounts that can be used to benefit their grasses. Dr. Allen Knutson, Extension entomologist, explained the best way to deal with fire ants on large fields.

"When we were originally looking at the reason for the sudden bermudagrass decline on the land, the assumption was it was because of potassium," said Provin. "After working on this plot for two years, we found out that this was not the case." He added that the findings showed a response in the amount of phosphorus in bermudagrass.

Provin explained that the response to phosphorus in bermudagrass was directly correlated to the initial soil test phosphorus levels. "We found out that if you have good fertility in bermudagrass, then it can survive a drought better."

The primary purpose of providing phosphorus is transferring energy into plant cells. "The biggest flaw for Comanche County is current specification on phosphorus. We are now going to alter these specifications to allow for more phosphorus."

He stated that it's difficult to put out a large amount of phosphorus, but if a farmer looks at the tremendous amount of manure nearby, it could be a good match to add the manure to the land.

"Adding more phosphorus to your land will change the mineralogy of the soil and the rate at which the soil breaks down. The goal is, in the end, to keep the phosphorus level at a reasonable level."

Classic symptoms of phosphorus deficiency in bermudagrass, he stated, is the older grass shows the lack of seed production.

"Phosphorus is part of all life. As you continually deplete it, you will see less plant growth. Plants that can have problems with too much phosphorus are those with high iron and zinc requirements. That is not the case with these grasses," he ended.

"Since we are dealing with this type of grass, we are usually dealing with sandy soil," explained Knutson. "The problem with fire ant control is that the mounds are not built out on this type of soil like it is on clay soil."

He said that usually, when a farmer talks about insects on their land, the threshold of dealing with the insect is usually what is discussed. "When dealing with fire ants, it's all a personal decision."

Knutson stated that the first thing to remember when putting out insecticide on pastures and hay fields is to make sure the pesticide is recommended and labeled as such. "Only a handful of products are labeled for pastures and hay fields.

"When dealing with large acreage, it's hard to deal with fire ants per mound. The best thing to use is bait."

Only two baits are for pastures and hay fields, he said. "These two products are Amdro and Extinguish. With Amdro, you must wait seven days before you cut the hay. Extinguish is a very safe insecticide. You can even use it around lakes and drinking water areas."

According to Knutson, Amdro is fast acting, but has a short residual. Extinguish is slow acting, but has a long residual. "I have seen very effective results when you combine both products.

"How quickly ants come back on your land depends on your individual situation. Just know that reinfestation will happen over time."