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Friday, Aug. 21, 1998
Drought, toxic fungus devalue area corn crop
The fungi, exacerbated by hot, dry weather, produce aflatoxin, a cancer-causing chemical
By MADELINE BARO
Associated PressHARLINGEN - The drought has dealt a two-fisted blow to corn growers in South Texas - not only do they have reduced yields, but most of what's left is contaminated with toxin-making fungi exacerbated by dry weather.
The hot, dry weather has caused corn kernels to crack open, clearing a path for aspergillus flavus and aspergillus parasiticus to grow. The fungi produce aflatoxin, a cancer-causing chemical that can cause liver damage in humans and animals.
According to federal restrictions, corn with aflatoxin levels at or above 20 parts per billion can't be sold for human consumption or as dairy cattle feed. The maximum level for livestock feed is 300 parts per billion. Corn with levels over 1,000 parts per billion must be destroyed.
``Aflatoxin is a chronic problem in South Texas,'' said Tom Isakeit, a plant pathologist with the Texas A&M Agricultural Research and Extension Service. ``We really don't have any good news for control of it.''
(Aflatoxin has also affected growers in the Coastal Bend and elsewhere in the state.
(``It wasn't just a problem in South Texas, it was statewide,'' Jeffrey Stapper, agricultural extension agent for San Patricio County, told the Caller-Times on Thursday.
(Many growers didn't know their corn had the cancer-causing fungus until they went to haul it to the grain elevator. ``It's difficult to tell until you actually pull a sample,'' Stapper said.
(Because aflatoxin levels are measured in parts per billion and levels of the fungus can vary widely within a sample, it's hard for local agricultural officials to quantify the impact. ``There's so much variability there, it's really tough to tackle,'' Stapper said.
(Because of early rains and weak cotton prices in the spring, many Coastal Bend farmers planted more corn than in 1996, the last year with a severe drought, Harvey Buehring, agricultural extension agent for Nueces County, told the Caller-Times.
(``That's what's really hurting the guys in South Texas with corn - low yields and the risk of high levels of aflatoxin,'' Buehring said.)
Mark Waller, an extension economist, said the indication from South Texas grain elevators this year is that at least 60 percent of the corn coming in is infected with aflatoxin, which can also be found on peanuts, cottonseed and sorghum.
Most growers didn't know their corn was infected until they tried to sell it and it was chemically tested.
``You can't see that you have a problem,'' Isakeit said. ``The corn looks fine but then you analyze it and it's filled with aflatoxin.''
The amount of aflatoxin in the corn determines how much money growers can make. Corn that's safe for human consumption sells for more than lesser grades used for livestock feed.
Growers are currently getting anywhere from $2 to $2.50 per bushel for their corn, Waller said. If the corn is infected, they have to sell it at a discount. Although growers can put the corn through a detoxification process, that also costs money.
``If you only had half a crop to begin with, all of a sudden you're in a whole lot worse shape,'' Waller said.
On top of that, other southern states, such as Arkansas, Mississippi and Louisiana, are contending with aflatoxin-contaminated crops and are trying to sell the lower-grade corn to the same feedlots as Texas growers. The increased competition means lower prices, even lower than during the 1996 drought.
``Two years later, we're looking at very large supplies,'' Waller said. ``It's very easy to get corn. The discounts that we're taking on this new crop of corn are much higher this time.''
Although aflatoxin can cause liver cancer in humans, there are few documented cases in the United States because grains meant for human consumption are first tested, Isakeit said.
In less developed countries with higher aflatoxin levels in food, there are higher rates of liver cancer, Isakeit said.
Aflatoxin also causes liver damage in animals and can be passed into the milk of dairy cows. Cattle raised for food, however, can be fed higher amounts of aflatoxin-contaminated grain because they are not going to live very long, Isakeit said. The carcinogen is not passed on to humans who eat the meat because it doesn't accumulate in the muscle.
Isakeit said researchers are trying to develop an aflatoxin-resistant strain of corn. So far, however, they've been unsuccessful.
Staff writer Jeffrey Tomich contributed to this report. He can be reached at 886-4316 or by e-mail at tomichj@scripps.comPost your comments about local news eventsFront Page || Main Index || News || Business || Texas || South Texas Outdoors || Birdwatching || Sports || Entertainment || Selena || Education || South Texas Attractions || World Wide Web