Insects reduced U.S. cotton yields by 4.12 percent in 2004, reflecting another year of low insect pressure over the Cotton Belt. Total losses from insect pests in 2003 were 4.16 percent.
“This also reflects a year in which management technologies were more responsive to the needs of production,” said Michael R. Williams, Mississippi State University Extension entomologist, speaking at the recent Beltwide Cotton Conferences in New Orleans.
This marks the fourth year that insect losses have not exceeded 5 percent, says Williams. “The fact that overall losses are at 4.12 percent for 2004 indicates that management tactics for insects are working.
“New innovations in scouting, new tools — pesticides and technology — and a continued awareness of the potential for loss keeps the cotton industry focused on the need for intensified management. But we dare not become inattentive,” he says.
Oklahoma and North Carolina reported a greater than 10 percent loss to insect pests in 2004, says Williams. The national average always is affected the greatest by Texas, with its 5.97 million acres of cotton. Insect losses in Texas this past year were 4.02 percent.
Oklahoma reported a 10.8 percent loss, representing 42,592 bales and North Carolina was second at 10.6 percent and 119,230 bales of cotton. South Carolina was third with reported losses of 6.13 percent, Missouri was fourth with 5.85 percent, and Florida was fifth in total insect losses with 5.29 percent.
Twelve states reported less than 5 percent losses to cotton insects. They included Arkansas (4.85 percent), Alabama (4.05 percent), Texas (4.02 percent), Arizona (3.92 percent), Mississippi (3.79 percent, Louisiana (3.46 percent), New Mexico (3.43 percent), Tennessee (3.26 percent) and Kansas (3.07 percent).
Others include Georgia (2.26 percent), California (2.02 percent) and Virginia (1.19 percent).
Texas reported 442,986 bales lost to insects while Arkansas lost 140,991 bales and North Carolina lost 119,230 bales.
Management of the bollworm/budworm complex, primarily by transgenic cotton, has greatly reduced their impact, says the entomologist. However, they remain the No. 1 pest for 2004 at 1.23 percent reduction in yield. They infested about 82 percent of the U.S. cotton crop in 2004, second only to thrips, which were found in 95 percent of the U.S. crop.
As for cotton losses, plant bugs were second to the bollworm/budworm complex at 1.04 percent reduction in yield. Stink bugs were third at 0.571 percent, thrips were fourth at 0.553 percent and cotton fleahoppers were fifth at 0.193 percent.
Of the bollworm/budworm complex, bollworms were the dominant species at more than 94 percent. “Total losses to all pests have been low since widespread acceptance of boll weevil eradication and the introduction of transgenic cotton. The 1.23 percent loss to the bollworm/budworm complex continues a downward trend, and the 94 percent bollworm dominance also points to the elimination of the tobacco budworm as an effective pest of cotton in 2004,” says Williams.
About 82 percent of the U.S. crop reported infestations of the bollworm/budworm complex, resulting in the loss of 378,491 bales of cotton. North Carolina at 3.22 percent, South Carolina at 3 percent, Oklahoma at 2.88 percent and New Mexico at 2.52 percent all reported losses to the bolloworm/budworm complex of greater than 2 percent.
Almost half of the total bales lost to the complex was attributed to Texas, with 153,983 bales lost. No other state lost more than 45,000 bales to this pest complex. California and Virginia reported no losses to the bollworm/budworm complex.
Bt cotton acreage increased to 6.53 million acres in 2004, with 2.91 million Bt cotton acres being sprayed for the bollworm/budworm complex. The cost of Bt is estimated at $11.11 per acre of the U.S. crop. This represents about 21 percent of the cost of insect management and is second only to foliar application costs. Bt technology is used on about 47 percent of the total U.S. crop.
The status of certain insect pests continues to change with minor pests now causing losses, says Williams. “Yellowstriped armyworms, Western flower thrips, darkling beetles, saltmarsh caterpillars, striped flea beetles, Southern armyworms and clouded plant bugs all contributed to the new look in losses.”
Slugs and snails became a major concern in some areas in pre-squaring cotton in 2004, he says, while bugs continue to increase in importance and overall rank among pests of cotton.
The total cost of cotton insect losses in 2004 is estimated at $1.103 billion, with direct management costs estimated at $53.86 per acre. The total insect losses translate into 1.267 million bales of cotton.