Welasco, Texas
June 11, 2003
Midway through the Lower Rio
Grande Valley's cotton growing season, the crop is much better
off than it was last year at this time, but rain is badly
needed.
John Norman, cotton IPM
entomologist at the Texas A&M
University Systerm Agricultural Research and Extension Center in
Weslaco, said fall and spring rains have given this year's
acreage a huge advantage. He predicts that, unlike last year,
the majority of the crop planted will be harvested.
"If not for the deep soil
moisture we got from rain late last year and the rains we got
through early April, our dryland crop would be ruined by now for
lack of rain, much as it was last year at this time," he said.
"Clearly irrigated cotton is doing better than dryland, but even
dryland cotton is showing a significant improvement over what
we've had the last two or three years, maybe even over what
we've had the past three to four years."
Norman estimates this year's crop
at 235,000 to 245,000 acres, 50 percent to 60 percent of which
is dryland, or without irrigation. Before the lingering drought
that dates back eight years or so, area producers normally
planted an overall ratio of about 60 percent irrigated cotton to
40 percent dryland.
"As less water is available to
farmers, more of the acreage is planted dryland. But there seems
to be a slight improvement in water availability this year.
Based solely on personal observations, there seems to be more
irrigated cotton this year than last," Norman said.
But rain is desperately needed to
carry dryland acreage and some irrigated cotton acreage to
harvest. Without moisture soon, immature cotton bolls will drop
from plants without ever producing open, harvestable cotton
bolls.
Dr. Bob Wiedenfeld, a soils
scientist at the Texas A&M center in Weslaco, said temperatures
and evapo-transpiration rates in May were higher than normal.
The evapo-transpiration rate is the rate in inches at which
plants lose moisture that needs to be replaced by irrigation or
rainfall.
Rain would also help leech
plant-stunting salt buildup in the soil that comes from salty
river irrigation water. Most irrigated fields have been watered
twice this year, replacing salts that previous rains had
diluted. But as badly as they are needed, rains could also have
a negative downside in the form of increased insect pest
populations, particularly of the area's two main cotton pests,
the boll weevil and bollworm. "The insect situation in cotton is
not too bad now," said Norman, "but rains could cool off soil
surfaces and increase the survival rates of these insects."
Boll weevils lay eggs in flower
buds. When they hatch, Norman said, the grubs fall to the ground
in the flower buds. If the soil is sun-baked and extremely hot,
grubs usually die. But if the ground has been cooled by rains,
grubs do well and can survive to damage cotton bolls as adults.
Bollworms also fare better in cooler fields.
"We're not overwhelmed with
insects right now; they're just getting started. But with rain,
they will definitely do better than they have been," said
Norman.
Harvest of the Valley's cotton
typically begins in earnest in late July and continues through
August. To eliminate over-wintering sites for boll weevils,
state law mandates that cotton growers destroy all cotton crop
residue by Sept. 1. Growers cannot legally plant before Feb. 1.
"The very early planted cotton
should be producing the nation's first bale of cotton here any
day now," Norman said. "I haven't seen too many open bolls of
cotton out there yet, but typically our first bale comes from
growers who planted very early in the year."
Norman planted a research field
plot of cotton on Feb. 14, which he said still has green,
unopened bolls.
Writer: Rod Santa Ana III,
956-968-5581,
r-santaana@tamu.edu
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