and adults. Literature
suggests that the peak hatch usually occurs in mid-June. So, we may
have these devils with us a little longer.
Fleahoppers:
Fleahoppers are beginning to show up in fields where roundup applications
are made. We are finding fleahoppers migrate from the weeds to the
cotton. As we initiate square set we want to monitor the numbers of
fleahoppers per 100 terminals and the square retention rate. Adult
fleahoppers are about 1/8 inch long and pale green. Nymphs resemble
adults but lack wings and are light green. They move very rapidly
when disturbed. Both adults and nymphs suck sap from the tender portion
of the plant, including small squares. Pinhead size and smaller squares
are most susceptible to damage. Treatment thresholds vary depending
on square retention rate. During the first week of squaring, 25 -30
fleahoppers per 100 terminals examined with less than 90% square retention.
During the second week 25-30 fleahoppers per 100 terminals examined
with square retention of less than 85%. During the third week of squaring
until first bloom the threshold is 25-30 fleahoppers per 100 terminals
examined and square retention of less than 75%. Now I realize this
would be in an ideal world where producers sell cotton for more than
their production costs...so we most consider all factors and what
one is willing to invest in the long run. These thresholds give us
a starting point to work from.
Final Over-the-Top
Roundup Application:
Fields are rapidly approaching the close of that window. Applications
should be made prior to the fifth true leaf opening to 1" or
the size of a quarter. If the plants were damaged due to wind or hail
and leaves are missing, one must count the scars left on the stem.
Dr. Randy Boman provided some excellent photos in last week's edition
of FOCUS from the TAEX District 2 center. These can be viewed on the
internet at:http://lubbock.tamu.edu/ipm/AgWeb/newsletters/
Focus2001/june08/June8B.html.
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Peanut News:
The lesser cornstalk bore is an important pest of peanuts. According
to a consultant in Gaines County some fields are running up to 10 percent
infestation at present. The treatment threshold is 15% infestation.
This small, slender larva is primarily a subterranean feeder, living
beneath the surface in a silken tube. The lesser cornstalk bore is usually
more harmful to peanuts grown under dry conditions and during drought
years. Prolonged rainfall and irrigation contribute to larval mortality.
Proper timing and adequate water applied at each irrigation may reduce
larval populations. If our current weather trend continues this pest
could be problem this season. Additional information on peanut production
in Texas is available in the newly revised Texas Peanut Production Guide,
publication B-1514. This guide is on the world-wide web at the Lubbock
TAMU site or can be picked up at TAEX County offices.
Boll Weevils:
In general boll weevil numbers remain very low. The Texas Boll Weevil
Eradication Foundation (TBWEF) has begun spraying fields in the Western
High Plains Zone. Information from one board member was that one recent
day only 400 acres were sprayed. It should be noted that the TBWEF trigger
for treatments is one weevil per field. Therefore if your field is squaring
and a single weevil is caught it will be sprayed. I again urge you to
stay in close contact with the TBWEF Field Unit Supervisor for your
area.
| T-Y
IPM News is a publication of the Texas Agricultural Extension Service
IPM Program in Terry and Yoakum Counties. |
Editor:
Scott A. Russell
EA-IPM,
Terry & Yoakum Counties |
Production:
Linda Waters |
Posted at this web site by:
texagnet Internet Services.
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