Northwest
Plains
Pest Management News
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| Volume 1 Issue 2 |
Bailey
and Parmer Counties
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June
21, 2002
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Northwest
Plains
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Current Crop Conditions Area cotton is looking
better, it is ranging from 2 to 8 true leaves and squaring. Corn is 18
to 48 inches tall and is growing rapidly. Sorghum planting is continuing,
some fields are up to 12 inches tall. Wheat harvest is underway, with
widely varying yields. Low test weights continue to be a problem in some Fleahoppers / Lygus Bugs Thrips pressure is on the decline in most fields. Populations range from 1 to 25 per plant. Most thrips control practices are not justified past the seven true leaf stage. Numbers of fleahopper
and Lygus bugs are being found in squaring cotton at levels presently
below our suggested treatment levels. Adult fleahoppers are about 1/8 inch long and pale green. Nymphs resemble adults but lack wings and are light green. Adult lygus bugs are 1/4 inch long, have a conspicuous triangle in the center of the back, are winged, and vary in color from pale green to yellowish brown with reddish brown to black markings. |
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Do this in several areas of the field and derive an average number per 3 row feet. If Lygus bugs are present, only one adult or nymph need be present per 3 row feet examined to justify a treatment in response to reduced square set. Where do all these plant bugs come from? Both fleahoppers and plant bugs have several weed hosts. Prairie sunflower, tansy mustard, lance leaf sage and silver leaf nightshade are some of the weed hosts for one or both of these insects. Alfalfa in particular is an important source of plant bugs in this area. Spider Mites Small spider mite colonies continue to be found. When looking at mite colonies look for thrips among the colonies, these thrips are actually feeding on the spider mites. These thrips can have a significant impact on mite populations. Grasshoppers Grasshoppers are jumping across Texas, with 107 counties throughout the state reporting moderate to severe infestations. Locally our numbers are increasing but not to alarming numbers. Most problem situations have been field margins adjacent to CRP, range land or weedy areas such as fence rows and ditches. Predators The crab spider is a hunting spider, does not weave a web and usually is found in plant terminals. The four front legs are longer than the four rear legs. Adults reach a length of about 1/4 inch. They are yellow, |
Monti Vandiver |
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| Educational programs
conducted by Texas Cooperative Extension serve people of all ages regardless
of socioeconomic level, race, color, sex, religion, handicap or national
origin. The information given herein is for educational purposes only.
References to commercial products or trade names is made with the understanding
that no discrimination is intended and no endorsement by Texas Cooperative
Extension is implied.
The Texas A&M University System, U.S. Department of Agriculture,
and the Commissioners Courts of Texas Cooperating
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Nymphs
are uniformly pale green with red-tipped antennae. We check for fleahoppers
by examining the terminal area of individual plants. Adults can readily
fly off as you approach a plant, especially if you cast a shadow on their
plant. Nymphs and adults can "hunker down" in the terminal whorl
or run down the cotton stalk. Fleahopper numbers of 25 or more per 100
terminals inspected would be needed in conjunction with reduced square
retention to justify treatment. Sampling for Lygus bugs at this time of
the season is best done with a drop cloth. This consists of a white to
off-white 36 inch X row width cloth with strips or dowels of wood stapled
to the two 36 inch sides. Carefully unroll and place the drop cloth between
two rows at the sample site selected and vigorously shake 18 inches of
plants from each row to the center of the cloth. This represents 3 row
feet. Count adults first as they will fly away before you get through
looking for nymphs. Then count nymphs.
