sorghum headworm sequential sampling system
DESCRIPTION
Sorghum Headworm Sequential Sampling System. Tom A. Royer Department of Entomology & Plant Pathology. Development of Headworm Sampling System. Data on Economic and Treatment thresholds collected from Texas, Oklahoma, and Kansas (Elliott et al. 2012) Objectives: - PowerPoint PPT PresentationTRANSCRIPT
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Sorghum Headworm Sequential Sampling System
Tom A. Royer
Department of
Entomology&
Plant Pathology
Oklahoma State University
Development of Headworm Sampling System
Data on Economic and Treatment thresholds collected from Texas, Oklahoma, and Kansas (Elliott et al. 2012)
Objectives: Create a simple, dynamic, economically accurate
sampling strategy for sorghum headworms Develop an educational tool with information on
headworm identification, and other sorghum pests. Develop a flexible system that could be expanded as
additional information became available and/or interface with real-time platform (such as I-Wheat).
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The Product
A computer program located at http://entoplp.okstate.edu/shwweb/index.htm
It has several elements:1. Information on sorghum headworm2. A calculator for determining economic thresholds for headworm
infestations3. Sequential sampling forms4. Sampling instructions5. Information on other sorghum pests
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It allows a producer to play the “what If” game with pesticide costs, market values
What Does the Headworm Decision Support System Provide?
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It has a full complement of treatment threshold forms that can be printed off to serve as a permanent record of the sampling results
What Does the Headworm Decision Support System Provide?
Assumptions: The Scout Needs to: Estimate sorghum plant populations Estimate composition of headworm sizes
(Large, Medium, Mixed) Mostly large headworms > ½ inch cause significant
damage Mostly medium headworms ¼ to ½ inches will also
cause damage (less so, due to field mortality) Small headworms < ¼ inches are not counted
because many will die
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What You Need to Know Plant Density
Number of sorghum heads per acre Number of sorghum heads per length of row spacing Pounds of seed planted per acre
(assume that a pound of seed per acre results in 35,000 heads per acre
None of the Above (assume that 1 inch of rainfall results in 1100 heads per
acre. Inches of rainfall is determined by clicking your location on the map.
(3 or 4 won’t give you as accurate an estimate)
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What You Need to Know Value of crop ($ per hundredweight)
Control Cost ($ per acre)
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What You Need to Know
Directions1. Walk 15-20 feet into field2. Grasp and bend head into bucket and
shake vigorously3. Walk 30 paces in row to next sample,
repeat 24. Walk 30 paces to next sample, repeat
2 (STOP 1)5. Count medium (1/4 – ½ inches) and
large > ½ inches) caterpillars, and determine whether most are Medium, Large or a Mixture (ca. 50/50).
Sampling Technique
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What You Need to Know
Directions1. Sample 3 more heads, combine
count from first three heads with new count, mark total in box (STOP 2). Determine if you need to treat, not treat, or sample 3 more heads.
2. If you need to sample 3 more heads, move over 25 rows, and sample 3 heads.
3. Repeat 1 (STOP 3).4. Repeat 1, and move over 25 rows
AFTER you sample 6 heads in each row.
Sampling Form
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What You Need to Know
Directions1. If you sample at 16 stops and
still can’t make a decision, return in 3 days and resample the field.
Sampling Form
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Data on time to decision.10 fields, 16 stops, no decision made:
10 fields, no treatment after 3 stops, 9 samples
Average time per stop:
Average time: 19 minutes 37 seconds
Average time: 3 minutes 4 seconds
1 minute 12 seconds
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Next?.
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An Application for Smart Phone use in field.
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Thanks!