Problem in Mid-South Cotton 2008 Crop Management Seminar Cotton - PowerPoint PPT Presentation

Spider Mites: A Persistent Problem in Mid-South Cotton 2008 Crop Management Seminar Cotton Incorporated November 12, 2008 Angus Catchot, J.F. Smith, J. Gore, F. Musser, S. Stewart, G. Lorenz, R. Bagwell, and R. Leonard

(QUOTE FROM 2006) Spider Mites “The Insecticide Budget Busters of Cotton Production in the Mid- South” STILL TRUE IN 2008!

Trends in Spider Mite Treatments in Mississippi (Acres Treated)

Mid-South Spider Mite Control Costs - 2004 1.32 1.13 2.90 1.56 0.89 US average Cost/A- $1.66 Mid-South Cost/A-$1.56

Mid-South Spider Mite Control Costs - 2007 19.50 2.99 8.21 7.68 2.78 US average Cost/A- $2.96 Mid-South Cost/A-$8.23

2007 Mississippi Cotton Insect Losses

Twospotted Spider Mite Biology • Egg, larval (3 pair of legs), two nymphal stages, adult • Generation time is highly temperature dependent • Lay ~100 eggs in 2-4-week lifespan • Multiple overlapping generations per year • Adults overwinter in leaf litter or debris • Become active in early-spring

Spider mites feed on the underside of leaves puncturing epidermal cells, reducing photosynthesis

Early-Season Damage

Late Season Damage

Possible Factors Contributing to Increased Frequency of Spider Mite Outbreaks in the South • Delayed burndown/Field Border Management • Hot and Dry Conditions • Beneficial Insect Reduction (Flaring) • Increased use of Insecticide Seed Treatments vs. Temik? • Resistance

Impact of Spring Burndown Timing on Mite Outbreaks 4/3/08 – Date of First Burndown

Impact of Spring Burndown Timing on Mite Outbreaks 5/8/08 – at-planting

Impact of Spring Burndown Timing on Mite Outbreaks Number Mites/Leaf in Cotton Untreated Check Tillage Roundup + Clarity (4/3/08) Roundup + Clarity (4/3/08) & Ignite (at-planting) 30 Gramoxone (4/25 - 12 d before planting) Ignite (4/25 - 12 d before planting) 25 20 15 10 5 0 5/19/2008 5/27/2008 6/3/2008 6/9/2008 6/17/2008 Cotyledon 2-3 Leaf Stage 4-5 Leaf Stage Pin-Head Square Match-Head Square

Avoid the “Green Bridge”

Yield Effects of Spring Burndown 1000 whole plot center 12 rw ft 900 NS 800 700 Lb Lint / Acre 600 500 400 300 200 100

Seed Treatments

Materials and Methods Cotton infested from 1 st to 4 th • true leaf • Bean leaves w/ mites stapled to cotton cotyledons • Uppermost full-size leaf examined with a microscope for mites/eggs at ~7 and 14 DAI • 4-6 reps, 5-10 plants/plot • 5 trials conducted in 2007 2 trials conducted in 2008

Effect of Seed Treatments, Temik and Foliar Insecticides on Mites Starkville, MS - June 2008. Number of Immature Mites/Leaf. 60 7 DAT 14 DAT a 50 ab 40 b bc bc a 30 ab ab bcd ab ab ab b cd 20 d 10 c 0 7 DAT - P=0.0473 14 DAT - P=0.0103

Effect of Seed Treatments, Temik and Foliar Insecticides on Mites Starkville, MS - June 2008 Visual Rating of Mite Injury (1-10, 10=best) 10 9 8 7 6 5 4 3 John Angus

Number of Times That Each Treatment Had the Greatest Number of Mites or Eggs in Each Test or Sampling Date Treatment Mites Eggs Untreated 2 0 Neonicotinoid 6 3 Temik 1 1 *Trends - Only 2 trials had significant differences

YIELD IMPACT Greenwood – Non Irrigated

Yield of Damaged and Undamaged Cotton Dryland Field – Greenwood 1200 Undamaged Damaged 1000 lb lint / acre 800 600 -22% -48% -73% 400 200 P=0.0003 P=0.001 P=0.29 P=0.0045 0 Total Yield Bottom (N5-10) Middle (N11-15) Top (N16+) -51.2% Fruiting Zone

Yield of Damaged and Undamaged Cotton Irrigated Field - Tchula 22% -23% -68% P=0.004 P=0.023 P=0.034 P=0.001 -9%

Cotton yield loss from infesting mites beginning at first bloom then at 200 HU intervals thereafter

Yield Effects from Spider Mite Infestation 1080 1066.01 1060 1028.4 1040 1020 NS 1000 976.2 980 960 946.7 940 920 900 880 First Bloom First Bloom + 200 HU First Bloom + 400 HU Uninfested

Summary • Winter Weed Management • Seed Treatments • Yield Loss

Questions? Special Thanks