Tarnished Plant Bug Threshold Developments in Cotton Musser, F., S. - PowerPoint PPT Presentation

Tarnished Plant Bug Threshold Developments in Cotton Musser, F., S. Stewart, G. Lorenz, R. Bagwell, A. Catchot, K. Tindall, G. Studebaker, R. Leonard, D. Cook, C. Daves and S. Akin

TPB Injury

Midsouth TPB Sprays & Losses AR, LA, MS, MO, TN 4 3.5 3 2.5 2 1.5 1 0.5 0 1990 1992 1994 1996 1998 2000 2002 2004 2006 # appl. % yield loss Compiled from Cotton Insect Losses (http://www.msstate.edu/Entomology/resources/Cotton/Cotton.html)

Relationship between # TPB sprays and yield in Midsouth (1990-2007) 4 3.5 # TPB applications 3 2.5 2 1.5 1 R 2 = 0.7208 0.5 0 500 600 700 800 900 1000 1100 Lint Yield (lb/ac) Compiled from Cotton Insect Losses (http://www.msstate.edu/Entomology/resources/Cotton/Cotton.html)

Relationship between # TPB sprays and yield in Midsouth 1990-2000 (red), 2001-2007 (blue) 4 3.5 # TPB applications 3 2.5 2 1.5 1 R 2 = 0.7208 0.5 0 500 600 700 800 900 1000 1100 Lint Yield (lb/ac) Compiled from Cotton Insect Losses (http://www.entomology.msstate.edu/resources/tips/cotton-losses/data/)

Pre-Bloom TPB Thresholds Trial Treatments – Auto: Automatic insecticide application at pinhead square and 7 and 14 days later – Low: Threshold of 8 PB / 100 sweeps or square retention below 80% – High: Threshold of 16 PB / 100 sweeps or square retention below 60% – UTC: No insecticide prior to first bloom Plots at least 24 rows wide and 100 ft long Conducted in 29 locations throughout the Midsouth from 2006-2008

Pre-bloom TPB Thresholds LA, 2006 Yield 1400 4 # of Sprays Number of Sprays 1200 3 1000 Lint (lb/acre) 800 2 600 a a b 400 1 200 0 0 Weekly 8 TPB Untreated Early Season TPB Thresholds

Pre-bloom TPB Thresholds AR, 2007 Yield 1400 5 # of Sprays Number of Sprays 1350 4 1300 Lint (lb/acre) 1250 3 1200 2 b a b 1150 1100 1 1050 1000 0 8 TPB 16 TPB Untreated Early Season TPB Thresholds

Pre-bloom TPB Thresholds MS, 2007 Yield 2000 5 Number of Sprays # of Sprays 1800 1600 4 1400 Lint (lb/acre) 1200 3 1000 800 2 600 b a c 400 1 200 0 0 Weekly 16 TPB Untreated Wk 1 = 36/100 sweeps Wk 1 = 30/100 sweeps Wk 1 = 29/100 sweeps Wk 2 = 37/100 sweeps Wk 2 = 33/100 sweeps Wk 2 = 33/100 sweeps Wk 3 = 50/100 sweeps Wk 3 = 46/100 sweeps Wk 3 = 53/100 sweeps Wk 3.5 = 17/100 sweeps Wk 3.5 = 20/100 sweeps Wk 3.5 = 48/100 sweeps

Pre-bloom TPB Thresholds MS, 2007 Week 1 Week 2 Week 3 Week 4 % square retention 80 73.75 70 68.75 68 70 65.5 58.8 58.5 60 55 50 41.5 40.5 37.75 40 b a c 30 23 20 10 0 Weekly Threshold Untreated

Percent Square Retention Lauderdale, TN 2008 Yield Auto Low High Untrt Plant Map 7/28 (lb/ac) 1st 10 Nodes 100 1691 a 90 1584 a 80 1439 ab 70 60 1287 b Untrt plots ≈ 2 PB/100 ≈ 26 PB/100 ≈ 15 PB/100 ≈ 11 PB/100 ≈ 25 PB/100 50 6/21 6/26 7/1 7/6 7/11 7/16 7/21 7/26 All plots oversprayed 7/21/08 with 6 oz. Bidrin

Pre-bloom TPB Thresholds Sites exceeding low threshold (2 in 2006, 7 in 2007, 5 in 2008) ns 1600 1500 1400 Lint (lb/acre) Weekly 1300 8 TPB ns 16 TPB 1200 Untreated 1100 ns 1000 900 800 2006 2007 2008

Pre-bloom Sites with few TPB (7 in 2006, 6 in 2007, 2 in 2008) 1300 ns b 1250 a Lint (lb/acre) 1200 ns Weekly 1150 Untreated 1100 1050 1000 2006 2007 2008 Early Season TPB Thresholds

Pre-Bloom TPB Threshold Summary • When TPB> threshold (8 TPB/100 sweeps OR square retention<80%) – Insecticide applications needed to preserve yield – Weekly applications not adequate under severe pressure • When TPB< threshold – Weekly insecticide applications tend to reduce yield slightly

TPB Thresholds- Mid Season Trial Treatments – Weekly: I nsecticide application every 7 days from first bloom to cutout – Low: Threshold of 1 PB / 5 row ft. – Med: Threshold of 3 PB / 5 row ft. – High: Threshold of 5 PB / 5 row ft. – VHigh: Threshold of 10 PB / 5 row ft.  All applications made using acephate or Bidrin  8 locations in 2006, 13 locations in 2007

Mid-Season TPB Thresholds Macon Ridge, LA, 2007 1200 7 Yield # of Sprays 1,2,3,4,5,6 6 Number of Sprays 1000 2,3,4,5 4,5 5 Lint (lb/acre) 800 5 4 600 3 400 2 200 1 ab cd d a bc 0 0 Automatic Low-1/5ft Med-3/5ft High-5/5ft Very High 10/5ft Drop Cloth Thresholds

Mid-Season TPB Thresholds MS, 2006 1600 7 Yield 1,2,3,5,6 # of Sprays 1,2,3,4,5,6 1400 Number of Sprays 6 1,3,6 2,4,5 2,4,5 1200 Lint (lb/acre) 5 1000 4 800 3 600 2 400 1 200 ab a ab b b 0 0 Automatic Low-1/5ft Med-3/5ft High-5/5ft Very High 10/5ft Drop Cloth Thresholds

Mid-Season TPB Thresholds Lee Co. AR, 2006 1800 6 Yield # of Sprays 1,2,3,4,5 3 1600 Number of Sprays 3 5 1,2,3 1400 Lint (lb/acre) 1200 4 1000 3 800 600 2 400 a a a a a 1 200 0 0 Automatic Low-1/5ft Med-3/5ft High-5/5ft Very High 10/5ft Drop Cloth Thresholds

Mid-Season TPB Actual Threshold 130% 120% 110% % of auto yield 100% 90% 80% R 2 = 0.1299 70% 60% 0 2 4 6 8 10 12 Threshold/5 ft

Alternate Threshold Measurements 5 TPB per drop cloth 4 3 2 1 0 Wk 1 Wk 2 Wk 3 Wk 4 Wk 5 Wk 6

Alternate Threshold Measurements • Highest threshold still sprayed the same – Set to pre-determined threshold if never sprayed 5 Max. threshold TPB per drop cloth 4 3 2 1 0 Wk 1 Wk 2 Wk 3 Wk 4 Wk 5 Wk 6

Alternate Threshold Measurements • Highest threshold still sprayed the same – Set to pre-determined threshold if never sprayed • Lowest threshold still sprayed the same – Set to just below highest density sprayed if always sprayed 5 Max. threshold TPB per drop cloth 4 3 2 Min. 1 threshold 0 Wk 1 Wk 2 Wk 3 Wk 4 Wk 5 Wk 6

Mid-Season TPB Maximum Thresholds 130% 120% 110% % of auto yield 100% 90% 80% R 2 = 0.0891 70% 60% 0 2 4 6 8 10 12 14 16 Maximum Threshold / 5 ft

Mid-Season TPB Minimum Thresholds 130% 120% 110% % of auto yield 100% 90% 80% R 2 = 0.1843 70% 60% 0 1 2 3 4 5 6 7 8 9 Minimum Threshold / 5 ft

TPB Yield Impacts Yield change for each increase in the TPB spray threshold Lint loss (lb/ac) Lint Loss (% yield) Min. Max. Min. Max. Threshold Threshold Threshold Threshold 2006 -19.5* -11.6 -1.6* -0.9 2007 -21.3* -11.5* -1.8* -1.0* Overall -20.9* -11.6* -1.7* -1.0* * P<0.05 Lint yield ranged from 630 to 1514 lb/ac in automatic treatment

Mid-Season TPB Insecticide Applications 6 # Insecticide Applications 5 2006 4 2007 3 2 1 0 0 2 4 6 8 10 TPB threshold/drop cloth

Mid-Season TPB Insecticide Applications 6 5 # applications 4 Max 3 Min Actual 2 1 0 0 1 2 3 4 5 6 TPB Threshold / 5 ft

Mid-Season TPB Costs Current Economics insecticide = $12/application $100 Insecticide Cost $80 $ / acre $60 $40 $20 $0 0 1 2 3 4 5 6 7 TPB threshold (/ 5 row ft)

Mid-Season TPB Costs Current Economics insecticide = $12/application, lint = $0.65/lb $100 Insecticide Cost Max. Yield Loss $80 Min. Yield Loss $ / acre $60 $40 $20 $0 0 1 2 3 4 5 6 7 TPB threshold (/ 5 row ft)

Mid-Season Total TPB Cost Current Economics insecticide = $12/application, lint = $0.65/lb $110 $100 $90 $ / acre $80 1.4 $70 2.5 $60 $50 $40 0 1 2 3 4 5 6 7 TPB Threshold (per 5 row ft)

Mid-Season Total TPB Cost Higher Input Costs insecticide = $16/application, lint = $0.65/lb $140 $120 1.5 $ / acre $100 $80 2.6 $60 $40 0 1 2 3 4 5 6 7 TPB per 5 row ft

Mid-Season Total TPB Cost Higher Cotton Price insecticide = $12/application, lint = $0.85/lb $140 $120 $ / acre $100 0.8 $80 2.1 $60 $40 0 1 2 3 4 5 6 7 TPB per 5 row ft

Bloom Threshold Conclusions • Lose between 12 and 20 lb lint/ac for each increase in threshold of 1 TPB/drop cloth • Number of applications per season altered greatly by changing the threshold • Threshold of 1.5-2.5 TPB per drop cloth (5 row ft) economically justified in 2006 and 2007 • Insecticide costs do NOT include indirect costs of insecticides • Threshold affected by scouting frequency and insecticide efficacy

Acknowledgements Cooperating Growers