Managing Irregular Ripening and Secondary Spread of TYLCV

Transcription

1 Managing Irregular Ripening and Secondary Spread of TYLCV Hugh Smith Vegetable Entomologist Gulf Coast Research and Education Center Balm, FL 33598

2 Silverleaf whitefly, Bemisia tabaci biotype B Adult whitefly Life cycle ~ about 3 wks from egg to adult. adults can live up to 2 wks. est. 5 wks btwn generations. Nymphal whiteflies

3 Whitefly insecticide rotations Divided into 5 wk treatment windows Avoid treating successive generations with same MOAs WK

4 1 st 5 Wk Treatment Window: Primary Transmission of TYLCV Colonization of crop (Whiteflies migrating into field) 2 nd 5 Wk Treatment Window: Secondary Transmission (Whiteflies developing in field) Irregular Ripening WK

5 Irregular ripening Incomplete ripening of longitudinal sections Increase in internal white tissue No foliar symptoms Associated with feeding by whitefly nymphs Whitefly Nymphs Photo: Gary Vallad

6 Thresholds established by Dave Schuster: Treat when < 5 nymphs per ten terminal leaflets

7 Treat when < 5 nymphs per ten terminal leaflets

8 Irregular ripening symptoms: correspond to nymph densities 1 3 weeks prior. 1 2 wks in spring (increasing temperature, day length) 2 3 wks in fall (decreasing temperature, day length) will disappear if nymphs are controlled Schuster, DJ Relationship between silverleaf whitefly population density to severity of irregular ripening of tomato. HortScience 36:

9 How does whitefly nymph feeding cause irregular ripening? Nobody really knows. Interferes with/delays ethylene processes McCollum, TG, PJ Stoffella, CA Powell, DJ Cantliffe, S. Hanif Khan Effects of silverleaf whitefly feeding on tomato fruit ripening. Postharvest Biology and Technology. 31: Reduces lycopene (red pigment) and its precursor phytoene Masuda, K, M. Kato, T. Saito Reduction in carotenoid and chlorophyll content induced by the sweetpotato whitefly Bemisia tabaci. Scientia Horticulturae 200:

10 Other Ripening Disorders Yellow shoulder Gray wall exposure to high temperatures/sun during maturation Common in fruit with dark green shoulders Not caused by whiteflies High nitrogen UMASS Low potassium High soil moisture High humidity Temperature fluctuations Low light intensity soil compaction Not caused by whiteflies

11 Irregular Ripening vs TYLCV IR Caused by high numbers of nymphs TYLCV Source of whiteflies does not matter Even low numbers of viruliferous whiteflies can cause high infestation Tomato is probably the only relevant source

12 Managing irregular ripening is similar to managing Tomato yellow leaf curl virus Clean culture (destroy whitefly reservoirs) Metalized mulches Insecticide rotations > Target both adults and nymphs > Use treatment window approach

13 Metalized mulch reduces whitefly numbers

14 Season long whitefly nymph densities: metalized vs white plastic mulch GCREC Whitefly Nymphs/Leaf A B A B A A Metalized 2013 White 2014 Metalized 2014 White 2015 Metalized 2015 White F 1,3 = 53.9; P <0.01 F 1,3 = 27.7; P < 0.05 F 1,3 = 0.17; P =0.7

15 TYLCV Tolerant Varieties acquire virus can be source of virus tolerance is overcome under high pressure. Susceptible Tolerant

16 Fall 2016 Whitefly Management Trial GCREC Factors 1. Tomato Variety: FL47 and HM Plastic Mulch: White vs Metalized 3. Insecticide Rotation: First Five weeks Neonicotinoids vs Biopesticides Funding provided by the Florida Tomato Committee

17 Biopesticides Low risk for resistance (No IRAC MoA) Pollinator compatible Biocontrol compatible Most have 4 hour REI Most have 0 day PHI

18 Fall 2016 FL 47 vs HM 1823 Egg and Nymph Densities 40 A Season Long Egg and Nymph /10 Leaves A B B FL 47 HM Eggs Nymphs F 1,432 = 13.95; P<0.01 F 1,432 = 11.71; P< 0.01 Funding provided by the Florida Tomato Committee

19 Fall 2016 GCREC Neonicotinoids vs Biopesticides: First 5 week Treatment Window Treatment Rate/Acre Timing Method Group 1 Venom 70 SG (dinotefuran) 2 Admire Pro (imidacloprid) Platinum 75SG (thiamethoxam) 6 oz At Plant; 21 DAP Drench Neonicotinoid 10.5 fl oz At Plant Drench Neonicotinoid 3.67 oz 21 DAP Drip Neonicotinoid 3 Agricolle 25.3 fl oz Weekly Foliar Propylene glycol alginate 4 EPL fl oz Weekly Foliar Octanediol 5 M Pede fl oz Weekly Foliar Insecticidal soap 6 Suffoil X fl oz Weekly Foliar Mineral oil 7 Surround WP 15 lb Weekly Foliar Kaolin clay

20 Fall 2016 GCREC Nymphs Per 10 Leaves Av 42 DAP MET 1823 VENOM MET FL47 VENOM MET 1823 ADMIRE/PLAT WH 1823 VENOM WH FL47 VENOM WH 1823 ADMIRE/PLAT MET 1823 SUFFOILX MET FL47 ADMIRE/PLAT WH FL47 ADMIRE/PLAT MET 1823 MPEDE MET 1823 EPL MET FL47 SUFFOILX MET FL47 MPEDE MET FL47 EPL MET 1823 AGRICOLLE MET 1823 UTC MET 1823 SURROUND MET FL47 AGRICOLLE WH 1823 SUFFOILX WH 1823 MPEDE WH FL47 SUFFOILX MET FL47 SURROUND WH FL47 MPEDE MET FL47 UTC WH 1823 AGRICOLLE WH FL47 EPL WH 1823 EPL WH FL47 AGRICOLLE WH 1823 SURROUND WH FL47 SURROUND WH 1823 UTC WH FL47 UTC Funding provided by Florida Tomato Committee

21 Material Inhibits Feeding Inhibits Movement Insecticidal Yes Yes Yes Soap Stylet Oil Yes Yes No Desiccates M Pede and Suffoil X kill mechanically Do not select for resistance Can cause phytoxicity

22 Spring 2017 Whitefly Management Trial GCREC Tomato Variety: FL 47 Mulch Type: White Factors evaluated: Conventional vs Biopesticides By Treatment Window 1 st 5 Wk Treatment Window 2 nd 5 Wk Treatment Window Planting WK 5 WK 10

23 Whitefly Nymph Materials Knack (pyriproxifen) MoA 7C Courier (buprofezin) MoA 16 Movento (spirotetramat) MoA 23 Prevent nymphs from completing development Reduce egg hatch Don t affect adults

24 Botanigard/Mycotrol (Beauvaria bassiana) Biopesticides: Fungal Entomopathogens Effects on Whitefly Nymphs PFR 97 (Paecilomyces fumosoroseus)

25 Trt 1 st 5 Wk Window 2 nd 5 Wk Window 1 Conventional Conventional 2 Conventional Biopesticide 3 Biopesticide Conventional 4 Biopesticide Biopesticide WK

26 Spring 2017 Whitefly Management Trial GCREC First Five Week Treatment Window Treatment WK 1 WK 2 WK 3 WK 4 WK 5 Conventional Venom 70 SG (7.5 oz) Venom 70 SG (4.5 oz) Biopesticide M Pede (2%) Botanigard ES (1.0 qt) Suffoil X (2%) M Pede (2%) Botanigard ES (1.0 qt) Second Five Week Treatment Window Treatment WK 1 WK 2 WK 3 WK 4 WK 5 Conventional Movento (5 fl oz) Knack EC (10 fl oz) Movento (5 fl oz) Knack EC (10 fl oz) Courier SC (13.6 fl oz) Biopesticide M Pede (2%) Botanigard ES (1.0 qt) Suffoil X (2%) M Pede (2%) Botanigard ES (1.0 qt)

27 Spring 2017 Whitefly Management Trial GCREC Eggs and Nymphs per 10 Leaves A a AB c B bc AB b AB b Eggs Nymphs Funding provided by FDACS/SCBGP

28 Managing Irregular Ripening and Secondary Spread of TYLCV Metalized Mulches TYLCV Tolerant Varieties Early use of systemics: Neonicotinoids Sivanto Prime Verimark/Exirel Nymph Materials (Two Applications Each) Knack Courier Movento Biopesticides, especially M Pede or other insecticidal soap Prompt destruction of harvested crop

29 Hugh Smith University of Florida Gulf Coast Research and Education Center Smith lab: Curt Nagle, Laurie Chambers, Justin Carter, Daniel Cabral, Deepak Shrestha, Pritika Pandey