Baseline Susceptibility of NPVs and their Potential Contributions to Management of Resistance to Chemical Insecticides and Traits

Transcrição

1 Baseline Susceptibility of NPVs and their Potential Contributions to Management of Resistance to Chemical Insecticides and Traits Celso Omoto (Esalq / USP) & Oderlei Bernardi (UFSM)

2 Outline Baseline susceptibility of Spodoptera frugiperda to SfMNPV and Chrysodeixis includens to ChinNPV; Cross-resistance between Baculovirus (SfMNPV and ChinNPV) and some major insecticides and Bt proteins

3 Crop growing seasons Maize 1 st season 5.1 million ha Maize 2 nd season 11.5 million ha Winter OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP Cotton 1.2 million ha Soybean > 35 million ha Source: Conab (2017/18)

4 Maize production areas 1st season 2nd season 5.1 Mi ha 11.5 Mi ha Source: Conab (2017/18)

5 Source: Conab (2017/18) Soybean and Cotton Production Areas Soybean Cotton 35 Mi ha 1.2 Mi ha

6 Cross-Crop Pests Soybean Spodoptera frugiperda S. eridania S. cosmioides Helicoverpa armigera Chloridea virescens Chrysodeixis includens Stink bugs and other bugs Whiteflies Spider mites Maize Spodoptera frugiperda Helicoverpa zea Stink bugs and other bugs Whiteflies Spider mites Cotton Spodoptera frugiperda S. eridania S. cosmioides Helicoverpa armigera Chloridea virescens Chrysodeixis includens Stink bugs and other bugs Whiteflies Spider mites

7 Spodoptera frugiperda (Lepidoptera: Noctuidae) Chrysodeixis includens (Lepidoptera: Noctuidae)

8 University of São Paulo Luiz de Queiroz College of Agriculture Baseline Susceptibility to SfMNPV in Spodoptera frugiperda (Lepidoptera: Noctuidae) populations from Brazil José Paulo Franco Bentivenha Celso Omoto Dept. Entomology and Acarology

9 S. frugiperda populations Population Origin Longitude Latitude Number of insects Date SUS Goiás Montividiu 17º29 58,92 51º07 23, larvae + 6 pupae 03/2017 Mato Grosso Campo Verde 15º29 27,89 55º20 52, larvae + 41 pupae 03/2017 Mato Grosso do Sul Laguna Carapã 22º42 33,98 55º02 54, larvae 03/2017 Paraná Toledo 24º40 14,01 53º48 48, larvae + 1 pupa 04/2017 São Paulo Pirassununga 21º53 9,42 47º20 57, larvae + 41 pupae 03/2017

10 Droplet feeding bioassay AgBiTech Virus: SfMNPV ( PIB/mL) Droplet Feeding: Dye (FDC Green) (10%) Sucrose (5%) Concentrations: , , , , , , Control Control: distilled water + dye + sucrose At least: 120 larvae/concentration

11 Droplet feeding bioassay Droplets (0,5 µl) in Petri dishes (60 mm) Neonates (3 to 4 h after hatching) After 15 min, rescue of infected larvae (magnifying glass and brush) Trays (32 cells; artificial diet, Greene et al., 1976) 28 C and 14 h photofase Evaluation: 24 h and 7 days Statistical analysis Mortality: Probit (POLO-PC) LC50

12 Baseline susceptibility of S. frugiperda to SfMNPV Population n a Slope (± SE) LC 50 (95% FL) b χ 2 df c SUS (0.09) ( ) GO (0.07) ( ) MS (0.05) ( ) MT (0.07) ( ) SP (0.07) ( ) PR (0.08) ( ) a/ Number of larvae assessed; b/ Oclusion bodies/ml; c/ degrees of freedom. 2.1-fold variation in LC 50 values Estimated LC 99 = OBs/mL diagnostic concentration for resistance monitoring

13 Cross-Resistance between SfMNPV and major insecticides and Bt proteins Resistant strains of S. frugiperda to insecticides: R chlorpyrifos; R lambda-cyhalothrin; R spinosad; R teflubenzuron; R chlorantraniliprole Resistant strains of S. frugiperda to Bts proteins: R Hx (Cry1F); R VTPro (Cry1A.105+Cry2Ab2); R Vip (Vip3Aa20)

14 Cross-Resistance between SfMNPV and major insecticides Strains n a Slope (± SE) LC 50 (95% FL) b χ 2 df c rr d SUS (0.09) ( ) R - lambda-cyhalothrin (0.05) ( ) R - teflubenzuron (0.12) ( ) R - spinosad (0.06) ( \ ) R - chlorantraniliprole (0.06) ( ) R - chlorpyrifos (0.06) ( ) a/ Number of larvae assessed; b/ Oclusion bodies/ml; c/ degrees of freedom; d/ rr = LC 50 of resistant strain/ LC 50 SUS.

15 Probit Cross-Resistance between SfMNPV and Bt proteins Strains n a Slope (± SE) LC 50 (95% FL) b χ 2 df c rr d SUS (0.09) ( ) R - Cry1F (0.05) ( ) R - Cry1A Cry2Ab (0.10) ( ) R - Vip3Aa (0.06) ( ) a/ Number of larvae assessed; b/ Oclusion bodies/ml; c/ degrees of freedom; d/ rr = LC 50 of resistant strain/ LC 50 SUS SUS Cry1F Cry1A Cry2Ab2 Vip3Aa ,E+03 1,E+04 1,E+05 1,E+06 1,E+07 1,E+08 1,E+09 PIB/mL

16 Universidade Federal de Santa Maria Centro de Ciências Rurais Departamento de Defesa Fitossanitária Baseline susceptibility to ChinNPV in Chrysodeixis includens (Lepidoptera: Noctuidae) populations from Brazil Oderlei Bernardi Departamento de Defesa Fitossanitária/UFSM

17 C. includens populations

18 Baseline susceptibility of C. includens to ChinNPV ChinNPV (OBs/ml) in droplet feeding bioassay Pop. code Generation n Slope ± SE LC 50 (95% FL) χ 2 df Lab ± ( ) RS-1 F ± ( ) PR-1 F ± ( ) SP-1 F ± ( ) MS-1 F ± ( ) MS-2 F ± ( ) MS-3 F ± ( ) MT-1 F ± ( ) GO-1 F ± ( ) BA-1 F ± ( ) BA-2 F ± ( ) BA-3 F ± ( ) fold variation in LC 50 values Estimated LC 99 = OBs/ml diagnostic concentration for resistance monitoring

19 Diagnostic concentration for resistance monitoring ChinNPV OBs/ml City, State Generation Tested Died % mortality (95% CI) Susceptible reference (Lab) ( ) a Victor Graeff, Rio Grande do Sul F ( ) a Londrina, Paraná F ( ) a Leme, São Paulo F ( ) a Chapadão do Sul, Mato Grosso do Sul F ( ) a Campo Grande, Mato Grosso do Sul F ( ) a Campo Verde, Mato Grosso F ( ) a Rio Verde, Goiás F ( ) a Correntina, Bahia F ( ) a

20 ChinNPV against C. includens resistant to insecticides Teflubenzuron (µg a.i./cm 2 ) Strain n Slope ± SE LC 50 (95% CI) LC 90 (95% CI) χ² df RR Sus ± ( ) ( ) Teflu-Res Sus ± ( ) ( ) Teflu-Res Sus ± ( ) ( ) Teflu-Res ± ( ) not estimated ,274 ChinNPV (OBs/ml) Strain n Slope ± SE LC 50 (95% CI) χ² df Sus ± ( ) Teflu-Res Sus ± ( ) Teflu-Res Sus ± ( ) Teflu-Res ± ( )

21 ChinNPV against C. includens resistant to insecticides Lambda-cyhalothrin (µg a.i./larva) Strain n Slope ± SE LC 50 (95% CI) LC 90 (95% CI) χ² df RR Sus ± ( ) ( ) Lamb-Res Sus ± ( ) 0.14 ( ) Lamb-Res Sus ± ( ) 0.12 ( ) Lamb-Res ± ( ) 0.95 ( ) ChinNPV (OBs/ml) Strain n Slope ± SE LC 50 (95% CI) χ² df Sus ± ( ) Lamb-Res Sus ± ( ) Lamb-Res Sus ± ( ) Lamb-Res ± ( )

22 Concluding Remarks Baseline susceptibility data and diagnostic concentrations of SfMNPV and ChinNPV were defined for monitoring insect susceptibility SfMNPV and ChinNPV can contribute to management of resistance to chemical insecticides and Bt Traits

23 Acknowledgments Celso Omoto Orientador José Paulo Bentivenha Pós-doutorando Juliana G. Rodrigues Iniciação Científica Oderlei Bernardi Orientador Regis F. Stacke Doutorando Dionei S. Muraro Mestrando Daniela N. Godoy Iniciação Científica Tiago Giacomelli Iniciação Científica Paula Marçon Vice-Presidente Holly J. R. Popham Pesquisadora Marcelo Lima Pesquisador