Lessons of PFD control in Brazil and the new forecast system. Update on citrus black spot control in Sao Paulo

Transcription

1 Citrus Disease Management Seminar Arcadia, FL February 8, 2017 Lessons of PFD control in Brazil and the new forecast system Update on citrus black spot control in Sao Paulo Dr. Geraldo J. Silva Junior Researcher Fundecitrus, Araraquara, SP, Brazil

2 Agenda Introduction to Fundecitrus Lessons of PFD control New PFD forecast system Update on CBS control

3 Who are we? Reference in research and extension on control of citrus diseases and pests; Maintained by growers and orange juice industries; For 40 years, we have been searching effective and sustainable solutions for citrus problems. ~ 100 Employees 12 Researchers Agronomists Agricultural Technicians Biologists Chemical Engineers

4 Areas of expertise Research and innovation Extension Education Master Program Orange production forecast

5 Lessons of PFD control in Brazil Introduction to Fundecitrus Lessons of PFD control New PFD forecast system Update on CBS control

6 Middle child syndrome What is the relationship between the postbloom fruit drop (PFD) and the middle child? In the Citrus Disease Family in SP Who is the oldest child? Citrus canker.reported in 1957 Who is the youngest? HLB.reported in SP in 2004 Who are the middle children? PFD (1979), black spot (1993), etc.

7 Causal agents Colletotrichum acutatum Colletotrichum gloeosporioides Colletotrichum abscissum

8 Occurrence Mexico Belize Panama Colombia Florida Jamaica Dominican Rep. Trinidad Brazil In SP, Brazil We consider the inoculum always present and important Why? Even after 10 years without PFD occurrence If consecutive rainy days with prolonged leaf wetness occur, PFD will cause severe losses! Argentina

9 Losses and damages in SP 4.0 Yield(box/tree) / / / / / /14 Seasons

10 Is PFD easy to control? No!!! Why? Fungicides will not be effective under PFD favorable weather condition; Consecutive rain that causes prolonged wetness (48-72h) increases the pathogen dispersal and reduces the fungicide efficacy; It is requested that large areas be sprayed in short time. Are there tools for PFD control? Yes! Are we prepared to control PFD? No, because we have still been using PFD control strategies from the 90 s! The growers still use high spray volume and low speed application, and most of them need 7-14 days to protect the entire farm.

11 Epidemiology Favorable Environment may or may not occur Pathogens are present Hosts are susceptible

12 PFD Cycle Secondary conidiation Apressoria on leaves and calyces Wind? Young trees? Bees? Symptomatic flowers Acervulus with conidia Splash dispersal from leaves and calyces to flowers Splash dispersal from flowers to flowers > 12h of wetness Infection of flowers Symptoms 2-7 days later Persistent calyces (2-3 months later) Symptoms 2-7 days later Infection of flowers > 12h of wetness Silva Junior (2016) PFD Guide

13 Epidemiology Conditions for PFD outbreaks 2-3 days with consecutive leaf wetness Denham & Waller (1981). Annals of Applied Biology

14 Survival on alternative hosts Survival until 3 months Different weed species Frare et al. (2016). Australasian Plant Pathology 45:

15 Susceptible stages 3 days after inoculation 5 days Pathogen on surface Marques et al. (2013a,b, 2015). Eur. J. Plant Pathol. 135: and 136:35-40 / AoB Plants 7:plu090. Silva Junior et al. (2014). Crop Protection 59:51-56.

16 Conidia germination equation Conidia germination C. acutatum and C. gloeosporioides Equation used in the new forecast system Lima et al. (2011)

17 Chemical control

18 Chemical control in SP, Brazil Fungicides Triazol (DMI) Strobilurin (QoI)

19 Chemical control in SP, Brazil Fungicides Triazol + Strobilurin Nativo = 20% tebuconazole + 10% trifloxystrobin Priori Top = 12.5% difenoconazole + 20% azoxystrobin

20 Chemical control in Florida Fungicides lb. a.i./ac. Best rate in SP (lb./acre) 0.14 lb. triazol (a.i.) lb. strobilurin (a.i) lb. a.i./ac lb. a.i./ac. Quadris Top = 11.4% difenoconazole % azoxystrobin = Rate of 15.4 fl oz./acre Luna Sensation = 21.4% trifloxystrovin % fluopyram = Rate of 7.6 fl oz./acre Quadris Top in FL (15.4 fl oz./acre) 0.11 lb. triazol (a.i.) lb. strobilurin (a.i)

21 Spray volume Conventional adult orchard TRV (m 3 /ha) = 10,000 / Row spacing 7 m (23 ft) row spacing x tree depth x tree height 10,000 / 7.0 m x 3.9 m x 4.1 m TRV = 22,800 m 3 /ha Recommendation 20 ml of mixture/m 3 of canopy 4.1 m (13.5 ft) Depth = 3.9 m (13 ft) Silva Junior et al. (2016). CBS Book Height Dr. Franklin will explain the TRV methodology (ml/m 3 ) 460 L/ha ~ 0.7 fl oz./m 3 of canopy ~ 50 gal/acre

22 Chemical control in SP, Brazil Spray volume In large areas, the low volume ml/m fl oz./m 3 ~ gal./acre contributes to reduce the time needed to protect the entire farm! Soares (2016) Master of Fundecitrus Spray volume (gal/acre)

23 Chemical control in SP, Brazil Speed application In large areas, high speed applications 6-7 km/h mph No sprays Speed application (mph) contribute to reduce the time needed to cover the farm!

24 Chemical control in SP, Brazil Adjuvants Efficacy of oil? * Spray volumes = 50 and 125 gal./acre ** Organosilicone = Silwet

25 Chemical control in SP, Brazil Timing Preventive sprays Beginning... LWD < 24 h < 24h > 48-72h...End Protect the farm in 3-4 days Reapplication after h of LWD Season 1 Season 2 Season 3 Leaf wetness duration (LWD) < h ***No spray > 48-72h LWD < h ***No spray

26 Weather conditions in Sebring, FL Source: FAWN

27 Chemical control in SP, Brazil Reapplication Rainfall > 1.0 in Leaf wetness > 48-72h Rainfall of 0.2, 0.5 or 1.0 in Simulated rainfall and pyraclostrobin application 30 minutes later Rainfall (inches/h) Fungicide was effective with up to 1.0 inch of rainfall Gonçalves et al. (2012)

28 Chemical control in SP, Brazil Rainfall effect Tank Jr. (2013) - Master of Fundecitrus

29 A NEW WEB B-BASED BASED FORECAST SYSTEM Introduction to Fundecitrus Lessons of PFD control New PFD forecast system Update on CBS control

30 PFD-FAD forecast system Timmer & Zitko (1993); Peres et al. (2004)

31 A new forecast system The beginning of all and The first ideas and Experiments with conidia germination in 56 combinations of temperature and leaf wetness (LWD)...The equation was developed... Germination (%) = 100*[(t-t min )/(t opt -t min )]^β1*(topt-tmin)/(tmax-topt) *[(t max -t)/(t max -t opt )] β1 *[1- β 2 *exp( β 3 *LWD)] Lima et al. (2011); Gonçalves et al. (2013) to Experiments in greenhouse with flowers inoculation 10 combinations of Temp and LWD Equation validated in screenhouse to 2016 Field trials Evaluation of thresholds 15, 20 and 25% of germination Forecast System developed

32 Field trials Field trial 1 Santa Cruz do Rio Pardo, SP, Brazil Field trial 2 Taquarituba, SP, Brazil 4 sprays US$ spray US$ sprays US$ sprays US$60.00 Gama et al. (2016)

33 A new forecast system Low Risk Moderate Risk High Risk Extreme Risk

34 A new forecast system Ace in the hole

35 A new forecast system Tutorial on:

36 Summary Lesson #1: Protect the entire farm in 3-4 days; Lesson #2: Use low spray volume and spray faster; Lesson #3: Spray triazol + strobilurin under highly favorable condition; Lesson #4: Reapply the fungicide when the system indicates Extreme Risk ; Advantages of the PFD system: i) reduces the number of spray and costs by up to 75%; ii) reduces the environmental impacts; iii) maintains quality of disease control.

37 Update on citrus black spot control in Sao Paulo Introduction to Fundecitrus Lessons of PFD control New PFD forecast system Update on CBS control Phyllosticta citricarpa

38 Occurrence CBS absent CBS present 1992 CBS reported in SP state Silva Junior et al. (2016). CBS Book

39 Losses and damages Premature fruit drop Depreciation of the fruit Export restrictions Oranges Limes and lemons Mandarins Silva Junior et al. (2016). CBS Book

40 Symptoms Hard spot False melanose Cracked spot Freckle spot

41 CBS cycle Silva Junior et al. (2015). CBS Guide Ascospores are dispersed by wind to other trees Symptoms after 40 to 300 days On diseased fruit, leaves or branches are produced conidia Conidia are dispersed by being washed down to other fruit Infected leaves fall and continue the cycle Infected nursery trees can introduce CBS to free areas The ascospores are formed in fallen leaves Infected leaves can introduce the disease to CBS-free areas

42 CBS Management

43 Sanitary measures Protected nursery Elimination of leaves from the trucks Reduction of traffic into the farm Silva Junior et al. (2016). CBS Book

44 Management of leaf litter and dead twigs Ecological mowing machine Pruning of dead twigs Silva Junior et al. (2016). CBS Book

45 Early harvest With sprays Without sprays Premature fruit drop (%) With sprays Without sprays Oct Nov Dec Jan Month of harvest Silva Junior et al. (2016). CBS Book

46 Chemical control

47 Products Fixed copper Copper hydroxide Copper oxychloride Cuprous oxide All formulations with same metallic copper rates showed similar CBS control 40 to 60 mg Cu met/m 3 of canopy ~ 0.7 to 1.0 lb. Cu met./acre Interval = 21 to 28 days Strobilurin Azoxystrobin Pyraclostrobin Trifloxystrobin Rate of 2.8 mg a.i/m 3 of canopy ~ 0.07 to 0.10 lb. a.i./acre Interval = 35 to 42 days Silva Junior et al. (2016). CBS Book

48 Period of control Application period in SP Symptoms expression period September April/May......harvest In FL March Out/Nov Silva Junior et al. (2016). CBS Book Blooming in September (Fl = Mar) Copper = Sep and Oct (Fl = Mar and Apr) Strobilurin = Nov to Mar/Apr (Fl = May and Sep/Oct)

49 Spray volume Recommendation ml/m 3 of canopy Yield (kg/tree) Severity (%) ** 50 50** No sprays Silva Junior et al. (2016). CBS Book Spray volume (ml/m 3 ) 125 ml/m 3 = gal./acre 100 ml/m 3 = gal./acre 75 ml/m 3 = gal./acre 50 ml/m 3 = gal./acre fl oz./m 3 of canopy 75 ml/m 3 of canopy 1,800 L/ha = ~ 200 gal/acre 1,800 L/ha = ~ 0.4 gal/tree

50 Spray program Early maturing Copper Copper QoI QoI Oil Oil Copper Copper QoI Oil QoI Oil QoI Oil QoI Oil Late maturing Silva Junior et al. (2016). CBS Book

51 Black spot and citrus canker In SP Aug-Sep Sep-Oct Oct-Nov Nov-Dec Dec-Jan Jan-Feb Feb-Mar Mar-Apr Apr-Mai In FL Feb-Mar Mar-Apr Apr-May May-Jun Jun-Jul Jul-Ago Ago-Sep Sep-Oct Oct-Nov Day 0 21 days 21 days 21 days 21 days 21 days Copper Copper Copper Copper Copper Copper Day 0 42 days QoI 42 days QoI 42 days QoI (?) 42 days QoI (?) Oil Oil Oil Oil Copper = > 40 mg metallic Cu/m 3 (~ lb. Cu met/acre) Strobilurin (QoI) = 2.8 mg a.i./m 3 (~ lb. a.i./acre) Oil = 0.25%

52 Guide for CBS-Canker-HLB control Available on:

53 Book of Citrus black spot (Only in Portuguese)

54 Acknowledgments: Fundecitrus team: Dr. Franklin and other colleagues MSc. Marcelo Scapin William Aparecido Ferreira Gleison Oliveira Santos Rosana Gonçalves Pereira Partnership: Dr. Lilian Amorim (Esalq/USP) Dr. Natalia Peres (UF) Dr. Clyde Fraisse (UF) Dr. Angélica Giarolla (INPE) Dr. Sin Chan Chou (CEPTEC) André Bueno Gama (Esalq/USP) EnsoAg Team Technical assistance: Orange juice industries Growers Master students Thanks!

55 "In science, paradigms are accepted or refuted, some by conformism become dogmas until a mortal scientist becomes a god and proves to others that science is not a religion and that truth is changeable." geraldo.silva@fundecitrus.com.br