The latest on managing Botryosphaeria (Bot) canker & blight

Transcription

1 The ltest on mnging Botryospheri (Bot) cnker & blight review, updtes, tril results - Jnine Hsey, UCCE Advisor, Sutter/Yub/Colus pruning chipping tril results Ktherine Pope, UCCE Advisor, Yolo/Solno/Scrmento Wlnut Dy Feb 23, Woodlnd; Feb 25 Yub City

2 cknowledgements Chrlie Stegll, Colus Co. (Chndler) Dnn Frms, Gry Wlker Yub Co. (Vin) CA Wlnut Bord Fungicide dontions/support BASF Syngent Byer DuPont Severl slides/photos - Themis Michilides, Plnt Pthologist, UC Kerney REC

3 history of Bot in wlnut 1st found S. Joquin Vlley (Michilides) Not thought cusing ny mjor dmge (on mny hosts) Sept 2003 found in Sutter Co scttered orchrds, often in ssocition with scle killing lrge brnches, fruitwood - strted seeing blight phse - worsening sttewide

4 min symptom types Brnch cnker & diebck Blighted shoots Twig blight Fruit & shoot blight Infected nuts

5 Conditions for infection Presence of inoculum Rin: t lest 1/4 Temperture: 50 F Presence of susceptible tissues

6 Infection Courts of Botryospheri nd Phomopsis During the seson: Wounds from hil, freeze, sunburn, wood peckers Pruning wounds Scle wounds Wlnut blight lesions (BAN)* At hrvest: Scrs from peduncles Fruit scrs Lef scrs Mechnicl wounds Posthrvest: Peduncle scrs Lef scrs Husks (remining on the tree) Pruning wounds Wounds from freeze dmge Injuries from wood peckers Other type of injuries

7 Wounds in the field during 1) the seson, 2) t hrvest nd 3) posthrvest Lef scrs * eduncle scrs * Cnker * Fruit scrs when wlnuts drop

8 CA Wlnut Bord funding Wht we ve lerned bout Bot

9 2012 All wlnut vrieties susceptible 10 species of Bot; 2 species Phomopsis Scle infested limbs more susceptible to Bot Scle Blck BOT Pycnidi

10 Botryosphericee Phomopsis Distribution of Botryospheri spp. in wlnut orchrds

11 2013 Direct infection of shoots (Bot) & fruit Confirmed scle increses BOT incidence nd cnker development Fusrium, Alternri & other fungi cn lso decy wlnut fruit

12 Alternri & Fusrium

13 2013 Direct infection of shoots (Bot) & fruit Confirmed scle increses BOT incidence nd cnker development Fusrium, Alternri & other fungi cn lso decy wlnut fruit Bot in wlnut hs two spore stges: Pycnidi (conidi)- wter-borne Ascospores wind-borne

14 Peritheci Pycnidi

15 2014 (spred & infection) Immture fruit cn be infected remin symptomless led to fruit blight Aug-Sept Infected/blighted fruit - Infect spur cusing cnker/kill buds

16 Fruit Peduncle Shoot

17 2014 (spred & infection) Infected/blighted fruit - Infect spur cusing cnker Pruning wounds just s susceptible fter 4 weeks s right fter pruning Fungicide trils most fungicides reduced infections/ cnkered spurs mid-my, mid-june, mid-july timing

18 2015 wht s new? Better understnd spred within/mong wlnut orchrds with other host plnts Cn detect low spore #s trpped fter rin events minly found My mid-sept Pycnidi spores relesed within 1 st 2 hrs fter rin begins; spent fter 4

19 2015 wht s new? Pruning cut wounds susceptible for 4 months fter wounds mde!

20 Susceptibility of pruning wounds of (1-, 2-, 3-, & 4-16 yer old wood to infection by Bot Averge cnker length (cm) e cde de bcd bc bcd b b cd bc b 0 control Pruning on 9 & 10 Feb dy 3 dy 1 week 2 week 3 week 4 week 8 week 12 week Post-pruning inocultion dte 16 week

21 2015 wht s new? Pruning cut wounds susceptible for 4 months fter wounds mde! 3-4 yr old shoots more susceptible thn 1-2 yr old shoots Likely due to pith tissue

22 Prune brnch Wlnut brnch Wlnut brnches

23 Susceptibility of pruning wounds to infection by Bot s ffected by shoot ge Averge cnker length (cm) Pruning on 9 & 10 Februry 2015 up to 2 inches b b 5-6 inches 1 yer 2 yer 3 yer 4 yer Age of inoculted shoots

24 2015 wht s new? 3-4 yr old shoots more susceptible thn 1-2 yr old shoots Likely due to pith tissue Pinting wounds immeditely fter pruning most fungicides did not protect wounds Two exceptions

25 Tretment of pruning wounds with fungicides, then inocultion with Neofusicoccum prvum Averge cnker length (cm) b Neofusicoccum prvum b b b 0 Control Qudris Top Merivon Merivon+VitiSel Abound

26 2015 wht s new? Timing spry study Best time for one-time spry Mid-June to erly July

27 Best-timing of single spry of Merivon in Chndler orchrd in Butte Co b Bloom b Posthrvest (PH) Blighted spurs (%) b Best timing b Nonspryed = 8% 1.0 Merivon: bloom Merivon: My Merivon: June Merivon: July Merivon: August Merivon: post: hrvest SPRAYS: Apr 9 (bloom); My 12; Jun 12; Jul 10; Aug 10; Nov 3 (PH)

28 2015 wht s new? Timing spry study Best time for one-time spry Mid/lte June Lef wetness model (LWM) Triggered 3 sprys ( 50 o F, ¼ wetness) Best disese control

29 Lef wetness model (LWM) where rin exceeded threshold in Chndler (Butte Co) 60 Lef wetness, hours spryed April 8-9 (8 mm) spryed Medium Risk High Risk April (18 mm) spryed Sept (3 mm) 10 0 Low Risk Temperture, C

30 2015 wht s new? Timing spry study Best time for one-time spry Mid/lte June Lef wetness model (LWM) Triggered 3 sprys ( 50 o F, ¼ wetness) Best disese control Most fungicides reduce Bot for 6 mos. pre-seson BUDMON ssy

31 BUD MONitoring (BUDMON) Technique 1. Bud surfce steriliztion 2. Plting on medi 3. Incubting t 81 F 4. Recording fter 6-7 dys BOT Februry/Mrch % of buds with Bot Results in 6-7 dys

32 Fungicide Trils Butte, Colus, Yub cos. Themis Michilides Jnine Hsey Emily Symmes D. Morgn, D. Felts, R. Puckett

33 Montgomery Effects of fungicides fungicide on Botryospheri efficcy 2014 in Chndler sesons wlnut ll tretments shoots/spurs (Butte Co.) SPRAYS: My 8, June 12, nd July 10 Merivon Qush Ph-D + Tebucon K Phite Fontelis + OR009 K Phite + Ltron EXP 1 + EXP 3 EXP1 + EXP 2 Lun Senstion 7.6 oz EXP 1 Pristine Lun Experience 10 oz Fontelis + Tebucon Lun Experience 6 oz Bdge + Mnzte Ph-D Fontelis Qudris Top Vithon Lun Senstion 5 oz Control 4X b b b b b b b b b b b bc bc bc bc c Blighted shoots (%)

34 Efficcy of four clendr sprys of fungicides in Chndler wlnut orchrd in Butte Co. (Scrmento River) SPRAYS: My 12, Jun 11, Jul 10, Aug (4X SPRAYS) Pristine Ph D + Tebuconzol Fontelis + Abound Font-Teb>QudTop>Font-Teb>QudTop Indr Fontelis + Vintre Lun Experience Vithon Qudris Top Fontelis + Tebuconzol Qush Lun Senstion Ph D Bdge-Mnzte Pro Stick Frcture Merivon Fontelis Control b b b b b bcd bc bc bc bcd bcd bcd bcd bcd bcd bcd cd d Blighted spurs (%)

35 Chndler No discolortion Brown kernels Blck kernels

36 Effects of fungicides on Botryospheri in Chndler wlnut blck nd brown kernels (Colus Co.) Botryspheri spp. (%) b b Control Lun Experience (1) Lun Experience (2) b Qudris Top (1) Qudris Top (2) Blck kernels b b b Merivon (1) Merivon (2) Fontelis+Tebucon (1) b Fontelis+Tebucon (2) b Botryospheri spp. (%) b Control Lun Experience (1) Lun Experience (2) b b Qudris Top (1) Qudris Top (2) Brown kernels b b b b Merivon (1) Merivon (2) Fontelis+Tebucon (1) Fontelis+Tebucon (2) b

37 Long-term effect of 2014 fungicide sprys ginst Bot in Chndler wlnut orchrd (Colus Co.) Fontelis + Tebucon + Posthrvest Merivon + Posthrvest Qudris Top Fontelis + Tebucon Merivon Qudris Top + Posthrvest Lun Experience Lun Experience + Posthrvest Control Buds with Botryospheri (%) Buds collected in Feb 2015 Similr dt for buds collected 1/25/16

38 Effects of fungicides on fruit with blck hulls t hrvest (cv. Chndler wlnut, Colus Co. 2015) Merivon Fontelis + Tebucon Qudris Top + PH Lun Experience Fontelis + Tebucon + PH Qudris Top Merivon + PH Lun Exp. + PH Control b b b b Fruit with blck hull t hrvest (%) Sprys: My 8, June 11, July 9 Recorded- Oct 14, 2015; (PH) Oct 19 Vintre t 1/qt/c ws used with ll tretments

39 Efficcy of vrious timings of Merivon fungicide ginst Bot/Phomopsis in Vin (Yub Co.) Recorded Dec 3, 2015 (+ProSilicone 100) Buds collected 1/25/16 (NS)

40 Efficcy of vrious timings of Merivon ginst Bot/Phomopsis in Vin (Yub Co.) Merivon-April/My/June Merivon-April/My/June Merivon-My/June/July Merivon-April/My/June/July Merivon-April/My/June/July Merivon-My/June/July Control Control b Botryospheri (%) Phomopsis (%) No effect on Fusrium (2% - 7%) or Alternri (14% - 18%) Sprys: April 13 (1/3 nutlet stge); My 21; June 22; nd July 20 Nuts with blck hulls were collected t hrvest (Sept 18); results for blck + brown kernels together

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42 Bot Mngement Culturl control (snittion) remove infected brnches do in summer when not rining Chemicl control (fungicides - protect susceptible tissues) sprys My, June, July/August reduce Bot bloom nd posthrvest sprys my lso reduce Bot sprys fter rin seem to be very effective (LWM) best time for one-time spry - mid-june to erly July Disese risk ssessment BUDMON

43 Bot Mngement Wht to do with ll tht pruned wood? Kt Pope Sc-Solno-Yolo Orchrd Advisor

44 How Bot spores cn move in the tree Pycnid (& Ascocrp) Wter Wind

45 1. Drip down cnopy (pycnidi)

46 2. Blow round cnopy wteror ir-borne

47 3. Splsh up into cnopy

48 4. Blow up into cnopy wteror ir-borne

49 Snittion by pruning is necessry step to remove disese, decrese future infection

50 Wht to do with ll tht pruned wood?

51 Bot Survivl in Chipped Wood

52 Bot Survivl in Chipped Wood Both hit with full coverge sprinklers Chips were in piles Could pycnidi send out spores to cuse infection? Anlyzed for spore vibility by Michilides lb

53 Vibility of Spores on Pieces % Vibility Vibility of spores in chipped pieces rpidly decresed in first two month. By end of summer, chipping decresed vible spores by 1/3.

54 Chipping pruned wood decreses spore vibility. Could be less tht results if chips not moistened. Could be more if chipped finer. In hevily infected orchrds, nd orchrd will be spryed, not much difference if chip in orchrd OR remove nd burn. Alredy plenty of inoculum. In light-to-medium infected orchrds, wood removl still best option. But if cn t burn, chipping hugely reduces vible spores in pruned wood. Likely better option thn piling on edge of orchrd. In Bot-free orchrds, wood cn be shredded nd left on the orchrd floor.

55 Side Note: Bewre of Bot When Replnting 45% of grfted replnts died 23/24 smples positive for Bot fmily THE LESSON? Don t grft replnts in block with hevy Bot

56 Questions?