/
Walnut Blight Walnut Blight

Walnut Blight - PowerPoint Presentation

test
test . @test
Follow
425 views
Uploaded On 2016-09-03

Walnut Blight - PPT Presentation

Management Using Xanthomonas arboricola pv juglandis Dormant Bud Population Sampling Richard P Buchner UC Farm Advisor Tehama County William H Olson UC Farm Advisor Emeritus Butte County ID: 459908

walnut buds sample blight buds walnut blight sample tehama california 2012 bud orchards butte population pathogen infested county damage

Share:

Link:

Embed:

Download Presentation from below link

Download Presentation The PPT/PDF document "Walnut Blight" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.


Presentation Transcript

Slide1

Walnut Blight Management Using Xanthomonas arboricola pv juglandis Dormant Bud Population Sampling

Richard P. Buchner – UC Farm Advisor, Tehama CountyWilliam H. Olson – UC Farm Advisor Emeritus Butte County Dr. Steven E. Lindow – Plant Pathology UC Berkeley Dr. James E. Adaskaveg – Plant Pathology UC Riverside Cyndi K. Gilles – Research Assistant Tehama CountyRenee Koutsoukis – Research Assistant UC BerkeleySlide2

Walnut Blight infestation in Northern California Xanthomonas arboricola pv juglandisSlide3
Slide4

Blight History – Vina VarietyTehama County, California

Location

2011 % pathogen

2011 % Blight

2012 % pathogen

2012 Spray Schedule

2012 %

Blight

South

16

1.49304/16 & 5/23.50Middle231.23104/16 & 5/26.49North62.00164/16 & 5/22.42

2011 Spray Schedule:

6.74 Kg/Ha Kocide

2000 +

2.7 Kg/Ha Pro-Stick

4/12, 4/26 and 5/5

2012 Spray Schedule:

4.49 Kg/Ha Badge

+

2.7 Kg/Ha Manzate

4/16 and 5/2Slide5

Tree #

Rating

Tree #

Rating

69

L

34

M

68

M

33L67L32L66L31M65M

30

M64L29L63H28L62H27L61H26L60H25Replant59H24L58H23M57H22L56H21L55M20054M19L53L18L52L17L51M16Replant50015049M14048L13047M12L46M11045M10L44L9043M8042H7041Replant6040L5L3904L38M3Replant37L2036L1035L

(no nut drop)

(0 to 30 nuts)

(30 to 100 nuts)

(over 100 nuts)

Xaj Histogram for Medium Blight Rating

0.0

1.0

2.0

3.0

4.0

5.0

6.0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

Bud #

Log (Cfu/bud)

2012

Vina Walnut in Tehama County, California

(30 to 100 nuts)

10% infested buds

40% infested buds

67% infested buds

5

0% infested budsSlide6

(G) or (A) indicates ground or air applications. (H) indicates half sprays every other row alternating. B=Badge at 4.49 Kg/Ha, M=Manzate at 2.7 Kg/Ha, S=Freeway at 292.30 ml/Ha and Z=Zinc Sulfate 36% at 1.12 Kg/Ha.

2011 % Path-ogen

2011% Blight

2012 % Path-ogen

Vina 2012 Spray Schedule

Butte County, California

2012 % Blight

60

2.60

43

4/2 (A) B,M,S,Z4/9 (GH) B,M,S,Z4/16 (A) B,M,S4/24 (GH) B,M,S,Z5/25 (GH) B,M16.173.5234/2(A) B,M,S4/9 (GH) B,M,S,Z4/16(A) B,M,S4/24(GH) B,M,S,Z

5/25

(GH) B,M.87Slide7

Walnut Blight damage for 14 walnut orchards in Tehama County from 2010 to 2013. Blight damage is increasing in one orchard with a history of high initial inoculum.Slide8

Walnut Blight damage for 15 walnut orchards from 2011 to 2013. Improved spray programs plus a low disease pressure year resulted in much better disease control in 2013.Slide9

Relationship of % buds with pathogen and the associated bud population. Very strong correlation of incidence of bud infestation with average population size of pathogen – disease prediction can be made based on more easily measured incidence of infestation rather than average population size. The lines drawn represent the linear regressions Y=0.0308X + 0.055 (R2=0.967) (2012); and Y=0.0398x + 0.067 (R2=0.626) (2013).Slide10

Relationship between the % buds infested with pathogen and the % walnut blight damage for 30 orchards in Butte and Tehama counties for 2012. The lines drawn represent the linear regression Y=0.218x – 0.28 (R2=0.56); and Y=0.001x + 0.14 (R2=0.001) for orchards in Butte and Tehama counties, respectively.Slide11

Relationship between the % buds infested with pathogen and the % walnut blight damage for 30 orchards in Butte and Tehama counties for 2013. The lines drawn represent the linear regressions Y=0.039x + 0.067 (R2=0.626); and Y=0.032x – 0.096 (R2=0.58) for orchards in Butte and Tehama counties, respectively.Slide12

Walnut Bud Sampling MethodologySample buds in December, January, February, March or early April for late leafing varieties. Buds can be sampled to the time they start to open. Early samples will allow more time to design disease control strategies.Slide13

Select 100 dormant walnut spurs with nice fat terminal buds. Cut off about a 3 inch length. Spurs reachable from the ground are easy to collect and represent a good sample location because bacteria sprinkle down through the tree canopy.Slide14

Walk the entire area collecting a random sample. One or two buds per tree should spread the sample adequately. Deciding how many samples to collect will depend upon experience on an orchard by orchard basis. One sample could easily represent 50 acres if experience suggests reasonable uniformity.Slide15

Save spurs in a paper bag and store in a cool dry place. The paper bag will allow samples to breathe and eliminate condensation. Mail or transport buds to a lab. The lab will select a 30 terminal bud subsample to plate on agar and save the remaining buds as a backup sample.Slide16

Walnut orchards can be highly variable. Try to achieve as representative sample as possible.Slide17

In California, samples can be analyzed at the California Seed and Plant Lab. www.calspl.com 916-655-1581Slide18

Incidence of populations of X. juglandis on walnut buds sampled following harvest on 12/1/10. This is a histogram typical for a low population sample. Notice that over 25 buds had zero pathogen.Slide19

Incidence of populations of X. juglandis on walnut buds sampled following harvest on 12/1/10. This is a histogram for a high population sample. Notice that only 8 buds had no detectable pathogen and most of the buds were in the ten to the fourth (10,000 colony forming units) or more range. This would be an example of a high risk orchard.Slide20

Additional Informationcetehama@ucanr.edu (Buchner website)walnutresearch.ucanr.edu (California Walnut Research Reports)www.calspl.com

(California Seed and Plant Lab)Thank you