Enhancing Plant Disease Enhancing Plant Disease Diagnostic Skills . . .Diagnostic Skills . . .

……to build a stronger partnership between to build a stronger partnership between Specialists, Agents and GrowersSpecialists, Agents and Growers

P. Bachi and J. Beale, DiagnosticiansP. Bachi and J. Beale, Diagnosticians

J. Hartman, D. Hershman, W. Nesmith, and P. Vincelli, J. Hartman, D. Hershman, W. Nesmith, and P. Vincelli, Extension Plant PathologistsExtension Plant Pathologists

Plant Pathology Department, University of KentuckyPlant Pathology Department, University of Kentucky

Diagnosis is . . . Diagnosis is . . .

Hypothesis-testingHypothesis-testing

Think of each diagnosis as a research Think of each diagnosis as a research project.project.

1.1. Examine samples and Examine samples and gather informationgather information

2.2. Formulate hypothesisFormulate hypothesis3.3. Test hypothesis Test hypothesis 4.4. Accept or reject Accept or reject

hypothesis based on hypothesis based on resultsresults

Examine samples and gather information to formulate hypothesis.

Test hypothesis.Test hypothesis.

Diagnostic Rule:Diagnostic Rule:

““DoDo make the diagnosis fit the make the diagnosis fit the symptoms (evidence);symptoms (evidence);

Don’tDon’t make the symptoms make the symptoms (evidence) fit the diagnosis.” (evidence) fit the diagnosis.”

Diagnostic Rule:Diagnostic Rule:

““Correlation is not causation.”Correlation is not causation.”oror

““Just because it’s there now, Just because it’s there now, doesn’t mean it caused the doesn’t mean it caused the problem.”problem.”

G. Kemmitt

R.E.Stall

W. E. Fry

Diagnostic Rule:Diagnostic Rule:

““Know when you know;Know when you know; know when you don’t know.” know when you don’t know.”

– Bill Nesmith– Bill Nesmith

How can we work better as partners?How can we work better as partners?

Specialists and DiagnosticiansSpecialists and Diagnosticians

- Stay focused on the Stay focused on the sciencescience- Timely diagnosis and reporting- Timely diagnosis and reporting- New initiatives for greater efficiency- New initiatives for greater efficiency- Education vs. service?- Education vs. service?

How can we work better as partners?How can we work better as partners?

County Extension AgentsCounty Extension Agents

- Key in DetectionKey in Detection- “Eyes and ears”- “Eyes and ears”

- Critical link between local community- Critical link between local community& lab/specialists& lab/specialists

- Rapport with public- Rapport with public

Diagnostic Initiatives for 2003 Diagnostic Initiatives for 2003 and Beyondand Beyond

- Real-time PCR- Real-time PCR

- Digital Consulting System- Digital Consulting System

Polymerase Chain Reaction (PCR)Polymerase Chain Reaction (PCR)

• The most important technique in The most important technique in molecular biologymolecular biology

• Amplifies specific DNA sequence Amplifies specific DNA sequence exponentiallyexponentially, by chain reaction, by chain reaction

Real Time PCRReal Time PCR

• Learn results of PCR test in real Learn results of PCR test in real timetime

• As a diagnostic technology, it is As a diagnostic technology, it is remarkably:remarkably:– RapidRapid– SensitiveSensitive– SpecificSpecific

Smart CyclerSmart Cycler® ® Real Time PCR MachineReal Time PCR Machine

Smart CyclerSmart Cycler® ® Real Time PCR MachineReal Time PCR Machine

Anticipated Diagnostic Applications Anticipated Diagnostic Applications

in the near termin the near term• Pierce’s disease of grapePierce’s disease of grape• Bacterial spot of pepper and tomatoBacterial spot of pepper and tomato

– Detection of pathogen species Detection of pathogen species and and racerace

• Bacterial speck of tomatoBacterial speck of tomato• Bacterial wilt of tomato and tobaccoBacterial wilt of tomato and tobacco• Bacterial canker of tomatoBacterial canker of tomato

Anticipated Diagnostic Applications Anticipated Diagnostic Applications

in the near term (cont’d)in the near term (cont’d)

• Bacterial wilt of cucurbitsBacterial wilt of cucurbits

• Yellow vine decline of cucurbitsYellow vine decline of cucurbits

• Verticillium wilt of woody Verticillium wilt of woody ornamentalsornamentals

• Spring dead spot of bermudagrassSpring dead spot of bermudagrass