How Forensic Agrologists Determine the True Cause of Crop Damage

Following the Evidence — Not Assumptions

When crop damage occurs, emotions often run high.

A producer may immediately suspect spray drift. A neighbour may blame hail. Someone else may point to disease, insects, fertilizer, drought, or equipment problems.

A Forensic Agrologist cannot afford to guess.

The goal is not to prove someone's theory—it is to determine what actually happened. Every investigation must begin with an open mind and end with conclusions supported by scientific evidence.

Avoiding Confirmation Bias

One of the greatest dangers in any investigation is confirmation bias.

Confirmation bias occurs when an investigator begins with a conclusion and then only looks for evidence that supports that belief while ignoring evidence that suggests another explanation. This can lead to costly mistakes in agriculture and forensic investigations alike.

A professional Forensic Agrologist approaches every investigation by asking:

• What evidence supports this theory?
• What evidence contradicts it?
• What other explanations are possible?

The investigation should eliminate possibilities one by one until the most likely scientific explanation remains.

Every Investigation Starts with Documentation

Good documentation often becomes the difference between a successful claim and one that cannot be proven.

Documentation begins immediately and may include:

• GPS photographs of affected plants
• Wide-angle and close-up images
• GPS boundaries of damaged areas
• Compass direction for every photograph
• Drone or aerial imagery
• Field sketches and maps
• Weather conditions
• Written observations
• Interviews with landowners or operators
• Equipment records
• Cropping history

Every photograph should answer four important questions:

• Where was it taken?
• When was it taken?
• Which direction was the camera facing?
• What exactly does it show?

Modern GPS cameras and smartphone applications make this information easy to preserve.

Weather Often Provides Critical Clues

Weather frequently determines whether damage could have occurred.

During an investigation, weather records may include:

• Wind speed
• Wind direction
• Temperature
• Relative humidity
• Rainfall
• Frost events
• Temperature inversions
• Growing Degree Days
• Historical weather patterns

For example:

• Spray drift may only be possible if winds carried droplets toward the damaged crop.
• Frost injury follows predictable low-lying patterns.
• Drought stress usually affects lighter soils first.
• Excess moisture often follows depressions or poor drainage.

Weather helps confirm—or eliminate—possible causes.

Looking for Damage Patterns

Plants rarely become damaged randomly.

Experienced investigators study patterns carefully.

Examples include:

• Spray drift gradients
• Fingering patterns
• Shadow effects behind shelterbelts
• Wheel tracks
• Sprayer overlap
• Boom shut-off errors
• Soil type changes
• Elevation differences
• Water movement
• Fertilizer application patterns

Patterns often tell the story before laboratory results arrive.

Collecting Physical Evidence

Proper evidence collection is essential.

Depending on the situation, samples may include:

• Plant tissue
• Soil
• Seeds
• Water
• Crop residue
• Weeds
• Insects
• Fertilizer
• Herbicide containers

Every sample should be:

• Properly identified
• GPS referenced
• Carefully labeled
• Protected from contamination
• Stored correctly (paper or plastic bags as appropriate)
• Frozen when required
• Accompanied by a documented chain of custody

Poor sampling practices can destroy valuable evidence before it ever reaches the laboratory.

Independent Third-Party Laboratory Testing

Laboratory testing should always be conducted by accredited independent laboratories whenever possible.

Laboratories provide objective scientific information that may include:

• Herbicide residues
• Nutrient analysis
• Plant tissue analysis
• Soil fertility
• Disease identification
• Insect identification
• Water quality
• Seed testing

However, laboratory testing is only one piece of the puzzle.

Many herbicides break down quickly within plants, meaning chemical testing may not detect residues even though the injury is real. In these cases, symptomology, field patterns, application history, and weather become especially important.

Considering Every Possible Cause

Good investigations work by eliminating possibilities.

Potential causes may include:

• Spray drift
• Sprayer contamination
• Residual herbicides
• Fertilizer burn
• Frost
• Hail
• Drought
• Flooding
• Disease
• Insects
• Nutrient deficiencies
• Soil compaction
• Salinity
• Wildlife damage
• Equipment malfunction
• Seed quality
• Variety sensitivity

The investigator asks:

"What evidence supports each possibility?"

Then:

"What evidence rules it out?"

Only after competing explanations have been carefully evaluated should conclusions be reached.

The Value of Second Opinions

Independent reviews strengthen investigations.

Complex cases sometimes benefit from:

• Additional Professional Agrologists
• Specialists
• Plant pathologists
• Entomologists
• Weed scientists
• Accredited laboratories
• Surveyors
• Engineers

Second opinions are not a weakness—they demonstrate a commitment to accuracy and scientific integrity.

Truth is the Goal

A Forensic Agrologist is not an advocate for either side.

The responsibility is to remain impartial, follow the evidence, and provide an independent expert opinion. Canadian courts expect expert witnesses to provide objective, unbiased opinions based on their expertise rather than advocate for a client.

Sometimes the investigation confirms the client's original concern.

Sometimes it proves something entirely different.

The investigator must be willing to follow the evidence wherever it leads.

Conclusion

Crop damage investigations require much more than looking at injured plants.

They require:

• Scientific investigation
• Careful documentation
• Weather analysis
• GPS mapping
• Proper evidence collection
• Independent laboratory testing
• Consideration of alternative explanations
• Elimination of competing causes
• Objective conclusions

The best Forensic Agrologists do not begin with answers.

They begin with questions.

Only after every reasonable possibility has been examined can the truth be confidently established.

Need an Independent Crop Damage Investigation?

If you are dealing with crop damage, spray drift, herbicide injury, fertilizer problems, livestock damage, or another agricultural dispute, an independent investigation completed as early as possible provides the strongest evidence.

George A. Lewko, P.Ag.

Certificate in Forensic Agrology

Independent Forensic Agrologist

📍 Saskatchewan • Manitoba • Alberta

🌐 www.forensicagrology.com

📞 306-961-0001

Remember: The purpose of a forensic investigation is not to support a theory—it is to discover the truth through objective science and defensible evidence.