Do Organically Grown Strawberries Have Higher Levels of Phytochemicals and Can Consumers Tell the Di

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Do Organically Grown Strawberries Have Higher
Levels of Phytochemicals and Can Consumers Tell
the Difference?
Ohio Strawberry

• Joe Kovach1, Mustafa Ozgen2, Loren Harper1,
  Simeon Wright1, Joe Scheerens2
• IPM Program1 Dept. Hort. Crop Science2
• The Ohio State University - OARDC

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Transitional Organic Strawberries
Field - OARDC, Wooster - 0.5 A, no pesticide
since 1996 2000 - April - cover crop (oats
peas) July - plowed under August - planted
rye (bet. rows) oat (rows) 2001 - May -
planted 6 cultivars (matted row) Earliglow,
Northeaster, Honeoye Seneca, Jewel, Idea (5
reps) 5 treatments 3
composts (UTC, fertilizer) - dairy barn -
yard waste - vermicompost
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August 2001
November 2001
Planted perennial rye in row middles Many hours
of weed pulling! (1,000 hr/A) Did the addition
of compost contribute to weed problems?
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2001 Weed Biomass from Pots (40 d)
a
a
Grams dried weeds
b
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Weeds in the Different Composts
Vermicompost
Dairy Barn
Yard Waste
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Organically Approved Herbicides
25 Acetic Acid
57 Pelagonic acid
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Organic Herbicide Results
a
a
Live Above Ground BioMass (48 hr)
b
1,444/A
4,642/A
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Conclusions for 2001(Planting year)

• Weeds were a significant problem
• Vermicompost had fewer weed seeds than other
  composts in GH trials
• Scythe (soap) was moderately effective, and may
  have a place at renovation, but it is expensive

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May 2002
June 2002
July 2002
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Conclusions for 2002

• Weeds remain a laborious significant problem
• Yard waste vermicompost had more weed biomass
• Yields were good in all treatments
• Disease and insects were not a problem
• Slugs were generally more of a problem in compost
  treatments

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Transitional Organic Strawberries
2003 Same except - renovation in July
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Transitional Organic Strawberries
2004
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Weed Biomass By Treatment
c
b
b
b
a
g/m
Weed labor hours 2002 1955/A 2003
1029/A 2004 527/A
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Harvest Evaluations
Tarnished Plant Bug
Botrytis or Gray Mold
Slug
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2002 Harvest Evaluations
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2003 Harvest Evaluations
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Harvest Evaluations 2002-2004
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Total Yield 2002-2004
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Economics
Breakeven Price 2002 2003 2004
Con. 1.08/qt 0.67/qt 0.67/qt
Org 2.59/qt 1.24/qt 0.99/qt
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Conclusions

• Weeds remain the biggest problem, however they
  are becoming less of a problem over time
• Disease and insects were not a problem
• Untreated check had the fewest weeds and the
  cleanest berries.

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Conclusions

• Yields were good in all treatments, as were plant
  nutrient levels
• Prices for organic strawberries need to be at
  least 25 greater than conventional berries to
  make up input costs
• Earliglow, Honeoye, Jewel are recommended for
  organic production

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Can consumers tell the difference between organic
and conventional strawberries?

• Compared
• same cultivar
• same field
• same size
• picked at the same time
• one group grown w/ DB compost, vermicompost,
  synthetic fertilizer, sprayed
• also checked if could detect difference between
  cultivars

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Triangle Test

• Judge given 3 samples, 2 are alike and 1 is
  different, find the 1 that is different
• 24 individuals
• appearance, smell and taste
• Jewel, Honeoye, Seneca Idea
• 2002 2003 2004

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Sensory Evaluation - 2002Syn. Fertilizer vs. DB
Compost

n24 need 54 correct for significance plt0.05
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Sensory Evaluation

Sprays 1-Brigade Switch 2-Brigade
Elevate captan 3-Brigade
Switch captan
n24 need 54 correct for significance plt0.05
2003
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Sensory Evaluation by Cultivar

n24 need 54 correct for significance plt0.05
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Anthocyanin Analysis

• Strawberries were frozen, blended, strained, pH
  balanced and mixed with ethyl alcohol
• Sample read using a spectrophotometer (500nm)

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Anthocyanin PhenolicsCultivars
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Anthocyanin PhenolicsTreatments
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Leaf Scorch vs Leaf Anthocyanins
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Conclusion from Sensory Analysis (Anthocyanin,
Phenolics)

• Consumers can tell the difference in (appearance,
  taste, smell) between cultivars from different
  breeding programs
• Consumers have a more difficult time
  distinguishing cultivars from the same breeding
  program
• Consumer cannot tell the difference between
  growing practices within the same cultivar

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Conclusion from Sensory Analysis (Anthocyanin,
Phenolics)

• The difference in phenolic compounds is greater
  between cultivars than between treatments
• Leaf anthocyanins and Leaf Scorch display a
  significant relationship suggesting that fungal
  infestation may trigger an increase in this
  pigment