0
Selectivity of Organic
Herbicides in Broccoli and
Onions

Richard Smith
Vegetable Crop and Weed Science Farm Advisor,
Mont...
Comparison of Organic vs Conventional
Broccoli and Onion Production Costs
Production
System

Weeding
Costs/A

Organic1

$2...
The waxy cuticle on cole crops and
onions protects them to some degree
from fertilizers and contact herbicides
Conventional Materials Commonly
Sprayed on Broccoli and Onions
• Liquid fertilizers
– AN20, NpHuric, Sulfuric Acid, Acid b...
Eco-Exempt

2-Phenethyl Propionate..................21.4.%
Eugenol (Clove Oil)..........................21.4%

Matran 2
[M...
Other important considerations:
Timing, weed species, weed size (< 2 true leaves)
Postemergence Trials on Broccoli
Number of Weeds in Broccoli
2006 Trial No. 1
140
120
100
80
60
40
20
0
Untreated

Transplants, 1 vs 2 passes

10.80%

Matr...
Hours Per Acre to Weed Broccoli
2006 Trial No. 1
35
30
25
20
15
10
5
0
Untreated

10.80%

Matran Rate

5.40%
Number of Weeds in Broccoli
2006 Trial No. 2
140
120
100
80
60
40
20
0
Untreated

5.00%

Matran Rate

2.50%
Hours Per Acre to Weed Broccoli
2006 Trial No. 2
70
60
50
40
30
20
10
0
Untreated

5.00%

Matran Rate

2.50%
Phytotoxicity Ratings
2006 Trial No. 3
6
5
4
3
2
1
0
Untreated

Matran 5% Matran 2.5% Scythe 3% Scythe 1.5%

Direct seeded...
Yield – Number of Heads/Plot
2006 Trial No. 3
35

a

30

ab

ab

ab

b

25
20
15
10
5
0
Untreated

Matran 5% Matran 2.5% S...
Scythe @ 1.0%
Over the Top
Directed

Sept 18
Scythe @ 1.5%
Over the Top
Directed

Sept 18
Scythe @ 2.0%
Over the Top
Directed

Sept 18
Scythe
Over the Top
1.5%
2.0%

Sept 18
Scythe @ 1.0%
Over the Top
Directed

Sept 26
Scythe @ 1.5%
Over the Top
Directed

Sept 26
Scythe @ 2.0%
Over the Top
Directed

Sept 26
Broccoli Summary
• The organic herbicides examined in these
studies are not safe for over-the-top use on
broccoli
• Low ra...
Onion Studies
• Onions are different in that there is little
opportunity for the spray material to be
directed to the base...
Untreated

Matran @ 20%
Matran EC @ 20%
Matran EC @ 20%
weed burn down and regrowth
if weed is too big at time of application
2005 Dry Bulb Onion Evaluation
Treatment

Weed
Control
Percent

Phyto
Rating

Weed
Time
hrs/A

Untreated

----

0.0

20.7
...
Green Onion Trial
1st true leaf

2nd true leaf
Shepherds Purse
1st true leaf

2nd true leaf
Goal 2XL @ 1st true leaf

untreated
Matran @ 20%
Scythe @ 5%
2005 Green Onion Trial
Weed Control Ratings
9
8
7
6
5
4
3
2
1
0
Untreated

Matran
20% 1st

Matran
20% 2nd

Scythe 5% Scyth...
2005 Green Onion Trial
Phyto Ratings
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
Untreated

Matran
20% 1st

Matran
20% 2nd

Scythe 5% ...
2005 Green Onion Trial
Yield – T/A
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Untreated

Matran
20% 1st

Matran
20% 2nd

Scythe 5% ...
Size of weeds
By 2nd true leaf
39 days after planting

2 days after
3% Scythe

2006 Dry Bulb Onion Trial
Onion Summary
• More effective weed control can be
achieved if the organic herbicides can be
applied at the first true lea...
Other Applications for Organic Herbicides
(Crazy ideas???)
Mechanical Harvest
Difficult, Tedious and Expensive to Hand Weed
There may be opportunities to use organic
Herbicides applications that are precision guided
And that are hooded to take ou...
The robotic system uses
microjets

These would lend
themselves to organic
materials
Conclusions
• Postemergence use of organic herbicides
on broccoli and onions is a bit dicey.
• Directed sprays on broccoli...
Conclusions
• These organic herbicides may have a role
in other ways in organic & conventional
systems
• They may feature ...
Acknowledgements
• Cooperating growers
– Chris Drew, Sea Mist Farms
– Bob Martin, Rio Farms
– Bill Peixoto, Dick Peixoto F...
Organic Herbicides for Broccoli and Onions
Organic Herbicides for Broccoli and Onions
Organic Herbicides for Broccoli and Onions
Organic Herbicides for Broccoli and Onions
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Organic Herbicides for Broccoli and Onions

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Selectivity of Organic Herbicides in Broccoli and Onions

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Transcript of "Organic Herbicides for Broccoli and Onions"

  1. 1. Selectivity of Organic Herbicides in Broccoli and Onions Richard Smith Vegetable Crop and Weed Science Farm Advisor, Monterey County
  2. 2. Comparison of Organic vs Conventional Broccoli and Onion Production Costs Production System Weeding Costs/A Organic1 $270 Conventional.2 $161 1 – Tourte and Smith, 2004; 2 – Smith et al. 2004 Hand weeding costs for onions can be extreme due to lack of cultivation and dense stands
  3. 3. The waxy cuticle on cole crops and onions protects them to some degree from fertilizers and contact herbicides
  4. 4. Conventional Materials Commonly Sprayed on Broccoli and Onions • Liquid fertilizers – AN20, NpHuric, Sulfuric Acid, Acid based fertilizers • Contact herbicides – Goal 2XL, Goal Tender, Buctril (onions) • These postemergence applications greatly reduce production costs • It seemed logical that postemergence applications of organic herbicides could be used in the same way
  5. 5. Eco-Exempt 2-Phenethyl Propionate..................21.4.% Eugenol (Clove Oil)..........................21.4% Matran 2 [Matran EC] Clove Oil (46%) Other Ingredients (54%) (Water and Lecithin) [Clove Oil (50%) Other Ingredients* (50%) (Wintergreen Oil, Butyl Lactate, and Lecithin) ] AllDown Citric Acid 5% Acetic Acid, yucca extracts, and water 94.8% Garlic oil 0.2% Burnout II Clove Oil ...... 12% Sodium Laurel Sulphate ... 8% Other Ingredients: Vinegar, Lecithin, Water, Citric Acid, Mineral Oil 80% Weed Zap Clove Oil 30% Inerts including vinegar 70% [Clove Oil 45% Cinnamon Oil 45%] Weed-A-Tak eugenol (clove oil), 2-phenethyl propionate (peanuts), castor oil, thyme oil and wintergreen oil. Scythe* Pelargonic acid 4.2 lbs ae/gal 40% inert ingredients * To be reviewed by NOP in 2007 Adapted from Cheryl Wilen, 2006
  6. 6. Other important considerations: Timing, weed species, weed size (< 2 true leaves)
  7. 7. Postemergence Trials on Broccoli
  8. 8. Number of Weeds in Broccoli 2006 Trial No. 1 140 120 100 80 60 40 20 0 Untreated Transplants, 1 vs 2 passes 10.80% Matran Rate 5.40%
  9. 9. Hours Per Acre to Weed Broccoli 2006 Trial No. 1 35 30 25 20 15 10 5 0 Untreated 10.80% Matran Rate 5.40%
  10. 10. Number of Weeds in Broccoli 2006 Trial No. 2 140 120 100 80 60 40 20 0 Untreated 5.00% Matran Rate 2.50%
  11. 11. Hours Per Acre to Weed Broccoli 2006 Trial No. 2 70 60 50 40 30 20 10 0 Untreated 5.00% Matran Rate 2.50%
  12. 12. Phytotoxicity Ratings 2006 Trial No. 3 6 5 4 3 2 1 0 Untreated Matran 5% Matran 2.5% Scythe 3% Scythe 1.5% Direct seeded, plants a bit old Treatments
  13. 13. Yield – Number of Heads/Plot 2006 Trial No. 3 35 a 30 ab ab ab b 25 20 15 10 5 0 Untreated Matran 5% Matran 2.5% Scythe 3% Scythe 1.5% Treatments
  14. 14. Scythe @ 1.0% Over the Top Directed Sept 18
  15. 15. Scythe @ 1.5% Over the Top Directed Sept 18
  16. 16. Scythe @ 2.0% Over the Top Directed Sept 18
  17. 17. Scythe Over the Top 1.5% 2.0% Sept 18
  18. 18. Scythe @ 1.0% Over the Top Directed Sept 26
  19. 19. Scythe @ 1.5% Over the Top Directed Sept 26
  20. 20. Scythe @ 2.0% Over the Top Directed Sept 26
  21. 21. Broccoli Summary • The organic herbicides examined in these studies are not safe for over-the-top use on broccoli • Low rates of these herbicides can be used on broccoli if they are applied as a directed spray to the base of the plant • If too much of the material gets up onto the foliage it can cause significant phytotoxicity • If however, the material is successfully applied acceptable yields can be achieved.
  22. 22. Onion Studies • Onions are different in that there is little opportunity for the spray material to be directed to the base of the plants • As a result, there is greater need for selectivity and careful selection of appropriate rates
  23. 23. Untreated Matran @ 20%
  24. 24. Matran EC @ 20%
  25. 25. Matran EC @ 20%
  26. 26. weed burn down and regrowth if weed is too big at time of application
  27. 27. 2005 Dry Bulb Onion Evaluation Treatment Weed Control Percent Phyto Rating Weed Time hrs/A Untreated ---- 0.0 20.7 Yield 1000 Bulbs/A 139.8 Matran EC @ 20% 38.8 0.5 14.3 134.6 Goal Tender @ 0.125 lb* 82.5 2.3 5.4 139.3 * First true leaf
  28. 28. Green Onion Trial
  29. 29. 1st true leaf 2nd true leaf
  30. 30. Shepherds Purse 1st true leaf 2nd true leaf
  31. 31. Goal 2XL @ 1st true leaf untreated
  32. 32. Matran @ 20%
  33. 33. Scythe @ 5%
  34. 34. 2005 Green Onion Trial Weed Control Ratings 9 8 7 6 5 4 3 2 1 0 Untreated Matran 20% 1st Matran 20% 2nd Scythe 5% Scythe 5% 1st 2nd Treatments
  35. 35. 2005 Green Onion Trial Phyto Ratings 5 4.5 4 3.5 3 2.5 2 1.5 1 0.5 0 Untreated Matran 20% 1st Matran 20% 2nd Scythe 5% Scythe 5% 1st 2nd Treatments
  36. 36. 2005 Green Onion Trial Yield – T/A 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 Untreated Matran 20% 1st Matran 20% 2nd Scythe 5% Scythe 5% 1st 2nd Treatments
  37. 37. Size of weeds By 2nd true leaf 39 days after planting 2 days after 3% Scythe 2006 Dry Bulb Onion Trial
  38. 38. Onion Summary • More effective weed control can be achieved if the organic herbicides can be applied at the first true leaf stage • However, we observed greater phytotoxicity on the crop when applied at this earlier growth stage • If applications go on too late and the weeds are too big, the low rates of organic herbicides will not be adequate to effectively control weeds.
  39. 39. Other Applications for Organic Herbicides (Crazy ideas???)
  40. 40. Mechanical Harvest
  41. 41. Difficult, Tedious and Expensive to Hand Weed
  42. 42. There may be opportunities to use organic Herbicides applications that are precision guided And that are hooded to take out some of the Weeds in this type of a situation
  43. 43. The robotic system uses microjets These would lend themselves to organic materials
  44. 44. Conclusions • Postemergence use of organic herbicides on broccoli and onions is a bit dicey. • Directed sprays on broccoli are very helpful to maintain safety • These trials indicate that there is hope for onions, but skill and good timing will be necessary to make this system work
  45. 45. Conclusions • These organic herbicides may have a role in other ways in organic & conventional systems • They may feature in hooded spray operations and possibly in robotic weeding
  46. 46. Acknowledgements • Cooperating growers – Chris Drew, Sea Mist Farms – Bob Martin, Rio Farms – Bill Peixoto, Dick Peixoto Farms – Jerry Rava, Rava Farms • Research assistants – Tiffany Bensen – Pat Headley – Dave Miltz.
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