use of herbicide for controlling of weeds. their use benefits and demerits. and impact on human beings.

1. Credit Seminar
on
Herbicides: Uses and Abuses
By: Durgesh Singh
Ph.D. Scholar
Reg. No.- BAC/D/AGRO/003/2016-17
DEPARTMENT OF AGRONOMY
Bihar Agricultural University, Sabour (Bhagalpur)

2.  Weeds account for highest economic losses.
 Yield losses due to weeds in different systems of rice
cultivation range from 15-90 % and in other crops range from 6
to 87 percent.
 In India 33 % of crop losses due to weeds (DRR, 2011).
 Herbicide use some important fact must be care.
 Herbicide residues need for knowledge-based, decision making
tools and site-specific weed management.
INTRODUCTION

3. Average reduction in yields of important crops due to weeds in India
Crop Reduction in yield (%)
Rice
a) Transplanted 15-35
b) Direct seeded 30-65
c) Upland 45-90
Wheat 6-35
Maize 30-50
Millets 11-56
Sesamum 17-40
Mustard & Rapeseed 30
Groundnut 18-52
Sugarcane 15-72
Jute 56-58
Cotton 47.5
Source: DRR (2011)

4. Annual losses caused by different pests in India
Pest Loss in value per year
Rs. in crores Loss (%)
Weeds 1980 33
Insects 1300 26
Diseases 1000 20
Storage pest 390 8
Rodents 300 6
Other pests 300 7
Total 5270 100
Source: Vision 2050 (NRCWS Perspective plan 2014)

5. Wheat
28%
Rice
20%
Soybean
9%
Sugarcane
7%
Others
36%
Crop wise Herbicide use in India
Wheat Rice Soybean Sugarcane Others
Source:Yaduraju (2012)

6. Global and Indian pesticides use scenario (% of total)
Global scenario of pesticide use Indian scenario of pesticide use
Source: Vision 2050 (NRCWS Perspective plan 2014)

7. Plant factors
Herbicidal
factors
Environmental
factors
FACTORS AFFECTING HERBICIDE PERFORMANCE

8. Plant Factors
Leaf/foliage
Root system
Stage of plants

9. Time of application
Adjuvants
Safeners
Rate of application
Herbicidal Factors
Methods of
application

10. Environmental Factors
Climatic factors Soil factors
Temperature
Relative humidity
Sunlight
Rainfall
Organic matter content
Texture of soil
Soil temperature
Soil moisture
Soil pH

11.  The ability of herbicide to control or kill certain plants (weeds)
without injuring other plants (crop plants) is called selectivity.
 Selectivity results from the differential response of plant species
to herbicides and is complex phenomenon achieved by complex
interaction between plant , herbicide and environment (climate
and soil).
Herbicide Selectivity

12. Schematic representation of three principal factors ( plants, herbicides and environment) interaction
towards activity and selectivity of herbicide in plants.
Plants (crops and
weeds)
Environment
(climate and soil)
Herbicides
Herbicide availability, retention, penetration, absorption at the
site of application (soil and foliage ) and its translocation at the
site of action inside the plants
Metabolism and reverse
metabolism of herbicide inside
the plants
Herbicide activity and selectivity
Source : Das, 2008

13. a
Application Methodology
Labels and technical
pamphlets
Sprayer calibration
Appropriate nozzle
selection

14. Trade Name
(Refers to this
specific formulation
of herbicide)
Chemical Name
(Shows what active
ingredients are in the
formulation)
Active Ingredient
Concentration
(Important to know this to
determine rates and
solutions for application)
RODEO – Page 1
EPA Registration
Number
(kind of like a social
security number for
herbicides. Each specific
formulation must be
registered with the EPA)

15. Sprayer calibration is mainly conducted to determine exact
volume of water required to dissolve the calculated amount of
the formulated herbicide to cover a measured area infested by
weeds.
Sprayer Calibration
Wrong sprayer
calibration
Crop injury
Pollution
Wastage of time
and money

16. Nozzles determines :-
 amount of spray generated over a given area
 coverage obtained
 amount of drift that occurs.
1. Flat fan nozzle
 Spray pattern is tapered from centre to the edges.
 Used for broadcast and post emergence herbicides where foliage
penetration and coverage is not essential.
 Produce medium size droplets.
 Gives even and uniform coverage.
 Spray angle is medium to wide.
Selecting an appropriate nozzle
Types of nozzles

17. 2. Deflector/cut nozzle
 The pattern of sprinkling liquid is wide angled flat that
covers a wide area.
 Mainly used for coarse application of liquid
herbicides.
3.Cone nozzle
 Produces finer droplets in different angles
that access to plants systematically.
 Spray angle is medium to wide.
 Suitable for insecticide and fungicide spray.
 Better penetration in plant foliage.

18. 4. Adjustable nozzle
 Most suitable for spraying targets which are not within the reach of
man.
 Difficult to calibrate as the flow and droplet
sizes vary widely with the nozzle angle.
Nozzles must be kept clean, calibrated and regularly replaced.

19. Treatments Dose g/Ha Panicle
length
(cm)
Effective tillers
(no./m2)
Grain Yield
(t/ha)
WCE %
Grass weed BLW
Clodinafop+metsulfuron 60+4+S 11.0 338.1 5.52 94.8 88.5
Clodinafop+metsulfuron 75+5+S 11.1 346.0 5.77 96.9 92.3
Clodinafop+metsulfuron 90+6+S 10.8 335.0 5.28 96.3 91.5
Clodinafop+metsulfuron 120+8+S 10.7 333.0 5.06 97.4 95.4
Clodinafop fb metsulfuron 160fb 4 11.0 338.0 5.52 95.3 90.8
metsulfuron 4 10.8 334.0 5.23 2.1 81.5
Clodinafop 160 10.4 327.0 4.72 91.1 3.8
Weed free - 11.0 338.0 5.49 100 100
Unweeded control - 9.3 284.0 2.84 - -
LSD (0.05 ) 0.05 5.9 0.11 - -
Source: Kaur et al. (2015)
Effect of herbicide on yield and yield components of wheat

20. Effect of herbicides on paddy yield in case of Direct Seeded Rice
Treatments
Dose/
hectare
Pre-treatment
weed density
(30x30cm)
Post -treatment
weed density
(30x30cm)
% Weed
control
Paddy
yield
(t/ha)
Ethoxysulfuron 62.5 g 71.97 9.22 87.19 3.38
Bispyribac
Sodium
250 ml 22.10 2.10 90.50 3.61
Ethoxysulfuron
+ Iodosulfuron
150 g 27.66 8.44 69.49 2.63
Ethoxysulfuron 200 g 67.00 12.00 82.08 3.36
Hand weeding - 36.77 0.67 98.18 4.17
Control - 40.08 51.44 -28.34 0.83
LSD Value at α
0.05
1.970 1.275 - 0.3452
Source : Hussain et al., (2008)

21. Treatment Pods/
plant
Seeds
/pod
Seed
yield
(t/ha)
Weed
index
WCE
(%)
B:C
Ratio
Propaquizafop 62.5 g/ha 49.0 2.07 2.06 27.9 78.7 2.04
Propaquizafop 75 g/ha 51.8 2.10 2.29 20.1 80.6 2.25
Imazethapyr 50 g/ha 58.6 2.12 2.32 19.1 94.6 2.28
Imazethapyr 75 g/ha 58.8 2.14 2.35 18.1 94.8 2.30
Imazethapyr 100 g/ha 63.1 2.18 2.37 17.4 95.5 2.31
Propaquizafop+ imazethapyr
50 + 50 g/ha
62.9 2.15 2.35 17.8 95.2 2.27
Propaquizafop + imazethapyr
62.5 +75 g/ha
66.1 2.20 2.42 15.6 96.0 2.33
Propaquizafop + imazethapyr
75 + 100 g/ha
66.2 2.23 2.52 12.1 96.5 2.41
Hand weeding (20 and 40
DAS)
67.3 2.27 2.67 0.00 98.6 1.91
Weedy check (control) 45.6 1.98 1.67 41.83 0.00 1.68
LSD (P=0.05) 0.74 NS 0.34 -
Effect of different weed control treatments on yield, WCE and economics of soybean
Source: Sandil et al. (2015)

22. Treatment Dose
(g/ha)
Cane
length
(cm)
Cane
girth
(cm)
Cane
yield
(t/ha)
Weed
Index
(%)
WCE
(%)
Ethoxysulfuron 46.87 256 8.5 69.2 32.7 31.3
Ethoxysulfuron 56.25 260 8.6 76.8 25.1 38.7
Ethoxysulfuron 60.00 271 8.8 82.3 19.6 40.0
2,4-D Na salt 1000 251 8.4 68.3 34.2 31.9
Three hoeings at
30, 60 and 90 DAP
- 274 8.9 102.0 0.00 99.1
Untreated control - 215 6.7 47.5 54.2 -
LSD (P=0.05) - 21 NS 6.8 - -
Yield attributes and yields of sugarcane as influenced by ethoxysulfuron against
Nutsedge
Source: Singh et al. (2014)

23. Treatment Grain
yield
(t/ha)
Stover
yield
(t/ha)
Net returns
(x103 `/ha)
B:C ratio
Topramezone (25.2 g/ ha) + MSO (adjuvant)
as PoE
4.99 6.84 43.13 2.50
Tembotrione (105 g /ha) + adjuvant as PoE 4.83 6.74 40.97 2.43
Topramezone + atrazine (25.2 + 250 g/ ha) +
adjuvant as PoE
6.44 7.60 62.61 3.17
Tembotrione + atrazine (105+250 g /ha) +
adjuvant as PoE
6.28 7.50 60.18 3.10
Hand weeding at 20 and 40 DAS 6.58 8.04 59.37 2.72
Unweeded control 2.59 5.36 14.73 1.60
LSD (P=0.05) 0.36 0.43 4.77
Effect of different weed control treatments on grain yield, stover yield and economics of
maize
Source: Swetha et al. (2015)

24. HERBICIDE
ABUSES

25. Crop Injury Symptom

26. Plant: wheat
MoA: Synthetic auxins
Chemistry: Phenoxy-carboxylic acid
Herbicide: 2,4-D
Symptoms: spike distortion, spike
malformation
Wheat Crop injury by 2,4,D late application

27. SOYBEAN
Mode: Photosynthetic Inhibitor
Herbicide: Atrazine, Metribuzin
Injury: Lower leaves go from chlorotic to
necrotic, fall off of stem, and in severe
cases, complete death of plant
Condition: Carryover of atrazine or high
rate of metribuzin; both herbicides are
influenced by high soil pH making the
herbicides more available to cause injury;
eroded knolls in field are likely areas
where injury may occur
Soybean Crop injury by Herbicides
Source: www.btny.purdue.edu/Extension/Weeds/HerbInj2/InjuryHerb1.htm

28. CORN
Mode: Growth Regulator
Herbicide: 2,4-D or Dicamba
Injury: Rolled "buggy-whip" Whorl
Condition: Late application of herbicide
where most of corn leaves and whorl
intercept the herbicide; misapplication
CORN injury due late application of 2,4-D
Source : www.btny.purdue.edu/Extension/Weeds/HerbInj2/InjuryHerb1.html

29. CORN
Mode: Cell Membrane Disruptor
Herbicide: Paraquat
Injury: Necrotic spots
Condition: Herbicide drift from nearby
field, most likely a no-till field where a
burndown treatment of paraquat was
applied
Herbicide drift from nearby field in the corn
Source : www.btny.purdue.edu/Extension/Weeds/HerbInj2/InjuryHerb3.htmln

30. Herbicides Dose
g/ha
Weed dry weight (g m2) Wheat yield
(t/ha)
P. minor Other weeds
Clodinafop 60 0.6 38.3 6.01
Fenoxaprop-p 120 5.9 25.2 5.96
Sulfosulfuron+S 25 0.3 1.8 6.20
Isoproturon 1000 242.0 3.0 3.99
Weed free - 0.0 0.0 6.21
Weedy check - 313.7 5.5 3.41
LSD at 5 % - 15 3.2 0.24
Performance of alternative herbicides against P. minor in wheat
incase of isoproturon resistance against P. minor
Source : Chhokar et al. (2007)

31. Source : Sondhia et al. (2015)
Residues of some of the herbicides in the soil , food grain and straw

32. Source : Sondhia et al. (2015)
Some herbicides which caused direct adverse effects on human beings

33. Cases of intentionally herbicide poisoning in human being India
Source : Sondhia et al. (2015)

34. Persistence of some herbicides under tropical condition in the soil
Source : Sondhia et al. (2015)

35. Herbicides ½ life in water
2,4-D 1 – several weeks
atrazine 55 days (range 10 – 105 days)
glyphosate 35 – 63 days
metribuzin 7 days
metsulfuron 29 – > 84 days (increasing with concentration)
oxyfluorfen adsorbed by sediments
paraquat 30 days – 23 weeks (mostly adsorbed by sediment)
simazine 30 days
Imazethapyr 57-71 days
Residue of some herbicides under in the water condition
Source : Tomilson (2002)

36. Treatment
Azotobacter (×104 cfu/g
dry soil wt.) *(142.46
×104 cfu/g dry soil wt.)
Phosphate solublising
microorganisms (×104 cfu/g
dry soil wt.)
*(87.28 ×104 cfu/g dry soil
wt.)
30 60 At
harvest
30 60 At harvest
T1- Farmer’s practice 101.0 122.3 128.6 47.2 57.0 64.5
T2- Isoproturon 1.0 kg + 2,4-D 0.75 kg/ha 80.3 86.5 89.2 34.7 37.9 41.8
T3-Clodinafop 75 g fb 2,4- D 0.75 kg/ha
Isoproturon* 1.0 kg + 2,4-D 0.75kg/ha
66.3 85.5 91.4 38.9 40.3 48.2
T4-Isoproturon 1.0 kg + 2,4-D 0.75 kg/ha 76.8 82.5 84.1 33.5 37.8 41.4
T5-Clodinafop 75 g + 2,4-D 0.75 kg/ha
Isoproturon* 1.0 kg + 2,4-D 0.75 kg/ha
65.1 79.1 82.1 32.5 38.5 40.5
T6-Isoproturon 1.0 kg + 2,4-D 0.75 kg/ha 77.2 79.3 81.2 34.3 38.6 40.8
T7-Clodinafop 75 g fb 2,4-D 0.75 kg/ha
Isoproturon* 1.0 kg + 2,4-D 0.75 kg/ha
67.8 79.0 86.8 36.1 41.4 44.3
LSD (P=0.05) NS NS NS NS NS NS
Long term effect of continuous use of herbicides on soil microflora in
wheat crop
Source : Kumar et al. (2015)

37. Treatment
Total bacterial population
(×106cfu/g dry soil wt.)
*(77.56 ×106 cfu/g dry soil
wt.)
Total fungal population
(×104 cfu/g dry soil wt.)
*(66.77 ×104 cfu/g dry soil
wt.)4 cfu/g dry soil
wt.)
30 60 At
harvest
30 60 At harvest
T1- Farmer’s practice 43.3 55.2 62.2 58.8 59.6 62.0
T2- Isoproturon 1.0 kg + 2,4-D 0.75 kg/ha 39.9 54.6 66.2 60.3 62.2 64.3
T3-Clodinafop 75 g fb 2,4- D 0.75 kg/ha
Isoproturon* 1.0 kg + 2,4-D 0.75kg/ha
40.4 53.1 58.5 55.0 58.6 60.7
T4-Isoproturon 1.0 kg + 2,4-D 0.75 kg/ha 42.0 54.2 60.9 60.4 62.5 64.9
T5-Clodinafop 75 g + 2,4-D 0.75 kg/ha
Isoproturon* 1.0 kg + 2,4-D 0.75 kg/ha
42.1 50.1 57.3 56.2 58.3 60.6
T6-Isoproturon 1.0 kg + 2,4-D 0.75 kg/ha 40.8 51.5 60.8 62.2 64.8 65.5
T7-Clodinafop 75 g fb 2,4-D 0.75 kg/ha
Isoproturon* 1.0 kg + 2,4-D 0.75 kg/ha
37.1 47.8 52.2 59.3 63.5 65.3
LSD (P=0.05) NS NS NS NS NS NS
Long term effect of continuous use of herbicides on soil microflora in
wheat crop
Source : Kumar et al. (2015)

38. Crop IWM Reference
Blackgram (i) Pendimethalin at 0.75 kg/ha fb HW 45
DAS
(ii) Pendimethalin at 0.50 kg/ha fb HW 60
DAS
(i) Kumar et al. (2006)
(ii) Rathi et al. (2004)
Okra Stale seed bed with glyphosate application
integrated with eucalyptus mulching
Ameena et al. (2006)
Pigeonpea/Grou
ndnut
intercrop
Sowing at 20 cm apart with two HW fb
pendimethalin at 1 kg/ha
Pendimethalin (1.0 kg/ha) or fluchloralin (1.0
kg/ha) each fb
two HW 30 and 42 DAS
Tewari et al. (2003)
Sugarcane Metribuzin or atrazine at 1 kg/ha+trash
mulching (3.5 t/ha)
in between cane rows at 60 DAP
Singh et al. (2001)
Most economical IWM methods for managing herbicide residue reduce India
Source : Rao et al. (2010)

39. CONCLUSION

40. Thank you