Herbicide mixtures Point Wise Notes Notes For Competitive Exam

Herbicide mixtures

HERBICIDE MIXTURES

• Mechanical and chemical mixing of two or more herbicides having different mode of action and varying level of activity and selectivity forms herbicide mixtures.

• Herbicides of the same class or different classes having similar mode of action are not ideal for herbicidal mixture.

• Herbicides having similar spectrum of weed control should not be opted for mixing.

Types of herbicide mixtures

1) Factory mix/premix/readymix

It is the mixture of desired herbicides prepared in the factory itself with definite proportions.

e.g., Isoguard plus (Isoproturon + 2,4-D)

Aniloguard plus (Anilophos + 2,4-D)

Primaguard (Atrazine + Metolachlor)

Atlantis (Mesosulfuron-methyl + Iodosulfuron methyl sodium)

Almix (Metsulfuron methyl + chlorimuron ethyl) – used in rice

Pursuit plus (Pendimethalin + Imazethapyr)

2) Tank mix/ field mix herbicide mixtures

It is mechanical mixing of two or more herbicides before their application in the field.

e.g., Atrazine + Alachlor

Atrazine + Pendimethalin

Isoproturon + Tralkoxydim

Sethoxydim + Chlorsulfuron

EFFECTS OF HERBICIDE MIXTURE INTERACTIONS

1) Synergistic effect: It is derived from the cooperative action of two or more herbicides in a mixture. (AB) > (A) + (B) Mixture effect of herbicide is more than the effect of herbicide A and B independently.

2) Antagonistic effect: The decrease in normal biological activity of one or all component herbicides in a mixture is referred as antagonistic effect. If (A) > (B) then (AB) < (A)

3) Additive effect: It refers to the combined action of component herbicides in the mixture when the total effect of mixture = sum total effect of the component herbicides when applied independently. (AB) = (A) + (B)

4) Enhancement effect: It generally occurs when adjuvant is mixed with active ingredient in the formulation and it increases the efficacy of herbicide than obtained with active ingredient alone. e.g., Fenoxaprop-p-ethyl

• Fenoxaprop-p-ethyl is a grass killer used in soybean under the tradename “whip super”, while same herbicide is used in wheat under different tradename “pumasuper”.

• The differential action of same herbicide is attributed to different adjuvants used in the formulations.

Advantages of herbicide mixtures

• Controls broad spectrum weeds.

• Prevents shift in weed flora.

• Delays development of resistance in weeds.

• Increases the weed control efficiency.

• Reduced dosage of herbicides per unit area.

• Because of reduced rate of application reduced residue in crop and environment.

HERBICIDE MIXTURES FOR CROPS

1) Rice:

Anilophos (0.4 kg) + 2,4-DEE (0.5 kg)/ha

Butachlor (1 kg) + Propanil (2.0 kg)

Anilophos (0.3 kg) + chlorimuron (0.004 kg)

Anilophos (0.3 kg) + metsulfuron – methyl (0.004 kg)

Pretilachlor + 2,4-DEE for upland rice

2) Wheat and Barley

Diclofop-methyl (750 g) + Isoproturon (500g)

Isoproturon (750 g) + 2,4-D (250 g)

Clodinafop (60 g) + Isoproturon (500 g)

Fenoxaprop – p- ethyl (120 g) + 2,4-D (500g)

3) Maize and sorghum

Atrazine (0.5 kg) + Alachlor (1.0 kg)

Atrazine (0.75 kg) + Pendimethalin (0.75 kg)

Atrazine + 2,43-D

4) Soybean

Pendimethalin + Imazethapyr

Metribuzin + Chlorimuron ethyl

Oxadiazon + Metolachlor

5) Sunflower

Fluchloralin + Metolachlor

6) Cotton

Pendimethalin + Diuron

7) Sugarcane

Atrazine + 2,4-D

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