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Current Category » Weed Management

Interaction of Herbicides with Moisture, Fertilizers, Bio Fertilizers, Insecticides and Fungicides

1) Herbicide Interactions:

A herbicide may show synergistic response in combination with one herbicide and antagonistic response with another herbicide. The response of one combination may also differ according to the different plant species.

Synergistic Effect:

E .g 2,4-D+ Dicamba.
2,4-D + Atrazine,
Amitrole + Ammonium thiocynate,
Atrazine + Alachlor

Antagonistic Response:

E .g EPTC with 2,4-D or
Dicamba in sorghum,
Simazine or Atrazine with glyphosate reduces the activity of glyphosate.

2) Herbicide-Antinode Interactions:

The herbicide antidote interactions are antagonistic in nature. The antidotes like NA, R-25788 and CDAA reduce the toxicity of Herbicdes like alachlor, EPTC and Butylate to certain plants( Crops).

3) Herbicide- Insecticide Interactions:

Herbicide and Insecticides are often applied simultaneously or serially to crops within a short period. These chemicals are usually not harmful when used as per recommended practices. The tolerance of plants to a herbicide may be altered in the presence of insecticide and vice versa. The Phyto-toxicity of monuron and diuron is increased on cotton when applied with phorate. Similar effects were also observed on oats.

Combination of Organo-phosphate insecticide and Atrazine on phyto-toxicity appeared to involve an effect of the insecticides on herbicides absorption and translocation.

4) Herbicide Interaction with Pathogens and Fungicides:

Herbicides interact with fungicides as the disease causing organisms. Dinoseb was know to reduce the severity of stem rot ( White mould) in groundnut.

Diuron and Atrazine which inhibit photosynthesis may make crops susceptible to tobacco mosaic virus. Where as diuron may decrease the incidence of root rot in wheat. Atrazine was found to have antagonistic interaction with the fungicide Dexon on many crops.

5) Herbicide- Fertilizer Interactions:

Application of fertilizer with herbicides is becoming increasingly popular in developed countries. No detrimental properties were observed when herbicide were combined with suspension of fertilizers.

Application of complete fertilizer ( Containing N.P and K) reduce the atrazine absorption by plants, thus reducing phytoxicity. Atrazine was more toxic in the presence of PK than in the presence of NP and NK.

The addition of Urea or ammonium sulphate in 2,4-D and glyphosate increased the efficiency of herbicides.

6) Herbicide and Soil Moisture or Irrigation Interaction:

Adequate soil moisture in surface soil is necessary for germination of large population of weeds and their effective killing by herbicides. The adequate soil moisture increase the adsorption and translocation of soil applied as well as foliage applied herbicides which increase efficiency of herbicides in killing weeds. The excess moisture as well as soil moisture stress affect the absorption and efficiency of herbicides and heavy rains after application of herbicides may cause washing away of foliar applied herbicides.


Current Category » Weed Management