Agriculture notes prepared by IAS Topper for all agriculture based competitive exams-Agronomy-Classification of Herbicides based on time of application

Classification of Herbicides based on time of application

It depends upon type of Herbicides, selectivity, solubility and volatility

a). Fallow application: Herbicide application well before 10 days of sowing. Non-selective to control Cyprus and cyanodon. Ex. Atrazine

b). Preplant application: Herbicide application before 2 to 10 days of sowing or planting. Ex. Fluchloralin is incorporated into soil to avoid volatility. This is also called as preplant incorporation.

c). Pre-emergence application: Herbicides applied after sowing but before emergence of the crop done 1-4 days after sowing. Only selective herbicides are used, affect germinating weeds.

d). Post emergence application:  Herbicides are applied 30-40 days after sowing of the crop.

Bio-Control of Weeds

Insetcs:

Name of the Weed                                                          Name of the insect

1. Lantana camara                                                         crosidosema lantana

2. Opuntia dilleni                                                            Dactylopius tomentosus

3. Salvinia molesta                                                        Cryptophagus salviniae

4. Euphatorium adenophorm                                       Procecidochares utilis

5. Eicharnea crassipus                                                  Nechetinae bruchae

6. Lantan camara                                                           Ophiomyia lantanae

7. Hypericum perforatum                                              Chrysomela gemellata

Mycoherbicides

Devine: Liquid suspension of Phytophthora palmivora causes root rot on Morrenia odorata in citrus orchard

Collego: Wettable powder of spores of Colletotrichum gloeosporoides sp aeschynomone on Aeschynomone sp.

Bipolaris: Bipolaris sorghicola on Sorghum halepense

Biolophos: Microbial toxin produced as fermentation product of Streptomyces hygroscopicus. It is non specific

Fish: Grass crop Ctenopharyngodon idella

List of exotic weeds

1.      Congress weed                                                   Parthenium hysterophorus

2.      Aligator weed                                                      Alternathera philaxeroides

3.      Water hyacinth                                                     Eichhornia crassipes

4.      Lantana                                                                Lantana camara

5.      Cocklebur                                                            Xanthium strumarium

6.      Puncture vine                                                       Tribulus terrestris