**4. Chemical control of sugar beet weeds**

#### **4.1 Introduction**

In the area of Tadla, sugar beet is regarded as an important crop. Weeds constitute a great constraint to crop production improvement and cause important yield losses (Rzozi and al., 1990). The farmers do not use herbicides efficiently. Generally, only one herbicide is applied and the results are not satisfactory (Baye et al, 2004). This work aims to develop a chemical weed control program by evaluating the effectiveness of some herbicide treatments.

#### **4.2 Material and methods**

#### **4.2.1 Field experiment localization**

A field experiment was conducted during the two sugar beet growing seasons 2003/2004 and 2004/2005 in three location Fqih Ben Salah, Afourer and Deroua to assess the efficacy of some herbicide treatments. These locations were chosen in order to have diversified weed flora and then have maximum information about herbicide activity spectrum.

#### **4.2.2 Herbicides and herbicide treatments studied**

The main and important herbicides homologated on sugar beet and registered in Morocco such as ethofumesat, desmedipham, phenmedipham, metamitron, triflusulfuron methyl and lenacil were experimented (Table 4). Thes active ingredients were tested either alone or in mixture (Table 5). A hand weeding taked place for all treatments when it was necessary.

#### **4.2.3 Observations on weeds**

394 Herbicides – Properties, Synthesis and Control of Weeds

CPWC

In the area of Tadla, sugar beet is regarded as an important crop. Weeds constitute a great constraint to crop production improvement and cause important yield losses (Rzozi and al., 1990). The farmers do not use herbicides efficiently. Generally, only one herbicide is applied and the results are not satisfactory (Baye et al, 2004). This work aims to develop a chemical

A field experiment was conducted during the two sugar beet growing seasons 2003/2004 and 2004/2005 in three location Fqih Ben Salah, Afourer and Deroua to assess the efficacy of some herbicide treatments. These locations were chosen in order to have diversified weed

The main and important herbicides homologated on sugar beet and registered in Morocco such as ethofumesat, desmedipham, phenmedipham, metamitron, triflusulfuron methyl and lenacil were experimented (Table 4). Thes active ingredients were tested either alone or in mixture (Table 5). A hand weeding taked place for all treatments when it was necessary.

weed control program by evaluating the effectiveness of some herbicide treatments.

flora and then have maximum information about herbicide activity spectrum.

Fig. 7. Critical period of weed control (2004/2005).

**4. Chemical control of sugar beet weeds** 

**4.1 Introduction** 

**4.2 Material and methods** 

**4.2.1 Field experiment localization** 

**4.2.2 Herbicides and herbicide treatments studied** 

The importance of weeds encountered in field experiments was estimated according to the Abundance – Dominance-Index (ADI).
