**4.2.4 Evaluation of herbicide efficacy**

Weed dry weight were measured during at 60 days after treatments (DAT) for all individual plots. Four 0.5 m x 0.5m quadrates per plot were placed randomly over the plot. Weeds within the sampling area were removed by hand, taken to laboratory and dried at 60° C for 48 h to determine total weed dry weight. The efficacy in percentage (%) for each treatment is calculated comparing its dry matter to that of the check.

#### **4.2.5 Observations on the crop**

The sugar beet yield was estimated on the two central rows at harvest. Sucrose percentage and the concentration of impurities (sodium, potassium, amino-N) were measured at the regional sugar factory.

#### **4.2.6 Experimental design and statistical analysis**

The experiment was a randomized complete block design with four replicates. Individual plots were 4m x 8m size. Data on efficacy (%) were first transformed to Arc Sin% if necessary. Sugar beet yield and efficacy data were subjected to an analysis of variance using statistical STATITCF software. The means were compared using Fisher's protected LSD (α = 0.05).


Table 4. herbicides tested.

#### **4.3 Results and discussion**

#### **4.3.1 Importance of weed flora**

In Fqih Ben Salah location, weed flora is dominated by gramineous mainly volunteer wheat. Some dicotyledonous species such as *Malva parviflora, Medicago polymorpha, Emex spinosa* and *fumaria parviflora* are important (Table 6). In Deroua location, infestation by gramineous was low and *cichorium endivia*, *Sinapis arvensis* and *convolvulus arvensis* were dominant in 2003/2004 and *Rumex pulcher*, *Papaver rhoas* and *Ridolfia segetum* dominated the weed flora in 2004/2005. Concerning Afourer, C*ichorium endivia*, *Sinapis arvensis, Polygonum aviculare, Lamium amplexicaule and Ridolfia segetum* were the most important species in both two growing season.

Sugar Beet Weeds in Tadla Region (Morocco):

**Species** 

Species Encountered, Interference and Chemical Control 397

as *Ridolfia segetum* and *Ammi majus* and brassicaceae maily *Sinapis arvensis.* Goltix (T3) did not control apiaceae, malvaceae and other species; however, it provides good control of polygonaceae such as *Rumex pulcher* and *Emex spinosa.* Betanal Progress presented the most large herbicide activity spectrum and controlled great number of species even applied alone

Generally, treatments achieved good efficacy when applied in tank mixtures than when applied individually alone because of their complementarily in eliminating maximum weed species. So, this must be taken in consideration in a weed chemical management program.

*Volunteer wheat* 4 3 1 2 2 2 *Phalaris brachystachys* 1 3 3 3 2 2 *Lolium rigidum* 3 2 2 1 1 1 *Avena sterilis* 2 2 1 2 2 2 *Bromus rigidus* + + + + + 1 *Malava parviflora* 4 3 + + + 1 *Emex spinosa* 3 1 2 + + 2 *Rumex pulcher* + + 1 1 2 4 *Anagallis foemina* 1 4 3 3 + 2 *Chenopodium album* 2 3 3 1 1 2 *Fumaria parviflora* 3 3 1 1 + 1 *Cichorium endivia* + 2 4 4 4 2 *Convolvulus arvensis* + 1 2 3 3 3 *Sinapis arvensis* 1 1 4 4 1 2 *Sonchus oleraceus* 1 1 2 2 1 2 *Polygonum aviculare* 1 + 4 3 + 1 *Lamium amplexicaule* 1 + 4 3 1 2 *Medicago polymorpha* 4 + 3 2 1 2 *Melilotus sulcata* 2 1 2 + 1 1 *Papaver rhoeas* 2 + 3 2 + 4 *Ridolfia segetum* + + 2 4 1 3 *Ammi majus* - + + + + + *Stellaria media* - + + + + 3 *Veronica polita* - + + 1 - 1 *Torilis nodosa* - - + + - - *Euphorbia exigua* - - + + - - *Galium aparine* - - 1 1 - 1 *Capsella bursa-pastoris* - - + + 2 3

Table 6. Weed species encountered in field experiments.

**Fqih Ben Salah Afourer Deroua 2003/04 2004/05 2003/04 2004/05 2003/04 2004/05** 

in some times. This is the case of Deroua in 2003/2004. The efficacy obtained is 82%.

#### **4.3.2 Efficacy of the herbicide treatments**

Generally, fluazifop- p- butyl (Fusilade Super) achieved a good gramineous control (data not showed). However, it is important to mention that some ray grass (*Lolium* spp) population had recently developed resistance to this herbicide.


Table 5. Herbicides treatments experimented.

In order to control gramineous species, all first post emergence application are mixed with Fusilade Super (1l/ha); an oil concentrate adjuvant (Seppic at 1/ha) is adjusted to the two application to obtain satisfactory activity. The second application is made 10 days after the first.

Concerning post sowing preemergence application treatments, Tramat combi (T1) provided good efficacy (90 % and more) and protected then the crop for a long period more than 2 months (Table 7). This allowed to sugar beet to grow vigorously. The treatment controlled both dicotyledonous and monocotyledonous species except *Emex spinosa* that showed some tolerance to this herbicide. The other treatment applied preemergence (T2) showed not satisfactory with efficacy lower than 68 %. This herbicide did not control monocotyledonous (volunteer wheat included) and many other dicotyledonous species such as *Medicago polymorpha and Melilotus sulcata.* 

For post emergence applications, it was noted that when treatments were applied alone (not mixed), the efficacy was not satisfactory. Effectively, efficacy was generally below 70 % except T5 in 2004/2005 at Deroua (Table 7). In this case, the percent control is above 80 %.

This difference in efficacy is explained mainly by the herbicide activity of each one. Safari (T4) provides low control against *Papaver rhoeas, Chenopodium album, Anagallis foemina, stellaria media, Cichorium endivia and Fumaria parviflora.* In contrast, it achieves good control against many other important species particularly malvaceae, *Malva parviflora*, apiaceae such

Generally, fluazifop- p- butyl (Fusilade Super) achieved a good gramineous control (data not showed). However, it is important to mention that some ray grass (*Lolium* spp)

T3 Goltix (5kg/ha) in 2 applications (2,5 + 2,5) kg/ha post emergence (2 true leaves

T6 (Safari (30g/ha) + Venzar (200g/ha) applied twice post emergence (2 true leaves

T7 (Betanal Progress(1,25l/ha) + Safari (30g/ha)) applied twice post emergence

T8 (Betanal Progress (1,25l/ha) + Goltix (1kg/ha)) applied twice post emergence

T9 (Goltix (1kg/ha) + Safari (30g/ha) applied twice post emergence (2 leaf stage) T10 (Betanal Progress (1L/ha) + Goltix (300g/ha) + Venzar (100g/ha)) applied twice post

T11 (Betanal Progress (0,8L/ha) + Safari (30g/ha) + Goltix (300g/ha) + Venzar (100g/ha)) applied twice post emergence (2 true leaves stage)

In order to control gramineous species, all first post emergence application are mixed with Fusilade Super (1l/ha); an oil concentrate adjuvant (Seppic at 1/ha) is adjusted to the two application to obtain satisfactory activity. The second application is made 10 days after the

Concerning post sowing preemergence application treatments, Tramat combi (T1) provided good efficacy (90 % and more) and protected then the crop for a long period more than 2 months (Table 7). This allowed to sugar beet to grow vigorously. The treatment controlled both dicotyledonous and monocotyledonous species except *Emex spinosa* that showed some tolerance to this herbicide. The other treatment applied preemergence (T2) showed not satisfactory with efficacy lower than 68 %. This herbicide did not control monocotyledonous (volunteer wheat included) and many other dicotyledonous species such as *Medicago* 

For post emergence applications, it was noted that when treatments were applied alone (not mixed), the efficacy was not satisfactory. Effectively, efficacy was generally below 70 % except T5 in 2004/2005 at Deroua (Table 7). In this case, the percent control is above 80 %. This difference in efficacy is explained mainly by the herbicide activity of each one. Safari (T4) provides low control against *Papaver rhoeas, Chenopodium album, Anagallis foemina, stellaria media, Cichorium endivia and Fumaria parviflora.* In contrast, it achieves good control against many other important species particularly malvaceae, *Malva parviflora*, apiaceae such

T4 Safari (60g/ha) in 2 applications (30+30) g/ha ) post emergence (2 true leaves stage) T5 Betanal Progress (5l/ha) in 2 applications (3 + 2) l/ha g/ha ) post emergence (2 true

**4.3.2 Efficacy of the herbicide treatments** 

Treatments Herbicide treatments tested

leaves stage)

(2 true leaves stage)

(2 true leaves stage)

emergence (2 true leaves stage)

T12 Hand weeding (Three times in the season)

Table 5. Herbicides treatments experimented.

stage)

stage)

T13 Check (Not treated)

*polymorpha and Melilotus sulcata.* 

first.

population had recently developed resistance to this herbicide.

T1 Tramat Combi (3,5l/ha) in post sowing preemergence T2 Goltix (5kg/ha) applied in post sowing preemergence as *Ridolfia segetum* and *Ammi majus* and brassicaceae maily *Sinapis arvensis.* Goltix (T3) did not control apiaceae, malvaceae and other species; however, it provides good control of polygonaceae such as *Rumex pulcher* and *Emex spinosa.* Betanal Progress presented the most large herbicide activity spectrum and controlled great number of species even applied alone in some times. This is the case of Deroua in 2003/2004. The efficacy obtained is 82%.

Generally, treatments achieved good efficacy when applied in tank mixtures than when applied individually alone because of their complementarily in eliminating maximum weed species. So, this must be taken in consideration in a weed chemical management program.


Table 6. Weed species encountered in field experiments.

Sugar Beet Weeds in Tadla Region (Morocco):

**Treatments** 

Species Encountered, Interference and Chemical Control 399

**T1** 74a 72.9a 75a 74.6a 78a 80.2a

**T2** 52.3c 53.6c 51c 49c 53.3bc 51.6c

**T3** 54.3bc 51c 50.9c 52.3c 53.4bc 50.3c

**T4** 52c 53.2b 52.6c 51c 50c 46c

**T5** 60b 62b 60.3b 59.2b 68a 51c

**T6** 62.1b 61.4b 54bc 58bc 60.6b 50.6c

**T7** 69a 70.5a 71.2a 72a 71.9a 73.2a

**T8** 61.6b 63b 64.5b 65.1b 69a 61b

**T9** 53c 60b 51c 50c 49c 52.3c

**T10** 60.8b 62.6b 57bc 55.4c 59b 61b

**T11** 70.2a 71.3a 72.6a 71.9a 73.3a 72.8a

**T12** 49.8c 50.9c 51c 52c 50.2c 51.9c

**T13** 7.2d 5d 3.9d 8d 4.8d 6.3d

Many studies relative to sugar beet weed chemical control were achieved in Morocco and other counties. Bensellam et al. (1993) reported that phenmediham + pyrazone achieved good control of weeds in sugar beet. Rzozi et al. (1990) found that nor metamitrone followed by phenmedipham neither chloridazone applied preemergence gave good efficacy. El Antri (2002) reported that triflusulfuron methyl + lenacil + clopyralid achieved good control of weeds in sugar beet. El Ghrasli and Allali (2002) estimated that farmers in Gharb region could use Safari, Goltix, Betanal and Venzar to control weeds in sugar beet. The pre sowing and preemergence herbicides: Tramat Combi and Goltix and the post emergence safari, Goltix, Betanal Progress and Venzar are widely used in France (Anonymous, 1999) and in

Means within columns followed by different letters are significantly different at α = 0.05.

Table 8. Effect of herbicide treatments on sugar beet yield.

USA (Stachler, 2011).

**Fqih Ben Salah Afourer Deroua** 

**2003/04 2004/05 2003/04 2004/05 2003/04 2004/05** 

#### **4.3.3 Effect of herbicide treatments on sugar beet yield**

Weed presence in sugar beet during all season caused yield losses between 86 and 93% following the nature of weed flora and the location. Herbicide treatments did not affect the sugar content percentage (Data not showed). Sugar beet yield was significantly affected by the herbicide treatments (Table 8). The post sowing preemergence treatment (Tramat Combi) achieved a satisfactory yield averaging 75 T/ha. This is due to its good weed control achievement during a long period. When used in tank mixtures (particularly 3 and 4 products), herbicide treatments provide high yields (Table 8). It is important to mention that weed chemical treatment alone is generally not sufficient to provide good root sugar beet production and it must be followed by other weed control methods such as mechanical, cultivation and hand weeding.


Means within columns followed by different letters are significantly different at α = 0.05.

Table 7. Efficacy of herbicide treatments (%) at 60 DAT.

Weed presence in sugar beet during all season caused yield losses between 86 and 93% following the nature of weed flora and the location. Herbicide treatments did not affect the sugar content percentage (Data not showed). Sugar beet yield was significantly affected by the herbicide treatments (Table 8). The post sowing preemergence treatment (Tramat Combi) achieved a satisfactory yield averaging 75 T/ha. This is due to its good weed control achievement during a long period. When used in tank mixtures (particularly 3 and 4 products), herbicide treatments provide high yields (Table 8). It is important to mention that weed chemical treatment alone is generally not sufficient to provide good root sugar beet production and it must be followed by other weed control methods such as mechanical,

> **Fqih Ben Salah Afourer Deroua 2003/04 2004/05 2003/04 2004/05 2003/04 2004/05**

**T1** 89.5a 86a 87.3a 86.9a 90.1a 92.6a

**T2** 62c 60.3c 65c 65.9b 64bc 68.4b

**T3** 69.3b 60.7c 65.2c 66.8b 69.5b 65.2bc

**T4** 65.4bc 69b 63.5c 65.2b 61.4c 50.1d

**T5** 72b 79ab 75b 70b 82a 62.9c

**T6** 75b 72.2b 65c 69b 72.6b 62c

**T7** 84a 86.4a 87.8a 85.7a 86.9a 66bc

**T8** 75.1b 79b 76b 62b 80.1a 74.1b

**T9** 72b 75.6b 69.3c 67b 65b 72.b

**T10** 75b 77b 62c 60b 69b 75b

**T11** 88.2a 86.7a 88.1a 86.3a 88.6a 80.6a

**T12** 70b 73b 74b 69b 73b 65bc

Means within columns followed by different letters are significantly different at α = 0.05.

Table 7. Efficacy of herbicide treatments (%) at 60 DAT.

**4.3.3 Effect of herbicide treatments on sugar beet yield** 

cultivation and hand weeding.

**Treatments** 


Means within columns followed by different letters are significantly different at α = 0.05.

Table 8. Effect of herbicide treatments on sugar beet yield.

Many studies relative to sugar beet weed chemical control were achieved in Morocco and other counties. Bensellam et al. (1993) reported that phenmediham + pyrazone achieved good control of weeds in sugar beet. Rzozi et al. (1990) found that nor metamitrone followed by phenmedipham neither chloridazone applied preemergence gave good efficacy. El Antri (2002) reported that triflusulfuron methyl + lenacil + clopyralid achieved good control of weeds in sugar beet. El Ghrasli and Allali (2002) estimated that farmers in Gharb region could use Safari, Goltix, Betanal and Venzar to control weeds in sugar beet. The pre sowing and preemergence herbicides: Tramat Combi and Goltix and the post emergence safari, Goltix, Betanal Progress and Venzar are widely used in France (Anonymous, 1999) and in USA (Stachler, 2011).

Sugar Beet Weeds in Tadla Region (Morocco):

begins relatively later.

**6. Acknowledgments** 

**7. References** 

data.

Species Encountered, Interference and Chemical Control 401

should start from 4 WAE and 7 WAE in 2003 and 2004, respectively. For the given 10% root yield reduction, weed control should be continued until 15 WAE and 12 WAE in 2003 and 2004. The results show that the critical period begins earlier in 2003 and its duration is longer (77 days) comparatively to that observed in 2004 which is shorter (35 days) and

A field experiment was conducted during two sugar beet growing seasons 2003/2004 and 2004/2005 in three locations 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. Concerning post sowing preemergence application treatments, Tramat combi (T1) provided good efficacy (90 % and more) and protected then the crop for a long period more than 2 months. This allowed to sugar beet to grow vigorously. The treatment controlled both dicotyledonous and monocotyledonous species. For post emergence applications, it was noted that when treatments were applied alone (not mixed), the efficacy was not satisfactory. Generally, herbicides (ethofumesate, metamitron, triflusulfuron methyl, phenmedipham, desmedioham and lenacil) achieved good efficacy when applied in tank mixtures than when applied individually alone because they are complementarily in eliminating maximum weed species. So, this must be taken in consideration in a weed chemical management program. These herbicide treatments allow to crop to grow within weed competitiveness nearly until the end of the critical period and

The authors thank M. Ait El Alia and O. Bennig for helping with collecting the research

Alaoui, S. B., Donald L. Wyse and A. G. Dexter. 2003 Minimum Weed-free Period for

Anonymous. 1999. Désherbage des betteraves pour 1999. La Technique betteravière 1999;

Baziramakenga, R. and Leroux, G. D. 1994. Critical period of quackgrass (*Elytrigia repens*)

Baye, Y., M. El Antri, M. Bouhache and A. Taleb. 2004. Situation actuelle du désherbage de la betterave à sucre au Tadla. 5 ème congrés de l'AMPP, 30-31 Mars, Rabat, p : 183-194. Baziramakenga, R. and Leroux, G. D. 1994. Critical period of quackgrass (*Elytrigia repens*)

Bensellam E.H., M.Bouhache and S.B.Rzozi. 1993. Effet du peuplement et de la stratégie du

Bensellam, E.H. 1994. Etude floristique des adventices des vergers d'agrume dans le Gharb.

Agronomique, Département de Recherche de Phytiatrie du Gharb. 45 p. Bouhache, M. and C. Boulet. 1984 . Etude floristique des adventices de la tomate dans le

désherbage sur le rendement et la qualité technologique de la betterave à sucre

Rapport de fin de stage de titularisation. Institut National de Recherche

removal in potatoes *(Solanum tuberosum*). *Weed Science* 42: 528-533.

removal in potatoes *(Solanum tuberosum*). *Weed Science* 42: 528-533.

dans le Gharb. Sucrerie Maghrébine, n°50-5: 13-24.

Souss. Homme, terre et eau; 14(57), 37-49.

Sugarbeet *(Beta vulgaris* L.) in the Gharb Region of Morocco. Journal of Sugar Beet

are often followed by a mechanical cultivation or a hand hoeing.

Research Vol 40 No 4: 251 -272

Protection de la culture, p: 45- 48.

### **4.4 Conclusion**

A field experiment was conducted during two growing seasons 2003/2004 and 2004/2005 in three locations in Tadla region to evaluate the effectiveness of some herbicides treatments. 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 individualy alone or in tank mixtures.

Tramat combi (Ethofumesate + lenacil) applied post sowing preemergence provided good efficacy (90 % and more) and protected then the crop for a long period more than 2 months.

Generally when applied post emergence, herbicides ethofumesate, metamitron, triflusulfuron methyl, phenmedipham, desmedioham and lenacil achieved good efficacy in tank mixtures than applied individually alone because they are complementarily in eliminating maximum weed species. So, this must be taken in consideration in a weed chemical management program. These herbicide treatments allow to crop to grow without weed competitiveness nearly until the end of the critical period and are often followed by a mechanical cultivation or a hand hoeing.
