Chemical Control Of Orobanche Spp In Faba Bean (Vicia Faba) In The Maghreb

Kaddour Saffour⁽¹⁾ M. Kharrat⁽²⁾ T. Souissi⁽³⁾ D. Bouya⁽⁴⁾ and M. Bouhache^(5)
(1)Centre Régional de la Recherche Agronomique, BP 578, Meknès, Morocco
E-mail(1): k.saffour@caramail.com
E-mail(2): olea@awamia.inra.org.ma
⁽²⁾INRA, Tunisia
⁽³⁾INAT- Tunisia
⁽⁴⁾Fac. des Sci. Fès, Morocco
⁽⁵⁾IAV Hassan II, Morocco

Abstract

Glyphosate is poorly adopted by Moroccan farmers for orobanche control in faba bean because it requires some expertise for its use. This work was carried out to study the efficacy of sulfosate and imidazolinones herbicides in the control of this parasite in faba bean. The following treatments were used: (i) four pre- emergence (PE) herbicides: imazapyr at 10, 12.5 and 25 g.a.i../ha, imazethapyr at 50, 75 and 100 g/ha, imazaquin at 40 and 80 g/ha and imazapic at 3, 4.5, 10 and 12 g/ha; (ii) one herbicide used at orobanche tubercle attachment (OTA): imazapic at 0.5, 1, 1.5, 10 and 15 g/ha; (iii) five herbicides used twice, at OTA and two weeks later: imazapic at 2 x 5 g/ha and 10 + 5 g/ha, imazapyr at 2x5 g/ha; imazaquin at 2x15 g/ha; sulfosate at 2x60 , 2x100 and 2x 120 g/ha; glyphosate at 2x60 g/ha. (iv) Glyphosate was also used three times at 7-8 faba bean nodes or at early flowering and (v) two and four weeks later and finally imazapic was used PE at 5 g/ha and 8 or 10 g/ha at OTA. These treatments were applied during 1999/2000 and 2000/2001 crop seasons at Douyet research station (Morocco) which is naturally infested by O. crenata and Beja research station (Tunisia) which is also naturally infested by O. foetida. All herbicides significantly reduced orobanche infestation and increased crop yield in 1999/00, which was a dry season. In PE treatment, except imazapic at 3 g/ha and imazapyr which were phytotoxic, all the other treatments were at least as efficient as glyphosate (2x60). However, these treatments were less efficient in 2000/01, which was a wet season until March, even for the high doses of imazapic. Used at post-emergence (PoE), imazapyr (2x5 g/ha), sulfosate (2x100 g/ha), imazapic (5+5; 10; 10+5 et 15 g/ha) and imazaquin (2x15 g/ha) have efficiently controlled orobanche and ensured a satisfactory equivalent yield to that obtained by the glyphosate treatment when the infestation rate was moderate. However, the yield was relatively low when the infestation rate was high. Imazapic used as PE or PoE efficiently controlled orobanche even at high infestation rate. Three Glyphosate sprays was the most effective treatment and ensured the highest crop yield.