The effect of growing beans together with maize on the incidence of bean diseases and pests

Abstract

Compared with mono-cultures, beans grown in association with maize showed generally less incidence of the following diseases and pests: halo blight, bean common mosaic, anthracnose, common blight, scab, Phoma, mildew, bolworm and to a lesser extent angular leaf spot. For white mold and the black beetle Systates the opposite was observed. Rust and aphids were erratic in this respect.Apparently a kind of cultural control of the major bean diseases in Kenya is effected by growing beans in association with maize.

Common Bean Rust: Pathology and Control

“…In some circumstances, maize in particular may decrease rust levels, possibly due to the provision of a physical barrier influencing factors such as spore dispersal and temperature (Msuku and Edje 1982;Sengooba 1990;Boudreau and Mundt 1992;Fininsa 1996). However, ambiguous results have also been obtained (Van Rheenen et al 1981;Boudreau and Mundt 1992) and in some studies, such as reported by Diaz (1981), an increase in rust incidence was observed for beans in association with maize. These differences may be due to variation in topography, wind patterns, and other local factors influencing microclimate and spore dispersal.…”

“…Panse et al (1997) obtained slight increases in yield using various mixture combinations. Other authors, however, reported an inconsistent effect of mixtures on rust as compared to monoculture (Van Rheenen et al 1981;Aylor 1988), although the general tendency does appear to be a lessening of the amount of disease.…”

“…Such mixtures can contain from two to 30 components, with three usually comprising 50 to 90% of the whole (Mohamed and Teri 1989;Mbewe and Mulila 1990;Trutmann et al 1993;Smithson and Lenn e 1996). Mixtures have been reported to have a suppressive effect on disease incidence (Van Rheenen et al 1981) and to be employed by farmers in a disease management program, even where very little knowledge of the causes of disease exists (Mohamed and Teri 1989;Trutmann et al 1993). Habtu (1994) reported that radial expansion of the disease from inoculation points was only 3 cm per day in a mixture containing 20% susceptible plants, as compared to a 16 cm per day in plots containing susceptible plants only.…”

“…Intercropping and Multiple Cropping. Intercropping of beans with nonhost crops, such as maize, is popular in many parts of Africa (Simbwa-Bunnya 1972;Van Rheenen et al 1981;Mbewe and Mulila 1990;Fininsa and Yuen 2001) as well as in Latin America (Woolley and Davis 1991). In some circumstances, maize in particular may decrease rust levels, possibly due to the provision of a physical barrier influencing factors such as spore dispersal and temperature (Msuku and Edje 1982;Sengooba 1990;Boudreau and Mundt 1992;Fininsa 1996).…”

Effects of Intercropping on the Performance of Maize and Cowpeas in Botswana

“…Legume intercrops are a potential source of plant nutrients that compliment/supplement inorganic fert ilizers [17]. Legu me intercrops have several socioeconomic [18], and biological and ecological [19,20,21,22,23] advantages compared to sole cropping for small-holder farmers [24]. In addition, certain legumes crops provide food to humans and livestock [17].…”