Screening of Alectra vogelii ecotypes on legume and non-legume crop species in Malawi

Abstract

The parasitic angiosperm Alectra vogelii Benth. is a growing problem in Malawi, particularly with the current emphasis on legume crops. Therefore, a screen-house study was conducted to determine the virulence of different ecotypes of A. vogelii and to confirm infestation on non-legume crops. Alectra vogelii collections were sourced from three agro-ecological zones and tested against groundnut, Bambara nut, soybean, chickpea, pigeon pea, common bean, green gram, quinoa, sunflower and flax grown in pots infested with A. vogelii. Number of days to first A. vogelii emergence, periodic A. vogelii shoot counts at 7, 8, 9, 10 and 11 weeks after planting, and crop biomass parameters at 100 d after sowing were recorded. Alectra vogelii source × crop species interaction significantly (p < 0.05) affected number of days to first A. vogelii emergence on Bambara nuts, pigeon pea and flax, but not on the other crop species. Alectra vogelii parasitises soybean, groundnut, bean, Bambara nut and cowpea, but not sorghum, millet and pigeon pea. However, weekly A. vogelii shoot counts were significantly affected by crop species. The study indicated that Nthawajuni pigeon pea, flax and notable host legumes suffered A. vogelii infestation. Therefore, screening for resistance in crops to suppress the weed should be conducted.

Keywords:

• agro-ecological zone
• Alectra vogelii
• ecotypes