Role of Variety and Fertilizer Practices on Cowpeas (Vigna unguiculata) Yield and Field Incidence of the Parasitic Weed Alectra vogelii (Benth) in Central Malawi

Abstract

Grain legumes are an important component of the food systems in Malawi. The parasitic legume witchweed species Alectra vogelii (Benth) is among the problem pests with serious infestations in groundnuts (Arachis hypogea), soybeans (Glycine max), cowpeas (Vigna unguiculata) and other legumes. A study was conducted in 2013/14 and ‘14/15 seasons to evaluate the effects of three cowpea varieties (IT82E-16, Sudan 1 and Alectra-resistant Mkanakaufi) and fertilizer practices (no fertilizer applied, 5 t ha-1 cattle manure and 100 kg ha-1 of inorganic 23:21:0+4S on cowpea grain yield, yield components and Alectra emergence at three sites in central Malawi. Cowpea grain yields ranged 400-2400 kg ha-1. There were significant (P < 0.05) variety effects on yield in 4 of 6 site-years, with variety IT82-16 consistently giving the highest yields (range 1200-2400 kg ha-1). There were significant variety effects on A. vogelii emergence with Mkanakaufiti having no Alectra throughout. Application of cattle manure strongly suppressed A. vogelii in 6 site-years all at 60 days after planting, while inorganic fertilizer suppressed Alectra in 3 of the 6 site-years. Cattle significantly but marginally (about 250 kg ha-1) increased yield in 2 of the 6 site-years. The results show potential to suppress A. vogelii with cattle manure application. However, further studies are required to understand the causes of the limited yield response under manure or fertilizer application to make the practices attractive to farmers. More variety improvement studies to produce a range of varieties with better local adaptability and response to fertility amendments are recommended.

Dual‐purpose cowpea grain and fodder yield response to variety, nitrogen–phosphorus–potassium fertilizer, and environment

“…Our results are in contrast to Ishikawa et al (2022), who reported no significant yield advantage from fertilizer application to cowpea but a 24% protein yield advantage from topdressing fertilizer at flowering in cowpea production. A significant impact of variety on yield but limited response to fertilizer application from cowpea was also reported (Kabambe & Bokosi, 2020). These suggest that application of fertilizer to cowpea production may be a function of environment, particularly soil nutrient status of the field.…”

Unraveling Seed Dormancy and Host Specificity of Alectra Vogelii in Malawi

“…However, lengthy periods of imbibition of Alectra seed in water, in the absence of stimulants do not induce the wet dormancy characteristic which commonly occurs in Striga seeds (CABI, 2017;Phiri et al, 2023). Several studies have been undertaken to find the effects of • Germinated seeds attach their hostrorium to the host Alectra and Striga sourced from different regions and countries on their reaction to cowpea, common bean, soybean, groundnut, flax, chickpea, pigeon peas, and other legume crops (Mwaipopo, 2014;Phiri et al, 2019;Kabambe and Bokosi, 2020). However, no studies have been done on Alectra vogelii sourced from a wide range of agroecological zones and dormancy-breaking periods within Malawi.…”

In vivo and in vitro performance studies on groundnut (Acharis hypogea L.) genotypes for yellow witchweed (Alectra vogelii Benth.) resistance

“…As a result, most resource-poor farmers are suffering from yellow witchweed (Alectra vogelii Benth.) infestation, which is a predominant obligate hemi-parasitic weed species of legumes in African arid and semi-arid regions (Njekete et al, 2017;Dieni et al, 2018;Kabambe and Bokosi, 2020). These regions are prone to drought stress and with more than 50% of arable land inherently infertile (Gwatidzo et al, 2020;Ichihashi et al, 2020;Soropa et al, 2021;Rugare et al, 2013;Itta et al, 2014;Mandumbu et al, 2017;Ojiewo et al, 2020;Mutuku et al, 2021).…”

“…The parasite has been reported widely distributed in Sub-Saharan Africa. The known hotspots of A. vogelii infestation in legumes include countries like Botswana (Fite et al, 2009), Ethiopia (Hussein et al, 2006), Malawi (Kabambe and Bokosi, 2020), Nigeria (Motagi et al, 2014), Tanzania (Mbega et al, 2010) and Africa-wide (Kureh and Alabi, 2003;Kureh et al, 2005). Its infestation has been reported largely in groundnuts, cowpeas, common beans and bambaranuts (Alonge et al, 2001a;Mandumbu et al, 2016;Mbwando et al, 2017;Phiri et al, 2019).…”

“…Nonetheless, the impact of A. vogelii is inevitable given the prevalence of A. vogelii weed, which is characterized by long lasting seed viability and prolificacy which ranges between 15-20 years and 400-600 thousand seeds respectively (Mukendi et al, 2017;Ugbaa et al, 2020;Aloni, 2021;Mutuku et al, 2020;Ichihashi et al, 2020;Masumoto et al, 2021;Aloni, 2021). This result in total crop damage and yield losses greater than 80% (Phiri et al, 2019;Kabambe and Bokosi, 2020).…”