The potato cyst nematodes (PCN) Globodera pallida and G. rostochiensis are key pests of potato, subject to strict quarantine regulations worldwide (EPPO, 2013a). Indigenous to South America, they have spread to numerous potato-growing regions around the world. G. rostochiensis, was reported from Kenya in 2015 (Mwangi et al. 2015). During a nationwide survey conducted in 2016, G. pallida was detected to occur in Kenya at an altitude of 2349 m above sea level in Nyandarua County (GPS “0.3150195, 36.48328”). Cysts were extracted from a 200 cm3 soil sample following EPPO diagnostic protocol (EPPO, 2013a), and then handpicked under a stereo microscope. The PCN recovered showed morphometric characteristics of G. pallida and is reported here. For further studies, the Nyandarua field was re-sampled in February 2017, to collected additional soil samples and confirm the occurrence of G. pallida. From the collected cysts, 10 cysts were inoculated on potato (Solanum tuberosum) ʻShangiʼ in pots with sterile soil and s...

The banana weevil (Cosmopolites sordidus) and the burrowing nematode Radopholus similis represent two of the most important pests of bananas. Previously, colonization of banana plants by the non-pathogenic Fusarium oxysporum (isolate V5w2) and the entomopathogenic Beauveria bassiana (isolate WA) have been shown to increase host resistance to various banana pests and diseases. However, there is limited data on how the combined inoculation of these isolates would affect field performance of bananas. In this study, the fungal endophytes were inoculated separately and in combination. Tissue cultured plantlets of cooking banana cultivar Mbwazirume and dessert banana cultivar Grande Naine were inoculated by root drenching with a suspension of 1.0 × 10⁷ spores mL⁻¹ of the endophytes on three occasions, separated 4 weeks apart, before transplanting into the field. Each plantlet was further inoculated with 1800 nematodes, composed primarily of R. similis. Inoculation of banana plants with the fungal endophytes significantly reduced nematode densities by >34%. Similarly, plant toppling was lower in the endophyte-enhanced plants (11 t ha⁻¹ year⁻¹ versus 9 t ha⁻¹ year⁻¹ achieved in the non-inoculated plants. These findings demonstrate the benefits of fungal endophytes in improving the yield of both cooking and dessert bananas via suppression of nematode densities and nematode-related damage.

The banana weevil (BW), Cosmopolites sordidus, is the main coleopteran pest of banana, causing up to 100% yield loss. In this study, we screened 20 isolates of entomopathogenic fungi (EPF) for the management of BW. In the lab, eight Beauveria bassiana isolates caused >50% mortality of the adult BW, whereas Metarhizium anisopliae and Isaria fumosorosea isolates were less pathogenic. B. bassiana isolates ICIPE 648, ICIPE 660 and ICIPE 273 were the most pathogenic, killing ≥80% of adult BW. B. bassiana isolate ICIPE 622 yielded the highest spores per BW cadaver (1.84 × 10⁸ spores), followed by ICIPE 660, ICIPE 273 and ICIPE 648—1.17 × 10⁸, 3.8 × 10⁷ and 3.6 × 10⁷ spores, respectively. ICIPE 273 had the shortest LT₅₀ (5.3 days) followed by ICIPE 648 (9.8 days) and 660 (11.1 days). Similarly, the LC₅₀ values for the three isolates were 5.18 × 10⁷, 5.49 × 10⁷ and 5.2 × 10⁷ spores mL⁻¹, respectively. In the field, ICIPE 273 and ICIPE 648 had the highest (31.3%) and lowest (20.8%) pathogenicity, respectively. This study indicates that the B. bassiana isolates ICIPE 273, ICIPE 648 and ICIPE 660 are potential candidates for the environmentally sustainable management of BW.

Potato cyst nematodes (PCN; Globodera rostochiensis and G. pallida) are quarantine pests (EPPO 2013) and have recently been reported from Kenya (Mburu et al. 2018) and Rwanda (Niragire et al. 2019)...

Summary: Bananas ( Musa spp.) are considered the most important fruit crop in Kenya, grown mostly by smallholder farmers. However, in the past two decades production has declined and has largely been attributed to plant pathogens, including plant-parasitic nematodes. To assess the understanding and awareness that banana farmers have of nematodes, a survey was conducted. The incidence, abundance and distribution of nematodes in relation to altitude were determined for different banana types on 180 farms and the pathogenicity of Pratylenchus goodeyi , originating from three different altitudinal locations, was compared on two banana cultivars. Just 2.3% of farmers were aware of nematode damage and symptoms, none of whom applied any management measures. The highest abundance of nematodes was recorded at an altitude range of 1601-2000 m a.s.l., with Pratylenchus , Meloidogyne and Helicotylenchus being the predominant genera. Across all altitudinal locations, cooking banana had higher densities of nematodes than dessert bananas. In pots, P. goodeyi populations from Embu (1300 m a.s.l.) appeared more aggressive and with higher levels of multiplication than the population from Oyugis (1100 m a.s.l.). Cooking banana (‘Ng’ombe’) was more susceptible than dessert banana (‘Sukari Ndizi’). Nematode damage is more prominent in areas at higher altitude and on cooking banana cultivars. The findings provide key information in guiding informed and suitable management decision thresholds in relation to potential climate change.

Summary: Within sub-Saharan Africa (SSA), although nematodes are viewed among the most important threats to crop production and food security, the presence of trained nematologists working within this discipline has traditionally been viewed as scarce. The few research studies concerning this subject address this topic from a country or sub-regional perspective and generally portray nematology as ‘insufficient’. Over the past two decades, a few initiatives have been instrumental in building greater nematology expertise. For the first time a structured survey was undertaken, involving interviews with individuals from SSA that were (or currently are) involved in nematology training programmes, research, national extension services or in African universities. This paper provides evidence of the positive impact of various initiatives and shows an increase in the number of available nematology positions, together with high rates of graduates that return home to occupy qualified positions. Our findings will help researchers, policy makers and donors to identify areas requiring support to increase the promotion of nematology in SSA and to make an impact for end-users.