Status of Root-Knot Nematode (<i>Meloidogyne</i> Species) and Fusarium Wilt (<i>Fusarium oxysporum</i>) Disease Complex on Tomato (<i>Solanum lycopersicum</i> L.) in the Central Rift Valley, Ethiopia

Abstract

Development of diseases in cultivated crops depends on the complex interrelationship among host, pathogen and prevailing environmental conditions. In nature, plants are rarely, if ever, subject to the influence of only one potential pathogen and this is especially true of soil-borne pathogens like fusarium wilt (Fusarium oxysporum). In the present study, the co-occurrence of root-knot nematode (Meloidogyne species) and Fusarium oxysporum f.sp. lycopersici was surveyed in the main tomato growing areas of the central rift valley of Ethiopia. Mineral and organic samples were collected from 59 farmlands representing five districts and two commercial farms during the main cropping season of 2017. Cultural, morphological and virulence analysis of these pathogens revealed their coexistence. Out of 59 samples, 39% were found infected with the disease complex [Meloilodogyne species.* Fusarium oxysporum f.sp. lycopesici (FOL)]. Off which, 16.9% and 6.8% resulted from concomitant infection of Meloidogyne incognita* FOL and Meloidogyne javanica* FOL, respectively. The percent prevalence of the disease complex ranged between 27.3% and 60%. The co-occurrence of these pathogens within a single host plant within the same ecological niche will indicate the probability of any type of interaction between each other. Therefore, subsequent research studies on their nature of interaction should be done in the future.

Identification of Pathogens Causing Bulb Rot Disease on Garlic (Allium sativum L.) in Central Java, Indonesia

“…had colonies that were white or accompanied by purple or pink coloration at the center of the colony. This was consistent with findings from Kassie (2019) that reported F. oxysporum on PDA media forms a mycelium which is insulated and initially white and gradually turns to purple. The occurrence of color differences over time is more likely due to the accumulation of colors produced during the growth of F. oxysporum (Ambar et al, 2019).…”

“…The synergistic interaction between D. dipsaci and Rhizoctonia solani were also reported in sugar beets (Hillnhütter et al, 2011). Other association between M. incognita and F. oxysporum in tomato plants caused complex diseases (Kassie, 2019). Therefore, investigation on the causal agents of bulbs rot disease was done and the role of both nematode and fungi were determined and the possible interaction between both of them in bulb rot disease incidences.…”

“…The pathogenic relationship on plant parasitic nematodes as an opening agent for fungal infection was tested (Griffin, 1990;Hillnhütter et al, 2011;Kassie, 2019). In this study F. oxysporum was chosen for the pathogenicity test because it was found in the field and have been reported to interact D. dipsaci.…”

“…BT3 isolates had the longest macroconidium, 40.14 -4.70 µm -75.75 × 5.00 µm. Kassie (2019) Kassie (2019) the microconidium was attached to the monophialid or conidiophoric branches, oval-ellipses shaped, straight or even curved, measuring between 6.75 × 1.93 µm -13.56 × 3.4 µm. Microconidia were always present, especially those that do not act as a result of monophialid or conidiophores with short branches or false heads (Figure 6).…”

Variations in Growth, Physiology, and Antioxidative Defense Responses of Two Tomato (Solanum lycopersicum L.) Cultivars after Co-Infection of Fusarium oxysporum and Meloidogyne incognita

“…Previously, it has been reported that Meloidogyne spp. causes severe infection in tomato when followed by Fusarium oxysporum infestation [16][17][18]. It induces changes in developmental and morphological attributes of crops, in addition to systemic symptoms such as wilting, dwarfing, yellowing, and susceptibility to other pathogens [19].…”