Evaluating the potential of soil management to reduce the effect of Fusarium oxysporum f. sp. cubense in banana (Musa AAA)

Abstract

Fusarium oxysporum f. sp. cubense (Foc) causes Fusarium wilt in banana (Musa AAA). Foc Race 1 devastated the subgroup Gros Michel during the first half of the twentieth century. The Gros Michel was largely replaced by the resistant subgroup Cavendish in the 1950s. However, in the 1980s, Foc Tropical Race 4 started to spread affecting Cavendish bananas. No proper control measures have been found to deal with the disease. This paper re-takes an important research line from the 1950s to evaluate the potential of soil management for Fusarium wilt management. The role of soil properties on Fusarium wilt in bananas was studied in two greenhouse experiments. It was evaluated whether the influence of two main soil properties (pH and N) on Fusarium wilt is similar for Race 1 and Tropical Race 4. Two soil pH levels (lower than 5.2 and higher than 6.0) respectively ensured through acidification and liming; and three levels of N (ammonium nitrate, 33.5% N) weekly doses (low:0 N g, medium: 0.08 N g and high: 0.25 N g per plant) were achieved. The first experiment in Costa Rica confirmed the earlier results about the influence of soil pH and nitrogen on Fusarium wilt (Race 1) on Gros Michel bananas. The second experiment in The Netherlands evaluated the influence of pH and N on interactions between Foc (both Race 1 and Tropical Race 4) and Cavendish bananas. Results in both experiments showed that soil pH affected crop development and the disease. Besides, the interaction of the lower pH x the higher N accelerated the infection and reduced plant development. As such, the results showed that soil management has the potential to reduce the impacts of Fusarium wilt while dealing with Race 1 and Tropical Race 4 although it requires confirmation and further evaluation under field conditions.

Nitrogen fertilizer rate but not form affects the severity of Fusarium wilt in banana

“…In Foc inoculated plants, disease severity was positively correlated with N fertilizer rate in either N form irrespective of changes to soil pH, resulting in curvilinear growth response to increased N (Figure 1). This result agrees with previous findings that N is positively correlated with disease severity of both Foc Race 1 and Tropical Race 4 (Segura-Mena et al, 2021;Teixeira et al, 2021), though disagrees with the general trend that acidification associated with the ammonium use increases Fusarium wilt and FWB severity, whereas nitrate use is protective (Orr and Nelson, 2018). δ 13 C was also positively associated with the N rate in both inoculated and disease-free plants indicating that water use efficiency of photosynthesis, of which δ 13 C is a proxy (Farquhar et al, 1982), was affected by N availability as expected (Evans, 1989) but not by the presence of water restricting wilt symptoms.…”

“…Separating the effect of N rate from the effect of pH decline caused by ammonium on Fusarium wilt disease symptoms and the growth of Foc is difficult (Orr and Nelson, 2018 ; Segura-Mena et al, 2021 ). Organisms differ in their capacities to function at low pH.…”

“…Indeed, field trials have sown a greater influence of N fertilizer form on FWB severity at low pH than at high (Jones et al, 1975 ). Segura-Mena et al ( 2021 ) found that the addition of ammonium nitrate fertilizer increased FWB severity, but less so at pH 5.1 than at 6.1. Only one soil-based study, performed on tomatoes, maintained similar pH between different N fertilizer forms and found nitrate to be significantly more suppressive to disease than ammonium (Woltz et al, 1992 ), suggesting a mechanism independent of pH.…”

“…The use of N fertilizer has substantial benefits, but also some detrimental effects. Excessive N use has been found to increase the severity of diseases such as Fusarium wilt of banana (FWB) (Pittaway et al, 1999 ; Mur et al, 2017 ; Segura-Mena et al, 2021 ). Disease severity is governed by the three-way relationship between host, pathogen and the environment (Agrios, 2005 ), with N supply an especially important environmental aspect in the context of FWB.…”

Soil Microbes Determine Outcomes of Pathogenic Interactions Between Radopholus similis and Fusarium oxysporum V5w2 in Tissue Culture Banana Rhizospheres Starved of Nitrogen, Phosphorus, and Potassium

“…This manifested in the form of enhanced root piece colonization under the three nutrient deficient regimes (Ochieno, 2010(Ochieno, , 2020. F. oxysporum V5w2 was expected to cause wilt symptoms (Ochieno, 2020), which are related to pathogenicity of F. oxysporum races in susceptible banana cultivars (Dita et al, 2018;Maryani et al, 2019;Segura-Mena et al, 2021). However, there was no basis for linking F. oxysporum V5w2 with wilt-related pathogenicity in the N-starved banana plants.…”