Effects of incubation temperature on the organic amendment‐mediated control of Fusarium wilt of tomato

Abstract

Organic soil amendments play important roles in the reduction of plant diseases caused by soil-borne plant pathogens. This study examined the combined effects of concentrations of organic amendments, temperature and period of incubation in soil on the management of Fusarium wilt of tomato caused by Fusarium oxysporum f. sp. lycopersici (Fol). In an experiment with substrate mixture, Fol reduction was higher when the soils were incubated at 35°C than at 30°C. Disease severity was proportionally reduced as the volume of amendment added increased. Furthermore, disease was significantly lower in substrates incubated for 30 days at both temperatures, as compared to substrates incubated for only 15 days. The most effective control was achieved with pelletised poultry manure (PPM). In experiments with natural sandy soil, the effects of amendments on Fol populations, measured by real-time quantitative PCR with TaqMan probes, were significant. The highest decreases in Fol DNA resulted when the soil was amended with 2% PPM and incubated at 35°C. The reductions in DNA concentrations was most likely related to the accumulations of high concentrations of NH 3 (27.3 mM) in soils treated with 2% PPM and incubated at room temperature (RT; 23 ± 2°C), or at 35°C. Severity of plants grown in soils incubated at RT decreased by over 40%, and more than 73% when incubated at 35°C, regardless of the rate of PPM. The results indicate that the management with PPM, when combined with heating or solarisation, is an effective control measure against Fusarium wilt of tomato.

Organic amendments conditions on the control of Fusarium crown and root rot of asparagus caused by three Fusarium spp.

“…This demonstrated a larger effect of temperature for Fs2 than for Fo5 and seems concomitant with sustained increase of total bacteria populations and overall moderate increases of pH and N content in PPM as compared to the other amendments tested (Borrego-Benjumea et al, 2014b). As a matter of fact, the N-richest amendments, with a low C/N ratio, which release and accumulate higher amounts of volatile toxic compounds such as NH 4 and HNO 2 in the soil during organic matter decomposition, are able to eliminate many soilborne fungi (Tsao & Oster, 1981;Tenuta & Lazarovits, 2002;Borrego-Benjumea et al, 2014a). However, amendments with high C/N ratio may be effective in the control of these pathogens because those compounds can stimulate microbial activity, enhancing depletion of N availability, and, consequently, impairing the pathogen infection process (Snyder et al, 1959).…”

“…dianthi and incubated at high temperature before transplanting rooted cuttings of carnation (Nava-Juárez, 2013), but these phytotoxic symptoms were absent from plants growing in greenhouse on soil to which equivalent dosages of PPM were applied (Melero-Vara et al, 2011). The reason is likely that volatile compounds generated by PPM-2%, mainly ammonia, develop more quickly at 30ºC (Lazarovits, 2001;Tenuta & Lazarovits, 2002;Borrego-Benjumea et al, 2014a). To this regard it is interesting the comparison of N content and electrical conductivity between PPM and PM, as those for PPM are, respectively, almost double and 4-times those of PM (Table 1).…”

Effect of different organic amendments on lettuce fusarium wilt and on selected soilborne microorganisms

“…The results of Borrego‐Benjumea et al . () point out the positive effect of a soil application of poultry manure at 1%, incubated at 23 ± 2°C and 35°C, in reducing tomato fusarium wilt by 40 and 95%, respectively. Gamliel & Stapleton () also indicated the ability of composted chicken manure, at 10 t ha −1 , to suppress P. ultimum on lettuce.…”

“…Some of these measures are also exploited to reduce the inoculum density of the pathogen in the soil, a factor that is involved directly in the efficacy of disease suppression. The role of organic amendments in the suppression of soilborne diseases, which involves inducing specific microbial, biological and chemical changes, has been reviewed in several pathosystems (Gamliel & Stapleton, ; Bailey & Lazarovits, ; Bonanomi et al ., ; Termorshuizen, ; Borrego‐Benjumea et al ., ,b; Ascencion et al ., ). In the present study, the impact of amendments based on Brassica , either as plants or dry matter (as pellets and flour), cattle and chicken manure and compost has been evaluated on lettuce fusarium wilt, considering the impact on yield, as well as through an evaluation of the soil bacterial and fungal population dynamics.…”

“…The management of fusarium wilt pathogens, which are responsible for severe losses on a number of economically important crops, has been investigated in recent years, with special attention being paid to the use of measures with a low environmental impact (Blok et al ., ; Reuveni et al ., ; Borrero et al ., ; Klein et al ., ; Gullino et al ., ; Borrego‐Benjumea et al ., ,b; Garibaldi et al ., ; Gilardi et al ., ,b).…”