Effect of chemical alternatives to methyl bromide on soil‐borne disease incidence and fungal populations in Spanish strawberry nurseries: A long‐term study

Abstract

BACKGROUND Chloropicrin (PIC) mixtures of 1,3‐dichloropropene and chloropicrin (DD:PIC), dazomet, and metam sodium (MS) have been applied as chemical alternatives to methyl bromide (MB) in Spanish strawberry nurseries since MB was banned as a soil fumigant in 2005. These chemical alternatives were applied to soil in two Spanish strawberry nurseries between 2003 and 2017 to test their efficacy against the main crown and root disease and soil fungal populations in comparison with the use of MB and PIC (MB:PIC). These chemicals were applied at several doses with different application methods under plastic films. Crown and root disease incidence was calculated as the percentage of plants with symptoms caused by soil‐borne pathogens. Soil fungal populations were estimated as colony forming units per gram of dry soil. RESULTS All chemicals significantly reduced soil‐borne fungal disease incidence and fungal population in both nurseries over the years. Phytophthora cactorum and Fusarium spp. were the main pathogens causing soil‐borne diseases, followed by Verticillium spp. MB:PIC remained the treatment that best controlled P. cactorum. MS and DD:PIC controlled Fusarium disease to a lesser extent than MB:PIC and dazomet in both nurseries. MB:PIC and PIC were the two treatments that most reduced Verticillium spp. The population of Verticillium spp. declined and the presence of other species such as Colletotrichum spp. and Rhizoctonia spp. was minimal during the study. CONCLUSION Chemicals are necessary to obtain healthy strawberry plants. The use of chemical alternatives to MB has resulted in changes in the incidence of soil‐borne diseases and soil fungal populations in strawberry nurseries. Dazomet was an effective alternative to MB as a soil‐borne disease control, except against Verticillium spp. MB alternatives in strawberry nursery soils have caused Fusarium spp. to displace Verticillium spp.

Efecto de la solarización en patógenos fungosos que afectan al Eucalipto (Eucalyptus urograndis) en condiciones de vivero

“…La integración de fungicidas con la solarización del suelo mostró una menor severidad del "damping off" en el cultivo de ají (Kadam et al, 2018). El dazomet se ha usado en los viveros como alternativa química al bromuro de metilo, encontrándose una reducción significativa sobre la incidencia de enfermedades fúngicas transmitidas por patógenos habitantes del suelo, como lo son los géneros Rhizoctonia y Cylindrocladium (Aiello et al, 2018;Santori et al, 2020;Villarino et al, 2021;Aiello et al, 2022).…”

Dual purpose: Predatory hoverflies pollinate strawberry crops and protect them against the strawberry aphid, Chaetospihon fragaefolii

“…Strawberry, as a crop, tends to be highly sensitive to several diseases and pests, 13 which has led to extensive use of agrochemicals 14 . Growing concern over the intensive use of agrochemicals and their undesirable side‐effects has promoted interest in integrated pest management (IPM) programs that include the use of biological control agents as a complement or an alternative to agrochemicals 15–17 . Biological control agents can be effective for the management of strawberry pests when used preventatively or on the condition that there is early detection and intervention 18,19 .…”

“…14 Growing concern over the intensive use of agrochemicals and their undesirable side-effects has promoted interest in integrated pest management (IPM) programs that include the use of biological control agents as a complement or an alternative to agrochemicals. [15][16][17] Biological control agents can be effective for the management of strawberry pests when used preventatively or on the condition that there is early detection and intervention. 18,19 An exception is found for the specialist strawberry aphid Chaetosiphon fragaefolii, a major strawberry pest worldwide.…”

Ecosystem Services Provided by Cover Crops and Biofumigation in Sunflower Cultivation

“…In the past, the control of diseases caused by soilborne pathogens, including that of verticillium wilt, was based on the use of chemical fumigants such as methyl bromide, especially on high-value vegetable crops [26]. However, such chemical fumigants have been banned from being used in the European Union since 2005 [27]. To limit SVW, the only disease control method available to date relies on varietal resistance [19].…”