A novel strategy to reduce overwintering inoculum of Monilinia laxa

Abstract

Brown rot on cherry and plum, caused by Monilinia laxa, is an important disease, for which overwintered mummified fruit is a significant inoculum source for infection of flowers and fruit in the spring. Experiments were conducted to assess the potential of applying plant protection products in winter and/or early spring to suppress sporulation on mummified fruit. Products tested included Indar 5 EW (a commercial fungicide, a.i. fenbuconazole), Aureobasidium pullulans Y126 [a candidate biocontrol agent (BCA)]), Bacillus sp. B91 (a candidate BCA) and Serenade (a commercially formulated BCA of Bacillus subtilis strain QST 713) in addition to control treated with tap water. Indar and A. pullulans Y126 significantly reduced sporulation when applied once in winter. Overall, a single treatment in early spring (February) was slightly more effective than single treatment in winter (November). Application of all products in both winter and early spring led to significant reduction in sporulation. Indar had the highest efficacy, reducing the number of spores from 9×10 5 to 5×10 3 per mummified plum when applied twice. Of the three BCAs applied on both occasions, A. pullulans Y126 had the highest efficacy, reducing the number of spores from 9×10 5 to 5×10 4 per mummified plum. There were no synergistic but additive effects between the two applications in winter and early spring based on the Bliss independence test. These results suggest that reducing overwintering inoculum in dormant season is effective and may be part of an integrated management strategy for brown rot on stone fruit.

Biological Control of Lettuce Drop and Host Plant Colonization by Rhizospheric and Endophytic Streptomycetes

“…In contrast, when application of S. sclerotiorum and Streptomyces was postponed until sowing, neither strain was able to reduce disease incidence and improve lettuce survival. The importance of application timing on biocontrol activity of BCAs against apple diseases was also reported for blue mold, bitter rot, and apple scab, as well as for brown rot of cherries and plums (Teixido et al, 1999 ; Poleatewich et al, 2012 ; Rungjindamai et al, 2014 ). For Streptomyces , the production of biocontrol related secondary metabolites is induced or increased when the aerial hyphae appear and sporulation starts (Hopwood, 1988 ; Chater, 1996 ; Pope et al, 1996 ).…”

Bacillus methylotrophicus has potential applications against Monilinia fructicola

“…For example, B. subtilis antagonizes M. fructicola by producing a wide variety of antimicrobial compounds including fengycin, iturin, and surfactin [ 18 , 29 ]. The agent bacillus B91 can significantly reduce the formation of spores [ 30 ]. The agent B. amyloliquefaciens C06 produced two antimicrobial compounds belonging to the iturin and fengycin families, and those two antimicrobial compounds combine to inhibit the conidial germination of M. fructicola [ 31 ].…”