Effects of stabilizers on shelf-life of Epicoccum nigrum formulations and their relationship with biocontrol of postharvest brown rot by Monilinia of peaches

Abstract

Aim: To find a formulation of Epicoccum nigrum conidia that maintains a high viability over time and which proves efficient to biocontrol peach rot caused by Monilinia spp. Methods and Results: We tested the effect of stabilizers and desiccants on the shelf‐life of Epicoccum nigrum conidia. Conidial samples were dried for 40 min at 40°C in a fluidized bed‐dryer to obtain moisture contents <15%. The toxicity of additives was tested by assaying production of conidia in fermentations and germinability of the produced conidia: 50% PEG300, 10%–5% KCl (stabilizers) and 95·24% Cl2Ca (desiccant) significantly (P = 0·05) reduced conidial germination. To enhance shelf‐life of dried conidia, nontoxic stabilizers were added at the following different stages of the production‐drying process: (i) to substrate contained in bags before production, (ii) to conidial centrifuge pellets obtained after production, before filtering and drying, (iii) to conidial centrifuge pellets obtained after production, before adding talc and drying, and (iv) to conidial centrifuge pellets obtained after production, before adding silica powder and drying. Conidial germinability was tested at 0, 180 and 365 days after storage at room temperature. Shelf‐life of formulations retaining the highest viability were conidia produced with 1% KCl or 50% PEG 8000, conidia dried with 2·5% methylcellulose, and conidia dried with 1% KCl + silica powder. All these formulations improved the shelf‐life of E. nigrum conidia and significantly reduced brown rot on peaches. Conclusions: Our results show that additives improve the shelf‐life of E. nigrum and assist controlling brown rot on peaches. Significance and Impact of the Study: New improved formulations of a biocontrol agent have been obtained which will improve the control of Monilinia on peach.

A new oil-based formulation of Trichoderma asperellum for the biological control of cacao black pod disease caused by Phytophthora megakarya

“…This half-life figure is close to that obtained by Batta (2004) with T. harzianum conidia formulated in reverse emulsion (21 weeks). Several studies have found that formulated conidia remain viable for longer periods than non-formulated conidia (Guijarro et al, 2007;Larena et al, 2007;Wijesinghe et al, 2010Wijesinghe et al, , 2011. This prolonged viability is thought to be related to the specific role of the various ingredients of the formulation -in this case glucose and soybean oil.…”

Population dynamics ofEpicoccum nigrum, a biocontrol agent against brown rot in stone fruit

“…1986; Madrigal et al. 1994) and postharvest brown rot caused by M. laxa and M. fructigena in laboratory and field commercial assays (Larena et al. 2005, 2007).…”

New formulation and delivery method ofCryphonectria parasiticafor biological control of chestnut blight

“…The estimated shelf life (DT50) of our hypovirulent Cp 4.2H strain preparation—2·5 months—was shorter than that of the Cp 4.2 virulent one and of other formulated biofungicides (Larena et al . ; Kobori et al . ).…”

“…HPMC has the property of gelation, and unlike methylcellulose used as additive in other biopesticide formulations (Larena et al . ), its hydration is temperature dependent. We hypothesize that such behaviour could enable embedding of the micro‐organism and protection from desiccation, so that revitalization and progressive release of the fungus is easily achieved (Hari et al .…”