Abstract

MIRANDA, Ileana; AREVALO, Jersys  and  HIDALGO-DIAZ, Leopoldo. Response surface methodology to evaluate stability of a biological control agent in storage conditions. Rev. Protección Veg. [online]. 2013, vol.28, n.3, pp. 224-228. ISSN 1010-2752.

Eight formulations elaborated according to combinations of the pure powder of the nematophagous fungus Pochonia chlamydosporia var. catenulata IMI SD 187, zeolite as additive at 50%, 80% or 90%, sealing in absence or presence of atmospheric air, and storage at 4°C or 25°C, for 16 treatments were evaluated. For each treatment, the percentage of humidity and the concentration of viable fungi (UFC.g-1) were measured; for stability identification, Friedman's non-parametric test was used comparing four evaluation times (beginning, 15, 30 and 45 days). By means of the principal component analysis, the main factors influencing chlamydospore germination were identified. Finally, using the response surface methodology, a maximum of germination percentage was identified. In all the treatments, the humidity percentage remained below 10%, but the concentration of viable fungi was stable only in six treatments. Results were not significantly modified by the presence of air in the packages. A point of maximum chlamydospore germination was reached using 30 to 40% of zeolite and the storage at 15°C. A compound central design 10+2x2+2 was recommend to validate the process.

Keywords : Pochonia chlamydosporia; biocontrol; formulation; shelf-life.

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