Increased <i>Hirsutella citriformis</i> Conidia Shelf Life in <i>Acacia</i> and <i>Hirsutella</i> Gum Formulations

Biological control by beneficial microorganisms is known to significantly reduce the effect of pests on crops yield. Among the biocontrol strategies is the use of entomopathogenic fungi such as <i>Hirsutella citriformis</i>, which has been applied to infect and kill hemipteran insect pes...

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Bibliographic Details
Main Authors: Rosa A. Flores-Villarreal, Alonso A. Orozco-Flores, Servando H. Cantú-Bernal, Ricardo Gomez-Flores, Orquídea Pérez-González, Patricia Tamez-Guerra
Format: Article
Language:English
Published: MDPI AG 2023-07-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/13/13/7912
Description
Summary:Biological control by beneficial microorganisms is known to significantly reduce the effect of pests on crops yield. Among the biocontrol strategies is the use of entomopathogenic fungi such as <i>Hirsutella citriformis</i>, which has been applied to infect and kill hemipteran insect pests, including <i>Diaphorina citri</i> Kuwayama (Hemiptera: Liviidae) and <i>Bactericera cockerelli</i> Sulc. (Hemiptera: Triozidae). These biological agents are applied in the form of conidia that are often combined with other inert materials to facilitate application, protect conidia, and improve their shelf life. The aim of this study was to implement strategies for developing formulations to increase conidia shelf life. We evaluated gum produced from one strain and conidia from two different <i>H. citriformis</i> strains. Conidia were formulated by evaluating different concentrations of <i>Acacia</i> and <i>Hirsutella</i> gums to enhance conidia viability during storage at 4 °C or 25 °C. Results indicated that formulations maintained conidia viability for at least 90 d after storage at 25 °C (≥70% viability) and at least 120 d after storage at 4 °C, which was significantly (<i>p</i> ≤ 0.05) higher than that of the control, without observing changes in pH values. We also demonstrated 100% formulation purity from days 0 to 120, among all treatments. In conclusion, evaluated formulations maintained <i>H. citriformis</i> conidia viability for at least three months, when stored at 4 °C.
ISSN:2076-3417