Antifungal Activity of ZnO and MgO Nanomaterials and Their Mixtures againstColletotrichum gloeosporioidesStrains from Tropical Fruit

Susana C De La Rosa-García,Nikte M Gómez-Ortíz,Patricia Quintana,Sergio Gómez-Cornelio,Mario Alberto Corral-Aguado,Pablo Martínez-Torres

doi:10.1155/2018/3498527

Abstract

Avocado (Persea americana) and papaya (Carica papaya) are tropical fruits with high international demand. However, these commercially important crops are affected by the fungusColletotrichum gloeosporioides, which causes anthracnose and results in significant economic losses. The antifungal activity of metal oxide nanomaterials (zinc oxide (ZnO), magnesium oxide (MgO), and ZnO:MgO and ZnO:Mg(OH)2composites) prepared under different conditions of synthesis was evaluated against strains ofC. gloeosporioidesobtained from papaya and avocado. All nanoparticles (NPs) at the tested concentrations significantly inhibited the germination of conidia and caused structural damage to the fungal cells. According to the radial growth test, the fungal strain obtained from avocado was more susceptible to the NPs than the strain obtained from papaya. The effect of the tested NPs on the fungal strains confirmed that these NPs could be used as strong antifungal agents againstC.gloeosporioidesto control anthracnose in tropical fruits.

Highlights

Colletotrichum gloeosporioides is a phytopathogenic agent that causes anthracnose disease in several fruits and crops, including avocado, papaya, mango, pitaya, tomatoes, citrus, and almonds, among others [1,2,3]
The minimum inhibitory concentrations (MICs) were equal to the minimum fungicidal concentration (MFC), indicating that the action of the NPs was fungicidal
With respect to the antifungal activity of the NPs against the C. gloeosporioides strains isolated from papaya (PG-16) and avocado (AP-14), we found that a MIC of 0.312 mg/mL was required to totally inhibit strain AP-14, independently of the type of NP (Table 2)

Summary

Introduction

Colletotrichum gloeosporioides is a phytopathogenic agent that causes anthracnose disease in several fruits and crops, including avocado, papaya, mango, pitaya, tomatoes, citrus, and almonds, among others [1,2,3]. The anthracnose pathogen invades the leaves, flowers, and fruits during preharvest and invades postharvest fresh products [4]. The severity of the disease is related with environmental conditions. The most severe attacks on fruits or crops occur when crops are most susceptible (e.g., during flowering and/or fruiting) and under conditions of high humidity (e.g., during the rainy season). The symptoms of anthracnose in papaya (Carica papaya L.) include sunken spots of different colors on the leaves and necrosis on the stems, fruits, or flowers, which often result in the wilting or death of plant tissues. Anthracnose does not fully develop until fruits mature yet eventually results in the appearance of sunken necrotic black spots [5]

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Conclusion