Essential oils control anthracnose in pepper seeds

Daniele Maria Do Nascimento,Paula Leite Dos Santos,Marcos Roberto Ribeiro-Junior,Adriana Zanin Kronka,Maria Márcia Pereira Sartori

doi:10.33448/rsd-v9i10.9028

Daniele Maria Do Nascimento, Paula Leite Dos Santos + Show 3 more

Open Access

https://doi.org/10.33448/rsd-v9i10.9028

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Abstract

Pepper (Capsicum annum) is one of the main vegetables consumed in the Brazilian market, however, an important fungal disease, anthracnose, caused by Colletotrichum gloeosporioides, can decimate all its fruits in the field. Chemical control is the most commonly used measure of control, but, some active ingredients are proving ineffective, and consumers appreciate healthier options such as organic foods. Therefore, studies with natural substances that may help in the management of diseases have been encouraged. Because it is transmitted via seed, seed treatment becomes an essential measure in the management and control of pepper anthracnose. The objective of this study was to evaluate the effect of basil (Ocimum basilicum), citronella (Cymbopogon winterianus), clove (Syzygium aromaticum), copaiba (Copaifera langsdorfii), eucalyptus (Eucalyptus citriodora), mint (Mentha arvensis), rosemary (Rosmarinus officinalis) and tea tree (Melaleuca alternifolia) essential oils on the development of C. gloeosporioides. Citronella, clove, eucalyptus, mint and basil essential oils totally inhibited the pathogen, regardless of the concentration used. These essential oils were then used to treat seeds infected with C. gloeosporioides, evaluating the physiological and health quality of these seeds. Clove essential oil reduced the incidence of fungi in seeds inoculated with the pathogen, without affecting their physiological quality.

Highlights

Anthracnose, caused by Colletotrichum species, infects over 3000 species of plants worldwide (O’Connell et al, 2012), including the Solanaceae family
Except for the essential oils of rosemary and copaiba, at 0.25%, in the first assay, all other treatments differed from the control by Dunnet test, promoting a decrease in mycelial growth
Concentrations higher than 0.25% of tea tree essential oil inhibited the radial growth of C. gloeosporioides completely

Summary

Introduction

Anthracnose, caused by Colletotrichum species, infects over 3000 species of plants worldwide (O’Connell et al, 2012), including the Solanaceae family. Wet season and fields with a history of pathogen incidence favor the development of the disease, and 100% of the pepper fruits can be affected (Pavan et al, 2016). Current management strategies for the anthracnose control are not efficient, because Colletotrichum species have acquired resistance to commonly used fungicides, such as azoxystrobion and thiabendazole (Kumar & Kudachikar, 2018; Torres-Calzada et al, 2013). This fungus can be transmitted via seeds (Pavan et al, 2016), which is an important source of inoculum, introduction and dissemination of the pathogen, making. In greenhouse experiments, Bi et al (2012) showed that oregano, red thyme and palmarosa essential oils reduced Phytophthora capsici population in soil and protected zucchini fruit against the pathogen. Chaijuckam and Davis (2010) found that cinnamon oil has potential to control Rhizoctonia oryzae-sativa, the cause of aggregate sheath spot disease in rice. Dagostin et al (2010) demonstrated that Salvia officinalis extract can protect grapevine against Plasmopara viticola in both greenhouse and field experiments

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