Ceratocystis cacaofunesta is the etiologic agent of “Ceratocystis wilt of cacao”, an irreversible disease that affects the vascular system of the plant. The management of the disease is difficult and economic and alternative solutions are needed. The medicinal plants compounds are known to have antimicrobial activity, and they could be an alternative choice in the C. cacaofunesta control. Considering this, this work aimed to verify the in vitro antifungal activity of aqueous and alcoholic solutions of Adiantum latifolium leaves on C. cacaofunesta. Plant material was collected at Atlantic Forest biome in cacao cultivation area in South of Bahia state. Aqueous and ethanolic solutions were made by boiling and maceration in 70% ethanol, respectively. After filtration, they were added to culture medium at 1, 5 and 10% dilution. A 7 mm disc colony of C. cacaofunesta was inoculated in the middle of the well containing Sabouraud dextrose agar (SDA) and the mycelial growth was observed. Controls consisted on SDA with sterile water or 70% ethanol at the same dilution of treatments, and Tebuconazole at 4 μg.mL-1. Neither aqueous nor ethanolic solutions inhibited the mycelial growth. However, aqueous solution presence induced a higher mycelial growth rate. Conversely, aqueous solution treatment induced mycelial growth. Tebuconazole showed important mycelial growth inhibition and it could be considered in C. cacaofunesta propagation control in areas where genetic selection or handling management still fail.

Cacao farmers use macerated Theobroma cacao pod husks as biofertilizer for restoration of environmentally important soil elements, i.e., N, P, K, Na, Mg, and Ca. The increasing popularity of this organic material for soil management justifies to experimentally ascertaining that its application does not produce environmental or human health risks. We therefore applied a battery of biological tests to assess possible health risks related to the extract of fermented cacao pod husks [CHE]. Minimal inhibitory concentration for selected bacteria and fungi was established and an antiviral assay (equine herpes virus -EHV-1) and insecticide assay (Aedes aegypti larvae), to observe possible environmental impact. Toxicity tests used Artemia salina, hemolytic activity and cytotoxicity were tested using HT-29 e Vero cells, respectively. Genotoxicity and anti-genotoxic activity was tested in the comet assay of leukocytes and a selection of Saccharomyces cerevisiae mutants allowed look for a possible interference of CHE with defined metabolic pathways. None of these established tests used to define toxicity and genotoxicity of chemical compounds indicated that CHE contained substances that would pose such risks. Our safety assessment on bacteria and yeasts, virus, insect larvae, and human leukocytes [3-(4,5-di-methylazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and comet assay] thus indicated that macerated cocoa pod husk can be safely used as biofertilizer.

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ABBREVIATION: minimal inhibition concentration (MIC) and minimal bactericidal concentration (MBC); brain heart infusion (BHI); agar nutrient (AN); Ampicyllin (AMP); Cefepime (CPM); Ampicyllin+Sulbactam (ASB); Chloramphenicol (CHLO); Cyprofloxacin (CYP); Gentamycin (GEN); Amoxicyllin+Clavulanic acid (AMC); Amicacyn (AMI); Cefixime (CFM); Penicillin (PEN); Hexane (Hex), chloroform (CHLO), ethyl acetate (EtAc), methanolic (MeOH); ethanolic residue (EtOHr).