Ecuador is one of the major cocoa producers worldwide, but its productivity has lately been affected by diseases. Endophytic biocontrol agents have been used to minimize pathogenic effects; however, compounds produced by endophytes are minimally understood. This work presents the chemical characterization of the Trichoderma species extracts that proved inhibition against cocoa pathogens. Solid–liquid extraction was performed as a partitioning method using medium with the fungal mycelia of Trichoderma reesei (C2A), Trichoderma sp. (C3A), Trichoderma harzianum (C4A), and Trichoderma spirale (C10) in ethyl acetate individually. The extract of T. spirale (C10) exhibited the growth inhibition (32.97–47.02%) of Moniliophthora perniciosa at 10 µg/mL, while a slight stimulation of Moniliophthora roreri was shown by the extracts of T. reesei (C2A) and T. harzianum (C4A) at higher concentrations. The inhibitory activity could be related to alkaloids, lactones, quinones, flavonoids, triterpenes, and sterols, as indicated by chemical screening and antifungal compounds, such as widdrol, β-caryophyllene, tyrosol, butyl isobutyrate, sorbic acid, palmitic acid, palmitelaidic acid, linoleic acid, and oleic acid, which were identified by gas chromatography–mass spectrometry (GC-MS). The results showed that the extracts, particularly T. spirale (C10), have the potential as biocontrol agents against witches’ broom disease; however, further studies are needed to confirm their effectiveness.

One of the main problems in the production of cacao in Ecuador is the disease caused by the fungus Moniliophthora roreri (frosty pod rot) which affects the pods. Here, we evaluate the genetic diversity of this fungus in Ecuador, and its sensitivity to the fungicide azoxystrobin. We evaluated 76 monosporic cultures from the Amazon and the Pacific coast regions. In vitro sensitivity assays tested several doses of the fungicide azoxystrobin to determine the percent of growth inhibition and the IC₅₀. Concentrations of 1 to 0.1 µg mL⁻¹ inhibited the growth of at least 91% of the isolates. Three isolates were the less sensitive (IC₅₀ = 0.0220–0.0364 µg mL⁻¹), two from Guayas (Pacific coast) and one from Sucumbíos (Amazon) provinces. However, M. roreri is highly sensitive, and it could be used in integrated management of the disease. Genetic analyses were carried out by amplifying microsatellite markers (SSR). All the genetic diversity statistics show a higher diversity in the Amazon compared to samples of the coast region; however, the molecular variance was low (F_ST = 0.11). Discriminant analysis clearly distinguishes three clusters concurrent with the provinces (Sucumbíos, Orellana and El Oro) and a group with the rest of the provinces. Minimum spanning networks shows, unexpectedly, that M. roreri from the coast were derived from at least three independent introductions from the Amazon. Findings are discussed in light of previous Pan-American genetic studies and available historical reports.

Rice (Oryza sativa) plays a fundamental role in the Ecuadorian diet. This study evaluated traceability and contamination by heavy metals in two rice-producing areas of Ecuador. Microwave-assisted digestion was used to process samples from rice agrosystems including irrigation water, soil, roots, stems, and leaves. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was employed for elemental analysis. Arsenic (As), cadmium (Cd), lead (Pb), and chromium (Cr) were measured in samples collected in Daule and Ventanas. In soils, the concentrations of As (1.50–2.82 mg/kg) and Cd (1.22–1.45 mg/kg) exceeded the internationally recommended safety thresholds. In irrigation water, the content of As (0.85–1.12 mg/L), Pb (0.25–0.38 mg/L), and Cr (0.37–0.53 mg/L) surpass the international/national permissible limits. However, the limits established by Ecuadorian legislation indicate that As in soils did not exceed contamination thresholds. Additionally, the bioaccumulation of As and Pb in roots from Daule and Ventanas, respectively, was observed, along with the movement of Pb to aerial parts in Daule. Finally, preliminary As found in commercial rice grains suggest a potential health concern to the Ecuadorian population. These findings highlight the need for stricter heavy metal restrictions for rice agrosystems and effective agricultural pollution mitigation.