The use of native Trichoderma strains has been proposed as a sustainable alternative to control cocoa diseases. The aim of this study was to assess indigenous Trichoderma strains from Bagua Province, Peru, with reference to their antagonistic characteristics in vitro and their potential for in vitro biocontrol against frosty pod rot (FPR) disease. A total of 199 strains were assessed for in vitro mycoparasitism, antibiosis, and potential antagonism. The effect of four strains was evaluated in vitro using epidemiological variables, yield, and efficacy at two sites (Copallín and La Peca). Significant differences (p < 0.05) were reported for all variables evaluated in vitro and in vitro. Mycoparasitism ranged from 32% to 100%, antibiosis from 33.36% to 57.92%, and potential antagonism from 42.36% to 78.64%. All strains were found to affect the in vitro-assessed parameters in addition to enhancing the productive yield. The efficiency ranged from 38.99% to 71.9% in Copallín, and 45.88% to 51.16% in La Peca. The CP24-6 strain showed the highest potential for biocontrol under field conditions when considering its effect on both sites.
Cacao plant cadmium accumulation has become a major concern, especially for small Amazonian producers. A sustainable alternative to address its toxicity is the use of cadmium removal bacteria. In this regard, 138 rhizosphere isolates from cacao were examined. Supported by their phenotypic characterization and in vitro cadmium tolerance, three hypertolerant bacteria were selected and identified as members of the Bacillus (S1C2, R1C2) and Pseudomonas (V3C3) genera. They were able to grow normally and reduce the cadmium content under in vitro conditions. However, only S1C2 and R1C2 evidenced to employ intracellular Cd2+ accumulation, suggesting the variability of bacterial detoxification mechanisms. Their bioremediation capacity for Theobroma cacao CCN51 was also analyzed. Surprisingly, we found high detectable levels of Cd2+ in the non-cadmium supplemented control, suggesting an extra source of cadmium in the pot. Moreover, despite their cadmium reduction performance under in vitro conditions, they exerted highly variable outcomes on stem cadmium accumulation. While S1C2 and R1C2 showed a considerable reduction of Cd content in cacao stems, the strain V3C3 did not show any effect on Cd content. This highlights the complexity of the plant–bacteria interactions and the importance of the in vivo test for the selection of promising PGPR bacteria. Overall, our results suggest the cadmium alleviation potential and promising prospects of native Bacillus strains associated with Amazonian cacao.
30 September 2023 in International Journal of Agronomy
Coffee (Coffea arabica) is the main commodity in Peru and is the economic support for thousands of small farmers. However, coffee production is affected by the coffee berry borer (Hypothenemus hampei). Currently, H. hampei is the most important pest in whole coffee-growing regions in Peru. This study aimed to evaluate in vitro biological activity of Beauveria bassiana, Beauveria peruviensis, and Metarhizium sp. against Hypothenemus hampei in two trials at different times. Conidia production, Conidia viability, and pathogenicity against H. hampei were evaluated at three concentrations (1 × 105, 1 × 107, and 1 × 109 conidia/mL−1). In addition, lethal times (LT50 and LT90) and lethal concentrations (LC50 and LC90) were calculated. There were significant differences in conidia production ( < 0.001) and conidia viability ( < 0.041). The highest conidia production and conidia viability were reached by B. bassiana and B. peruviensis, respectively. Likewise, there were differences in the pathogenicity of the strains in the two tests carried out (test 1: < 0.0009 and test 2: < 0.0001). The highest mortality occurred in the treatments of B. bassiana 1 × 109 conidia/mL−1, B. bassiana 1 × 107 conidia/mL−1, and B. peruviensis 1 × 109 conidia/mL−1. The treatments with lower LT50 and LT90 were B. bassiana 1 × 109 conidia/mL−1 and B. peruviensis 1 × 109 conidia/mL−1, and the strains with the lowest LC50 and LC90 were B. peruviensis and B. bassiana. The in vitro characteristics shown by B. bassiana and B. peruviensis conditions suggest they should be evaluated in the field to determine the capability of these strains to reduce populations of H. hampei.
As part of our study of saproxylic fauna in cocoa (Theobroma cacao Linnaeus, 1753) sites in northern Peru, we present a new record of Xylopsocus capucinus (Fabricius, 1781) in the country. The species X. capucinus is considered an invasive beetle in the Bostrichidae family to Central America. Our report includes biological and ecological data from this site, as well as detailed taxonomic information and images to facilitate identification.
30 June 2026 in International Journal of Tropical Insect Science
Neorthopleura pomahuacensis Hernández-May, Chuquibala-Checan and Leavengood, sp. nov. (Coleoptera: Cleridae: Korynetinae) from Pomahuaca, Peru, is described. This beetle species is named after the locality where it was collected. Similar species are discussed and the lectotype of N. suturalis (Chevrolat, 1874) is illustrated for comparison.