Integrating new variables into a framework to support cacao denomination of origin: a case study in Southwest Colombia.

BACKGROUND: Cocoa quality plays a pivotal role in establishing denominations of origin, with genotypes, geography, climate and soil conditions being key variables. However, these factors have not been comprehensively explored in defining cacao denominations of origin. The present study addresses this gap by laying the foundation for cacao denomination of origin, focusing on the Buenaventura region on Colombia's Pacific coast. Our goal is to provide a holistic understanding of the elements underpinning cacao denomination of origin, emphasizing Buenaventura's unique cocoa quality and geographical significance. RESULTS: Through the Buenaventura case, we propose a robust framework applicable to other cacao-producing regions, elevating the recognition and value of cacao denomination of origin. Our framework encompasses geography, agronomy, genetics, microbial diversity, pests and diseases and cocoa quality. In a pioneering move, we propose a cacao denomination of origin in Colombia, specifically examining Bajo Calima, Sabaletas and Cisneros within Buenaventura region. Buenaventura stands out for its cocoa quality, characterized by fruity flavors attributed to the rich biodiversity of the lowland rainforest. CONCLUSION: Our analysis indicates specific geographical indicators for each of the study zones, with Buenaventura identified as a region with natural characteristics to produce fine flavour cocoa products. Each zone exhibited a high differentiation and diversity of cacao cultivars. Buenaventura has the potential to be designated as a future denomination of origin for cacao from the Pacific region of Colombia, characterized by its unique fruity-aroma chocolates. Our framework is adaptable to other cacao-producing regions, facilitating the establishment of denominations of origin within the cocoa industry and agriculture. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

A scarab beetle (Coleoptera: Scarabaeidae) causes tree mortality, delayed growth, and yield reduction in cacao with genotype-specific susceptibility to herbivory.

BACKGROUND: This study explored the impact of Leucothyreus femoratus, a previously unreported folivorous pest in cacao cultivation, on cacao tree survival, development, and yield. The study was conducted in an experimental cacao plot in the Colombian plains, it featured 20 cacao genotypes in an agroforestry system, with plantain and Mexican sunflower providing temporary shade, and yopo offering permanent shade. RESULTS: We found an infestation rate of 2.9 ± 0.3 adult beetles per cacao tree. L. femoratus larvae were discovered in association with the roots of all plants within the agroforestry arrangement; however, yopo and plantain exhibited the highest incidence of root-feeding larvae among these associated plants. Interestingly, male and female L. femoratus displayed distinct leaf consumption patterns in the laboratory, with females consuming more foliage relative to their body weight. Moreover, field observations highlighted the detrimental impact of L. femoratus herbivory on cacao tree survival and growth, leading to leaf skeletonization, reduced plant height, and stem diameter. Trees with over 50% leaf consumption suffered more than 20% mortality. Additionally, herbivory negatively affected cacao yield, correlating higher leaf surface damage with a decrease in harvested pods. The study also identified varying antixenotic resistance in different cacao genotypes, with some consistently displaying resistance while others showed variable levels during tree establishment and production stages. CONCLUSION: This research underscores the significant role of L. femoratus as a cacao pest, emphasizing its adverse effects on cacao tree survival, development, and yield. Consequently, implementing effective control measures is vital for ensuring sustainable cacao cultivation. © 2023 Society of Chemical Industry.

Cacao (Theobromacacao L.) climate zones and its associated agrobiodiversity in Arauca, Colombia.

Background: Cacao (Theobromacacao L) is one of the most relevant crops in terms of economy and social rural development in Colombia. Cacao is also an important crop due to its potential to replace illicit crops and it is related to less deforestation and preserves the biodiversity. There are several cacao districts in Colombia, one of these being Arauca. The Department of Arauca is the second largest cocoa producing region in Colombia; however, it is heavily affected by armed conflict. To raise the knowledge and technology available in the region, integrating data on the occurrence of cacao farms with climatic variables becomes a powerful socioeconomic mapping tool for maintaining agrobiodiversity and food security in the region. Consequently, this type of agrodiversity data and agroclimatic approaches help to better manage agrobiodiversity, as in the cacao region of Arauca. These tools are even more relevant in biodiverse regions, such as flooded savannahs and tropical forest ecosystems, which are currently undergoing drastic changes due to agricultural expansion and climate change. One of the knowledge gaps in Colombia´s cacao regions is that there are currently no agroclimatic maps made with a social and scientific approach. This study aimed to provide a database of the spatial distribution of cacao farms in Arauca, as well as agroclimatic maps that identify and locate cacao climate regions in Arauca. We also present a presence-only matrix consisting of twenty-six tree species, or agrobiodiversity, distributed across the study region and specifically associated with the cacao forestry systems in Arauca. New information: We present the first database of both climate and agrobiodiversity data related to cacao farms in Arauca, developed with a research and socioeconomic vision that generated a novel approach for the agroclimatic zoning of cocoa in the Arauca Region and Colombia. Using 1,538 cacao farms at the regional scale, we identified two national and six regional-scale climate and soil regions. The selection at the local scale allowed us to classify 180 cacao farms comprising nine agroclimatic clusters in Arauca. We found twenty-six tree species distributed across the cacao climate zones. This dataset and its related maps also represent the agrobiodiversity of cultivated cacao locally. This is the most complete climate and agrobiodiversity dataset of cacao farms distribution in one of the top cocoa-producing regions in the country. These outputs are crucial because they constitute a baseline for developing research in the biodiversity of agroforestry systems, pests and diseases, pollutant presence, genetics, post-harvest processing and cocoa quality and safety.

A Framework for the Selection of Plant Growth-Promoting Rhizobacteria Based on Bacterial Competence Mechanisms.

The use of plant growth-promoting rhizobacteria (PGPR) is increasingly meaningful for the development of more environmentally friendly agricultural practices. However, often the PGPR strains selected in the laboratory fail to confer the expected beneficial effects when evaluated in plant experiments. Insufficient rhizosphere colonization is pointed out as one of the causes. With the aim of minimizing this inconsistency, we propose that besides studying plant growth promotion traits (PGP), the screening strategy should include evaluation of the microbial phenotypes required for colonization and persistence. As a model, we carried out this strategy in three Rhizobium sp. strains that showed phosphorus solubilization ability and production of siderophores. All strains displayed colonization phenotypes like surface spreading, resistance to hydrogen peroxide, and formed biofilms. Regarding their ability to persist, biofilm formation was observed to be influenced by pH and the phosphorus nutrient provided in the growth media. Differences in the competence of the strains to use several carbon substrates were also detected. As part of our framework, we compared the phenotypic characteristics of the strains in a quantitative manner. The data analysis was integrated using a multicriteria decision analysis (MCDA). All our results were scored, weighted, and grouped as relevant for PGP, colonization, or persistence. MCDA demonstrated that, when the phenotypes related to PGP and colonization are weighted over those for persistence, strain B02 performs better than the other two Rhizobium sp. strains. The use of our framework could assist the selection of more competent strains to be tested in greenhouse and field trials.IMPORTANCE Numerous plant growth-promoting rhizobacteria (PGPR) have been inoculated into the soil with the aim of improving the supply of nutrients to crop plants and decreasing the requirement of chemical fertilizers. However, sometimes these microbes fail to competitively colonize the plant roots and rhizosphere. Hence, the plant growth promotion effect is not observed. Here, we describe a new screening strategy aiming at the selection of more competent PGPR. We evaluated bacterial phenotypes related to plant growth promotion, colonization, and persistence. Our results demonstrated that despite the fact that our Rhizobium sp. strains successfully solubilized phosphorus and produced siderophores, their abilities to spread over surfaces, resist hydrogen peroxide, and form biofilms varied. Additionally, a multicriteria decision analysis was used to analyze the data that originated from bacterial physiological characterizations. This analysis allowed us to innovatively evaluate each strain as a whole and compare the performances of the strains under hypothetical scenarios of bacterial-trait requirements.

Aphid-infested beans divert ant attendance from the rosy apple aphid in apple-bean intercropping.

Ecological intensification of cropping systems aims at restoring multi-functionality while supporting current productivity levels. Intercropping is a form of ecological intensification involving ecological processes beneficial to farmers that do not take place in monocultures. Thus, it represents a practical approach to decrease the use of synthetic inputs such as insecticides in cultivated systems. Whereas insecticide reduction via intercropping-facilitated suppression of aphids is reported in literature, the majority of published studies focussed on herbaceous crops. Thus, the effect of intercropping on aphid populations of cultivated trees remains largely unaddressed. In this study we hypothesized that intercropping a specific companion plant within perennial crops would divert ant attendance from an aphid attacking the crop to another aphid feeding on the newly introduced plant, reducing aphid damage on the crop. We tested our hypothesis in the system of apple (Malus domestica Borkhausen), the rosy apple aphid (Dysaphis plantaginea Passerini) and the black garden ant (Lasius niger L.). Bean plants (Vicia faba) with the black bean aphid (Aphis fabae Scopoli) were intercropped within apple trees inoculated with D. plantaginea. We measured ant attendance, aphid development and survival as well as honeydew composition on both plant species through semi-field and field experiments. The majority of ants chose to attend A. fabae over D. plantaginea in the semi-field experiment with potted plants. In the orchard, a larger majority of scouts were scored on A. fabae over D. plantaginea. A higher number of D. plantaginea colonies remained active in the apple control, whilst they were almost eradicated by intercropping. Although chemical analyses of honeydew disclosed differences in the carbohydrate and amino acid profiles between aphid species, the difference in honeydew composition did not explain the preference for A. fabae. Ants did not discriminate between the two honeydew mimics both in laboratory and field bioassays. Our results showed the potential of intercropping apple trees with beans as a method to reduce ant attendance and thus colony survival. We propose that intercropping represents a bottom-up approach towards ecological intensification of perennial crops. Together with other ecosystem-based measures such as habitat management, intercropping should be considered when planning ecosystem redesign to increase biological control of pests.

Recruiting on the Spot: A Biodegradable Formulation for Lacewings to Trigger Biological Control of Aphids.

Upon herbivory, plants release herbivore-induced plant volatiles (HIPVs), which induce chemical defenses in the plant as well as recruit natural enemies. However, whether synthetic HIPVs can be employed to enhance biological control in a cultivated crop in the field is yet to be explored. Here we show that a biodegradable formulation loaded with induced and food-signaling volatiles can selectively recruit the common green lacewing, Chrysoperla carnea, and reduce pest population under field conditions. In apple orchards, the new formulation attracted lacewing adults over a 4-week period, which correlated well with independent assessments of the longevity of the slow-release matrix measured through chemical analyses. In barley, lacewing eggs and larvae were significantly more abundant in treated plots, whereas a significant reduction of two aphid species was measured (98.9% and 93.6% of population reduction, for Sitobion avenae and Rhopalosiphum padi, respectively). Results show the potential for semiochemical-based targeted recruitment of lacewings to enhance biological control of aphids in a field setting. Further research should enhance selective recruitment by rewarding attracted natural enemies and by optimizing the application technique.

Methods to identify the prey of invertebrate predators in terrestrial field studies.

Predation is an interaction during which an organism kills and feeds on another organism. Past and current interest in studying predation in terrestrial habitats has yielded a number of methods to assess invertebrate predation events in terrestrial ecosystems. We provide a decision tree to select appropriate methods for individual studies. For each method, we then present a short introduction, key examples for applications, advantages and disadvantages, and an outlook to future refinements. Video and, to a lesser extent, live observations are recommended in studies that address behavioral aspects of predator-prey interactions or focus on per capita predation rates. Cage studies are only appropriate for small predator species, but often suffer from a bias via cage effects. The use of prey baits or analyses of prey remains are cheaper than other methods and have the potential to provide per capita predation estimates. These advantages often come at the cost of low taxonomic specificity. Molecular methods provide reliable estimates at a fine level of taxonomic resolution and are free of observer bias for predator species of any size. However, the current PCR-based methods lack the ability to estimate predation rates for individual predators and are more expensive than other methods. Molecular and stable isotope analyses are best suited to address systems that include a range of predator and prey species. Our review of methods strongly suggests that while in many cases individual methods are sufficient to study specific questions, combinations of methods hold a high potential to provide more holistic insights into predation events. This review presents an overview of methods to researchers that are new to the field or to particular aspects of predation ecology and provides recommendations toward the subset of suitable methods to identify the prey of invertebrate predators in terrestrial field research.

Soil application of Beauveria bassiana GHA against apple sawfly, Hoplocampa testudinea (Hymenoptera: Tenthredinidae): Field mortality and fungal persistence.

Low impact alternatives to synthetic insecticides for the control of apple sawfly (Hoplocampa testudinea Klug) are scarce encumbering pest management in organic apple orchards. We investigated the soil persistence and field efficacy of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin (BotaniGard) against apple sawfly under common organic orchard practices. We also assessed the efficacy of B. bassiana GHA and Metarhizium brunneum Petch (indigenous strain) against sawfly in the laboratory. Larvae treated with either fungus in the laboratory died faster than control larvae and displayed 49.4%-68.4% mycosis. In the field, B. bassiana density remained high in the week after application, during larval descent to the soil. Fungal density decreased to 25% at 49 d after application and to 0.4% after 55 weeks. Molecular markers revealed that the majority of fungal isolates recovered comprised the applied B. bassiana strain GHA. Larvae pupating in soil cages in the orchard for 49 d displayed 17% mycosis. The high efficacy under laboratory conditions was not seen in the field. B. bassiana application resulted in densities above the upper natural background level during the growing season, but reversion to background levels occurred within a year. It remains to be investigated whether this has a detrimental effect on nontarget organisms. Additional work is needed to bridge the knowledge gap between laboratory and field efficacy in orchards.

Analysis of the pathogenic potential of nosocomial Pseudomonas putida strains.

Pseudomonas putida strains are ubiquitous in soil and water but have also been reported as opportunistic human pathogens capable of causing nosocomial infections. In this study we describe the multilocus sequence typing of four P. putida strains (HB13667, HB8234, HB4184, and HB3267) isolated from in-patients at the Besançon Hospital (France). The four isolates (in particular HB3267) were resistant to a number of antibiotics. The pathogenicity and virulence potential of the strains was tested ex vivo and in vivo using different biological models: human tissue culture, mammalian tissues, and insect larvae. Our results showed a significant variability in the ability of the four strains to damage the host; HB13667 did not exhibit any pathogenic traits, HB4184 caused damage only ex vivo in human tissue cultures, and HB8234 had a deleterious effect in tissue culture and in vivo on rat skin, but not in insect larvae. Interestingly, strain HB3267 caused damage in all the model systems studied. The putative evolution of these strains in medical environments is discussed.

Mating disruption of Spilonota ocellana and other apple orchard tortricids using a multispecies reservoir dispenser.

BACKGROUND: A new mating disruption formulation for population control of a wide range of tortricid pests, including Spilonota ocellana, was tested in Swedish apple orchards during 2012-2013. Owing to the characteristics of the local agricultural landscape, mating disruption was evaluated in isolated orchards rather than through an area-wide approach. Parameters such as trap shutdown, communication disruption in field cages, damage level and dispenser emission were measured as efficacy indicators. RESULTS: The test formulation reduced the catches in monitoring traps for the entire range of the tested species. In field cages, communication between sexes was disrupted for both Adoxophyes orana and Cydia pomonella. The fruit damage caused by leafrollers (including S. ocellana) was reduced by the treatment. The device showed a constant release of all components for the entire flight activity period of these pests. CONCLUSION: Single-orchard experiments showed a significant effect on field populations of the leafroller species complex. While promising, in light of the variability of the result, field scouting may be required to enable practitioners to estimate the density of the pests and avoid possible unexpected attacks. Additional experiments are needed to evaluate the efficacy of the product against C. pomonella.

Antibiotic resistance determinants in a Pseudomonas putida strain isolated from a hospital.

Environmental microbes harbor an enormous pool of antibiotic and biocide resistance genes that can impact the resistance profiles of animal and human pathogens via horizontal gene transfer. Pseudomonas putida strains are ubiquitous in soil and water but have been seldom isolated from humans. We have established a collection of P. putida strains isolated from in-patients in different hospitals in France. One of the isolated strains (HB3267) kills insects and is resistant to the majority of the antibiotics used in laboratories and hospitals, including aminoglycosides, ß-lactams, cationic peptides, chromoprotein enediyne antibiotics, dihydrofolate reductase inhibitors, fluoroquinolones and quinolones, glycopeptide antibiotics, macrolides, polyketides and sulfonamides. Similar to other P. putida clinical isolates the strain was sensitive to amikacin. To shed light on the broad pattern of antibiotic resistance, which is rarely found in clinical isolates of this species, the genome of this strain was sequenced and analysed. The study revealed that the determinants of multiple resistance are both chromosomally-borne as well as located on the pPC9 plasmid. Further analysis indicated that pPC9 has recruited antibiotic and biocide resistance genes from environmental microorganisms as well as from opportunistic and true human pathogens. The pPC9 plasmid is not self-transmissible, but can be mobilized by other bacterial plasmids making it capable of spreading antibiotic resistant determinants to new hosts.