P. Bayman’s research while affiliated with University of Puerto Rico at Río Piedras and other places

Coffee fruit rot (CFR) is a well-known disease worldwide mainly caused by Colletotrichum spp., the most important species being C. kahawae subsp. kahawae. In Puerto Rico, Colletotrichum spp. were identified as pathogens of coffee fruits. The coffee berry borer (CBB) was shown to be a dispersal agent of these fungi and the role of Fusarium affecting coffee fruits was suggested. In this study we demonstrated that Fusarium spp. also cause CFR in Puerto Rico. Fusarium spp. are part of the CBB mycobiota, and this insect is responsible for spreading the pathogens in coffee fields. We identified nine Fusarium spp. (F. nirenbergiae, F. bostrycoides, F. crassum, F. hengyangense, F. solani-melongenae, F. pseudocircinatum, F. meridionale, F. concolor and F. lateritium) belonging to six Fusarium species complexes isolated from CBBs and from rotten coffee fruits. Pathogenicity tests showed that F. bostrycoides, F. lateritium, F. nirenbergiae, F. solani-melongenae and F. pseudocircinatum were pathogens causing CFR on green coffee fruits. Fusarium bostrycoides was the predominant species isolated from the CBB mycobiota and coffee fruits with symptoms of CFR, suggesting a close relationship between F. bostrycoides and the CBB. To our knowledge, this is the first report of F. bostrycoides, F. solani-melongenae, F. pseudocircinatum and F. nirenbergiae causing CFR worldwide and the first report of F. lateritium causing CFR in Puerto Rico. Understanding the CFR disease complex and how the CBB is contributing to disperse different Fusarium spp. in coffee farms is important to implement disease management practices in Puerto Rico and in other coffee-producing countries.

Anthracnose of coffee fruits caused by Colletotrichum species is responsible for major losses in coffee production worldwide. In most coffee-producing countries, this disease has been present for many years. Recently coffee fruit rot (CFR), a disease complex of Colletotrichum spp. and Fusarium spp. as casual agents, was described in Puerto Rico but it has not yet been quantified. This study surveys incidence and severity of CFR, correlates it to elevation, cultivation methods (full sun, shade or intercalated with taller plants) and the presence of the coffee berry borer (CBB), and identifies rot-associated fungi. We found that CFR is present throughout Puerto Rico at varying levels and that environmental and cultivation factors are associated with CFR incidence and severity. Specifically, increased altitude and shade correlated with lower CFR incidence. In addition, fruits damaged by the CBB were found to have significantly more disease than undamaged fruits. Lastly, we isolated 7 fungal genera associated with CFR, the most prevalent being Colletotrichum and Fusarium. Overall, this study suggests that planting coffee at higher altitude under shade and controlling CBB can reduce CFR.

Coffee berry borer (CBB) is the most serious insect pest of coffee worldwide, causing significant reductions in yield and quality. Following the introduction of CBB to Puerto Rico (2007) and Hawaii (2010), researchers, extension agents, industry representatives, and coffee growers have worked together to develop an integrated pest management (IPM) program that is both effective and economically feasible for each island. Since the introduction of the IPM program in Hawaii, research efforts have led to a better understanding of CBB population dynamics, as well as optimized monitoring, cultural practices, and commercial Beauveria bassiana applications. As a result of these efforts, a substantial reduction in average CBB infestation and an increase in coffee yields and quality have been documented in Hawaii over the last decade. However, significant challenges remain in addressing high production and labor costs, limited availability of labor, and a lack of training for field workers in both regions. Although considerable effort has gone into research to support CBB IPM in Hawaii and Puerto Rico, the adoption of these strategies by coffee farmers needs to be increased. More diversified methods of outreach and education are needed to reach growers in rural, isolated areas. Significant gaps exist in the ability and willingness of growers and workers to access and digest information online, emphasizing the importance of on-farm workshops and farmer-to-farmer teaching. Additional methods of training are needed to help coffee farmers and field workers learn how to properly conduct cultural controls and optimize the use of biological control agents such as B. bassiana.

Vanilla planifolia is an orchid of cultural and economic value. However, its cultivation in many tropical countries is threatened by water stress. In contrast, V. pompona is a species that is tolerant of prolonged periods of drought. Due to the need for plants’ resistant to water stress, the use of hybrids of these two species is considered. Therefore, the objective of this study was to evaluate the morphological and physio-chemical responses of in vitro vanilla seedlings of the parental genotype V. planifolia, and the hybrids V. planifolia × V. pompona and V. pompona × V. planifolia, which were then exposed over five weeks to polyethylene glycol-induced water stress (−0.49 mPa). Stem and root length, relative growth rate, number of leaves and roots, stomatal conductance, specific leaf area, and leaf water content were determined. Metabolites potentially associated with the response to water stress were identified in leaves, through untargeted and targeted metabolomics. Both hybrids exhibited a smaller decrease in the morphophysiological responses compared to V. planifolia and exhibited an enrichment of metabolites such as carbohydrates, amino acids, purines, phenols, and organic acids. Hybrids of these two species are considered as a potential alternative to the traditional cultivation of vanilla to face drought in a global warming scenario.

Entomopathogenic fungi (EPF) infect insects and are of interest for understanding host-pathogen interactions and biological control of insect pests. The fruit fly Drosophila melanogaster offers an excellent model system for exploring the biology of EPF and their interactions with insects. In this review, we describe the advantages of using D. melanogaster as a model system to study EPF and highlight EPF of relevance to agriculture. We also propose possible directions for future research in this area. We predict that in the future, D. melanogaster will continue to be a productive system for understanding the biology of the fungi attacking insects and will no doubt contribute to the future of biological control, conservation and other areas.

he Caribbean is influenced by Sahara Dust Storms (SDS) every year. SDS can transport a diversity of microorganisms, including potential pathogens of humans, animals, and plants. In fact, SDS have been suggested as a source of Aspergillus sydowii, reported to cause aspergillosis disease in gorgonian sea fans. However, the diversity of fungal spores in SDS remains unknown and there are con- flicting studies as to whether A. sydowii spore are capable of crossing the Atlantic Ocean. In this study, we estimated the fungal diversity of the Saharan dust trapped on air filters during five days of a ship’s tra- jectory in the eastern Atlantic during a dust event. Also, we investigated whether SDS is a potential source of opportunistic fungal pathogens. We isolated 30 morphospecies including the ascomycetes Asper- gillus (33% of identified isolates), Thielavia (18%), Penicillium (12%), Chaetomium strumarium (3%), Periconia (2%), and Cladosporium sphaerosper- mum (1%). Many of these groups include opportun- istic pathogens. Species diversity was similar across days but with significant differences between Days 3 vs 5 and between hazy vs clear days. We report for the first time that Thielavia, Chaetomium strumarium and Periconia are present in SDS and are capable of surviving long-distance transport in SDS. The pres- ence of A. sydowii isolates is consistent with reports of SDS as a source of inoculum for sea fan aspergillo- sis. This could signify that SDS are carriers of viable, potentially pathogenic spores which can be deposited on terrestrial or aquatic substrates.

The coffee berry borer (CBB) Hypothenemus hampei Ferrari is the most serious pest of coffee worldwide. Management of the CBB is extremely difficult because its entire life cycle occurs inside the fruit, where it is well protected. Knowing which life stages contribute most to population growth, would shed light on the population dynamics of this pest and help to improve CBB management programs. Two staged-classified matrices were constructed for CBB populations reared in the lab on artificial diets and CBB populations from artificial infestations in the field. Matrices were used to determine demographic parameters, to conduct elasticity analyses, and to perform prospective perturbation analysis. Higher values of the intrinsic rate of natural increase (rm) and population growth rate (λ): were observed for CBB populations growing in the lab than in the field (rm: 0.058, λ: 1.74 lab; rm: 0.053, λ: 1.32 field). Sensitivity values for both CBB populations were highest for the transitions from larva to pupa (G2: 0.316 lab, 0.352 field), transition from pupa to juvenile (G3: 0.345 lab, 0.515 field) and survival of adult females (P5: 0.324 lab, 0.389 field); these three vital rates can be important targets for CBB management. Prospective perturbation analyses indicated that an effective management for the CBB should consider multiple developmental stages; perturbations of >90% for each transition are necessary to reduce λ to <1. However, when the three vital rates with highest sensitivity are impacted at the same time, the percentage of perturbation is reduced to 25% for each transition; with these reductions in survival of larvae, pupae and adult females the value of λ was reduced from 1.32 to 0.96. Management programs for CBB should be focused on the use of biological and cultural measures that are known to affect these three important targets.

Adult orchids in the Susúa State Forest show a trend of growing towards the East and under 0.75 m above ground. The orchid occupies 14 out of the 27 identified tree species. Oplonia spinosa and Coccoloba microstachya have a significant positive and negative effect on the presence of the orchid, respectively. More data is being collected on physical characteristics of the bark and on the orchid mycorrhizal fungi (OMF). These data will be used in combination with in situ and ex situ seed germination experiments to identify the factors that influence seed germination and determine whether or not it mirrors the distribution of adults. Discussion and Future Projections: Results: A) Cardinal orientation of orchids growing on phorophytes. A chi-square goodness of fit test revealed that there are more orchids growing towards East and less towards NorthEast and SouthWest than expected if distribution was normal. B) Height above ground of orchids growing on phorophytes. Most orchids grow below 0.5 m above ground. C) Average number of orchids per tree of most common species. A loglinear analysis revealed that O. spinosa (+) has the most positive effect on the presence of the orchid, whereas C. microstachya (-) has the most negative effect. Abstract: Most orchid species are tropical epiphytes, and their dispersion is often characterized by small, scattered populations. The availability of suitable host trees (phorophytes) may not only affect orchids but their mycorrhizal fungi for which they depend upon for successful germination. Although abiotic factors such as precipitation, temperature, and light certainly affect seed germination and establishment, we expect that bark characteristics of host trees and availability of mycorrhizal fungi are paramount. This project addresses the relationships of Psychilis kraenzlinii (peacock orchid) with its mycorrhizal fungi and phorophytes to elucidate how these affect the dispersion of the orchid within a local population in the Susúa State Forest of Puerto Rico. Herein we present results for the first phase of the project, a phorophyte specificity assessment. The next steps in this investigation are describing the physical characteristics of the phorophyte species, identify the orchid mycorrhizal fungi (OMF) that trigger seed germination, and conduct in situ and ex situ seed germinations. Understanding the relationships of orchids with other organisms is critical for the development of conservation strategies.