Location: Sustainable Perennial Crops Laboratory
2020 Annual Report
Objectives
Over the next five years we will focus on the following objective:
Objective 1: Develop novel pest management technologies for control of coffee berry borer, involving the use of sesquiterpene repellents and the fungal entomopathogen Metarhizium anisopliae.
• Sub-objective 1.A. Determine the effectiveness of a recently identified sesquiterpene as a coffee berry borer repellent.
• Sub-objective 1.B. Evaluate the biological control potential of microsclerotial formulations of the fungal entomopathogen Metarhizium spp.
These objectives will integrate various components that we believe are essential to greatly improving available pest management tactics and to move the field into a new direction.
Approach
The coffee berry borer, Hypothenemus hampei, is the most devastating insect pest of coffee worldwide. Endemic to Africa, the beetle is now present in most coffee growing regions. Since most of its life cycle is spent inside the coffee berry, it is extremely difficult to control. Recent efforts aimed at managing the coffee berry borer have focused on biological control alternatives, including the release of parasitoids and the use of fungal entomopathogens. Mass production of some parasitoids has not been optimized, and in cases where these have been imported from Africa and released in the field, results have not been promising. Delivery of fungal entomopathogens remains a major obstacle due to the cryptic nature of the insect and the difficulty and cost of spraying in coffee plantations. This project will focus on two areas that will likely result in improved control of the coffee berry borer: (1) Determining the effectiveness of a repellent in reducing infestation levels; and (2) Assessing the effectiveness of microsclerotial granules of various species of the fungal entomopathogen Metarhizium against coffee berry borers that remain inside berries that have fallen on the ground. The results of this research project will greatly contribute towards the development of novel control tactics against this important agricultural pest.
Progress Report
Progress was made on Objective 1, Subobjective 1A, which falls under National Program 304, Crop Protection and Quarantine, Component 3, Insects and Mites, Sub-component 3A: Agricultural and Horticultural Cropping Systems, Problem Statement 3A2: Systems approach to environmentally-sound pest management. Under Subobjective 1A, we have been conducting research aimed at determining whether the bacteria involved in caffeine breakdown in the coffee berry borer are transmitted from the mother to its progeny via the egg. We have sequenced 50 different bacterial isolates and have focused the bioinformatics efforts on determining whether caffeine breakdown or antimicrobial peptide genes are present in these isolates. In collaboration with a scientist at the University of Alabama we have also sequenced a bacterial strain, which through bioinformatics, has been shown to have five caffeine-breakdown genes. Finally, we have been studying possible acoustic communication in the coffee berry borer.
The project is terminating during this annual report cycle. Several coffee berry borer-related research projects were completed during the duration of this project, including: the identification of a repellent against the coffee berry borer; the development of a technique that allows to study the social behavior of the insect; the visualization of the mesathoracic spiracles in the insect; the elucidation of the mouthparts structure and elemental composition of the mandibles; the visualization of the internal anatomy, including the respiratory system, using micro-computerized tomography; studies on the use of a nematode to negatively affect insect population levels; the elucidation of plant hosts and native distribution of the insect using herbaria collections; and the determination of differential metabolic responses in seeds infested by the insect.
Accomplishments
1. Discovery of a chemical repellent that targets the coffee berry borer. The coffee berry borer continues to pose a formidable challenge to coffee growers worldwide. Because of the cryptic life habit of the insect inside coffee berries, effective pest management strategies have been difficult to develop. An ARS scientist from Beltsville, Maryland, identified a compound that acts as a repellent against the coffee berry borer. In a field experiment in Hawaii, the repellent resulted in up to 80% decreased in coffee berry borer captures in traps where the repellent was present, compared to traps containing just an attractant. The repellent was placed inside a plastic wrapper known as a bubble cap, which allowed the repellent to exit at controlled rates letting the repellent remain active for at least 19 weeks after installation in the coffee plantation. These findings have potential national and international impact for coffee producer, the coffee industry and for consumers.
Review Publications
Vega, F.E., Pionar, G. 2020. Entomopathogenic fungi (Hypocreales: Ophiocordycipitaceae) infecting bark lice (Psocoptera) in Dominican and Baltic amber. Mycology. 11:71–77.
Vega, F.E., Smith, L., Davies, N., Goral, T., O'Sullivan, R., Moat, J., Davis, A. 2019. Elucidation of hosts, native distribution, and habitat of the coffee berry borer (Hypothenemus hampei) using herbaria and other museum collections. Frontiers in Plant Science. 10:1188.
Vega, F.E., Ziska, L.H., Simpkins, A., Infante, F., Davis, A., Rivera, J., Barnaby, J.Y., Wolf, J.E. 2020. Early growth phase and caffeine content response to recent and projected increases in atmospheric carbon dioxide in coffee (Coffea arabica and C. canephora). Scientific Reports. 10:5875.
Alba-Tercedor, J., Alba-Alejandre, I., Vega, F.E. 2019. Revealing the respiratory system of the coffee berry borer (Hypothenemus hampei, Coleoptera: Curculionidae: Scolytinae) using micro-computed tomography. Scientific Reports. 9:17753.
Alba, A.I., Alba, T., Vega, F.E. 2019. Anatomical study of the coffee berry borer (Hypothenemus hampei) using micro-computed tomography. Scientific Reports. 9:17150.
Castro-Moretti, F.R., Cocuron, J., Vega, F.E., Alonso, A. 2020. Differential metabolic responses caused by the most important insect pest of coffee worldwide, the coffee berry borer (Hypothenemus hampei). Journal of Agricultural and Food Chemistry. 68:2597-2605.
Poinar, G., Vega, F.E. 2020. A new genus of Empididae (Diptera) with enlarged basal flagellomeres in Mid-Cretaceous Burmese amber. Historical Biology. https://doi.org/10.1080/08912963.2020.1743700.
