Influence of climatic variables and biological control agents (nematodes) on the distribution and survival of the coffee berry borer, <em>Hypothenemus hempei</em>, in Puerto Rico

Abstract

Coffee is the second largest export product of developing countries and is one of the ten most important cultivated crops in Puerto Rico, especially in the mountainous region. The coffee berry borer (CBB) <em>Hypothenemus hampei</em> Ferrari (1967), which arrived in Puerto Rico in 2007, is considered the most destructive pest in all coffee producing areas worldwide. The control of CBB is an enormous challenge because this insect spends most of its life inside the coffee berry, even, the use of insecticides has proved ineffective. Therefore, the development and implementation of biological control alternatives, as part of integrated pest management (IPM), is very important for the sustainability of the coffee industry. In this dissertation, I combine the spatial distribution of suitable habitats for CBB, detection of entomopathogenic nematodes (EPNs), a potential biocontrol agent and determining soil factors that affect the natural occurrence of EPNs in any given site. Species distribution model models (Chapter II) was performed using a total of 97 (241 sites sampled) georeferenced CCB presence and nineteen bioclimatic variables and altitude. Distribution maps were generated illustrating the suitable area for coffee berry borer in Puerto Rico. CBB distribution is favored by precipitation of wettest quarter, highest altitude and precipitation seasonality. In order to validate the model result, field percent of infestation was also calculated by the total of borer berries divided on total of berries in selected 3 branches in each sample site and positive relationship between model suitable index and field infestation of CBB was found. Furthermore, we sampled a total of 32 farms throughout the coffee production area in Puerto Rico using the insect bait method to extract EPNs (Chapter III). A total of 143 EPN isolates were recovered. I also made the first ix report of the presence of the recently recognized as an EPN <em>Oscheius myriophila</em> which was identified, based on molecular and morphometrical analysis, in 90.85% of the sample site. Finally, each nematode sampled site was characterized, firstly, according to coffee agroecosystem (full sun or under shade) and second, by soil physicochemical characteristics (Chapter IV). Using a generalized linear model (GLM), I determine the interaction of soil parameters such as pH, texture and elevation coupled with shade coffee to predict <em>O. myriophila</em> occurrence. In conclusion, dissertation provides a basic framework to develop integrated pest management for CBB integrating better knowledge about its preferences in climatic condition in order to prevent outbreak and the use of native EPN <em>O. myriophila</em>.