Altitude and shade tree density influence parasitism by Metaparasitylenchus hypothenemi in the coffee berry borer

Metaparasitylenchus hypothenemi is an endoparasitic nematode of the coffee berry borer (Hypothenemus hampei). Its presence has been documented in Mexico, Guatemala, and Honduras, although the influence of microclimatic and structural conditions in coffee plantations that promote its occurrence remains unknown. The objective of our study was to examine the impact of rainfall seasonality, microclimate (temperature and relative humidity), altitude, and shade tree density on the occurrence of M. hypothenemi in coffee plantations in the Soconusco region, Mexico. The presence of parasitism was monitored bi-weekly in four coffee plantations with different shade tree densities and at two different altitudes (450 and 1000 m a.s.l.), between March 2023 and June 2024. The persistence of M. hypothenemi varied between 12.5% and 81.2%, with a prevalence range of 0.1-2.7%, and a higher incidence of parasitism during the rainy season (May-October) at all four sites. Relative humidity did not exhibit a statistically significant effect on parasitism. Temperature showed a weak positive association with parasitism, whereas altitude and shade tree density were positively associated with parasitism. Sites with higher shade tree density and higher altitude showed the highest levels of parasitism. These results indicate that M. hypothenemi parasitism is associated with coffee agroecosystems characterised by high shade tree density and high altitude. This study provides evidence for the importance of shade-grown coffee in the natural control of coffee berry borer populations, in biodiversity conservation, and in the resilience of this agroecosystem.