DISTRIBUTION OF ENTOMOPATHOGENIC FUNGI IN SOILS OF CATTLE FARMS AND FACTORS ASSOCIATED WITH THEIR PRESENCE IN THE MEXICAN TROPICS

Abstract

Background. Ticks are one of the main threats that affect cattle production in Mexico. In the ecosystems, these parasites are naturally regulated by microorganisms such as entomopathogenic fungi (EPF) and bacteria, wich are capable of causing them disease and death. However, some studies mention that the effects of climate change and wrong practices in the management of grasslands, trees and animals affect the distribution of these beneficial organisms in the livestock areas of Mexican tropic. Objectives. 1) To determine the distribution of EPF in cattle farm soils from the Mexican Tropics, 2) to identify the sites within the cattle farms with greatest presence and richness of EPF and 3) to identify factors associated with their presence. Methodology. Soil samples of seventy-two cattle farms from twelve municipalities of Veracruz, México, with high prevalence of ectoparasites, were collected. Galleria mellonella larvae were used as bait in order to isolate EPF from soils; then, fungi were identified by molecular methods. Results. Four genera of EPF were isolated and M. anisopliae was the most prevalent. Live fences soils showed the greatest EPF richness. The mountainous region (OR=2.25), cattle farm altitude (401-600 meters above sea level) (OR=3.81) and cattle farms where they do not use herbicides (OR=3.66) are factors associated to the presence of EPF in cattle farms soils (P < 0.05). Implications. Information about distribution and diversity of EPF, as well as the knowledge of factors that may affect them, will help to understand their importance as natural regulators of pests in cattle farms, to regulate agronomic activities to optimize their survival and help to design strategies for isolation of native EPF with potential bio-regulatory effects of ectoparasites. Conclusions. The isolation and richness of EPF in soils destined for the production of grazing cattle where Metarhizium anisopliae was the most isolated is reported for the first time in Mexico. The live fences soils presented the greatest wealth of EPF and some management and geographic characteristics were identified as factors associated with the fungal presence.