C. Calderón-Ezquerro, I. Santiago-López, C. Guerrero-Guerra, M. R. Reyes-Montes, M. E. Calderón-Segura and C. Toriello
Centro de Ciencias de la Atmósfera, Circuito Exterior, Ciudad Universitaria, Universidad Nacional Autónoma de México (UNAM), 04510 México, D.F., Mexico
We describe a technique to detect the presence of airborne conidia from the fungus M. acridum (formerly Metarhizium anisopliae var. acridum) (Hypocreales: Clavicipitaceae) with great accuracy. Airborne conidia were collected using Hirst-type spore traps. DNA extractions were optimized to achieve the best possible recovery. DNA was examined using polymerase chain reaction (PCR) with specific oligonucleotides to enable the detection of a single conidium. Experiments using a mini-wind tunnel were conducted to validate the method. Subsequently, this technique was applied to an agricultural region of Mexico, where M. acridum was sprayed to control the grasshopper, Sphenarium purpurascens, population (Orthoptera: Pyrgomorphidae). M. acridum conidia were detected 2 days after spraying in San Mateo Coatepec (Puebla, site of grasshopper study).