Evidence for hyperparasitism of coffee rust (Hemileia vastatrix) by the entomogenous fungus, Lecanicillium lecanii, through a complex ecological web

The entomogenous fungus, Lecanicillium lecanii is hyperparasitic on Hemileia vastatrix , the cause of coffee leaf rust in the laboratory, and has frequently been observed attacking it in the field. The existence of a complex ecological web involving the spatially clustered mutualism of an ant ( Azteca instabilis ) with a scale insect ( Coccus viridis ), where the scale insect was infected by L. lecanii , prompted a search for a spatial correlation between the attack of L. lecanii on the scale insect and the incidence of rust in a commercial coffee crop. A weak but statistically significant effect of hyperparasitic control of coffee rust was observed on two distinct scales: in a 45-ha plot and on a scale of approximately 10 m. It was concluded that this effect was linked to an indirect effect of the ant–coccid mutualism, where L. lecanii was a parasite of the coccid.