Mycobiota of the date palm phylloplane: description and interactions.

We have analysed the mycobiota of date palm (Phoenix dactylifera, L.) leaves using several techniques. Profusely sporulating fungi (Penicillium spp. and Cladosporium spp.) developed when plating leaf fragments and leaf washings. Fusarium oxysporum, was particularly abundant in leaves infested with the red scale insect Phoenicococcus marlatti Cockerell, 1899, but an undescribed Lecanicillium cf. psalliotae was also found. Dual and overlay cultures showed interactions between palm pathogens, entomopathogenic and saprotrophic fungi. The most significant was the strong inhibition of the palm pathogen Penicillium vermoesenii caused by the entomopathogen Beauveria bassiana. No symptoms developed when F. oxysporum isolated from scale insects or the entomopathogens B. bassiana or Lecanicillium dimorphum were wound-inoculated on P. dactylifera petioles.