Susceptibility of Brevipalpus phoenicis to entomopathogenic fungi.
The pathogenicity of 52 isolates from several fungus species was studied for the false spider mite Brevipalpus phoenicis. In addition, the main stages during the course of infection by Hirsutella thompsonii, by far the most virulent pathogen, were studied by means of light and electron microscopy. Adult mites were confined to arenas prepared with citrus leaves in acrylic dishes containing agar-water. Conidial suspensions containing 10(8) conidia/ml were applied, except for H. thompsonii, where a concentration of 10(7) conidia/ml was used. The H. thompsonii isolates caused higher mortality, with indices higher than 90%. Observations under the scanning electron microscope (SEM) were performed at 0, 6, 12, 24, 48, 72, and 120 h after application of a H. thompsonii suspension containing 10(7) conidia/ml. Twenty-four hours after inoculation, H. thompsonii conidia were observed attached to the mite's integument. The conidia germinated and penetrated through the base of the setae on the hysterosoma. Colonization occurred after 48 h, as evidenced by mortality. Conidiogenesis occurred after 120 h, with the development of mycelium and conidiophores emerging from the posterior and anterior parts of the mite.
Rossi-Zalaf
Luciana Savoi
LS
Departamento de Entomologia, Fitopatologia e Zoologia Agrícola of Escola Superior de Agricultura Luiz de Queiroz (ESALQ/USP), Avenida Pádua Dias, CEP 13418-900 Piracicaba, SP, Brazil. lsrossi@esalq.usp.br
Alves
Sérgio Batista
SB
D000818:Animals; D001938:Brazil; D002957:Citrus / Q000469:parasitology; D005260:Female; D008854:Microscopy, Electron; D008924:Mite Infestations / Q000517:prevention & control*; D008925:Mites / Q000382:microbiology* / Q000648:ultrastructure; D003904:Mitosporic Fungi / Q000254:growth & development / Q000472:pathogenicity*; D010572:Pest Control, Biological / Q000379:methods*; D010935:Plant Diseases / Q000469:parasitology; D018515:Plant Leaves / Q000469:parasitology