Penicillium brevicompactum causing bulb rot on Hyppeastrum x hybridum in Argentina

QUIROGA, G.A.; SILVESTRO, LUCIANA BELÉN; HERRERA, O. ; WRIGHT, E.R.; RIVERA, M.C.; STENGLEIN, SEBASTIAN ALBERTO

JOURNAL OF PLANT PATHOLOGY

EDIZIONI ETS

Lugar: Pisa; Año: 2017

1125-4653

In July 2015, bulbs of Hippeastrum x hybridum imported for cultivation in Buenos Aires (Argentina) showed loss of firmness, rot and green mold. Small pieces from the edge of the lesions were surface disinfected with 2% sodium hypochlorite for 90 sec, rinsed in sterilized distilled water and incubated on potato dextrose agar at 22ºC. Isolates of Penicillium brevicompactum Dierckx (Raper and Tom, 1968) were consistently obtained, and one of them coded NTA-IF-502 was chosen to confirm pathogenicity. Healthy, unwounded and needle-punctured bulbs were immersed for 1 minute in suspensions of 1.4 x 106 conidia mL-1 while bulbs immersed in sterilized water served as controls. The bulbs were individually planted in pots filled with a sterile substrate, and enclosed in polyethylene bags for three days. After 45 days, all the inoculated plants showed yellowish foliage and loss of turgidity. Ten days after, the plants from inoculated punctured bulbs had died and those from inoculated unwounded bulbs showed an advanced wilt. Rotten bulbs and roots and green mold were observed on inoculated plants eased out of the pots. Controls remained healthy. The pathogen was successfully recovered from infected organs. The morphological identification was confirmed by DNA sequence data of the ß-tubulin gene (GenBank accession No. KY216143). This finding represents the first record of this pathogenic species associated with bulb rot of Hippeastrum x hybridum in Argentina.