ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Effect of packhouse procedures on the viability of Phyllosticta citricarpa, anamorph of the citrus black spot pathogen.

Korf, H.J.G. Schutte, G.C. and Kotze, J.M.

African Plant Protection. Volume 7, Issue 2, 2001. Pages 103-109.

2001

บทคัดย่อ

Conidia of P. citricarpa [Guignardia citricarpa] did not infect unwounded packhouse-treated citrus fruit (Citrus sinensis cv. Valencia) maintained at -0.5 and 25 deg C in artificial and natural inoculation studies, but infrequently produced black spot lesions (G. citricarpa) from which the pathogen could be isolated on artificially inoculated wounded fruit kept at 25 deg C. Conidial germination and appressorium formation by seven P. citricarpa isolates from various countries were completely inhibited in vitro by the postharvest fungicides guazatine and o-phenylphenol (sodium salt) at recommended rates, whereas thiabendazole, imazalil sulfate, two emulsion formulations of imazalil, and particularly prochloraz, provided significant inhibition. Chlorine dioxide suppressed conidial germination more effectively and at lower concentrations than calcium hypochlorite. Packhouse treatments which consistently reduced the viability of P. citricarpa in black spot lesions on fruit included warm water (43-47deg C for three minutes), chemical tank (guazatine, imazalil sulfate, 2,4-D), and a combination of chlorine, high-pressure spraying, warm water, chemical tank, and polyethylene waxing. Conidial viability was reduced to zero on black spot-infected fruit stored for three weeks at 25 deg C, as well as on fruit exposed to chlorine, warm water, the above chemicals, or all treatments combined.