บทคัดย่องานวิจัย

หมวดหมู่ : ฐานข้อมูลงานวิจัย

Systemic activity and efficacy of E-0858 and Iprodione in brown rot disease control of stone fruit (fruit disease)

Osorio, Juan M.

Ph.D., University of California, Davis, 1990, 74 pages

1990

บทคัดย่อ

SYSTEMIC ACTIVITY AND EFFICACY OF E-0858 AND IPRODIONE IN BROWN ROT DISEASE CONTROL OF STONE FRUIT (FRUIT DISEASE).

Using in vitro assays, the experimental fungicide E-0858 (SC-0858) and iprodione inhibited mycelial growth of both benomyl-sensitive and benomyl-resistant isolates of Monilinia laxa and M.  fructicola.  In vivo, the fungicides controlled blossom and twig blight of almond and brown rot of peach fruit.  In this assay, E-0858, like iprodione and benomyl suppressed almond blossom blight development when applied within 24 hr after inoculation.  In fields with high or low disease incidence, a single spray application of E-0858 to almond blossoms at the pink bud stage of bloom (prebloom) controlled blossom and twig blight in orchards with and without benomyl-resistant populations of M.  laxa.  Under low disease incidence, a single spray of iprodione applied to closed blossoms controlled the disease; however, under high disease pressure, disease control was significantly better when it was applied twice during bloom.

 Translocation of E-0858 and iprodione from petals and sepals into the inner blossom parts was detected by bioassay and by using (14)C-labelled material when the fungicides were applied to closed blossoms.  E-0858 showed greater systemic activity than iprodione.  Extracts of blossoms treated with (14)C-E-0858 yielded three radioactive spots when constituents were separated by thin layer chromatography.  Only the parent compound, however, inhibited mycelial growth of M.  laxa.  Thin layer chromatograms of extracts of blossoms treated with (14)C-iprodione revealed four radioactive spots and two spots, the parent compound and one metabolite, had fungitoxic activity.

 Iprodione, benomyl, and E-0858, when used as pre- or postharvest spray on peach fruit limited the size of brown rot lesions on fruit inoculated with conidia of M.  fructicola.  In all cases, however, brown rot lesions on fruit treated with E-0858 were significantly smaller than lesions on fruit treated with either of the other two fungicides.  In bioassays and in tests with (14)C-labelled fungicide, both E-0858 and iprodione penetrated peach fruit when applied to the fruit surface, with E-0858 showing greater penetration.  Postharvest hydrocooling using chlorinated water after fungicide treatment reduced the efficacy of iprodione and benomyl, but not that of E-0858 for control of brown rot.