Possibilities of using chemical products for the protection of Rhododendron sp. against Phytophthora plurivora

DOI: 10.35205/0558-1125-2019-74-177-186
UDC 582.912.42:632.4:632.934

POSSIBILITIES OF USING CHEMICAL PRODUCTS FOR THE PROTECTION OF RHODODENDRON SP. AGAINST PHYTOPHTHORA PLURIVORA

KORZENIOWSKI M., PhD
Bayer CropScience, Poland
CHMIELOWIEC-KORZENIOWSKA A., PhD
University of Life Sciences in Lublin, Akademicka 13, 20-033 Lublin, Poland
TERESHCHENKO Ya., YARESHCHENKO A., PhDs
Institute of Horticulture, NAAS of Ukraine, 03027, Kyiv-27, 23, Sadova st., e-mail: yantereshchenko@gmail.com, yareshchenko_a@ukr.net

Considering the continuous intensification of production of ornamental plants (Rhododendron sp.), losses caused by species from genus Phytophthora, and limited possibilities of chemical protection, research was undertaken for the purpose of development of effective chemical methods of protection of rhododendron against Phytophthora with consideration of the way of their application. The objective of this study was the assessment of the usefulness of seven fungicides in the protection of rhododendron against Phytophthora plurivora. The research was conducted on rhododendron of Nova Zembla cultivar (Rhododendron Nova Zembla) in the University of Life Sciences in Lublin, Poland.
Under laboratory conditions, the activity of the tested products was assessed based on the growth of P. plurivora on agar containing fungicides, and the size of necrosis of inoculated rhododendron leaves. In greenhouse tests, the growth and degree of infestation of plants planted in infested substrate was evaluated.
The research showed that the introduction to the agar of 1 g/ml of active substances of Infinito 687.5 S.C. and Previcur Energy 840 SL limited growth of P. plurivora. Complete inhibition of its development was observed after the application of Infinito 687.5 S.C. and Acrobat MZ 69 WG at a concentration of 10 g/ml, and Previcur Energy 840 SL and Mildex 711.9 WG at the highest concentration of 100 g/ml.
Irrespective of concentration, the applied products Acrobat MZ 69 WG and Infinito 686.5 SC after four and six days of incubation protected rhododendron leaves against P. plurivora. Mildex 711.9 WG and Previcur Energy 840 SL inhibited the development of phytophthorosis at concentrations of 0.15 % and 0.2 %.
Differences were evidenced in the efficiency of the analysed agents depending on the application method. The height of experimental rhododendrons was considerably greater in comparison to control plants only in the case of agents applied in the form of spraying. A stimulating effect on the number of developed leaves was observed in the group of plants watered with Previcur Energy 840 SL.
Key words: Phytophthora plurivora, rhododendron, chemical agents

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