Peronosporales Species Associated with Strawberry Crown Rot in the Czech Republic

Abstract

The symptoms of crown rot on strawberry plants are considered typical for the pathogen Phytophthora cactorum, which causes high losses of this crop. However, an unknown number of related species of pathogens of Peronosporales cause symptoms quite similar to those caused by P. cactorum. To determine their spectrum and importance, strawberry plants were sampled from 41 farms in the Czech Republic. The cultures were isolated from the symptomatic plants using the baiting method, with subsequent cultivation on a semiselective medium. Isolates were identified to the species level using nuclear ribosomal internal transcribed spacer (ITS) barcoding after preliminary morphological determination. In total, 175 isolates of 24 species of Phytophthora, Phytopythium, Pythium, and Globisporangium were detected. The most represented was Phytophthora cactorum, with 113 (65%) isolates, which was recorded in 61% of farms, and the Pythium dissotocum complex with 20 (11%) isolates, which was recorded in 27% of farms. Other species were represented in units of percent. Large differences between farms in the species spectra were ascertained. The differences between species in cardinal growth temperatures and different management of the farms are discussed as a main reason for such a diversification. Regarding the dissimilar sensitivity of various species of Peronosporales against fungicides, the proper determination of the cause of disease is of crucial significance in plant protection.

Diversity of Phytophthora Species Involved in New Diseases of Mountain Vegetation in Europe with the Description of Phytophthora pseudogregata sp. nov.

“…In Europe, aerial Phytophthora diseases have been studied mainly on agricultural crops [1,26,[35][36][37][38] and to a much lesser extent on forest trees, especially in subalpine ecosystems [14]. Alpine and subalpine regions are important biodiversity hotspots for the flora, including a large number of plants and many endemisms in very confined environments and extreme conditions [39].…”

Genome analysis of Phytophthora cactorum strains associated with crown- and leather-rot in strawberry

“…The pathogen has two distinct pathotypes that causes crown rot and/or leather rot in strawberry ( Fragaria × ananassa Duch)( van der Scheer, 1971 ; Harris and Stickels, 1981 ; Eikemo et al, 2004 ). Both diseases cause substantial yield losses in strawberry production; in addition the leather rot affects post-harvest processing of strawberry fruits ( Harris and Stickels, 1981 ; Ellis and Grove, 1998 ; Stensvand et al, 1999 ; Pánek et al, 2022 ). The crown rot pathotype can cause disease in both crown and fruit tissues, while the leather rot pathotype causes disease only in the strawberry fruit.…”