African fan palm (Borassus aethiopum) and oil palm (Elaeis guineensis) are alternate hosts of coconut lethal yellowing phytoplasma in Mozambique

In this study, potential alternate hosts of the phytoplasma causing coconut lethal yellowing disease (CLYD) in Mozambique were investigated based on 16S rRNA and secA genes. The results reveal that the naturalized palm species, Elaeis guineensis and Borassus aethiopum are alternate hosts of CLYD phytoplasma in Mozambique. Based on the iPhyClassifier online software, the phytoplasma detected in B. aethiopum belongs to the 16Sr group XXII-A, which include ‘Candidatus Phytoplasma palmicola’ and ‘Candidatus Phytoplasma cocosnigeriae’. This is the first report associating ‘Candidatus Phytoplasma palmicola’ with wild naturalized palm species in the world. Key words: Alternate hosts, Borassus aethiopum, „Candidatus Phytoplasma palmicola‟, Elaeis guineensis, Mozambique, palm lethal phytoplasma phylogeny

Alternate host ranges of Cronartium flaccidum and Cronartium ribicola in northern Europe

Attached and detached leaves of 60 potential host species were inoculated in the greenhouse and laboratory with aeciospores of Cronartium ribicola J.C. Fisch. from six Finnish locations and of Cronartium flaccidum (Alb. &amp; Schw.) Wint. from 20 locations in Finland and Sweden in 2011. Candidate hosts represented 16 plant families: Solanaceae, Verbenaceae, Asclepiadaceae, Grossulariaceae, Paeoniaceae, Balsaminaceae, Gentianaceae, Scrophulariaceae, Loasaceae, Tropaeolaceae, Acanthaceae, Myricaceae, Phrymaceae, Plantaginaceae, Orobanchaceae, and Apocynaceae. Inoculations of C. flaccidum produced uredinia after 2 weeks and (or) telia after 4 weeks of incubation on 25 hosts. Inoculation trials identified several new hosts for C. flaccidum in Fennoscandia, namely Impatiens balsamina, Swertia fedtschenkoana, Loasa tricolor, Myrica gale, Verbena canadensis, Saxifraga spp., Paeonia obovata, and Veronica daurica. Myricaceae and Saxifragaceae represent new host families for these rusts. Cronartium ribicola formed uredinia or telia on 10 species: Ribes spp. (7 species/cultivars), Pedicularis palustris subsp. palustris, Bartsia alpina, and Loasa triphylla. Results suggest wider alternate host ranges for both C. flaccidum and C. ribicola than previously recognized. Spores were virulent regardless of their source location, suggesting a lack of host-specificity among Fennoscandian populations of Cronartium. </jats:p

Cronartium rusts sporulate on a wide range of alternate hosts in northern Europe

2015

Geographic distribution of C. flaccidum and P. pini in Sweden and Finland

2015