Phaeoacremonium species associated with olive wilt and decline in southern Italy

Abstract

Six Phaeoacremonium species (spp.) were isolated from symptomatic wood of olive trees (Olea europea) in Apulia (southern Italy) that showed crown wilt and twig and branch dieback. These Phaeoacremonium spp. were identified according to their morphological characteristics and by analyses of partial sequences of the actin and β-tubulin genes. Combining these cultural, morphological and molecular data, three Phaeoacremonium spp. were isolated that are already known to be responsible for severe decline of olive in Apulia, Phaeoacremonium aleophilum, Phaeoacremonium al vesii and Phaeoacremonium parasiticum, together with three other Phaeoacremonium spp. that are associated for the first time with wilt, decline and dieback of olive orchards in Italy and worldwide: Phaeoacremonium italicum, Phaeoacremonium sicilianum and Phaeoacremonium scolyti. To understand and to confirm their involvement in wilt and decline of olive trees, pathogenicity assays were performed on shoots of young olive plants. The data indicate that all six of these Phaeoacremonium spp. can cause discolouration, necrotic wood, and death of shoots, although different levels of virulence were observed, with Pm. italicum, Pm. aleophilum and Pm. sicilianum producing greater necrotic lesions than the other Phaeoacremonium spp. investigated here.

Canker disease of willow and poplar caused by Cryptosphaeria pullmanensis recorded in China

“…; Carlucci et al. ). Both inoculated and mock‐inoculated plants were kept in a moist chamber maintained at 28°C for 48 h. Any changes observed in the willow and poplar stems in the region around the inoculation site were recorded.…”

“…To isolate the pathogen, samples were taken from five to 10 cankers of five trees per region. Samples were taken from diseased and healthy tissues at the canker margins and cut into three pieces with a side length of 2-5 mm per canker (Carlucci et al 2015), surface sterilized with 75% ethanol for 3-5 s and 0.1% mercuric chloride for 1 min, and then washed three times in sterile distilled water and blotted dry with sterilized filter paper. The sections of twig were placed on sterile plates of potato dextrose agar (PDA) and incubated at 28°C.…”

“…There were five replicates of each Cryptosphaeria isolate on each of the two hosts (S. alba and P. alba). Mock-inoculated stems were inoculated with sterile PDA plugs (Adesemoye et al 2014;Carlucci et al 2015). Both inoculated and mock-inoculated plants were kept in a moist chamber maintained at 28°C for 48 h. Any changes observed in the willow and poplar stems in the region around the inoculation site were recorded.…”

A canker disease of apple caused by Cytospora parasitica recorded in China

“…Re-isolations were made from inoculated tissues showing symptoms of a disease similar to those observed on the specimens collected from orchard sites. The isolates were identified as described previously (Adesemoye et al, 2014;Carlucci, Lops, Cibelli, & Raimondo, 2015).…”

Phaeoacremonium: From esca disease to phaeohyphomycosis

“…Because of the involvement of members of this genus in Petri disease and esca of grapevines (Vitis vinifera), isolates from this host have been intensively studied in the past. Even though Phaeoacremonium species can infect a wide range of woody hosts (Fig 1, Table 1), more recent publications have shown the importance of Phaeoacremonium species in causing brown wood streaking of Olea europea (Nigro et al 2013;Carlucci et al 2015) and Prunus spp. (Damm et al 2008;Gramaje et al 2012;Olmo et al 2014).…”