Outcome of Ceratocystis platani inoculations in Platanus × acerifolia in relation to season and inoculum dose

Abstract

Ceratocystis platani is the causal agent of canker stain, the most destructive disease of Platanus spp. The selection of resistant tree genotypes should be an effective method of disease control. Although breeding programs for resistance have been developed, there is no validated protocol for an in depth evaluation of the resistance phenotype. Testing the variables to identify the conditions that fully challenge the genetic potential of the host is crucial not to overestimate labile resistant phenotypes. Here we report results of testing different inoculum doses and inoculation times -early and late spring, summer and autumn -on the response of susceptible plane genotypes. Late spring inoculation gave rise to the quickest death pattern, followed by early spring inoculation. Nevertheless Ceratocystis platani was aggressive also in the hottest period of the summer. The capacity of C. platani to initiate canker stain in the hottest period of the year underlines its capacity to be virulent across a wide range of temperatures. Although autumnal inoculation enabled fungus entry, its progression was precociously halted, as effective and stable resistance reactions were opposed by most trees. An in vitro study of mycelial growth and conidial germination confirmed the capacity of the fungus to be active or to keep its viability across a wide range of temperatures, such as in the three seasons that were taken into consideration. Thus, we hypothesize that the failure of symptom expression after autumnal inoculation might be due to a combination of a temperature-linked reduction in pathogen virulence, and a season-linked resistant reaction of the host. Overall, our data suggest that, in the context of legal sanitary measures, only the coldest and driest periods of the year should be considered for pruning and the removal of infected trees. The different inoculum doses did not condition the death pattern. Comparing germination in suspensions at 1000 and 10 000 conidia per µl, self-inhibition germination occurred, as the germination rate was inversely correlated with the conidia concentration. This is a first step in the definition of a resistance-testing protocol for an in depth evaluation of resistance to canker stain.

Use of overburden waste for London plane (Platanus × acerifolia) growth: the role of plant growth promoting microbial consortia

“…However, the selection for resistant genotypes is very extensive while large-scale usage of a small number of clones can be detrimental for plane trees biodiversity (Pilotti et al 2015). This emphasizes the need …”

“…Considering the prevalence of plane trees in urban areas all over the world it is important to develop suitable measures to prevent or restrict the pathogens. However, up to now, the application of phytosanitary measures, chemical treatments and biological control measures were not particularly efficient (Panconesi 1999, Pilotti et al 2015). A genetic approach with the aim of selecting resistant plane genotypes is believed to be an effective way of disease control (Pilotti et al 2015).…”

“…However, up to now, the application of phytosanitary measures, chemical treatments and biological control measures were not particularly efficient (Panconesi 1999, Pilotti et al 2015). A genetic approach with the aim of selecting resistant plane genotypes is believed to be an effective way of disease control (Pilotti et al 2015). Breeding programs with American sycamore (Platanus occidentalis L.) and oriental plane tree (Platanus orientalis L.) resulted in cultivars "Columbia" and "Liberty", which are highly resistant to Apiognomonia veneta (Sacc.…”

Screening for resistance of progenies derived from Castanea sativa × C. crenata and C. crenata to Cryphonectria parasitica

“…In this work, the ratio of surviving seedlings was similar in both June and September inoculations, but survival analysis suggested differences in the survival patterns of seedlings between the two treatment times. Pilotti, Di Lernia, Modesti, Lumia, and Brunetti () observed a significant effect of inoculation date on survival of 5‐year‐old Platanus × acerifolia inoculated with an isolate of C. platani , the cause of canker stain, the most destructive disease of Platanus spp. Late spring inoculation (May) caused trees to die quickly, followed by early spring (April) and summer inoculations (July).…”

Ceratocystiswilt and canker – a disease that compromises the growing of commercialAcacia-based plantations in the tropics

“…In Indonesia, wilt and canker symptoms and mortality in A. mangium plantations caused by C. manginecans occurred after trees were singled at 6-8 months old using poor pruning practice (Tarigan et al 2010;Tarigan et al 2011b). Timing of singling or pruning may also be important, with lower disease incidence if conducted during dry than wet weather (Pilotti et al 2016). Climate is also correlated with insect-vector activity; in South Africa beetle activity is much higher during spring and early summer than winter (Heath et al 2009a).…”