Survival of Fusarium circinatum in soil and Pinus radiata needle and branch segments

Abstract

Survival of Fusarium circinatum in colonized pine needles and wood pieces was measured. Naturally colonized branches and their needles were cut into small pieces and placed in mesh bags on the soil surface at two locations in northern Spain. Pieces were recovered periodically, cultured on a selective medium, and microscopically examined to identify the species. After 507 days, F. circinatum was recovered from 0 to 27% of the wood pieces and from none of the needles. After 858 days, F. circinatum was not recovered from any wood pieces but was found to be present on 1 out of 220 needle pieces analysed. Artificially infested pieces of wood and needles were placed on 5-mm sieved soil either in plastic boxes at controlled temperature or in mesh bags under field conditions. No survival was recorded after 794 days under field conditions and the decline over time occurred more rapidly in inoculated pieces under field conditions. Soil was also infested with conidia of F. circinatum and survival was estimated. No conidia were recovered after 224 days at 30°C, although at 20 and 5°C the respective populations were 20 and 3700 cfu/g soil. Fusarium circinatum was not recovered from 2-mm-sieved soil collected under pitch canker-infected pines. Results indicate that branch segments and needles naturally colonized by F. circinatum will not be a potential source of inoculum, and the fungus in soil is not likely to contribute to reinfection of new plantations after 2 years.

Response to Temperature and Virulence Assessment of Fusarium circinatum Isolates in the Context of Climate Change

“…Spore germination after a 24-h incubation was extremely low but also highly variable for each isolate tested. While some isolates had better germination at 25 • C, others showed higher number of germinated microconidia at 28 or even at 31 • C. Experiments on spore survival under controlled temperatures have shown better survival of F. circinatum spores at 20 • C than at 30 • C [48]. While we did not test survival for long periods, isolates with higher germination at 28 • C or 31 • C could be better adapted to a warmer climate.…”

Survival of Phytophthora cinnamomi and Fusarium verticillioides in commercial potting substrates for ornamental plants

“…Spores and viability of F. verticillioides and other Fusarium species were able to germinate under high salinity conditions in fluvial channels and sea beds (Palmero Llamas, De Cara, Iglesias Gonzalez, Ruíz Lopez, & Tello Marquina, ). The causal agent of pine pitch canker, F. circinatum , was recovered in low proportions (relative to the initial inoculum load) after inoculation onto pine needles and wood pieces, possibly due to decreasing in humidity and increasing temperatures in infested forest soils (Serrano, Iturritxa, Elvira‐Recuenco, & Raposo, ).…”

EU Legislation on Forest Plant Health: an Overview with a Focus on <em>Fusarium Circinatum</em>

“…Fusarium circinatum can also be disseminated by movement of soil. The pathogen survives in infested debris onthe soil surface for up two years, but not in soil [69]. This is more likely due to the lack of survival structures and low inoculum potential.…”

“…This is more likely due to the lack of survival structures and low inoculum potential. Serrano et al (2017) indicated that the number of surviving F. circinatum spores in soil is high for a short time. This finding provides additional evidence that the pathogen may persist in soil long enough to be regarded as a vehicle for spreading to new areas [69].…”

“…Serrano et al (2017) indicated that the number of surviving F. circinatum spores in soil is high for a short time. This finding provides additional evidence that the pathogen may persist in soil long enough to be regarded as a vehicle for spreading to new areas [69]. In addition, F. circinatum can overwinter in infected branches and logs from which insect vectors can emerge and spread the pathogen.…”