The BSPP’s MRes/MSc bursary allowed me to complete the necessary practical work for my MRes thesis titled “Investigating the potential for forest insects to mediate needle blight pathogens”. This project aimed to investigate whether forest beetles were carriers of Dothistroma septosporum. It also aimed to investigate whether two other commonly misidentified needle blight pathogens, Dothistroma pini and Lecanosticta acicola, were also present at the study site. These two needle blight pathogens have not yet been detected in the UK. Dothistroma needle blight and brown spot needle blight both pose very severe risks to the forestry sector and timber industry. Pines are favoured in the timber industry as they are fast growing and as the global demand for softwood is rising these specific pine pathogens could continuously have detrimental effects on national economies. Increased frequency and range of international trade and personal travel is contributory to the dispersal of spores, infected material and the consequential globalisation of plant pathogens. This, coupled with, the increase of the movement of plants and plant material, poses a great challenge to biosecurity. Even with quarantine procedures in place, without the consideration of alternative dispersal mechanisms, such as beetle carriers, the threat of D. septosporum, D. pini and L. acicola to both pine plantations and natural woodland could continue to increase.
This project commenced with field-based sampling. Six flight intercept invertebrate traps were placed, to capture invertebrates for downstream analysis, at Roddlesworth forest, Lancashire, England. Tarpaulins were used to shelter the traps from the usual dispersal mechanisms of D. septosporum, which is rain splash. In order to confirm the effectiveness of the protective tarpaulin, six pairs of spore traps were placed at each trap location with one trap under the tarpaulin protected from the usual dispersal mechanisms and one exposed to the elements. After collection DNA was extracted from whole beetle samples, and the ethanol used to lure and store the samples, using the Qiagen DNeasy Plant Pro kit following the manufacturer’s instructions. Preliminary PCR’s were conducted to detect the presence of the three fungal pathogens, following this presence-absence analysis was done using QuantStudio5 Real-Time PCR system for more sensitive detection.
In total 219 beetles across 12 species were used for further molecular analysis, the molecular presence-absence analysis tentatively proposes the presence of all three fungal pathogens at the sample site. D. septosporum was present on three beetle species out of twelve, D. pini was apparent on five species out of twelve and L. acicola occurred on three species out of twelve. The ethanol used to store the samples also showed apparent presence of all three fungal pathogens. A significant difference was also found in the total number of fungal spore like structures counted on covered and uncovered spore traps. This indicated that the protective tarpaulin was an effective protection method and would be appropriate to trial in further invertebrate-fungi studies.
Throughout this study, all three needle blight pathogens: red band needle blight (D. septosporum and D. pini) and brown spot needle blight (L. acicola) were tentatively discovered at the sample site. Primarily, it can be confirmed that D. septosporum is present at the sample site as initially reported. Secondly, it can also be cautiously reported that D. pini and L. acicola are also present throughout this location based on the preliminary molecular investigations undertaken in this study, however further analysis needs to be performed to be completely certain. If confirmed, this would be the first confirmation of D. pini and L. acicola in the UK.
Further molecular work, since the completion of this project, showed there to be no evidence of the three needle blight pathogens in the invertebrate samples. However, the molecular presence absence analysis used in the original MRes has the potential to be a valuable tool when exploring the geographical range of plant pathogens. As well as investigating further ecological interactions between pathogens, hosts, vectors and potential carriers.
Edge Hill University