The Brazilian peppertree seed-borne pathogen, Neofusicoccum batangarum, a potential biocontrol agent

The invasive exotic Brazilian peppertree, Schinus terebinthifolius Raddi (Sapindales: Anacardiaceae) has become a serious threat to the delicate ecosystem of Everglades National Park in Florida, USA. More than 4000 ha in the Hole-in-the-Donut (HID) area within the park have been infested with Brazilian peppertree. Brazilian peppertree is a prolific seed producer, which enhances its invasive potential. Native phytopathogens can be a viable tool in the management of exotic species; no prior studies have reported on the occurrence of native seed-borne pathogens of Brazilian peppertree in Florida. This study showed that drupes of Brazilian peppertree are affected by seed-borne fungal pathogens. These fungal pathogens either cause germination failure or attack seedlings after germination, which results in reduced vigor or seedling death. The seed-borne fungal isolate BPSPF-1 was found to be virulent, and when inoculated it was able to kill Brazilian peppertree seedlings in seedling assays, and 1 year old saplings in greenhouse trials. Field inoculation of Brazilian peppertree branches with BPSPF-1 resulted in dieback symptoms. Host range studies on one related native species (winged sumac, Rhus copallinum) and one non-native species (mango, Mangifera indica) showed that neither was affected by girdle inoculation of stems. The BPSPF-1 isolate produced dark melanized mycelium on agar media and did not produce conidia or other fruiting structures. Based on ITS DNA sequence analyses, the isolate was identified as Neofusicoccum batangarum.

Brazilian peppertree sapling death and vascular discoloration following Neofusicoccum batangarum inoculation.Figure optionsDownload as PowerPoint slideResearch highlights
► Seed viability and survival of invasive exotic Brazilian peppertree affected by seed-borne fungi.
► Neofusicoccum batangarum, a seed-borne fungus caused die-back symptoms on Brazilian peppertree.
► Neofusicoccum batangarum did not cause die-back symptoms on mango and winged-sumac.