| Abstrakt: |
From 2016 to 2021, nematode surveys in Florida strawberry fields revealed several species of foliar nematodes (Aphelenchoidesspp.). Aphelenchoides besseyi sensu strictowas detected only in 2016 and 2017 on photosynthetic strawberry leaves/buds, but other not well characterized populations of Aphelenchoidessp. were found on declining/dessicated leaves. Morphological analyses showed that these samples of Aphelenchoidessp. consisted of A. bicaudatus, a species detected in Florida for the first time, and A. rutgersi, a species previously reported in Florida from the citrus rhizosphere. These two species differed from A. besseyiin the shape of their tail terminus: bifurcate in A. bicaudatus; mucronate with a ventral thin mucro in A. rutgersi; and stellate in A. besseyi. One population each of these species was used for morphological and molecular analyses after being reared on Monilinia fructicola. Body and tail length differences were observed among Florida A. bicaudatusand other populations from the Far East and South Africa. Phylogenetic analyses of the rRNA gene sequences showed that Florida A. bicaudatusgrouped with those of species from South Korea, Taiwan, and the Netherlands and several other populations listed as Aphelenchoidessp. from Brazil, Costa Rica, and Japan, which were considered as representatives of A. bicaudatusin this study. Similarly, sequences of Florida A. rutgersigrouped with those from environmental samples in Japan and North Carolina, which were listed as Aphelenchoidessp. and were considered as representatives of A. rutgersiin this study. Photosynthetic strawberry leaf samples were free from both A. bicaudatusand A. rutgersi, indicating that these two species did not damage strawberry. They were associated with desiccated leaves and/or propagative stolons, usually infected by fungi, confirming that they are mycetophagous under field conditions in this study. Results of soybean leaf inoculation on moist filter paper containing A. bicaudatusspecimens showed that this species could become phytophagous under artificial conditions. Nematodes penetrated the leaf epidermis and migrated into the mesophyll causing leaf tissue discoloration/necrosis, which remained localized within the infested area. Soybean leaf damage was almost negligible, and no nematode reproduction was observed in the inoculated soybean areas. |
