Feeding Selectivity ofAphelenchoides besseyiandA. pseudogoodeyion Fungi Associated with Florida Strawberry

Abstract

Aphelenchoides besseyi and A. pseudogoodeyi are foliar nematodes associated with commercial strawberry production in Florida, United States. The reproductive and feeding habits of these two nematode species were assessed on Florida isolates of the fungi Botrytis cinerea, Colletotrichum gloeosporioides, Macrophomina phaseolina, and Neopestalotiopsis rosae, which are pathogenic to strawberry, and nonpathogenic isolates of Fusarium oxysporum and Monilinia fructicola grown on potato dextrose agar in Petri dishes. Each culture was inoculated with six specimens of mixed life stages of A. besseyi or A. pseudogoodeyi and incubated at 24°C under axenic and nonaxenic conditions 23 and 31 days after inoculation, respectively. A. besseyi reproduction rates were greater on strawberry-pathogenic isolates of B. cinerea, C. gloeosporioides, and N. rosae than on the nonpathogenic isolates of F. oxysporum and M. fructicola. In contrast, reproductive rates of A. pseudogoodeyi did not vary among fungi cultures. For both nematode species, M. phaseolina was a poor host because it did not produce mycelium on the media used. Our findings indicate that A. besseyi is more selective in its fungal-feeding preference than A. pseudogoodeyi. Additionally, A. pseudogoodeyi eggs and juveniles were significantly more numerous than adults. Yet, for A. besseyi, adult stages were more abundant. Fungi aid in the maintenance of soil-dwelling populations of these two nematode species. Removing fungus-infected strawberry plant residues is both a desirable and effective management practice to limit A. besseyi in central Florida commercial strawberry fields.