First Report of <i>Pythium dissotocum</i> and <i>Globisporangium sylvaticum</i> associated with Kiwifruit Vine Decline Syndrome in Italy

Kiwifruit (<i>Actinidia deliciosa</i>) represents a crop of high economic importance, with Italy ranking as the third-largest global producer. In recent years, Italian kiwifruit orchards have been severely affected by Kiwifruit Vine Decline Syndrome (KVDS), a disease characterised by root rot, leaf chlorosis, phylloptosis, and progressive vine decline. To investigate the potential involvement of soilborne oomycetes in KVDS, a survey of symptomatic plants was conducted in the Latina province (Lazio, Italy). Two oomycete species, <i>Pythium dissotocum</i> and <i>Globisporangium sylvaticum</i>, were consistently isolated from diseased roots. Pathogenicity tests on <i>A. deliciosa</i> cv. 'Hayward' revealed that both species induced severe symptoms under waterlogged conditions, whereas only mild or no symptoms developed under regular irrigation. These results provide the first evidence that <i>P. dissotocum</i> and <i>G. sylvaticum</i> can contribute to KVDS symptomatology in Italy. These findings offer new insight into KVDS dynamics, highlighting the variability of pathogenic species involved. Similar oomycetes with comparable pathogenic traits have been previously reported, reinforcing the multifactorial nature of the disease and the influence of environmental stress, particularly waterlogging, on its expression.