Four members of Fusarium solani species complex (FSSC), F. cucurbiticola, F. petroliphilum, F. falciforme and F. keratoplasticum, cause foot, crown, stem and fruit rot in cucurbits. Although previous studies revealed that F. cucurbiticola was the pathogen causing crown and fruit rot in Taiwan melons, these are unreliable in assessing FSSC infection in cucurbits in Taiwan. We collected 47 FSSC isolates from the stem or fruit rot of bitter gourd, cucumber, luffa, melon and pumpkin, and three FSSC isolates from pumpkin seeds. Eleven pumpkin fruit rot isolates and two pumpkin seed isolates could not infect cucurbit seedlings. Luffa seedlings were tolerant to most FSSC isolates. None of the FSSC isolates could infect cucumber fruits and showed variable virulence in different cucurbit fruits. In addition, only certain FSSC isolates could be amplified by specific primers for F. cucurbiticola and F. petroliphilum. Multilocus sequence typing analyses separated FSSC isolates from the stem or fruit rot or seeds into three molecular groups with high bootstrap values: Group I isolates were F. petroliphilum (FSSC1), Group II isolates were F. solani‐melongenae (FSSC 21) and Group III isolates were F. falciforme (FSSC 3+4). The FSSC isolates amplified by specific primers for race 2 belonged to F. petroliphilum; however, the FSSC isolates amplified by specific primers for race 1 were not F. cucurbiticola. To our knowledge, the three species of the FSSC are novel causative agents in Taiwan.

Strawberry (Fragaria x ananassa Duch.) is an important crop worldwide. Tontonaka, Aroma and Benihoppe, are most popular cultivars in Taiwan, especially cv. Aroma is dominated in the market. In September 2021, the target spot outbreak occurred on the leaves of cv. Aroma and Benihoppe in Nantou County. In a greenhouse, the target spot incidents were estimated at 90-100% and 40-50% in Aroma and Benihoppe, respectively, and caused 2~5% plants lost. Between April and June of 2022, the target spot occurred in another greenhouse where the target spot incidents were 90% and 5-8% in Aroma and Benihoppe, respectively. Early symptoms were small and circular to irregular brown spot on the leaves with its diameter at 1-2 mm. Then the brown lesion expanded to 2-5 mm in diameter with pale green halo. Some lesions appeared with gray center, and 2-3 spots might merge into one lesion, and some lesions were surrounded with yellow tissues later. The round to oval brown spots were also observed on stems. Ten symptomatic leaves and stems each were collected for pathogen isolation. Pieces of tissue from the edge of the brown lesion on leaf were cut and disinfested with 0.6% NaOCl for 30 sec, and rinsed three times with sterile distilled water (SDW) followed by being placed on 2% water agar. The isolates obtained from symptomatic leaves/stems of Aroma and Benihoppe showed same colonies with 100% isolation rate. Isolates from cv. Benihoppe (Cos21-1) and Aroma (Cos21-2) were selected for further observation and tests. Colonies on potato dextrose agar exhibited gray aerial mycelium at 28 °C in dark after 7-day. Conidiophores were brown, single or in clustered, unbranched, 2 to 11 septa. Conidia were 5.6-6.7× 28.1-270.0 μm (n=50) in size with obclavate to cylindrical shape, 1 to 16 septa, and olivaceous to dark brown. Based on the morphology, two fungal isolates were identified as Corynespora cassiicola. Four regions, internal transcribed spacer (ITS), β-tubulin, translation elongation factor (TEF), and actin, were used to confirm the two isolates. Sequences of ITS and β-tululin shared 100% identity to ITS (MZ093622) and β-tululin (MW961419) of C. cassiicola in GenBank. Sequences of TEF and actin shared 99.60% and 99.70% identity to C. cassiicola (MK882240 and FJ853005), respectively. For the pathogenicity test, the conidial suspension (1x105 spores/ ml) of Cos21-1 and Cos21-2 was sprayed on leaves of two-month-old strawberry cv. Benihoppe and Aroma without wounds, respectively. Three plants each with more than two leaves were spray-inoculated with the selected isolates whereas three plants with SDW as controls and the test was repeated once. Inoculated plants were covered with plastic bags in the greenhouse, then removed when the initial symptoms were observed on leaves 5 days after inoculation whereas symptoms on stems were observed within 7 days. Re-isolation of the pathogens from the symptomatic leaves/stems demonstrated that the pathogen was C. cassiicola. The leaf spot or target spot caused by C. cassiicola on strawberry has been reported in Mainland China and North America. To our knowledge, this is the first report of target spot disease of strawberry caused by C. cassiicola in Taiwan.