First Report of Pestalotiopsis dyospiri Causing Calyx Blight of Sweet Persimmon in Huelva Province (Southwestern Spain)

Abstract

In November 2006, necrotic calyxes were observed in more than 90% of harvested sweet persimmon fruits (Diospyros kaki L. fil.), cv. Triumph, in orchards located in Huelva Province. Symptoms appeared on sepals as brown-to-black necrotic areas; one to four sepals per fruit could be affected. Necrotic sepal tissues were surface disinfected and placed on potato dextrose agar medium (PDA). A fungus was consistently isolated from affected tissue on 60% of fruits sampled. Isolates formed acervular conidiomata (75.7 ± 4.69 μm in diameter) with fusiform conidia that were straight or rarely curved. Conidia were five celled, including three umbercolored medial cells and hyaline apical and basal cells. All conidia possessed two to three apical appendages and a single basal one. Conidia (N = 60) were 17.03 ± 0.25 μm long × 4.55 ± 0.1 μm wide; the three medial cells were 11.78 ± 0.15 μm long and apical cells were 2.34 ± 0.11 μm, with apical appendages measuring 12.45 ± 0.36 μm. Basal cells were 2.98 ± 0.11 μm and basal appendages were 3.93 ± 0.14 μm long. On the basis of these characteristics, the causal agent was identified as Pestalotiopsis diospyri Sidow et P. Sidow (2), that was previously described as a persimmon pathogen on leaves in Japan (3). To confirm pathogenicity, calyxes of healthy unwounded fruits were sprayed with 3 ml of a conidia suspension (1.5 × 105 conidia per ml) and maintained in moist chambers at 24°C for 10 days. All fruits presented necrotic calyxes, and the pathogen was reisolated from affected tissue in 100% of the samples. P. diospyri has been reported to be present on calyxes of unhealthy persimmon fruits in different productive regions in New Zealand (1), but to our knowledge, this is the first time that pathogenicity of this fungus was demonstrated on sweet persimmon fruits in Spain. References: (1) H. H. Goh et al. Proc N Z Weed Pest Control Conf. 44:265, 1991. (2) E. F. Guba. Page 184 in: Monograph on Monochaetia and Pestalotia. Harvard University Press, Cambridge, MA. 1961. (3) F. Yasuda et al. J. Gen. Plant Pathol. 69:29, 2003.