Neopestalotiopsis formicidarum Maharachch., K. D. Hyde & Crous [as ‘ formicarum’], Mycol. 79: 140 (2014)

Fig. 29

Description.

Pathogenic to rambutan ( Nephelium lappaceum) and associated with dry leaf spots of lemon drop mangosteen ( Garcinia intermedia). Sexual morph not observed. Conidiomata pycnidial on PDA, globose to clavate, solitary or aggregated in clusters, semi-immersed, black; with dark brown conidial masses. Conidiophores reduced to conidiogenous cells. Conidiogenous cells hyaline, smooth, ampulliform to lageniform, 5–15 × 2–6 μm. Conidia straight to slightly curved, ellipsoid, 4 - septate, 18.5–25.5 × 5–7.5 μm (mean = 22 × 6 μm, n = 30); basal cell conic, thin-walled, 3–7 μm long; three median cells doliiform, pale to dark brown, septa darker than the rest of the cell, 11–16 μm long (second cell from base pale brown, 3.5–6.5 μm long; third cell dark brown, 3.5–8 μm long; fourth cell brown, 3.5–7 μm long); apical cell hyaline, subcylindrical, 3–5 μm long; with 2–3 tubular apical appendages, unbranched, 15–33 μm long (mean = 23); basal appendage centric, single, unbranched, tubular, 4–7.5 μm long (mean = 5).

Culture characteristics.

Colonies on PDA reach 30–40 mm in diameter after 7 days of growth at 25 ° C under 12 h daylight, cottony, with moderate aerial mycelium on the surface, edge undulate. The upper view is whitish with a black fruiting body. The reverse is yellow to pale honey-colored, with black, gregarious conidiomata.

Material examined.

Thailand • Chiang Rai Province, Mueang Chiang Rai District, Ban Du, the fruit of rambutan ( Nephelium lappaceum, June 2023, Maryam Fallahi, dried culture L 2-7 (MFLU 24-0259), living culture MFLUCC 24-0254 ; Thailand, Chiang Rai Province, Mueang Chiang Rai District, Doi Hang, on lemon drop mangosteen ( Garcinia intermedia), January 2023, Maryam Fallahi, dried culture MF 11-3 (MFLU 24-0257), living culture MFLUCC 24-0233 .

Notes.

The strain MFLUCC 24-0254 and MFLUCC 24-0233 clustered with strains of Neopestalotiopsis formicidarum in the same subclade with 80 % ML bootstrap support and 0.90 BYPP (Fig. 28). The base pair differences between N. formicidarum strains MFLUCC 24-0254 and ex-type CBS: 362.72 revealed a 0.79 % nucleotide difference in ITS (4 / 506 bp) and a 0.75 % difference in tub 2 (3 / 445 bp). They showed no difference in tef 1. Neopestalotiopsis formicidarum (MFLUCC 24-0254) is similar to the ex-type strain of N. formicidarum (CBS: 362.72) (Maharachchikumbura et al. 2014). However, it produces slightly shorter conidia than that of the ex-type strain with an L / W ratio = 3.6 (18.5–25.5 × 5–7.5 μm (mean = 22 × 6 μm) in N. formicidarum (MFLUCC 24-0254) vs. 21–28 × 7.5–9.5 μm (mean = 24.6 × 8.6 μm) in N. formicidarum (CBS 362.72, ex-type)). Neopestalotiopsis formicidarum was first reported as a saprobic species collected from dead ants in Ghana and plant debris from Cuba (Maharachchikumbura et al. 2014). This is the first host record on rambutan and lemon drop mangosteen for N. formicidarum worldwide.