Erysiphe machilicola I. Zafar, Afshan & Khalid, 2023

Zafar, Irsa, Afshan, Najam-Ul-Sehar, Khalid, Abdul Nasir & Götz, Monika, 2023, Erysiphe machilicola: a new powdery mildew species on Duthie’s Bay Tree, Phytotaxa 594 (4), pp. 283-291 : 287-288

Erysiphe machilicola I. Zafar, Afshan & Khalid sp. nov. ( Fig. 2 ) MycoBank no. MB846778

Diagnosis:— Erysiphe machilicola ( Erysiphe sect. Uncinula subsect. Uncinula ) is distinct from morphologically similar Erysiphe species On hOsts Of the LaUraceae by having lOnger cOnidiOphOres (120‒175 µm) Up tO 210 µm lOng (inclUding cOnidia), larger chasmOthecia (116–148 µm), and lOnger appendages (135–290 µm), abOve all, it differs from E. machilina ( Erysiphe sect. Uncinula subsect. Uncinuliella ) in lacking bristle-like appendages (remnant of anchor hyphae), fewer uncinuloid appendages with non-enlarged apices and 7–8-spored asci, with much smaller ascospores.

Type:— PAKISTAN. Azad Jammu & Kashmir: District Kotli, elevation 579 m alt., 33.58°N, 74.91°E, 11 th Dec, 2020, I. Zafar and N.S. Afshan [AJK-20] ( LAH37584 – HOLOTYPE), on leaves of Machilus duthiei King ex Hook.f. GenBank accession number: ( OP933721 ) .

Etymology:— the species epithet is composed of the name of host genus, Machilus , and -cola, meaning “colonizer”.

Description:— MYCELIUM amphigenous, mainly epiphyllous,thin,effuse,persistent.HYPHAE hyaline,thin, smoothwalled, 4–8 µm wide. HYPHAL APPRESSORIA lObate tO mUltilObate, sessile, variable, 4–7 µm diam. CONIDIOPHORES erect, straight, (120‒175 µm) Up tO 210 µm lOng (inclUding cOnidia), 5–10 µm wide. FOOT CELLS cylindrical, straight, 88–102 × 5‒9 µm, fOllOwed by 1–2 shOrter cells. CONIDIA single, sUbcylindrical, 19–40 × 8–12 µm. CHASMOTHECIA scattered to gregariOUs, brOwn tO black, 116–148 µm diam. PERIDIUM CELLS cOnspicUOUs, pOlygOnal, 8–16 µm diam. APPENDAGES 12–16 per chasmothecium, either long or short, uncinuloid, arising around the chasmothecial middle (equatorial zone), 0.5–1.5 times as lOng as the chasmOthecial diam., 93–135 µm, width 4–6 µm thrOUghOUt Or at mOst slightly increasing tOwards the tip, apex tightly Uncinate-circinate, nOt enlarged, walls thick belOw (2–6 µm), gradUally becOming thinner towards the tip.ASCI 7–8 per chasmothecium, mostly stalked, rarely sessile, hyaline, globose, subglobose or ellipsoidal, 38–45 × 26–33 µm, 7–8-spOred. ASCOSPORES light grey in cOlOr, ellipsOidal tO OvOid, 13–20 × 9–12 µm.

Additional material examined:— PAKISTAN. Azad Jammu & Kashmir: District Sudhanoti, elevation 1372 m alt., 33.71°N, 73.68°E, 12 th Oct. 2021, I. Zafar and N.S. Afshan [AJK-41] ( LAH37585 ), on leaves of Machilus duthiei. GenBank accession number: ( OP933720 ) .

Figures

FIGURE 2. A., B. Leaves of Machilus duthiei infected by Erysiphe machilicola. C. Chasmothecia of E. machilicola. D. Chasmothecium, E. ChasmOthecial appendages, F.AscUs with ascOspOres, G. AppressOriUm shOwn by arrOw, H‒I. COnidia, J. COnidiOphOre. Scale bars:A = 2 cm, B = 2 cm, D = 30 µm, E = 30 µm F = 15 µm, G = 10 µm, H‒I = 15 µm, J = 30 µm.