Phytophthora heveae A.W. Thomps., Malayan Agric. J.

Weir, Bevan S., Paderes, Elsa P., Anand, Nitish, Uchida, Janice Y., Pennycook, Shaun R., Bellgard, Stanley E. & Beever, Ross E., 2015, A taxonomic revision of Phytophthora Clade 5 including two new species, Phytophthora agathidicida and P. cocois, Phytotaxa 205 (1), pp. 21-38 : 34-35

Phytophthora heveae A.W. Thomps., Malayan Agric. J. 17(3–4): 77, 1929. IF252580.

≡ Phytophthora palmivora var. heveae (A.W. Thompson) Orellana, Phytopathology 49: 213, 1959.

Typification: — MALAYSIA. “ P. heveae Thompson , showing sporangia and oospore formation”, Plate 1 D (line drawing) in A.W. Thompson, Malayan Agricultural Journal 17(3–4): 53–100 (1929), lectotype designated here [IF550520]. MALAYSIA. Selangor: pod rot of Hevea brasiliensis (Willd. ex A. Juss.) Müll. Arg., Dec. 1927 , A.W. Thompson, culture preserved in a metabolically inactive state, CBS 296.29 (= IMI 180616 = WPC P3428 = ATCC 58815 = ICMP 19451 = KACC 44943), epitype designated here [IF550521].

Thompson (1929) did not designate a type specimen in his manuscript (not a requirement for valid publication prior to 1958). However, in the same year he deposited a culture of P. heveae as CBS 296.29. In 1974 this culture was deposited as IMI 180616, and in 1980 a dried culture of CBS 296.29 was deposited in the CBS herbarium as CBS H-7641. These cultures have the note “ isotype ” in the collection databases, but we have not been able to find any publication mentioning the typification of P. heveae , and the dates of deposition are too far apart for the cultures to be accepted as isotypes. Thus, to clarify the typification of P. heveae we designate Thompson’s original protologue line drawing of sporangia and oogonia (reproduced here as Fig. 7 ) as the lectotype, and his authentic culture as the epitype.

Description: —A description of this species is provided by Thompson (1929), and more recently by Erwin & Ribeiro (1996). Descriptions of sporangial caducity are inconsistent in the secondary literature. Caducous sporangia were not noted by Thompson despite extensive description of the sporangia on different media; if free sporangia had been observed he would very likely have described them, as he did for another species ( P. palmivora ) in the same article. The epitype culture CBS 296.29 = ICMP 19451 is described by the fungal database at Q-bank as non-caducous (www.q-bank.org). A P. heveae isolated from Rhododendron in North Carolina, USA (1400 = ICMP 19453) had persistent sporangia (Benson & Jones 1980). However, Albuquerque et al. (1974) reported caducous sporangia on P. heveae isolated from leaf blight of Brazil nut ( Bertholletia excelsa Bonpl. ), but also reported some paragynous antheridia, a character not observed in P. heveae in our research, nor reported by others. We examined sporangial caducity for an additional two isolates (ICMP 16691 and ICMP 19452) and found only persistent sporangia, even with very vigorous shaking in an attempt to dislodge the sporangium. Therefore we emend the description of P. heveae to include persistent (non-caducous) sporangia, the same characteristic as all other Phytophthora Clade 5 species ( Table 3).

Other specimens examined:— AUSTRALIA. New South Wales: Wyong, soil under Eucalyptus pilularis Sm., 1976 , L. Gerrettson-Cornell, culture ATCC 64863 = DAR 27023 = ICMP 16691 = IMI 208224= WPC P3475. CHINA. Hainan Island: forest soil, Hon Ho, culture LMM6 = ICMP 17964 = WPC P10660. GUATEMALA. Los Aposentos: canker on trunk of Persea americana Mill., 1975 , G.A. Zentmyer, culture ATCC 38692 = CBS 954.87 = ICMP 19452 = WPC P1000. MALAYSIA. Trengganu: Jerangau Estate, Theobroma cacao , 14 Jan 1968, P.D. Turner, specimen Herb. IMI 131093, culture ICMP 16914 = IMI 131093 = WPC P0578. USA. North Carolina: dieback of Rhododendron , 1976, DM Benson, culture 1400 = ATCC 46299 = CBS 958.87 = ICMP 19453 = WPC P1717.

Figures

FIGURE 7. Plate ID (lectotype) from Thompson (1929), original caption: “P. heveae Thompson, showing sporangia and oospore formation”.