Characterization of Phytophthora spp. on Floriculture Crops in North Carolina

Abstract

Olson, H. A., and Benson, D. M. 2011. Cbaracterization of Phytophthora spp. on floriculture crops in Nortb Carolina. Plant Dis. 95:1013-1020.Isolates of Phytophthora in floriculture crops were collected from North Carolina commercial greenhouse facilities in 2t)()7 and 2008, identified, and characterized for mating type and mefenoxam sensitivity. In all, 163 isolates from 13 host species at 11 locations were identified primarily as Phytophthora nicotianae (59%), P. drechsleri (23%), P. cryptogea (9%), and P. tropicalis (4%). Multiple Phytophthora spp. were found at five locations. DNA sequencing was more reliable for differentiating P. cryptogea and P. drechsleri. Only tbe A1 mating type of P. drechsleri was collected; bowever, both mating types of P. nicotianae. P. cryptogea, and P. tropicalis were found. Overall, 66% of Phytophthora isolates were resistant or intermediate in resistance to mefenoxam at 1 (jg a.i./ml. Tbree groups of P. drcchsleri isolates had effective concentration of mefenoxam providing 50% growth inhibition (EC51,) estimates over 7(K) \ig a.i./ml. EC,n estimates for P. nicotianae ranged from 246 to 435 |jg a.i./ml. Isolates of P. nicotianae exbibited phenotypic heterogeneity at several locations, suggesting multiple separate introductions to tbe facilities. In contrast, P. nicotianae and P. drechsleri isolates from two locations were pbenotypically identical to a previous survey, suggesting tbat tbe facilities bave Phytophthora spp. established onsite.

Identification and Characterization of Fusarium Species Associated with Wilt of Eleocharis dulcis (Chinese water chestnut) in China

“…Fungal growth was examined daily for up to 5 days. Isolates were transferred to fresh PDA and purified by single-spore culturing (23). All fungal isolates were placed on fresh PDA slants and stored at 4°C.…”

Host Specificity and Variations in Aggressiveness of North Carolina Isolates of Phytophthora cryptogea and P. drechsleri in Greenhouse Ornamental Plants

“…Three isolates of P. cryptogea (Pc597, Pel 105, and Pel 146) and three iso-lates of F. drechsleri (PdlO3, Pd957, and Pdfdm5) were chosen from a collection of isolates obtained during two surveys of North Carolina greenhouse ornamentals (Table 1) (12,25). Eight ornamental plant speeies commonly grown in North Carolina greenhouses were tested as hosts of isolates of P. cryptogea and P. drechsieri.…”

“…Both species, along with P. nicotianae and P. tropicalis, were recovered during a 2007 to 2008 survey of floriculture crops in North Carolina greenhouses (25). Both species, along with P. nicotianae and P. tropicalis, were recovered during a 2007 to 2008 survey of floriculture crops in North Carolina greenhouses (25).…”

Phytophthora Species Recovered From Irrigation Reservoirs in Mississippi and Alabama Nurseries and Pathogenicity of Three New Species

“…As nurseries develop the capacity to pump irrigation water from containment basins that capture runoff from nursery production areas, even more attention and concern are being focused on the dispersal of Phytophthora spp. by irrigation water (Bush et al 2003;Hong et al 2008a;Loyd et al 2014;Olson and Benson 2011;Schwingle and Blanchette 2008;Warfield et al 2008;Yakabe et al 2009). The dispersal pattern of Phytophthora spp.…”

“…The research generated lists of Phytophthora spp. recovered from symptomatic leaf, stem, crown, and root tissues; and from organic substrate, soil, and waterways in nursery production systems (Bush et al 2003;Ghimire et al 2009Ghimire et al , 2011Olson and Benson 2011;Olson et al 2013;Schwingle et al 2007;Warfield et al 2008;Yakabe et al 2009). Interestingly, species diversity varied with location, sampling source, and season.…”