trichoderma species are among important antagonists of plant pathogenic fungi. the main purpose of this study was to evaluate the biocontrol potential of native trichoderma spp. isolates from sugar beet fields against phytophthora drechsleri and p. cryptogea, the causal agents of phytophthora root rot of sugar beet. during 2007–08, 85 isolates of trichoderma spp. from sugar beet fields in eight...

Water molds of the genus Phytophthora include many plant pathogens responsible for epidemics such as potato blight and sudden oak death, causing global economic damages. Sexual reproduction is of biological importance in Phytophthora and has been believed to be stimulated by unknown endogenous factors named a hormones. We describe here the chemical characterization of a Phytophthora mating horm...

Oomycetes, or water moulds, are fungal-like organisms phylogenetically related to algae. They cause devastating diseases in both plants and animals. Here, we describe seven oomycete species that are emerging or re-emerging threats to agriculture, horticulture, aquaculture and natural ecosystems. They include the plant pathogens Phytophthora infestans, Phytophthora palmivora, Phytophthora ramoru...

To date the majority of work on the systemic fungicide phosphite (phosphonate) to control Phytophthora diseases has been conducted on horticultural crops. There is a paucity of work on the control of Phytophthora root and collar rots in natural plant communities. This paper gives an overview of studies conducted in Western Australia which examine the potential of using phosphite in plant commun...

In order to limit the incidence and severity of diseases caused by Phytophthora, effective management strategies are needed. Management of phytophthora diseases is based on a number of principles such as avoiding infection through basic hygiene, limiting susceptibility through drainage and irrigation, improving soil health, use of disease-resistant germplasm, and biological and chemical control...

Phytophthora is a microbial genus that includes species causing many diseases (Erwin and Ribeiro, 1996). These species infect and kill nearly all species of deciduous fruit trees. Phytophthora crown and root rots, which are caused mainly by P. cactorum, P. megasperma, P. citrophthora, P. cinnamomi, P. cambivora, P. syringae and P. cryptogea (Sarejanni, 1935; Kouyeas, 1971; Kouyeas, 1977; Flores...

American chestnut is one of hundreds of plant species plagued by root rot caused by Phytophthora cinnamomi. Phytophthora root rot is thought to have contributed to chestnut dieback prior to the arrival of chestnut blight, and it may now present a serious limitation to establishment of blight-resistant hybrid chestnut. We manipulated soil compaction and moisture to evaluate the effect of soil ph...

In 2008 statewide surveys of symptomatic foliage of nursery plants from Tennessee resulted in isolation of 43 isolates of Phytophthora spp. This sample set includes four described species (P. citrophthora, P. citricola, P. nicotianae, P. syringae), and a provisional species of Phytophthora ('P. hydropathica'). At the same time a stream-baiting survey was initiated to recover Phytophthora from e...

A recent study to determine the cause of collar and root rot disease outbreaks of cold tolerant Eucalyptus species in South Africa resulted in the isolation of two putative new Phytophthora species. Based on phylogenetic comparisons using the ITS and beta-tubulin gene regions, these species were shown to be distinct from known species. These differences were also supported by robust morphologic...

ABSTRACT Phytophthora nicotianae and P. palmivora infect and cause rot of fibrous roots of susceptible and tolerant citrus rootstocks in Florida orchards. The infection and colonization by the two Phytophthora spp. of a susceptible citrus host, sour orange (Citrus aurantium), and a tolerant host, trifoliate orange (Poncirus trifoliata), were compared using light and electron microscopy. Penetra...