01812nas a2200229 4500008004100000022001300041245008200054210006900136300001500205490000700220520111000227653002301337653001001360653003101370653001801401653001701419653001901436100001701455700001201472700001501484856008301499 1995 eng d a0032086200aAn unusual Phytophthora associated with widespread alder mortality in Britain0 aunusual Phytophthora associated with widespread alder mortality  a999 - 10070 v443 a

During 1993 and 1994 an unusual Phytophthora was consistently isolated from bark lesions at the stem bases of dying alder in Southern Britain. The Phytophthora resembles P. cambivora in both its gametangial and sporangial morphology. However, it is distinct from this species in being homothallic rather than outcrossing; in producing a significant proportion of small and sometimes partially developed oogonia; in having a high frequency of oosphere abortion; in having an appressed felty colony type with little or no aerial mycelium; and in exhibiting a lower optimum temperature for growth (c.22.5°C) and lower growth temperature maximum (c.29°C) on carrot agar than P. cambivora (c.27.5° and 33.5°C respectively). An inoculation test confirmed its pathogenicity to Alnus. The status of the alder Phytophthora is discussed. On the basis of its unusual characteristics and unusual host it is suggested that it might be a new or recently introduced organism rather than a previously unrecorded indigenous variant of P. cambivora.

10aAGRICULTURAL pests10aALDER10aALDER – Diseases & pests10aGREAT Britain10aPhytophthora10aPLANT diseases1 aBrasier, C M1 aRose, J1 aGibbs, J N uhttp://onlinelibrary.wiley.com/doi/10.1111/j.1365-3059.1995.tb02658.x/abstract02186nas a2200157 4500008004100000245015800041210006900199260001200268300001200280520161700292100001801909700002201927700002001949700001601969856004301985 2014 eng d00aUpdate on the 35-year expansion of the invasive root pathogen, Phytophthora lateralis, across a landscape of Port Orford cedar (Chamaecyparis lawsoniana)0 aUpdate on the 35year expansion of the invasive root pathogen Phy c11/2014 a165-1683 a

Port Orford cedar (Chamaecyparis lawsoniana) is endemic to northern California and southwestern Oregon and is considered a foundation species that plays critical roles in riparian areas and on nutrient-poor soils. Since 1952, a non-native, pathogenic oomycete (Phytophthora lateralis) has been spreading throughout the range of the cedar. Most spread occurs by vehicles carrying infested soil along gravel roads primarily used for timber harvest. In a previous study conducted in 1998 and 1999, Port Orford cedar and P. lateralis were censused in a 37-km2 study area and dendrochronology was used to reconstruct the history of pathogen invasion. That work, which represents the only detailed analysis of spread rates for P. lateralis, showed that the first successful invasion into the study area took place in 1977 and that 43% of the susceptible host sites (stream crossings) were infested by 1999. In the work presented here, all sites that were uninfested in 1999 were re-censused in 2012, extending the historical reconstruction of P. lateralis spread to 35 years. Two new infestations were initiated between 1999 and 2012, suggesting that the rate of spread of P. lateralis has slowed greatly. Between 1980 and 1989, the average number of new site infestations was 1.8 infestations per year, while between 1990 and 1999 the average was 0.4 infestations per year and between 2000 and 2009 the average was 0.2 infestations per year. Several potential explanations for the reduced number of new infestations are discussed.

1 aJules, E., S.1 aSteenbock, C., M.1 aCarroll, A., L.1 aVannini, Á uhttp://doi.wiley.com/10.1111/efp.1215800377nas a2200121 4500008004100000245003900041210003900080300001000119490000600129100001400135700001200149856009400161 1870 eng d00aÜber die Fäule der Cactusstämme0 aÜber die Fäule der Cactusstämme a51-570 v11 aLebert, H1 aCohn, F uhttps://forestphytophthoras.org/references/%C3%BCber-die-f%C3%A4ule-der-cactusst%C3%A4mme00499nas a2200121 4500008004100000245008400041210006900125260003700194300000700231490000700238100001800245856011400263 1970 eng d00aAn undescribed Phytophthora sp. recovered from beneath stands of Pinus radiata.0 aundescribed Phytophthora sp recovered from beneath stands of Pin aNew ZealandbAuckland University a630 vMS1 aMcAlonan, M J uhttps://forestphytophthoras.org/references/undescribed-phytophthora-sp-recovered-beneath-stands-pinus-radiata03268nas a2200193 4500008004100000022001400041245014000055210006900195260001600264300000600280490000700286520263600293100001902929700001802948700001802966700001902984700001803003856005303021 2014 eng d a1179-539500aThe use of adjuvants to improve uptake of phosphorous acid applied to Pinus radiata needles for control of foliar Phytophthora diseases0 ause of adjuvants to improve uptake of phosphorous acid applied t cJan-01-2014 a80 v443 a

Background

Phosphorous acid is being investigated as a fungicide for the management of a needle disease caused by Phytophthora pluvialis in Pinus radiata in New Zealand. However, little is known about the penetration characteristics of this fungicide into Pinus radiata foliage. This study was undertaken to determine: i) the penetration characteristics of a commercial phosphorous acid formulation, applied at 3 kg ha-1 and 12 kg ha-1 in 100 L water, into Pinus radiata foliage and, ii) the effect of four commercially available adjuvants on phosphorous acid uptake into Pinus radiata foliage. Efficacy of the best treatment was tested in vitro with two Phytophthora species, Phytophthora kernoviae and P. pluvialis.

Methods

Foliar uptake of orthophosphoric acid radio-labelled with [32P] was used to determine penetration characteristics of phosphorous acid as affected by the adjuvants tested. Needles collected from potted Pinus radiata plants sprayed with the best performing treatment were used in a detached needle assay, where treated needles were exposed to the zoospores of the Phytophthora species being tested.

Results

Uptake of the phosphorous acid formulation into Pinus radiata needles applied without adjuvants was low (3.9-6.6%) at both concentrations tested. An alcohol ethoxylate adjuvant (applied at 0.2%) and two organosilicone adjuvants (applied at 0.2%) were found to significantly increase uptake of the fungicide over that applied alone or in combination with pinolene (applied at 0.35%). Highest uptake of phosphorous acid into Pinus radiata foliage (51.6%) occurred over a period of 72 hours when the phosphorous acid was applied at the equivalent of 12 kg ha-1 with an organosilicone blend adjuvant at 0.2%. A significant reduction in lesion length on infected needles was found relative to the control when the two phosphorous acid treatments were applied with 0.2% organosilicone blend adjuvant. However, there were no significant differences in lesion length between the two treatments.

Conclusions

These results show that an organosilicone adjuvant significantly enhances uptake of phosphorous acid into Pinus radiata needles and may increase its efficacy against Phytophthora species.

1 aRolando, Carol1 aGaskin, Robyn1 aHorgan, David1 aWilliams, Nari1 aBader, Martin uhttp://www.nzjforestryscience.com/content/44/1/8