M 188: Biology and ecology of Phytophthora citricola in native plant communities affected by mining. Felicity Bunny Dr Bryan Shearer July 1995 . '' Acknowledgements This work was funded by Mineralsand Energy Research Institute of Western Australia. Facilities were provided by the Department of Conservation and Land Management. Thanks go to the many people who provided assistance with this project, especially; Alcoaof Australia Limited for help with the section on distribution of Phytophthora citricola in the northemjarrah forest, Giles Hardy foradvice and encouragement, Sue Broughton, Carla Wilkinson, Brendan Smithand Joanne Robinson for technical assistance. Summary .................................................................................................................................................... l Management recommendations. ................................................................................................................. 2 Section l. Distribution of Phytophthora citrico/a on soil surface and at depth in the northern jarrah forest....................................................... ......................................................................................... 4 Abstract ........................................................................................................................... 4 Introduction.......................................................... ........................................................... 4 Materials and Methods................................... ................................................................. 5 Results....... ....................................................................................................................... 6 Discussion....................................................................................................................... 11 Section 2. Differentiation of local isolates of Phytophthora citrico/a into subgroups basedon isozyme analysis, morphology andcultural characteristics, andvariability in pathogenicity.. ...................... 14 Abstract.................................... ....................................................................................... 14 Introduction....................................................................................................... .............. 14 2. l lsozyme analysis ..................................................................................................................... 15 Materials and methods................................................................... .................................. 15 Results ............................................................................................................................. 18 Discussion ....................................................................................................................... 20 2.2 Cultural variationbetween isolates of Phytophthora citrico/a .................................................. 21 Introduction.............................. ....................................................................................... 2 l Materials and methods........................................................... .......................................... 22 Results............................................................................................................................. 22 Discussion ....................................................................................................................... 23 2.3 Variability in sporangiaand oospore dimensions between electrophoretic types of Phytophthora citricola. ................................................................................................................. 24 Introduction......................... ............................................................................................ 24 Materials and methods..................................................................................................... 24 Results ............................................................................................................................. 25 Discussion ....................................................................................................................... 26 2.4 Variability in pathogenicity of isolates of Phytophthora citrico/a on jarra11 (Eucalyptus marginala) clones. ................................................................................................. ... 29 Introduction......................... ............................................................................................ 29 Materials and methods............................... ...................................................................... 29 Results ............................................................................................................................. 30 Discussion ............................................................................... ....................................... 3 l 2.5 Effect of phosphonate amendment of media on in vitro growth of Phytophthora citricola . ................................................................................................................. 32 Introduction ..................................................................................................................... 32 2.5.1 Effectof amendment of media with 10 ppm phosphonate on isolates of SG 1 and SG 2 ........................................................................................................... ........... 33 Materials and methods..................................................................................................... 33 Results................................................................ ............................................................. 33 Discussion ....................................................................................................................... 33 2.5.2 In vitro effect of 15, 30 and 50 ppm phosphonate on isolates of Phytophthora citricola of SG l and SG 2 ......................................................................... 35 Materials and methods................................................... .................................................. 35 Results...................................... ....................................................................................... 35 Discussion ....................................................................................................................... 36 3. Seasonal effect of soil temperature and moisture on survival of different propagules of Phytophthora citricola at two field sites ................ ........... ........ ........................... ........ .. .......... ..... ........... ... 37 Abstract .... ... ................................... ... .... ... ............ ... .. .. ... ... ... .... ..... ... .............. ..... ... .... .... 3 7 Introduction ..... ... ................ ..................... ... ..... ..... .. ... ..... ... ................. ............ ... ... .. .. ... .... 3 7 Materials and methods ...... .. ............... ....... ...... ........... .... ...... ........................................... 38 Results ............. .... ..... .. .................... .. .... .... .. .. .... .. ... ..................... ..... ...... ... ............. ...... .... 43 Discussion ...... ..... ......... .. ... .... ... .......... .. ... .... ....... ..... , ..... ..... .... ..... ... .................... ... ...... .... 57 4. Production of oospores by Phy tophthora citricola in two field soils ... ........ ....... ...... .... ... ................ ...... .... 63 Abstract .... .. .... .... ... ................. ... .... ....... .... .......... .. ..... .... .. ............ ,._. .. ... ..... .. .. ..... .... ..... .. .. 63 Introduction ....... ..... ... .... ... .. .... .. .. ... ............. ...... .. ..... ........ ... ............. : .. .......... ... .......... ..... 63 Materials and methods .......... ... .... ....... ..................................... ... ...... ... ... .. ... .... .. ... ... .. ..... 63 Results .... ....... ...... ...... ..... .. .. ..... .... ..... ..... ......... ... ...... .... ....... .... .. .............. ..... .... .... ...... ...... 64 Discussion .... ........ ... .. .................................. ..... .. .. ........ ... ............. ... ..... .. ................... .... .. 65 5. In vivo effects of phosphonate on Phytophthora citricola isolates of SG l and SG 2 ........ ........ .... .. .. ... .... 67 Abstract .. .. ..... .. ......... ........... ... ... .... ... .... ... ... ... ...... .. .... .. ... ........ ... .. ........ ... .. ... .... ..... .. ......... 67 Introduction ......................................... .. .. ... .. .... .................... ... ... .... ................ ....... ..... ... .. 67 Materials and methods .......... ... ...................... .... ... ... ....... ............. .... ..... .. ... .... ... .. .. ........ .. 67 Results ..... ... .... .. .. .... .... ... ............ ............ ...... .. .. ........ ... ..... ............ .. .... .... ..... ... ... ....... ........ 68 Discussion .... ........................................................................... .............. .... ...................... 71 Table 4.2. Numbers of oospores produced in two soils at Moore River and Dwellingup by four Phytophthora citricola isolates ... ............ ... .. ....... ..................... .... ..... .. ...............