SEPTEMBER 1981

Native plant species -Acacia baileyana F. Muel/., Banksia spinulosa Sm., B.ericitotie L. f., Callistemon viminalis D.C., Casuarina strictaDryand. in Ait., Dodondaea viscosa (L.) N.J. Jacq., Epacrisimpressa Labil/., Eucalyptus citriodora Hook., E. ticitoiie F.Muell., E. leucoxylon F. Muel/., E. ntchotti Maid. and Blake­ly, Exocarpos cupressiformis Labill., Grevillea juniperinaR.Br., G. punicea R. Br., Kennedya sp., Kunzea sp., Lep­tospermum laevigatum (J. Gaertn.) F. Muel/., Melaleucaelliptica Labil/., M. incana R.Br., M. nesophylla F. Muel/.,Polygala myrtitolie L., Tristania conferta R.Br.

Introduced species -Acer palmatum Thunb., Abelia grandif/ora (Andre) Rehd.,Azalea indica (L.) Sweet, Camellia sp., Citrus spp.,Cotoneaster sp., Erica canaliculata Andr., Euonymusjuponica L., Fraxinus sp., Fuchsia hybrida Voss, Hibiscusspp., Hydrangea macrophylla Ser., Jacaranda acutifolia

11027, 11057). From the known distribution of thisorganism (2) it is likely to be the most important causalspecies although in the Dandenong Rages other Armillariaspecies associated with wet sclerophyll eucalypt forestscould also be involved. Spread of A. luteobuba/ina is byroot contact (3,1). Infections often extend across adjoiningproperties and in several cases there has been evidence ofspread throughout whole street blocks.

Replanted trees and shrubs have died within a fewmonths in most cases due to remaining inoculum in theground from previously infected trees. Remaining infectedmaterial is a critical factor relative to any attempt made tocontrol spread of Armillaria in the suburban garden andoften results in a long-term expensive operation. Nospecies are known from field observations to be resistantto infection.

Recorded hosts include a wide range of native and in­troduced plant species:

NUMBER 3VOL. 10

Distribution and Hosts of Armillaria root rotin Melbourne Suburban Gardens

RESEARCH NOTES

Lynda SmithGarden Advisory Service, Department of Agriculture,

Swan Street, Burnley, Victoria 3121and

G. A. KileC.S.I.R.O., Division of Forest Research,

Creswick, Victoria 3363

Armillaria root rot has been found in over 50 home gar­dens in the past two years and, according to records thenumber is increasing substantially each year. The diseasehas been found mainly in the inner suburban and baysideareas, the highest incidence being between Hampton andBeaumaris. It has also been recorded outside the main ur­ban area at Altona, Emerald, Ferny Creek, Olinda andPearcedale (Fig. 1).

Losses attributed to Armillaria include not only the directcost of removing dead trees and the purchase of replace­ment plants, but also the reduced aesthetic value of thegardens and municipality. While the problem is not new, itssignificance is greater than has been previously ap­preciated. Trees affected by Armillaria root rot showwilting, marginal leaf scorch, crown thinning and branchdleback. Large trees may be infected for many yearsbefore declining rapidly as mycelial sheets spreadthroughout the root collar. Smaller surface rooted treesand shrubs often flower profusely before dying, generallywithin 6 to 24 months of the first appearance of symptoms.

Armillaria luteobuba/ina Watling and Kile (3, 1) has beenassociated with a number of infections by the occurrenceof basidiomes on infected plants (V.P.R./. 10993, 11003,

41

Scale 0 10 milesj:;;1:::=::=:::=::=:::=::=:iiiiiiiiiiiiiOiil!l~!!!!!!!!!!!!!!!!!!!!!!!!~""!

o l~ kilometers

Altona (I)o

Port Phillip Bay

(3)

o Chadstone (1)

oo Black Rock (9)

(4)

0Frankston (1)

Olinda (2)o

Ferny Creek (2)o

Emerald (3)o

Leongatha (1) c-

Pearcedale (1)o

Figure 1. Recorded occurence 0 of Armillaria root rot in the Melbourne region. Numbers in brackets indicate incidenceper suburb or town.

Humb, and Bon pI., Kalmia sp., Malus spp., Meliaazedarach L. var australasica C. D.C., Metrosideros ex­celsa Sol ex. G aertn., Photinia glabra (Thunb.) Maxim.,Picea pungens Engelm., Pinus radiata D. Don, Prunusspp., Syringa spp., Taxus sp., Tibouchina grandifoliaCogn., Virgilia oroboides (Berg.) Salter, Wisteria sinensisSweet.

REFERENCES

(1) Kile, G. A. (1981) - Armillaria luteobubalina: Aprimary causeof tree decline and death in mixed species eucalyptforests in central Victoria. Aust. For. Res. Vol. II. No.1. p.63-77.

(2) Kile, G. A., and Watling, R. (1981) - An expanded concept ofArmillaria luteobubalina. Trans. Br. Mycol. Soc. (in press).

(3) Podger, F. D., Kile, G. A., Watling, R., and Fryer, J. (1978) ­The spread and effects of Armillaria luteobubalinasp, nov. in an Australian eucalyptus regnans plantation.Trans. Br. Mycol. Soc. 71: 77-87.

42

Evaluation of Methods of Seed PickleApplication for Control of Loose Smut(Ustilago nude) in Barley

M. J. BarbettiDepartment of Agriculture,

Jarrah Road, South Perth, Western Australia 6151

Loose smut (Ustilago nuda (Jens.) Rostr.) of barley is aminor problem in Western Australia in most seasons (3).During spring 1978 numerous reports were received of abuild-up of loose smut in "Clipper" barley, especially in thewetter areas, with some crops having up to 10% of headssmutted. As tests showed that the fungus had notdeveloped resistance to the two main pickles (viz. Vitavax(carboxin) and Panoram (fenfuram)) used in these areas(M. J. Barbetti, unpublished data) it was thought that thebuild-up in loose smut may have been due to poor and un­even application of the pickle to the seed. To investigatethis possibility four methods of applying Vitzvax pickle tocv "Clipper" seed were compared in 1979 using seed with3.8% infection (assessed by an embryo staining technique