Disease Notes Root and Basal Stem Rot of Rose Caused by Phytophthora citrophthora in Italy A. Salamone, CRA-SFM Unit�� di Ricerca per il Recupero e la Valorizzazione delle Specie Floricole Mediterranee, 90011 Bagheria, Palermo, Italy; G. Scarito, Dipartimento di Scienze Entomologiche, Fitopatologiche, Microbiologiche Agrarie e Zootecniche, University of Palermo, 90128 Palermo, Italy; A. Pane, Dipartimento di Scienze e Tecnologie Fitosanitarie, University of Catania, 95123 Catania, Italy; and S. O. Cacciola, Dipartimento di Chimica Biologica, Chimica Medica e Biologia Molecolare, University of Catania, 95125 Catania, Italy Approximately 800 ha of cut flower roses are cultivated for commercial production in Italy. During autumn of 2004 in an experimental greenhouse in western Sicily (southern Italy), 60% of 2-year-old plants of rose cv. Red France on Rosa indica cv. Major rootstock grown in soil showed leaf chlorosis and wilt. A dark brown lesion lined by a water-soaked area was noticeable at the stem base near the soil surface. Root rot was found consistently associated with aboveground symptoms and plants collapsed within 4 months after the appearance of the first symptoms. The same symptoms were observed sporadically on rose plants of the same cultivar during the last 6 years in commercial nurseries in western Sicily. In all cases, a Phytophthora species has been consistently isolated from rotted roots and stems on Phytophthora-selective media. Pure cultures were obtained by single-hypha transfers. The species was identified as Phytophthora citrophthora on the basis of morphological characters and electrophoretic analysis of mycelial proteins on polyacrylamide gel (1). On potato dextrose agar, isolates produced petaloid colonies with optimum growth temperature at 25��C. On V8 agar, mono- and occasionally bipapillate, ovoid to limoniform sporangia, measuring 44 to 55 �� 27 to 28 ��m, with a mean length/breadth ratio of 1.4:1 were produced. All isolates were heterothallic but did not produce gametangia in dual cultures with P. nicotianae isolates of A1 and A2 mating type. Electrophoretic patterns of total mycelial proteins and four isozyme (acid and alkaline phosphatases, esterase, and malato dehydrogenase) of the isolates from rose were identical to those of reference isolates of P. citrophthora, but clearly distinct from isolates of other heterothallic species with papillate sporangia, including P. capsici, P. nicotianae, P. palmivora, and P. tropicalis. All isolates from rose showed the same electrophoretic profiles. Blast search of rDNA-ITS sequence from PCR-amplified ITS4/ITS6 primers (2) of a representative isolate from rose (IMI 392044) showed 98% homology with a reference isolate of P. citrophthora (GenBank No. EU0000631), thus confirming the identification. Pathogenicity of isolate IMI 392044 was tested on 10 12-month-old plants of rose cv. Red France grafted on R. indica cv. Major transplanted in pots containing a mixture of sphagnum peat moss and sandy loam soil (1:1 vol/vol) infested with 80 g of inoculum per liter of mixture. Inoculum was produced by growing the isolate on wheat kernels. Plants transplanted in pots containing noninfested soil served as controls. Plants were kept in a greenhouse at 22 �� 3��C and watered to soil saturation once a week. Inoculated plants developed symptoms of leaf chlorosis and root and crown rot within 15 to 30 days and wilted within 40 to 80 days after inoculation. Control plants remained healthy. P. citrophthora was consistently reisolated from inoculated plants. Root and basal stem rot of rose may be caused by several Phytophthora spp. and has been reported in various countries of Asia, Europe, and North America (3,4). However, to our knowledge, this is the first report in Italy. The occurrence of this disease may be attributed to excessive irrigation practices. References: (1) S. O. Cacciola et al. EPPO Bull. 20:47, 1990. (2) D. E. L. Cooke et al. Fungal Genet. Biol. 30:17, 2000. (3) Y. Nagai et al. Phytopathology 68:684, 1978. (4) B. W. Schwingle et al. Plant Dis. 91:97, 2007.

Perhaps number 11 is to be sure and place them where small children and pets can easily stop and admire them. That way they are sure to be nibbled on regularly and knocked down often, ensuring their leaves are snapped, and the roots knocked about. Especially helpful when combined with Numbers 1 and 3 above. :-) Best, Judy

Rick, you will do just fine. I have to admit that I've had several cuttings that I will root with inflos on them. They are mainly cuttings that I am not sure what cultivar they are because they were "mystery" cuttings or unknown to me. Sometimes, I simply do not have the patience and I just can't wait to see the flower. Somehow, I just can't bring myself to cut them off most of the time. Perhaps having the greenhouse has made me spoiled in that regard. As for the reds, I know that I have to wait longer for it to root, however, and I've never had a red cultivar that possessed an inflo while rooting. Kohala has been my main challenge as of yet. Like I said before, I have a couple in the greenhouse right now and have been trying to root them for months now. They finally have "claws" but if they had inflos I would most defintely cut them off at this point. Getting tired of waiting for them to progress. I keep thinking that in the future I will buy the "reds" already rooted like my Hilo Beauty & Morgan's Midnight Ruby. It is so much easier and the payoff is ten-fold when they bloom. :) But be patient my friend and don't give up - I just know it will be worth it! You can always find great advice on this forum from so many experienced growers. I wish you the best of luck! Happy Growing! Karen R.

I chopped till . . .I have just a few leaves left.. I think I know what I did to cause it to rot..I just recently got liners for my shelves and I quickly watered it before going to bed and with the liners it kinda prevents drainage. So I need to be more careful in allowing it to drain before going back on the shelf