Anthracnose of Lucky Bamboo Dracaena Sanderiana Caused by the Fungus Colletotrichum Dracaenophilum in Egypt
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Journal of Advanced Research (2016) 7, 327–335 Cairo University Journal of Advanced Research ORIGINAL ARTICLE Anthracnose of lucky bamboo Dracaena sanderiana caused by the fungus Colletotrichum dracaenophilum in Egypt Ahmed A. Morsy, Ibrahim E. Elshahawy * Plant Pathology Department, Agricultural and Biological Research Division, National Research Centre, Giza, Egypt GRAPHICAL ABSTRACT ARTICLE INFO ABSTRACT Article history: Dracaena sanderiana, of the family Liliaceae, is among the ornamental plants most frequently Received 4 November 2015 imported into Egypt. Typical anthracnose symptoms were observed on the stems of imported Received in revised form 21 January D. sanderiana samples. The pathogen was isolated, demonstrated to be pathogenic based on 2016 Koch’s rule and identified as Colletotrichum dracaenophilum. The optimum temperature for Accepted 22 January 2016 its growth ranges from 25 to 30 °C, maintained for 8 days. Kemazed 50% wettable powder Available online 16 February 2016 (WP) was the most effective fungicide against the pathogen, as no fungal growth was observed * Corresponding author. Tel.: +20 1279180670; fax: +20 57 2403868. E-mail address: [email protected] (I.E. Elshahawy). Peer review under responsibility of Cairo University. Production and hosting by Elsevier http://dx.doi.org/10.1016/j.jare.2016.01.002 2090-1232 Ó 2016 Production and hosting by Elsevier B.V. on behalf of Cairo University. 328 A.A. Morsy and I.E. Elshahawy over 100 ppm. The biocontrol agents Trichoderma harzianum and Trichoderma viride followed Keywords: by Bacillus subtilis and Bacillus pumilus caused the highest reduction in fungal growth. To Anthracnose the best of our knowledge, this report describes the first time that this pathogen was observed Dracaena sanderiana on D. sanderiana in Egypt. Colletotrichum dracaenophilum Ó 2016 Production and hosting by Elsevier B.V. on behalf of Cairo University. Lucky bamboo Introduction Pathogenicity tests Lucky bamboo (Dracaena sanderiana hort. ex Mast.) is among Pathogenicity was confirmed by fulfilling Koch’s postulates on the ornamental plants most frequently imported into Egypt. rooted cuttings of lucky bamboo plants as well as detached This bamboo is also known as Dracaena braunii [1]. Although stem segments, according to Bobev et al. [4]. Twenty cuttings the word bamboo occurs in several of its common names, D. of lucky bamboo plants were surface disinfected with 1.5% sanderiana is actually of an entirely different taxonomic order sodium hypochlorite (NaOCl) for 5 min, followed by several from true bamboos. In Egypt, lucky bamboo is the most popular rinses with sterile distilled water before being sown in five glass indoor plant and is frequently imported and resold in attractive bottles containing 500 mL sterile water. Thirty days later, these pots. Colletotrichum spp. is an imperfect fungus belonging to the bamboo plants were divided into two sets. The stems of the Melanconiales. Members of the genus Colletotrichum cause dis- first set were wounded (ten wounds per plant) using a sterile eases on a number of host plants. These diseases, often referred needle at 4 cm intervals. The stems of 5 plants of the first set to as anthracnose, include strawberry black spot and key lime were inoculated by inserting small mycelial plugs from 10- anthracnose (caused by Colletotrichum acutatum), tomato fruit day-old potato dextrose agar (PDA) cultures of C. dra- anthracnose (caused by Colletotrichum coccodes), red sorghum caenophilum into wounds, which were subsequently covered stalk rot (caused by Colletotrichum graminicola), coffee berry with Parafilm strips. Pure agar plugs were used to inoculate disease (caused by Colletotrichum kawahae), bean anthracnose the wounded stems of the control plants (5 plants). Both inoc- (caused by Colletotrichum lindemuthianum) and many others ulated and control plants were kept at 28 ± 2 °C. Anthracnose [2]. Additional species of Colletotrichum with conidia greater symptoms were observed visually for sixty days after inocula- than 20 lm have been encountered on living plants of D. sande- tion. The stems of the second set (5 plants) were injected with À riana (lucky bamboo) from China [3]. In Bulgaria and Iran, 0.5 mL plant 1 of C. dracaenophilum conidial suspension À Bobev et al. [4] and Komaki et al. [5], respectively, provided (2 Â 106 conidia mL 1) using a sterilized syringe [9]. The the first reports that Colletotrichum dracaenophilum infects the injected and un-injected (5 plants) stems of lucky bamboo stems of potted D. sanderiana plants, causing anthracnose dis- plants were covered with plastic polyethylene bags for 24 h ease. In the United States, Sharma et al. [6] isolated, character- to provide humid conditions. Anthracnose symptoms were ized and tested fungicide treatments to control Colletotrichum observed visually. In addition, the stems of apparently healthy spp. causing anthracnose on lucky bamboo, D. sanderiana. They lucky bamboo plants were cut longitudinally and horizontally also reported that C. dracaenophilum caused the most severe dis- into 1–3 cm segments. These segments were inoculated with ease on lucky bamboo, whereas one isolate of the Colletotrichum one drop of C. dracaenophilum conidial suspension (2 Â 106 À gloeosporioides species complex was less pathogenic to all Dra- conidia mL 1) after surface disinfection. Five stem segments caena spp. and varieties tested. In Egypt, during March 2015, from each type of longitudinal and horizontal pieces were used anthracnose symptoms were recorded on D. sanderiana plants. as replicates, and the experiment was replicated twice. The rot Therefore, the objectives of this work were (i) to describe the of the detached stem segments was observed visually. symptoms of lucky bamboo anthracnose, (ii) to isolate, identify and test the pathogenicity of the causal agent, (iii) to determine Effect of temperature on the growth of C. dracaenophilum the effect of temperature on the growth of the causal pathogen and (iv) to evaluate the effect of certain fungicides and biocon- Fresh potato dextrose agar (PDA) plates were inoculated with trol agents on the growth of the pathogen. a 5 mm mycelial disk cut with a sterile cork borer from the margin of a 10-days-old colony of C. dracaenophilum. Plates Material and methods were incubated in an incubator at 5, 10, 15, 20, 25, 30, 35 and 40 °C. The radial growth of C. dracaenophilum was mea- Isolation and identification of the causal pathogen sured in two perpendicular directions at 4, 8, 10 and 14 days after inoculation. Four Petri plates were used as replicates In March 2015, disease problems on the stems of imported for each combination of temperature and incubation period. (Netherlands) indoor lucky bamboo plants (D. sanderiana) were observed. The symptoms were observed during several months Inhibitor effect of fungicides on the growth of C. dracaenophilum after the consumer purchased them from the retail stores located in Giza governorate. More than 50 diseased samples with typi- The inhibition effects of ten different fungicides under different cal anthracnose symptoms were collected to isolate the patho- concentrations viz., 0, 25, 50, 100, 200, 300, 400, 500 and gen based on Koch’s rule [7]. The obtained fungal colonies 600 ppm against the pathogen were determined. The systemic were identified according to the Colletotrichum description fungicides were dimethomorph 6% + copper oxychloride reported by Sutton [8] and according to Farr et al. [3]. 40% (Acrobat Copper 46%), carbendazim (Kemazed 50% Anthracnose of lucky bamboo Dracaena sanderiana in Egypt 329 Table 1 Analysis of variance for RCBD. SOV Table 3 Table 4 df P-values df P-values Replication (r À 1) = 3 0.48 (r À 1) = 3 <0.01 A (temperature T or fungicide F) A À 1 = 7 <0.01 A À 1 = 9 <0.01 B (incubation period I or concentration C) B À 1 = 3 <0.01 B À 1 = 7 <0.01 AB (A À 1) (B À 1) = 21 <0.01 (A À 1) (B À 1) = 56 <0.01 Error (AB À 1) (r À 1) = 93 (AB À 1) (r À 1) = 237 Total (ABr À 1) = 127 (ABr À 1) = 314 WP), flutolanil (Moncut 25% WP), mancozeb (Tridex 80%), C = Average growth of C. dracaenophilum in control and metalaxyl M + mancozeb (Ridomil Glod 68%), and T = Average growth of C. dracaenophilum in biocontrol thiophanate-methyl (Topsin-M 70% wettable granul (WG) agent treatment. and the protective fungicides were Mancozeb 80% (Dithane M-45), pencycuron (Monceren 25% WP) and thiram Statistical analysis + tolclofos-methyl (Rizolex T 50% WP). The Metalaxyl 8% WP + Mancozeb 64% (Tasoline) is systemic and protective Statistical analysis for a randomized complete block design fungicide. The inhibition effect was tested using the poisoned (RCBD) with two factors and interaction terms was performed food technique described by Uribe and Loria [10]. Four Petri for all experiments according to Gomez and Gomez [14]. Least plates were used as replicates for each treatment as well as significant difference (LSD) values were calculated to test the untreated control. The average radial growth of C. dra- significance of differences between means according to Steel caenophilum was measured in two perpendicular directions et al. [15] (Table 1). when C. dracaenophilum reached full growth in the control plate. Results and discussion Inhibitor effect of biocontrol agents on the growth of C. Symptomatology and the causal pathogen dracaenophilum The primary symptoms of lucky bamboo anthracnose were Fungal and bacterial biocontrol agents viz., Trichoderma pale green yellowish lesions that appeared on the stems. harzianum, Trichoderma viride, Trichoderma virens, Tricho- These symptoms extended to the upper and lower intern- derma koningii, Pseudomonas fluorescens, Bacillus subtilis, odes, which became yellow. The hard tissues turned soft, Bacillus megaterium and Bacillus pumilus were obtained from the plant showed wilt symptoms, and the entire stem was the Plant Pathology Department, National Research Centre covered with numerous black globose ellipsoid acervuli with (NRC). The inhibitor effect of the fungal biocontrol agents sparse, black setae Fig.