First Report of Bacterial Fruit Blotch of Watermelon Caused by Acidovorax avenae subsp. citrulli in Illinois

In August 2001, symptomatic mature fruit of watermelon (Citrullus lanatus) cvs. Crimson Sweet and Royal Sweet were collected from six fields (48 ha) in Iroquois, Kankakee, and Mason counties in Illinois. The fruit surface had dark green, water-soaked lesions, and the rind's epidermis was cracked. Sections of infected rind were examined with a light microscope, and bacterial streaming was observed. Rind tissue was disinfested by rubbing the fruit surface with a paper towel moistened with 70% ethanol. Pieces of rind from the margins of lesions were placed in a test tube containing sterile-distilled water. The tube was shaken, and the suspension was streaked on King's medium B agar in petri plates. The plates were incubated at 26°C for 3 days. A nonfluorescent, gramnegative, anaerobic, oxidase-positive, rod-shaped bacterium was isolated that produced creamy white colonies on nutrient agar. The bacterium was identified as Acidovorax avenae subsp. citrulli based on an enzyme-linked immunosorbent assay test specific for A. avenae subsp. citrulli (kit PSA 14,800; Agdia Inc., Elkhart, IN). The disease was diagnosed as bacterial fruit blotch (1,2). The occurrence of bacterial fruit blotch of watermelon in Illinois is important because (i) watermelon is widely grown in Illinois, (ii) the pathogen also infects melons and pumpkins, and (iii) Illinois grows approximately 1,000 ha of melons and 8,000 ha of pumpkins. References: (1) R. X. Latin. Bacterial fruit blotch. Pages 34-35 in: Compendium of Cucurbit Diseases. The American Phytopathological Society, St. Paul, MN,1996. (2) G. S. Somodi et al. Plant Dis. 75:1053, 1991.

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First Report of Bacterial Fruit Blotch of Watermelon in Oregon

Plant Disease ◽

10.1094/pdis.1997.81.1.113a ◽

1997 ◽

Vol 81 (1) ◽

pp. 113-113 ◽

Cited By ~ 9

Author(s):

P. B. Hamm ◽

D. S. Spink ◽

G. H. Clough ◽

K. S. Mohan

Keyword(s):

Citrullus Lanatus ◽

Nutrient Agar ◽

Green Water ◽

Hypodermic Needle ◽

Identification System ◽

Columbia Basin ◽

Plastic Mulch ◽

First Report ◽

Bacterial Fruit Blotch ◽

Test Plants

Most of the watermelons, Citrullus lanatus (Thunb.) Matsum. & Nakai, consumed in the Pacific Northwest during the summer months are grown in the southern Columbia Basin under dry (<5 cm rainfall), low relative humidity (46 to 57%), and high temperature (29 to 41°C) conditions, using transplants, plastic mulch, and drip irrigation. During May 1996, irregularly shaped, water-soaked lesions were observed on cotyledons and first true leaves of watermelon cv. Sangria transplants growing in a greenhouse. Similar lesions were observed later on older leaves in a commercial field of cv. Millionaire. Microscopic examination of symptomatic tissue revealed bacterial streaming, and isolation on nutrient agar consistently yielded numerous creamy to off-white bacterial colonies. Bacteria from purified, single colonies were Gram negative and rod shaped. Physiological characterization by the Biolog GN Bacterial Identification System (version 3.5) showed a similarity of 0.971 to the Biolog description for Acidovorax avenae subsp. citrulli. Pathogenicity of two strains was confirmed in three separate tests by hypodermic needle infiltration of cotyledons or by stab inoculation into hypocotyls of 12 to 24 21-day-old cv. Crimson Sweet seedlings with aqueous suspensions of bacteria containing approximately 6.0 × 108 CFU/ml. Inoculum was prepared from 48-h-old nutrient agar cultures. Test plants were incubated in the greenhouse at 21°C, under a 16-h photoperiod. Hypocotyl and cotyledon inoculations produced water-soaked lesions within 24 to 48 h on both the hypocotyl and cotyledons or just the cotyledon, respectively, on plants inoculated by either method. No symptoms developed on control plants infiltrated or stabbed with sterile water only. Isolations from three symptomatic seedlings yielded colonies similar in morphology to those used for inoculation. Tests of two purified cultures by Biolog indicated the bacteria were A. avenae subsp. citrulli. The symptomatic test plants were transplanted to fields, and the maturing melons developed large, dark green, water-soaked lesions with irregular margins. Similar fruit symptoms were seen in commercial fields. Labels on seed used in commercial production and in our tests warned of risks related to fruit blotch. This is the first report of bacterial fruit blotch of watermelon in Oregon. This disease may have a significant impact on watermelon production in the Columbia Basin.

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DETEKSI PENYAKIT BACTERIAL FRUIT BLOTCH PADA MELON MENGGUNAKAN ELISA (DETECTION OF BACTERIAL FRUIT BLOTCH OF MELON USING ELISA)

Jurnal Perlindungan Tanaman Indonesia ◽

10.22146/jpti.16012 ◽

2016 ◽

Vol 19 (1) ◽

pp. 1

Author(s):

Utik Windari ◽

Tri Joko ◽

Siti Subandiyah

Keyword(s):

Detection Method ◽

Yield Losses ◽

Elisa Method ◽

Bacterial Fruit Blotch ◽

Acidovorax Citrulli ◽

Commercial Seed ◽

Seedborne Disease ◽

Dark Green ◽

Das Elisa ◽

Special Region

Bacterial fruit blotch (BFB) caused by Acidovorax citrulli is a serious seedborne disease in Cucurbitaceae causing 90-100% yield losses. The aim of this study was to explore BFB symptom on melon and also to detect A. citrulli infection in commercial seed and symptomatic fruits from the field in Yogyakarta Special Region province and its surrounding using DAS-ELISA method. Samples include melon from Sleman, Bantul, Kulon Progo, Gunung Kidul, Magelang, Purworejo regencies while commercial seeds i.e. Action 434, Glamour and Mai 116 were collected. DASELISA detection method used reagent set from Agdia. Based on the field observation, this study found melon commercial fruit shares similar symptom with BFB, which showed discrete oily dark green spots, while the netting failed to develop over necrotic areas, resulting in smooth sunken spots. DAS-ELISA detection revealed that samples collected from Jetak village, district of Mungkid, Magelang and from Bligo village, district of Ngluwar, Magelang and in commercial seed Mai 116 were positively infected byA. citrulli.Keywords: Acidovorax citrulli, bacterial fruit blotch, ELISA, melonBacterial fruit blotch (BFB) merupakan penyakit penting pada famili Cucurbitaceae yang disebabkan oleh Acidovorax citrulli. Penyakit ini dilaporkan dapat menurunkan hasil mencapai 90-100%. Tujuan dari penelitian ini adalah untuk mengetahui gejala penyakit BFB pada melon dan deteksiA. citrulli pada benih komersial dan sampel buah bergejala dengan metode DAS-ELISA di DIY dan sekitarnya. Pengambilan sampel dilakukan di kabupaten Sleman, Bantul, Kulon Progo, Gunung Kidul, Purworejo dan Magelang. Selain dari lapangan, diuji pula benih melon komersial yaitu Action-434, Glamour dan Mai 116. Metode deteksi dengan ELISA menggunakanreagent set dari Agdia. Dari hasil pengamatan di lapangan ditemukan buah melon dengan gejala yang mirip dengan gejala BFB yaitu adanya becak berwarna hijau tua kebasahan pada permukaan buah, jaring tidak terbentuk sempurna dan pada bagian daging buah di bawah becak tadi membusuk. Hasil deteksi dengan DAS-ELISAmengindikasikan bahwa A. citrulli terdeteksi pada sampel yang berasal dari desa Bligo, kecamatan Ngluwar dan desa Jetak, kecamatan Mungkid, kabupaten Magelang, serta pada benih komersial MAI 116.Kata kunci: Acidovorax citrulli, bacterial fruit blotch, ELISA, melon

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First Report of Cucurbit aphid-borne yellows virus in Iran Causing Yellows on Four Cucurbit Crops

Plant Disease ◽

10.1094/pd-90-0526a ◽

2006 ◽

Vol 90 (4) ◽

pp. 526-526 ◽

Cited By ~ 7

Author(s):

K. Bananej ◽

C. Desbiez ◽

C. Wipf-Scheibel ◽

I. Vahdat ◽

A. Kheyr-Pour ◽

...

Keyword(s):

Citrullus Lanatus ◽

Healthy Plant ◽

Enzyme Linked Immunosorbent Assay ◽

Rt Pcr ◽

First Report ◽

Chain Reactions ◽

Reference Isolate ◽

Sigma Chemical ◽

International Mycological Institute ◽

Das Elisa

A survey was conducted from 2001 to 2004 in the major cucurbit-growing areas in Iran to reassess the relative incidence of cucurbit viruses. Severe yellowing symptoms were observed frequently on older leaves of cucurbit plants in various regions in outdoor crops, suggesting the presence of Cucurbit aphid-borne yellows virus (CABYV, genus Polerovirus, family Luteoviridae) (1,2). Leaf samples (n = 1019) were collected from plants of melon (Cucumis melo L.), cucumber (C. sativus L.), squash (Cucurbita sp.), and watermelon (Citrullus lanatus L.) showing various virus-like symptoms (mosaic, leaf deformation, yellowing). All samples, collected from 15 provinces, were screened for the presence of CABYV by double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) with IgGs and alkaline phosphatase-conjugated IgGs against a CABYV reference isolate (1). Of the 1,019 samples tested, 471 were positive for CABYV using DAS-ELISA. Some of the positive samples had typical severe yellowing symptoms while symptoms in other samples were masked by mosaic or leaf deformations caused by other viruses frequently found in mixed infections (data not shown). During the entire survey, CABYV was detected by DAS-ELISA in 201 of 503 melon samples, 72 of 129 cucumber samples, 158 of 249 squash samples, and 40 of 138 watermelon samples. These results indicate that CABYV is widely distributed on four cucurbit species in the major growing areas of Iran. In order to confirm CABYV identification, total RNA extracts (TRI-Reagent, Sigma Chemical, St Louis, MO) were obtained from 25 samples that were positive using DAS-ELISA originating from Khorasan (n = 4), Esfahan (n = 6), Teheran (n = 3), Hormozgan (n = 4), Azerbaiejan-E-Sharqi (n = 4), and Kerman (n = 4). Reverse transcription-polymerase chain reactions (RT-PCR) were carried out using forward (5′-CGCGTGGTTGTGG-TCAACCC-3′) and reverse (5′-CCYGCAACCGAGGAAGATCC-3′) primers designed in conserved regions of the coat protein gene according to the sequence of a CABYV reference isolate (3) and three other unpublished CABYV sequences. RT-PCR experiments yielded an expected 479-bp product similar to the fragment amplified with extracts from the reference isolate. No amplification of the product occurred from healthy plant extracts. To our knowledge, this is the first report of the occurrence of CABYV in Iran on various cucurbit species. The high frequency (46.2%) with which CABYV was detected in the samples assayed indicates that this virus is one of the most common virus infecting cucurbits in Iran. References: (1) H. Lecoq et al. Plant Pathol. 41:749, 1992 (2) M. A. Mayo and C. J. D'Arcy. Page 15 in: The Luteoviridae. H. G. Smith and H. Barker, eds. CAB International Mycological Institute, Wallingford, UK, 1999. (3) H. Guilley et al. Virology 202:1012, 1994.

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First Report of Tomato Brown Rugose Fruit Virus Infecting Tomato Crop in Saudi Arabia

Plant Disease ◽

10.1094/pdis-05-21-1065-pdn ◽

2021 ◽

Author(s):

Ahmed Sabra ◽

Mohammed Ali Al Saleh ◽

I. M. Alshahwan ◽

Mahmoud A. Amer

Keyword(s):

Saudi Arabia ◽

Mosaic Virus ◽

Solanum Lycopersicum ◽

Tomato Mosaic Virus ◽

Enzyme Linked Immunosorbent Assay ◽

Rt Pcr ◽

First Report ◽

Pcr Products ◽

Dark Green ◽

Leaf Symptoms

Tomato (Solanum lycopersicum L.) is the most economically important member of family Solanaceae and cultivated worldwide and one of the most important crops in Saudi Arabia. The aim of this study is screening of the most common viruses in Riyadh region and identified the presence of tomato brown rugose fruit virus (ToBRFV) in Saudi Arabia. In January 2021, unusual fruit and leaf symptoms were observed in several greenhouses cultivating tomatoes commercially in Riyadh Region, Saudi Arabia. Fruit symptoms showed irregular brown spots, deformation, and yellowing spots which render the fruits non-marketable, while the leaf symptoms included mottling, mosaic with dark green wrinkled and narrowing. These plants presented the symptoms similar to those described in other studies (Salem et al., 2015, Luria et al., 2017). A total 45 Symptomatic leaf samples were collected and tested serologically against suspected important tomato viruses including: tomato chlorosis virus, tomato spotted wilt virus, tomato yellow leaf curl virus, tomato chlorotic spot virus, tomato aspermy virus, tomato bushy stunt virus, tomato black ring virus, tomato ringspot virus, tomato mosaic virus, pepino mosaic virus and ToBRFV using Enzyme linked immunosorbent assay (ELISA) test (LOEWE®, Biochemica, Germany), according to the manufacturers' instructions. The obtained results showed that 84.4% (38/45) of symptomatic tomato samples were infected with at least one of the detected viruses. The obtained results showed that 55.5% (25/45) of symptomatic tomato samples were found positive to ToBRFV, three out of 25 samples (12%) were singly infected, however 22 out of 45 (48.8%) had mixed infection between ToBRFV and with at least one of tested viruses. A sample with a single infection of ToBRFV was mechanically inoculated into different host range including: Chenopodium amaranticolor, C. quinoa, C. album, C. glaucum, Nicotiana glutinosa, N. benthamiana, N. tabacum, N. occidentalis, Gomphrena globosa, Datura stramonium, Solanum lycopersicum, S. nigrum, petunia hybrida and symptoms were observed weekly and the systemic presence of the ToBRFV was confirmed by RT-PCR and partial nucleotide sequence. A Total RNA was extracted from DAS-ELISA positive samples using Thermo Scientific GeneJET Plant RNA Purification Mini Kit. Reverse transcription-Polymerase chain reaction (RT-PCR) was carried out using specific primers F-3666 (5´-ATGGTACGAACGGCGGCAG-3´) and R-4718 (5´-CAATCCTTGATGTG TTTAGCAC-3´) which amplified a fragment of 1052 bp of Open Reading Frame (ORF) encoding the RNA-dependent RNA polymerase (RdRp). (Luria et al. 2017). RT-PCR products were analyzed using 1.5 % agarose gel electrophoresis. RT-PCR products were sequenced in both directions by Macrogen Inc. Seoul, South Korea. Partial nucleotide sequences obtained from selected samples were submitted to GenBank and assigned the following accession numbers: MZ130501, MZ130502, and MZ130503. BLAST analysis of Saudi isolates of ToBRFV showed that the sequence shared nucleotide identities ranged between 98.99 % to 99.50 % among them and 98.87-99.87 % identity with ToBRFV isolates from Palestine (MK881101 and MN013187), Turkey (MK888980, MT118666, MN065184, and MT107885), United Kingdom (MN182533), Egypt (MN882030 and MN882031), Jordan (KT383474), USA (MT002973), Mexico (MK273183 and MK273190), Canada (MN549395) and Netherlands (MN882017, MN882018, MN882042, MN882023, MN882024, and MN882045). To our knowledge, this is the first report of occurrence of ToBRFV infecting tomato in Saudi Arabia which suggests its likely introduction by commercial seeds from countries reported this virus and spread in greenhouses through mechanical means. The author(s) declare no conflict of interest. Keywords: Tomato brown rugose fruit virus, tomato, ELISA, RT-PCR, Saudi Arabia References: Luria N, et al., 2017. PLoS ONE 12(1): 1-19. Salem N, et al., 2015. Archives of Virology 161(2): 503-506. Fig. 1. Symptoms caused by ToBRFV showing irregular brown spots, deformation, yellowing spots on fruits (A, B, C) and bubbling and mottling, mosaic with dark green wrinkled and narrowing on leaf (D).

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Xanthomonas ricini. [Descriptions of Fungi and Bacteria].

IMI Descriptions of Fungi and Bacteria ◽

10.1079/dfb/20056400379 ◽

1973 ◽

Author(s):

J. F. Bradbury

Keyword(s):

Hong Kong ◽

Geographical Distribution ◽

Leaf Spot ◽

World Wide ◽

Ricinus Communis ◽

Green Water ◽

Leaf Spot Disease ◽

Atypical Symptoms ◽

Wet Weather ◽

Dark Green

Abstract A description is provided for Xanthomonas ricini. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Ricinus communis. DISEASE: Normally a leaf spot disease in which the bacteria are confined to the parenchymatous tissues. The tiny, dark green, water-soaked spots expand and become brownish, angular and necrotic. They may coalesce to form larger necrotic areas and badly infected leaves become chlorotic and may drop. Occasionally petioles and succulent branches have minute oval or linear spots. Sabet (40, 334) obtained atypical symptoms from inoculation of buds. When the leaves opened, the main veins became infected and tissues dependent on infected veins became yellow and flaccid and finally withered. GEOGRAPHICAL DISTRIBUTION: Scattered, more or las world-wide (CMI Map 394, ed. 1, 1962). Extra references include Hong Kong (43, 345), Poland (48, 554b), Zambia and confirmation of Kenya. TRANSMISSION: Probably in wind and rain; it is rapid in wet weather. One report suggests that it is also seedborne (33, 181).

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FRUIT DISORDER OF GLASSHOUSE TOMATOES CAUSED BY A TOBACCO FORM OF TOBACCO MOSAIC VIRUS

Canadian Journal of Plant Science ◽

10.4141/cjps75-088 ◽

1975 ◽

Vol 55 (2) ◽

pp. 597-604

Author(s):

W. R. ALLEN ◽

K. C. CHADHA

Keyword(s):

Lycopersicon Esculentum ◽

Tobacco Mosaic Virus ◽

Mosaic Virus ◽

Tomato Fruit ◽

Cross Protection ◽

Mature Fruit ◽

Leaf Stage ◽

Lycopersicon Esculentum Mill ◽

Dark Green

A severe fruit disorder of tomato (Lycopersicon esculentum Mill.) was induced with a tobacco form of tobacco mosaic virus isolated from blemished tomato fruit (cv. Ohio WR25) from a glasshouse crop in southwestern Ontario. Symptoms on green tomatoes consisted of slightly sunken, pale or yellowish-brown lesions with a thin, dark green margin. Lesions frequently expanded and coalesced along the flutes. The shoulders of the fruit were the most extensively affected areas. On mature fruit, the lesions appeared either silvery or silvery-brown and generally had a scabby appearance due to cracking and lifting of the surface tissues. Lesions were superficial and internal symptoms were not detected. First-truss inoculations prevented or delayed the fruit disorder. Inoculations at truss stages two, three, and four, however, resulted in development of affected fruit on inoculated as well as lower and subsequent trusses with the exception of the first truss. Similar susceptibilities to the fruit disorder occurred among the glasshouse cultivars Michigan Ohio (Burghart strain), Ohio WR25, Vantage, Veegan, and Vendor. No cross protection against the fruit disorder was provided by a mild tomato form of TMV introduced at the second-leaf stage.

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Parasitological and serological studies on amoebiasis and other intestinal parasitic infections in the rural sector around Recife, Northeast Brazil

Revista do Instituto de Medicina Tropical de São Paulo ◽

10.1590/s0036-46651990000600007 ◽

1990 ◽

Vol 32 (6) ◽

pp. 428-435 ◽

Cited By ~ 19

Author(s):

José Felipe Gonçalves ◽

Masanobu Tanabe ◽

Francisco de Paula de Melo Medeiros ◽

Fernando José Gonçalves ◽

Ivanize da Silva Aca ◽

...

Keyword(s):

Intestinal Parasites ◽

Strongyloides Stercoralis ◽

Common Species ◽

Test Tube ◽

Enzyme Linked Immunosorbent Assay ◽

Parasitic Infections ◽

Intestinal Parasitic Infections ◽

High Prevalence ◽

Serological Studies ◽

Diffusion Precipitation

Parasitological examinations were carried out during July to December, 1989, on 485 inhabitants of four villages in São Lourenço da Mata, 25 km northwest of Recife, Pernambuco, Brazil. Approximately 99.6% of the inhabitants were infected with at least one species of intestinal parasites. A high prevalence of Schistosoma mansoni (82.1%), hookworm (80.2%) Trichuris trichiura (69.9%), Ascaris lumbricoides (61.9%) and Entamoeba coli (36.7%) infections were demonstrated. Test tube cultivation revealed that the most common species of hookworm in this region was Necator americanus (88.4%), and also that the prevalence of Strongyloides stercoralis was 5.8%. Three hundred and thirty-four sera were serologically examined for amoebiasis by the gel diffusion precipitation test (GDP) and enzyme-linked immunosorbent assay (ELISA). No positive reaction was observed in all sera as examined by GDP, while 24 sera were positive by ELISA.

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Influence of Fruit-to-Fruit Contact on the Susceptibility of French Prune to Infection by Monilinia fructicola

Plant Disease ◽

10.1094/pdis.1997.81.12.1416 ◽

1997 ◽

Vol 81 (12) ◽

pp. 1416-1424 ◽

Cited By ~ 20

Author(s):

Themis J. Michailides ◽

David P. Morgan

Keyword(s):

Methylene Blue ◽

Brown Rot ◽

Early Summer ◽

Monilinia Fructicola ◽

Distilled Water ◽

Prunus Domestica ◽

Mature Fruit ◽

Breeding Programs ◽

Contact Surfaces ◽

Selection For

In eight commercial prune (Prunus domestica cv. French) orchards, 43 to 69% of brown rot (caused by Monilinia fructicola or M. laxa) infections occurred in clustered fruit as opposed to solitary fruit. Fruit-to-fruit contact surfaces had cracked and thin cuticles and larger microcracks (up to 2,255 μm in length) surrounding the lenticels than those of non-contact surfaces (cracks up to 351 μm in length). Furthermore, fruit-to-fruit contact surfaces retained greater proportions of methylene blue, indicating absence of epicuticular wax, than the non-contact surfaces. Carbohydrate content of exudates in water placed on fruit-to-fruit contact surfaces was 15 and 22 mg/ml, while those of non-contact surfaces were 13 and 19 mg/ml after 15 and 28 h, respectively. Conidia of M. fructicola germinated faster and at higher rates, and the incidence of infection was significantly higher on fruit-to-fruit contact than on non-contact surfaces. Densities of fungal CFU were greater (27 to 98 CFU/cm2) on fruit-to-fruit contact compared to those of non-contact surfaces (7 to 29 CFU/cm2). In four experiments, after spraying to runoff with distilled water, surfaces of solitary fruit dried after 7 to 8 h at 23 ± 1°C compared to 12 to 14 h for groups of 5 to 6 fruit. After spraying the same mature fruit with 1.2 × 105 conidia/ml of M. fructicola and incubating at 24°C and >97% relative humidity, 26 to 70% and 38 to 100% of fruit placed in groups of 5 to 6 were infected after 3 days and 5 days, respectively, whereas only 2 to 13% and 21 to 65% of solitary fruit became infected. These results suggest that fruit-to-fruit contact surfaces predispose prune fruit to infection by M. fructicola, and that it might be possible to reduce fruit losses from brown rot in prune orchards by thinning fruit to reduce fruit clustering, applying early summer fungicide sprays before fruit contact occurs, and ultimately, by selection for non-clustering cultivars in prune breeding programs.

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Postharvest Development and Transmission of Watermelon Fruit Blotch

HortTechnology ◽

10.21273/horttech.9.2.217 ◽

1999 ◽

Vol 9 (2) ◽

pp. 217-219 ◽

Cited By ~ 1

Author(s):

James W. Rushing ◽

Anthony P. Keinath ◽

Wilton P. Cook

Keyword(s):

Citrullus Lanatus ◽

Temperature Management ◽

Postharvest Storage ◽

Diseased Fruit ◽

Marketable Fruit ◽

Fruit Surface

Watermelon fruit blotch (WFB) symptoms did not appear on healthy watermelon [Citrullus lanatus (Thunb.) Matsum. and Nakai] fruit placed in contact with the diseased surface of other fruit and stored at either 52 or 68 °F (11 or 20 °C) for 1 week. After 3 weeks in storage, some WFB transmission was observed and the frequency of transmission was greater at 68 than 52 °F. Surface abrasion of either the healthy fruit, diseased fruit, or both fruit did not promote transmission of WFB compared with unabraded controls. Some healthy fruit harvested from a field with diseased fruit developed very minor symptoms of WFB in postharvest storage, but the symptoms were not severe enough to cause market problems. Harvesting appeared to halt the spread of WFB symptoms on individual fruit with less than ≈10% of the fruit surface affected at harvest. If care is taken during harvest and grading to exclude diseased fruit, and if proper precooling and subsequent temperature management is implemented for marketable fruit, WFB does not appear to be of concern for the marketing of watermelons.

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First Report of Botrytis Gray Mold on Common Calla Lily in Buenos Aires, Argentina

Plant Disease ◽

10.1094/pd-90-0970b ◽

2006 ◽

Vol 90 (7) ◽

pp. 970-970 ◽

Cited By ~ 2

Author(s):

M. C. Rivera ◽

S. E. Lopez

Keyword(s):

South African ◽

Buenos Aires ◽

Pathogenic Fungi ◽

Gray Mold ◽

Distilled Water ◽

First Report ◽

Zantedeschia Aethiopica ◽

Calla Lily ◽

Japanese Quince ◽

Dark Green

Common calla lily (Zantedeschia aethiopica (L.) Spreng., family Araceae) is an evergreen herbaceous South African ornamental plant that forms a tuft of fleshy-stalked, glossy, dark green leaves. At bloom during the summertime, large, funnel-shaped, waxy-white spaths that surround a bright yellow spadix form at the end of high stalks. In August 2003, large, irregular brown spots with a 3- to 4-mm yellow halo were observed on leaves of 10 plants growing near Japanese quince shrubs (Chaenomeles lagenaria (Loisel.) Koidz.) in Escobar, Buenos Aires. Debris of Japanese quince petals were attached to the center of the lesions with profuse sporulation of Botrytis cinerea Pers. (1). Pathogen spores were disposed on potato dextrose agar (PDA) and incubated at 22°C. Mycelium was initially whitish and turned gray with age. Black conidiophores bore botryose heads of hyaline, ellipsoid, unicellular conidia, gray in mass, 7.5 to 10.5 μm × 6.8 to 7.5 (average 9.2 to 7 μm). Black, irregular sclerotia formed at random in culture. Inoculum was prepared from 7-day-old cultures on PDA. Six flowering common calla lilies planted in 5-liter plastic pots were inoculated by spraying a suspension of 2.5 × 106 conidia per ml of sterile distilled water. Six healthy plants were sprayed with sterile distilled water. Each plant was covered with a transparent polyethylene bag for 3 days and kept at 21°C under a 12-h photoperiod. After a 12-day incubation period, leaves showed elliptic to irregular brown spots surrounded by yellow halos. Tiny round to irregular brown spots developed on flower spaths that finally blighted. Water-treated plants remained symptomless. Koch's postulates were fulfilled by pathogen reisolation from diseased organs. To our knowledge, this is the first report of B. cinerea on Z. aethiopica in Argentina. Infection efficiency of B. cinerea increases when inoculated petals are positioned on leaves (2), which has epidemiological importance in landscapes with association of plant species that are potential hosts of this pathogen. Reference: (1) M. V. Ellis and J. M. Waller. No. 431 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1974. (2) C. Sirjusingh et al. Plant Dis. 80:154, 1996.

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