First Report of Macrophomina phaseolina, Fusarium brachygibbosum, and Lasiodiplodia theobromae Causing Fungal Watermelon Vine Decline in Southwest and West-Central Florida

2021 ◽  
Author(s):  
Cristina Pisani ◽  
Scott Adkins ◽  
William W Turechek ◽  
Pragna C Patel ◽  
Erin Rosskopf
Keyword(s):  
Disease Severity ◽  
Fungal Pathogens ◽  
Disease Incidence ◽  
Macrophomina Phaseolina ◽  
Lasiodiplodia Theobromae ◽  
First Report ◽  
Central Florida ◽  
Untreated Check ◽  
Vine Decline ◽  
Yellowing Virus

Wilt and vine decline symptoms were observed on watermelon plants in Glades and Hardee Counties in Florida in spring 2017 that resembled viral watermelon vine decline caused by squash vein yellowing virus (SqVYV). When no SqVYV was detected, greenhouse studies and morphological and molecular analyses revealed three fungal pathogens, Macrophomina phaseolina, Fusarium brachygibbosum, and Lasiodiplodia theobromae, that were not previously reported on watermelon in Florida. A previously reported oomycete, Pythium spinosum, was also detected in some, but not all isolates, and but when applied independently, resulted in disease incidence that was comparable to the untreated check, ruling it out as a primary causal agent of the symptoms observed in the field. In one of three experiments, seedlings inoculated with a combination of Macrophomina phaseolina, Fusarium brachygibbosum, and Pythium spinosum suffered the highest disease severity based on AUDPC values. In another experiment, seedlings inoculated with F. brachygibbosum exhibited the most severe symptoms and rapid disease development following inoculation. When seeds were inoculated with either a single or a combination of the isolated fungi, those inoculated with L. theobromae resulted in seedlings with the greatest disease severity. This is the first report of these three fungal pathogens on watermelon in Florida.

Influence of Insecticides and Reflective Mulch on Watermelon Vine Decline Caused by Squash vein yellowing virus (SqVYV)

2015 ◽  
Vol 16 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Chandrasekar S. Kousik ◽  
Scott Adkins ◽  
Craig G. Webster ◽  
William W. Turechek ◽  
Philip Stansly ◽  
...  
Keyword(s):  
Fruit Quality ◽  
Significant Interaction ◽  
Limiting Factor ◽  
Plastic Mulch ◽  
Central Florida ◽  
Chemical Treatments ◽  
The Past ◽  
Growing Seasons ◽  
Vine Decline ◽  
Yellowing Virus

Watermelon vine decline (WVD) caused by the whitefly-transmitted Squash vein yellowing virus (SqVYV) has been a serious limiting factor in watermelon production in southwest and west-central Florida over the past few years. Symptoms of WVD typically appear as sudden decline of vines a few weeks before harvest or just after the first harvest. Fruit symptoms include rind necrosis and flesh discoloration that affects fruit quality and marketability. The combination of insecticide treatments consisting of an imidacloprid drench (Admire Pro, 560 ml/ha) at transplanting followed by two foliar applications of spiromesifen (Oberon, 2SC, 490 ml/ha) and reflective plastic mulch was evaluated for management of WVD during fall growing seasons of 2006, 2007, and 2009. Virus inoculum source was introduced by planting SqVYV-infected squash plants at the ends of each plot. In all three experiments, the insecticide-treated plots had significantly lower levels of WVD on foliage and fruit compared to non-treated plots. In 2007, the reflective plastic mulch was effective in reducing foliar WVD compared to non-reflective mulch, but not in 2006 and 2009. No significant interaction between plastic mulch and chemical treatments was observed on WVD development on foliage or fruit. Our results suggest that application of insecticides for managing whiteflies can help manage SqVYV-caused WVD. Accepted for publication 13 January 2015. Published 25 March 2015.

scholarly journals Incidence of leaf blight disease of Egusi melon in South-west Nigeria

2020 ◽  
Vol 28 (2) ◽  
pp. 255-265
Author(s):  
J.F. Ogunsola ◽  
B. Ikotun ◽  
K.E. Ogunsola
Keyword(s):  
Fungal Pathogens ◽  
Citrullus Lanatus ◽  
Disease Incidence ◽  
Leaf Blight ◽  
Economic Damage ◽  
Colletotrichum Truncatum ◽  
Southwestern Nigeria ◽  
Lasiodiplodia Theobromae ◽  
Ondo State ◽  
Blight Disease

Egusi melon (Citrullus lanatus (Thumb) Mansf.) is an important vegetable crop grown for edible seeds and oil in West Africa. Leaf Blight Disease (LBD) is one of the major constraints to its production, with potential to cause economic damage. The objective of this study was to investigate the incidence and distribution of leaf blight on Egusi melon in Southwestern Nigeria. A survey of LBD of Egusi melon was conducted in 2015 and 2016, in five southwestern States of Nigeria (Ogun, Oyo, Osun, Ekiti and Ondo States). Twenty plants each, were randomly sampled from 150 farms comprising 30 farms each, from each State. The distribution of different Egusi melon varieties planted was recorded. “Bara” cv. was the most cultivated variety (51.6%); followed by “Bojuri” (30.4%) and “Serewe” (18%). Leaf blight was observed in most farms in the five States, from 73% in Osun and Oyo states to 83% in Ondo State. Disease incidence and severity varied with locations and cultivars, and ranged from 0.0-87.5±18% and 1.0±0-4.5±0.8 in Osun State to 20.0±19 - 95.0±4.5% and 2.3±1.5 - 5.0±0 in Ondo State. Out of the twelve fungal pathogens from ten genera isolated from infected plants, only Colletotrichum truncatum, C. gloeosporioides and Lasiodiplodia theobromae caused Leaf blight on Egusi melon. Key words: Colletotrichum gloeosporioides, Colletotrichum truncatum, Lasiodiplodia theobromae

scholarly journals Squash vein yellowing virus Identified in Watermelon (Citrullus lanatus) in Indiana

Plant Disease ◽  
2007 ◽  
Vol 91 (8) ◽  
pp. 1056-1056 ◽  
Author(s):  
D. S. Egel ◽  
S. Adkins
Keyword(s):  
Citrullus Lanatus ◽  
Amino Acid Sequences ◽  
Rt Pcr ◽  
Strain Vector ◽  
First Report ◽  
Pcr Product ◽  
Field Samples ◽  
Health Progress ◽  
Vine Decline ◽  
Yellowing Virus

During September 2006, moderate vine decline symptoms including vine collapse and wilt and root rot were observed on numerous watermelon plants growing in a commercial field in Sullivan County, Indiana. No symptoms were observed on the fruit. Six plants displaying typical vine decline symptoms were collected and assayed for potyvirus infection and subsequently for Squash vein yellowing virus (SqVYV) and Papaya ringspot virus type W (PRSV-W). SqVYV is a whitefly-transmitted member of the Potyviridae, recently shown to cause watermelon vine decline in Florida (1,4). Plants infected with SqVYV in Florida are also frequently infected with PRSV-W, although SqVYV is sufficient for watermelon vine decline. The six field samples harbored one or more potyviruses as determined by ELISA (Agdia, Elkhart, IN). Mechanical inoculation of squash (Cucurbita pepo) and watermelon with sap from three of the field samples induced mosaic symptoms in both that are typical of potyviruses. Vein yellowing in squash and plant death in watermelon typical of SqVYV (1) later developed in plants inoculated with one field sample. A coat protein gene fragment was amplified by reverse transcription (RT)-PCR with SqVYV primers (1) from total RNA of five of the six field samples and also from the symptomatic, inoculated plants. Nucleotide and deduced amino acid sequences of a 957-bp region of the RT-PCR product (primer sequences deleted prior to analysis) were 100% identical to SqVYV (GenBank accession No. DQ812125). PRSV-W also was identified in two of the five SqVYV-infected field samples by ELISA (Agdia) and by sequence analysis of a 3′ genome fragment amplified by RT-PCR with previously described degenerate potyvirus primers (3). No evidence for infection by other potyviruses was obtained. To our knowledge, this is the first report of SqVYV in Indiana and the first report of the virus anywhere outside of Florida. The whitefly (Bemisia tabaci, B strain) vector of SqVYV is relatively uncommon in Indiana and the cold winter temperatures make it unlikely that any SqVYV-infected watermelon vines or whiteflies will overseason, necessitating reintroductions of virus and vector each season. We feel that the moderate and restricted occurrence of SqVYV in Indiana observed in September 2006 should pose little or no threat to commercial watermelon production in Indiana and should not cause growers to alter their growing practices. The occurrence of SqVYV in Indiana does not appear to explain the similar symptoms of mature watermelon vine decline (MWVD) that has been observed in Indiana since the 1980s. In contrast with the insect vectored SqVYV, MWVD seems to be caused by a soilborne biological agent (2). References: (1) S. Adkins et al. Phytopathology 97:145, 2007. (2) D. S. Egel et al. Online publication. doi:10.1094/PHP-2000-1227-01-HN. Plant Health Progress, 2000. (3) A. Gibbs and A. Mackenzie. J. Virol. Methods 63:9, 1997. (4) P. Roberts et al. Citrus Veg. Mag. December 12, 2004.

scholarly journals Sources of Resistance in U.S. Plant Introductions to Watermelon Vine Decline Caused by Squash Vein Yellowing Virus

HortScience ◽  
2009 ◽  
Vol 44 (2) ◽  
pp. 256-262 ◽  
Author(s):  
Chandrasekar S. Kousik ◽  
Scott Adkins ◽  
William W. Turechek ◽  
Pamela D. Roberts
Keyword(s):  
Citrullus Lanatus ◽  
Field Trials ◽  
Limiting Factor ◽  
Sources Of Resistance ◽  
Central Florida ◽  
Plant Introductions ◽  
Disease Progress ◽  
Vine Decline ◽  
Moderate Resistance ◽  
Yellowing Virus

Watermelon vine decline (WVD) is a new and emerging disease caused by the whitefly-transmitted squash vein yellowing virus (SqVYV). The disease has become a major limiting factor in watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] production in southwest and west–central Florida and is estimated to have caused more than $60 million in losses. Symptoms of WVD typically occur at or just before harvest and are manifested as sudden decline of the vines, often with a reduction in fruit quality. In this study, we present results of greenhouse and field evaluations of U.S. plant introductions (PIs) for resistance to SqVYV. Of the 218 PIs we evaluated for resistance to SqVYV, none were completely immune, but several showed varying levels of resistance and these were further evaluated in two greenhouse and field trials. Disease progress was significantly slower on the selected PIs compared with disease progress on susceptible watermelon cultivars Mickey Lee and Crimson Sweet. Moderate resistance was observed in two C. colocynthis (PI 386015 and PI 386024), a Praecitrullus fistulosus (PI 381749), and two C. lanatus var. lanatus PIs (PI 482266 and PI 392291). Variability in the resistant reaction to SqVYV within most PIs was observed. The identification of potential sources of partial resistance to SqVYV suggests that watermelon germplasm with moderate resistance can be developed by careful screening and selection of individual resistant plants within these PIs for use in breeding programs.

scholarly journals First Report of Squash vein yellowing virus Affecting Watermelon and Bitter Gourd in Puerto Rico

Plant Disease ◽  
2013 ◽  
Vol 97 (11) ◽  
pp. 1516-1516 ◽  
Author(s):  
V. Acevedo ◽  
J. C. V. Rodrigues ◽  
C. E. de Jensen ◽  
C. G. Webster ◽  
S. Adkins ◽  
...  
Keyword(s):  
Puerto Rico ◽  
Fungal Pathogens ◽  
Citrullus Lanatus ◽  
Direct Sequencing ◽  
Bitter Gourd ◽  
Growth Stages ◽  
Mechanical Inoculation ◽  
First Report ◽  
South Central ◽  
Yellowing Virus

In 2005, symptoms of watermelon vine decline (WVD) were observed on a 200-acre watermelon farm in Santa Isabel, on the south central coast of Puerto Rico. WVD symptoms included leaf curling, mosaics, and internode necrosis. In early growth stages of WVD, reduced vigor and plant stunting occurred. At flowering, symptoms progressed to necrosis and wilting of vines. A 2006 to 2007 survey demonstrated that fungal pathogens were not associated with the presence of WVD symptoms (3,4). By 2006, other watermelon fields were also affected. Field trials in 2007 and 2008 with insect-proof cages and insecticides suggested a role of whiteflies (Bemisia tabaci) in the transmission of a virus (3,4). Here, we report that watermelon and pumpkin plants were successfully infected in Puerto Rico by mechanical inoculation and through B. tabaci transmission assays, similarly to transmissions previously conducted in Florida with Squash vein yellowing virus (SqVYV) (1). In addition, plants of Cucurbita moschata exhibited vein clearing symptoms typical of SqVYV after mechanical inoculation with extracts from watermelon plants with WVD symptoms. In 2011, eight watermelon samples from plants exhibiting WVD syndrome were collected in Guánica, Santa Isabel, Juana Díaz, and Mayagüez, and two Momordica charantia samples were collected from Mayagüez. RNA was extracted from all 10 original samples, as well as from plants that were used in mechanical and vector transmission assays, using RNeasy Plant Mini Kit (Qiagen, Valencia, California), and all samples were found positive for SqVYV by reverse transcription-PCR, using previously described primers and methods (1,2). In all cases, a single ~1-kb PCR fragment was revealed, and PCR fragments from four samples were selected for direct sequencing. All sequences showed high levels (>99%) of nucleotide identity with SqVYV sequences from Florida (JF897989, JF897985, and JF897984). Sequences of the SqVYV CP gene from Puerto Rico were deposited in GenBank under accession numbers KC713961 to KC713964. To our knowledge, this is the first report of SqVYV in Puerto Rico associated with WVD syndrome in cucurbits, and thus has implications for management of viral diseases of watermelon in the Caribbean. This is also the first detection of SqVYV outside of the continental United States in both watermelon and a wild species, M. charantia (bitter gourd). References: (1) S. Adkins et al. Phytopathology 97:145, 2007. (2) S. Adkins et al. Plant Dis. 92:1119, 2008. (3) C. Estévez de Jensen et al. Phytopathology 98:S52, 2008. (4) L. Polanco-Florián. El marchitamiento súbito de la sandía [Citrullus lanatus (Thumb.) Matsum & Nakai]. M.S. thesis, University of Puerto Rico, Mayagüez, PR, 2009.

scholarly journals First Report of Lasiodiplodia theobromae Associated with Stem Canker of Almond in California

Plant Disease ◽  
2013 ◽  
Vol 97 (7) ◽  
pp. 994-994 ◽  
Author(s):  
S. F. Chen ◽  
D. Morgan ◽  
R. H. Beede ◽  
T. J. Michailides
Keyword(s):  
Average Length ◽  
Stem Canker ◽  
Macrophomina Phaseolina ◽  
Disease Diagnosis ◽  
Type Specimens ◽  
Lasiodiplodia Theobromae ◽  
First Report ◽  
Agar Plug ◽  
Almond Trees ◽  
Negative Controls

California is a major almond (Prunus dulcis) producer in the world. In September 2012, 2-year-old almond trees from an orchard in Fresno Co. with stem cankers were submitted for disease diagnosis. In a survey of the orchard, 12 ha (1,500 Nonpareil and 1,800 Monterey almond trees) of 48 ha trees had been killed apparently due to a stem canker. The cankers developed above the graft union, were covered with amber sap, and often girdled the trunk. Isolations made from tissues at the canker margins onto acidified potato dextrose agar (PDA) yielded two fungi, Macrophomina phaseolina (Tassi) Goid and Lasiodiplodia theobromae (Pat.) Griffon & Maubl (1). M. phaseolina and L. theobromae were isolated from eight and two of 10 cankered trees, respectively. No mixed infections were found. M. phaseolina isolates were characterized by gray hyphae that turned black with developing microsclerotia. L. theobromae isolates were characterized by white, aerial mycelium that turned mouse gray after 5 days. Young conidia were ellipsoidal, thick walled, initially hyaline, granular, and nonseptate; aged conidia were brown, 1-septate with longitudinal striations in the wall. Identity was confirmed by analyses of the internal transcribed spacer (ITS), β-tubulin 2 (BT2), and the translation elongation factor 1-alpha (TEF-1α) gene regions. BLAST searches at GenBank showed a high identity with reference sequences of type specimens both for M. phaseolina (isolates 7E64 to 7E69: ITS, 100%; BT2, 99%; TEF-1α, 99%) and L. theobromae (isolates 7E86 to 7E88: ITS, 99%; BT2, 99%; TEF-1α, 100%). Sequences of three gene regions were deposited as GenBank accessions KC357271 to KC357279 (ITS); KC357280 to KC357288 (BT2); and KC357289 to KC357297 (TEF-1α). The pathogenicity of M. phaseolina and L. theobromae to P. dulcis cultivars Butte, Carmel, Nonpareil, and Padre was investigated in an orchard at KARE using four isolates of M. phaseolina (7E64, 7E65, 7E66, and 7E69) and two isolates of L. theobromae (7E86 and 7E88). Ten 2-year-old branches per isolate from 7-year-old trees were inoculated with each isolate in late September 2012, after removing the bark with a 7-mm cork borer and placing a 7-day-old 7-mm-diameter agar plug bearing mycelium of each isolate directly into the fresh wound, mycelium side down. Ten additional branches of each of the four cultivars were inoculated with sterile PDA plugs and served as negative controls. Three weeks after inoculation, the average lesion produced by M. phaseolina on Butte, Carmel, Nonpareil, and Padre was 53, 52, 41, and 37 mm in length, respectively. Lesions produced by L. theobromae were 191, 206, 194, and 103 mm in length on the four cultivars, respectively. No disease lesion, only wounds, were produced on negative controls. Lesions produced by both pathogens were longer (P < 0.05) than wounds on the controls (average length 10 mm on all cultivars). Both L. theobromae isolates killed branches of cultivars Butte, Carmel, and Nonpareil in 2 weeks. M. phaseolina and L. theobromae were reisolated from the inoculated branches, and no fungus was reisolated from controls. Based on pathogenicity results, L. theobromae is more virulent to almond branches than M. phaseolina. To our knowledge, this is the second report of M. phaseolina (2) and the first report of L. theobromae as pathogens of P. dulcis trees in California. References: (1) A. Alves et al. Fungal Diversity 28:1, 2008. (2) P. Inderbitzin et al. Mycologia 102:1350, 2010.

scholarly journals Wilt and Root Diseases of Asclepias tuberosa L.

Plant Disease ◽  
1997 ◽  
Vol 81 (10) ◽  
pp. 1203-1205 ◽  
Author(s):  
L. Tsror (Lahkim) ◽  
M. Hazanovski ◽  
O. Erlich ◽  
N. Dagityar
Keyword(s):  
Disease Severity ◽  
Disease Incidence ◽  
Severity Index ◽  
Disease Severity Index ◽  
Dry Rot ◽  
First Report ◽  
Binucleate Rhizoctonia ◽  
Root Diseases ◽  
Tuberous Roots

Chlorosis and wilting, followed by weak flowering or death, have been occurring in Asclepias tuberosa plants grown in Israel. Roots have been rotted and tuberous roots have shown dark lesions, sometimes with sclerotia. A binucleate Rhizoctonia sp. was detected on 39% and Pythium intermedium on 23% of diseased samples. Other organisms were less prevalent. Wilting began 7 days after seedlings were inoculated with P. intermedium or the binucleate Rhizoctonia sp. or both, with disease incidence ranging from 25 to 65% and disease severity index ranging from 0.30 to 0.85 (scale of 0 to 3). Healthy tuberous roots inoculated with the binucleate Rhizoctonia sp. exhibited dry rot within 4 to 7 days, and irregular black sclerotia of the pathogen were present 2 weeks later. This is the first report of either a binucleate Rhizoctonia sp. or P. intermedium occurring in A. tuberosa.

scholarly journals Identity and prevalence of wheat damping-off fungal pathogens in different fields of Basrah and Maysan provinces

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Mohammed Hamza Abass ◽  
Qusai Hattab Madhi ◽  
Abdulnabi Abdul Ameer Matrood
Keyword(s):  
Fusarium Solani ◽  
Seed Treatment ◽  
Fungal Pathogens ◽  
Laboratory Experiments ◽  
Disease Incidence ◽  
Macrophomina Phaseolina ◽  
Cereal Crops ◽  
Damping Off ◽  
Fungal Isolation ◽  
The World

Abstract Background Wheat is the most consumed cereal crops in the world infected by several pathogens and pests causing significant losses. The most threatening pathogens are fungi which cause serious diseases on roots, leaves and heads as one of the most threatening pathogens in specific wheat-growing countries. This study aimed to identify and evaluate the prevalence of damping-off fungal pathogens in different wheat fields at Basra and Maysan provinces. Results Disease incidence determination and fungal isolation were carried out from two sites at Basra province (Al-Qurna and Al-Madinah) and three sites at Maysan province (Al-Amarah, Kumit, Ali Al Sharqi and Ali Al Gharbi). Al-Qurna fields had the highest disease incidence (32%), while Ali-Alsharqi fields had the lowest one (11%). Fourteen fungal genera were identified. Rhizoctonia solani had the highest appearance (21.6) and frequency (20.20%) percentages followed by Fusarium solani (16.11,14.01) percentages and Macrophomina phaseolina (12.2,11.1) percentages. Seed treatment with R. solani (Rs1 isolate) showed significant decrease in germination (56.6%) compared to F. solani and M. phaseolina treatments. Seed treatment with R. solani (Rs1 isolate) showed significant decrease in germination (56.6%) compared to F. solani and M. phaseolina treatments. Conclusions These results revealed the prevalence of wheat damping-off disease in all examined fields at both Basra and Maysan province; the highest disease incidence was seen in Basra wheat fields (Al-Qurna fields); the identification of fungal pathogens showed that the most isolated fungus was R. solani followed by F. solani and M. phaseolina. Laboratory experiments showed the pathogenicity of isolated fungi which varied according to the isolate type.

scholarly journals SEVERITY AND INTENSITY OF FUNGAL DISEASES OF CUCURBIT CROPS OF HAMIRPUR REGION, HP, INDIA

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Manu Vineet Sharma ◽  
Hem Chander
Keyword(s):  
Cucumis Sativus ◽  
Disease Severity ◽  
Leaf Spot ◽  
Fungal Pathogens ◽  
Disease Incidence ◽  
Fungal Diseases ◽  
Lagenaria Siceraria ◽  
Coccinia Grandis ◽  
Downy Mildews ◽  
Powdery Mildews

Cucurbitaceae is the vegetable family enriched with numerous vitamins and minerals. In early rainy season cucurbits are the host of different fungal pathogens. In present study, four fungal diseases dominant on three members of cucurbitaceae family are observed in Bhoranj block of District Hamirpur, lie in lower foot hills of Himachal Pradesh. Four fungal diseases along with host plants are leaf spot of Lagenaria siceraria, downy mildews of Cucumis sativus, powdery mildews of Coccinia grandis and powdery mildews of Cucumis sativus. Among all these diseases, Disease Incidence and Disease Severity of Powdery mildews of Coccinia grandis are most dominant i.e. 40.3±1 and 51.2±1 respectively. Disease Incidence and Disease Severity of Leaf spot of Lagenaria siceraria is least i.e. 12.5±1 and 1.1±1, respectively.

scholarly journals First Report of Crown and Root Rot in Strawberry Caused by Macrophomina phaseolina in Israel

Plant Disease ◽  
2005 ◽  
Vol 89 (9) ◽  
pp. 1014-1014 ◽  
Author(s):  
A. Zveibil ◽  
S. Freeman
Keyword(s):  
Root Rot ◽  
Fungal Pathogens ◽  
Macrophomina Phaseolina ◽  
Crown Rot ◽  
Plant Mortality ◽  
Charcoal Rot ◽  
First Report ◽  
Production Stages ◽  
Pure Cultures ◽  
Pathogenicity Assay

A phenomenon of wilting in strawberry (Fragaria × ananassa Duchesne) transplants, cultivated for annual winter production, was observed on several cultivars at 14 farmers' plots in nine growing regions in Israel during September and October 2004. Typical ‘charcoal rot’ symptoms included necrotic root and crown rot accompanied by plant wilting and chlorosis of leaves (1). Pure cultures of Macrophomina phaseolina were isolated from affected roots and crowns of plants (1) when incubated at 25°C in the dark on potato dextrose agar (PDA) (Difco Laboratories, Sparks, MD) medium containing 250 mg/l of chloramphenicol. Dark, oblong sclerotia averaging 40 μm wide by 200 μm long were observed in the infected root tissue and in culture 7 to 10 days after isolation (2). Twenty-two single sclerotium isolates were recovered from five infected cultivars (Yuval, Herut, Tamar, Hadas, and Malach) and three representative isolates were used in two pathogenicity assays. Inoculum of M. phaseolina was produced by blending 3-week-old cultures on PDA plates (9 cm diameter) in 100 ml of sterile distilled water, filtering the suspension through eight layers of gauze, and adjusting the concentration to 105 sclerotia per ml. In the first pathogenicity assay, each of the three isolates was inoculated on five plants (cv. Malach). Plants were produced from nursery runners and potted in a soilless coconut and styrofoam (3:1 vol/vol) medium, 1 liter per pot. Each plant was inoculated by pouring 50 ml of sterile water containing 105 sclerotia per ml per pot. Plants were incubated at 30°C with 12-h day/night conditions and watered with 100 ml every 3 to 7 days. Five noninoculated control plants were included. Necrosis at the base of petioles and chlorosis of leaves, followed by initial wilting of leaves, were observed after 2 weeks on inoculated plants. Plant mortality was first recorded approximately 5 weeks after inoculation and 100% mortality was recorded 10 weeks postinoculation. In the second pathogenicity assay, the same three isolates were used to inoculate four plants each of two different cultivars (Malach and Hadas) as described previously. Identical disease symptoms, as described previously, were observed 17 days after inoculation. Initial plant mortality was observed approximately 6 weeks postinoculation. In both pathogenicity assays, M. phaseolina was readily reisolated on amended PDA from all symptomatic and dead plants, which successfully completed Koch's postulates. Noninoculated control plants remained healthy. Although M. phaseolina has been reported in other crops in Israel, to our knowledge, this is the first report of the pathogen on strawberry in our country. This study suggests that the current soil fumigation regimen for control of fungal pathogens such as M. phaseolina, utilizing alternatives to methyl bromide which is currently being phased out in Israel, may not be adequate to maintain healthy strawberry material at all production stages. A similar observation was recently reported in Florida (2). Charcoal rot of strawberry has also been recorded on strawberry in France, India, and Egypt (1). References: (1) J. Maas. Macrophomina leaf blight and dry crown rot and Macro-phomina root rot and charcoal rot. Pages 26 and 59 in: Compendium of Strawberry Diseases. 2nd ed. J. L. Maas, ed. The American Phytopathological Society, St. Paul, MN, 1998. (2) J. Mertely et al. Plant Dis. 89:434, 2005.

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