scholarly journals Identification of Pathogens Causing Bulb Rot Disease on Garlic (Allium sativum L.) in Central Java, Indonesia

2021 ◽  
Vol 25 (1) ◽  
pp. 74
Author(s):  
Lutfi Arifin ◽  
Siwi Indarti ◽  
Arif Wibowo

Garlic bulb rot disease was found from garlics (Allium sativum L.) cultivated from 2017 to 2019 by farmers in Central Java Province, Indonesia. The initial symptoms of the disease were stunted, leaf yellowing, and necrotizing to rotten bulbs. This research was conducted to determine the major causal agent of garlic bulb rot disease in Central Java. A survey was carried out in five regencies across Central Java that were major garlic-producing areas. Nematodes were isolated using water immersion methode and pathogenic fungi were isolated on Potato Dextrose Agar (PDA). Nematode identification was carried out based on the Ditylenchus dipsaci morphological and morphometric character. Seven isolates of Fusarium species were obtained from infected garlic. Identification of four chosen isolates were performed by sequencing the TEF-1α gene. The TEF sequence of isolate TB3, KK1, and KK4 showed 99% similarity with several F. oxysporum, BT3 sequences showed 98% identity with several F. solani, and all were deposited in the NCBI GenBank. Three locations were positively infected by the interaction between D. dipsaci and Fusarium sp. Based on the results of the morphological identification, parasitic nematode was identified as D. dipsaci, while based on the morphological and molecular identification isolates Fusarium were identified as F. oxysporum and F. solani, respectively, as first report causal agents of garlic bulbs rot in Central Java.

Plant Disease ◽  
2010 ◽  
Vol 94 (7) ◽  
pp. 919-919 ◽  
Author(s):  
T. Shi ◽  
C.-P. Li ◽  
J.-F. Li ◽  
J.-M. Cai ◽  
G.-X. Huang

Cassava (Manihot esculenta Crantz) is an important food crop in tropical regions of China. Seventy percent of the cassava output is used for starch and ethanol production and it has become the base of food and bioenergy industries. In July 2009, a new leaf spot disease was found on cv. HuaNan205 from a cassava plantation in Danzhou, Hainan Province. Disease occurred on 50% or less of the plants. Initial symptoms were elliptical, chlorotic, and water-immersion lesions of 2 to 4 mm in diameter. These lesions became dry and yellow due to the progress of the disease. A brown halo was around the lesions, and in wet conditions, a dark gray mildew often appeared in the middle of the lesion. Diseased leaves turned yellow and the plants eventually became defoliated. The pathogen was isolated and pathogenicity was established by following Koch's postulates. Young, healthy, and fully expanded green leaves of Cassava cv. HuaNan205 were surface sterilized and then inoculated by spraying them with a suspension of conidia (1 × 105 conidia per ml) of the isolate. Sterile water was used as a control. The leaves were kept in a humid chamber at 28°C for 4 days, at which time similar symptoms to those described above were observed on the leaves. The pathogen was reisolated from inoculated leaves. Microscopic examination showed the conidiophores were fasciculate and brown, septate and straight, and the basal cell was enlarged and hemispherical. Well-developed conidia were long-obclavate, obtuse at both ends, straight, brown, with five to eight transverse septa, and measured 49.7 to 117.1 × 13.3 to 17.2 μm. Genomic DNA of this isolate was extracted with a cetyltrimethylammoniumbromide protocol, and amplification and sequencing of the internal transcribed spacer (ITS) region of rDNA was performed with procedures outlined by Cooke et al. (2). The sequence of the region was deposited in GenBank (Accession No. GU290228). Comparison of the sequences available in the GenBank database revealed that the current ITS sequence differs by three base pairs from two Bipolaris setariae isolates (EF452444 and FJ606786). Morphological identification and sequence analysis of ITS rDNA showed that the pathogen was B. setariae. B. setariae is one of the most important pathogens of lawn grass, gramineous crops, and other plants (1,3). However, no leaf spot disease caused by B. setariae has been recorded previously on cassava in China or elsewhere. References: (1) P. Busey. Crop Sci. 43:1899, 2003. (2) D. E. L. Cooke et al. Fungal Genet. Biol. 30:17, 2000. (3) H. D. Wells and W. W. Hanna. Phytopathology 78:1179, 1988.


Plant Disease ◽  
2011 ◽  
Vol 95 (6) ◽  
pp. 768-768 ◽  
Author(s):  
S. T. Koike

Tarragon, also known as estragon or dragon's-wort (Artemisia dracunculus), is a perennial plant in the Asteraceae. Tarragon is grown for use in cooking as a fresh and dried herb. In May 2010, commercial tarragon grown in a field on California's central coast was affected by a previously undescribed disease. Initial symptoms consisted of chlorosis of leaves and wilting of shoot tips. As the disease progressed, entire shoots and branches turned brown and died. The plant crown epidermis and cortex and the upper cortex of the main roots turned brown with occasional black streaking. Diseased plants died several weeks after the onset of wilting. A Fusarium species was consistently isolated from symptomatic crown and root tissues. On carnation leaf agar (CLA) incubated under lights, the isolates produced stout, slightly curved macroconidia having blunt apical cells. One- and two-celled oval to cylindrical microconidia were abundant and born in false heads on extremely long monophialides. Chlamydospores were present in 1-month-old cultures. On potato dextrose agar incubated under lights, the isolates produced abundant white aerial mycelium with bluish coloration of the culture surface. The isolates were identified as Fusarium solani (2). Pathogenicity tests were conducted using six isolates, with inoculum produced on CLA. For each isolate, 250 ml of a spore suspension (1 × 106 conidia/ml) were poured onto the roots of 10-cm potted tarragon plants. Ten plants were inoculated for each of the six isolates. A control set of tarragon was treated with 250 ml of water. All plants were maintained in a greenhouse set at 24 to 25°C. After 8 weeks, plants inoculated with the spore suspensions began to show wilting and browning of leaves. Crown epidermis and cortex and root cortex tissues were brown; Fusarium solani was reisolated from the crowns and roots. The experiment was repeated and the results were the same. To my knowledge, this is the first report of F. solani causing a crown and root rot disease of tarragon. The disease caused significant damage with approximately 50% of the commercial field affected. The other Fusarium species previously reported on tarragon is an uncharacterized F. oxysporum isolated from roots of plants grown in California (1). References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , March 8, 2011, (2) P. E. Nelson et al. Fusarium Species: An Illustrated Manual for Identification. Pennsylvania State University Press, University Park, PA, 1983.


Foods ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1063
Author(s):  
Laura Gálvez ◽  
Daniel Palmero

In recent years, different postharvest alterations have been detected in garlic. In many cases, the symptoms are not well defined, or the etiology is unknown, which further complicates the selection of bulbs during postharvest handling. To characterize the different symptoms of bulb rot caused by fungi, garlic bulb samples were collected from six Spanish provinces in two consecutive years. Eight different fungal species were identified. The most prevalent postharvest disease was Fusarium dry rot (56.1%), which was associated with six Fusarium species. Fusarium proliferatum was detected in more than 85% of symptomatic cloves, followed by F. oxysporum and F. solani. Pathogenicity tests did not show a significant correlation between virulence and mycotoxin production (fumonisins, beauvericin, and moniliformin) or the mycelial growth rate. Penicillium allii was detected in 12.2% of the samples; it was greatly influenced by the harvest season and garlic cultivar, and three different morphotypes were identified. Stemphylium vesicarium and Embellisia allii were pathogenic to wounded cloves. Some of the isolated fungal species produce highly toxic mycotoxins, which may have a negative impact on human health. This work is the first to determine the quantitative importance, pathogenicity, and virulence of the causative agents of postharvest garlic rot in Spain.


Toxins ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 463
Author(s):  
Amal Rabaaoui ◽  
Chiara Dall’Asta ◽  
Laura Righetti ◽  
Antonia Susca ◽  
Antonio Logrieco ◽  
...  

In 2017–2018, extensive symptoms of sudden decline and fruit rot were observed on date palms in southern Tunisia. Samples of diseased plants were randomly collected in six localities. Based on morphological identification, Fusarium was the most frequent fungal genus detected. A sequencing of translation elongation factor, calmodulin, and second largest subunit of RNA polymerase II genes was used to identify 63 representative Fusarium strains at species level and investigate their phylogenetic relationships. The main species detected was Fusarium proliferatum, and at a much lesser extent, Fusarium brachygibbosum, Fusarium caatingaense, Fusarium clavum, Fusarium incarnatum, and Fusarium solani. Pathogenicity on the Deglet Nour variety plantlets and the capability to produce mycotoxins were also assessed. All Fusarium species were pathogenic complying Koch’s postulates. Fusarium proliferatum strains produced mainly fumonisins (FBs), beauvericin (BEA), and, to a lesser extent, enniatins (ENNs) and moniliformin (MON). All F. brachygibbosum strains produced low levels of BEA, diacetoxyscirpenol, and neosolaniol; two strains produced also T-2 toxin, and a single strain produced HT-2 toxin. Fusarium caatingaense, F. clavum, F. incarnatum produced only BEA. Fusarium solani strains produced MON, BEA, and ENNs. This work reports for the first time a comprehensive multidisciplinary study of Fusarium species on date palms, concerning both phytopathological and food safety issues.


2019 ◽  
Author(s):  
Gláucia Mara Moreira ◽  
Camila Primieri Nicolli ◽  
Larissa Bitencourt Gomes ◽  
Claudigo Ogoshi ◽  
Klaus K. Scheuermann ◽  
...  

Ninety three samples of rice were obtained from research and commercial plots at eight rice-producing regions of Brazil and analyzed for the presence of Fusarium species and 14 mycotoxins. A total of 352 isolates belonging to Fusarium genus were obtained from 85 % of the samples. These were assigned to four species complexes (SC) based on morphological identification. The most frequent SC detected was F. incarnatum-equiseti (FIESC, 32.4 %) followed by F. fujikuroi (FFSC, 26.1 %), F. graminearum (FGSC, 24.7 %) and F. chlamydosporum (FCSC, 16.8 %). FGSC was limited geographically and dominant in the southern subtropical production regions while the others occurred in all regions, particularly FIESC, the most widespread among them. The samples were individually contaminated with three to eight mycotoxins. The most common mycotoxins detected were zearalenone (ZEA), beauvericin, and acetylated forms of deoxynivalenol (AcDON). Other toxins included enniatins, T-2, HT-2, DON, neosolaniol and moniliformin. The concentration levels were all below the Brazilian promulgated limits established only for DON (< 750 ppb), and ZEA (< 100 ppb) with one exception for the latter. Most toxins were found in both the husk and flour fractions, but AcDON tended to concentrate more in the husk. Our survey extends considerable our knowledge of the Fusarium complexes infecting rice and provides an update on the status of rice mycotoxin contamination at the country level, which can be considered generally safe. However, attention should be paid to the widespread contamination of beauvericin.


Plant Disease ◽  
2015 ◽  
Vol 99 (5) ◽  
pp. 723 ◽  
Author(s):  
L. Gálvez ◽  
J. Gil-Serna ◽  
M. García-Díaz ◽  
D. Palmero

Plant Disease ◽  
2021 ◽  
Author(s):  
Sheng Deng ◽  
Xin Ma ◽  
Yifan Chen ◽  
Hui Feng ◽  
Dongmei Zhou ◽  
...  

The yields of edible rhizome from the cultivation of the perennial hydrophyte lotus (Nelumbo nucifera) can be severely reduced by rhizome rot disease caused by Fusarium species. There is a lack of rapid field-applicable methods for detection of these pathogens on lotus plants displaying symptoms of rhizome-rot. Fusarium commune (91%) and Fusarium oxysporum (9%) were identified at different frequencies from lotus samples showing symptoms of rhizome-rot. As these two species can cause different severity of disease and their morphology is very similar, molecular-diagnostic based methods to detect these two species were developed. Based on the comparison of the mitochondrial genome of the two species, three specific DNA loci targets were found. The designed primer sets for conventional PCR, qPCR and loop-mediated isothermal amplification (LAMP) precisely distinguished the above two species when isolated from lotus and other plants. The LAMP detection limits were 10 pg/μl and 1 pg/μl of total DNA for F. commune and F. oxysporum, respectively. We also carried out field-mimicked experiments on lotus seedlings and rhizomes (including inoculated samples and field diseased samples), and the results indicated that the LAMP primer sets and the supporting portable methods are suitable for the rapid diagnosis of the lotus disease in the field. The LAMP-based detection method will aid in the rapid identification of whether F. oxysporum or F. commune are infecting lotus plants with symptoms of rhizome-rot, and can facilitate efficient pesticide use and prevent the disease spread through vegetative propagation of Fusarium-infected lotus rhizomes.


Author(s):  
Said Ezrari ◽  
Rachid Lahlali ◽  
Nabil Radouane ◽  
Abdessalem Tahiri ◽  
Adil Asfers ◽  
...  

2016 ◽  
Vol 56 (3) ◽  
pp. 231-236 ◽  
Author(s):  
Nur Baiti Abd Murad ◽  
Nor Azizah Kusai ◽  
Nur Ain Izzati Mohd Zainudin

Abstract Fruit rot of tomato is a serious disease caused by Fusarium species. Sampling was conducted throughout Selangor, Malaysia and fungal species identification was conducted based on morphological and gene encoding translation elongation factor 1-α (tef1-α) sequence analysis. Five species of Fusarium were discovered namely F. oxysporum (including F. oxysporum f. sp. lycopersici), F. solani, F. equiseti, F. proliferatum and F. verticillioides. Our results provide additional information regarding the diversity of Fusarium species associated with fruit rot disease of tomato.


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