scholarly journals First Report of Black Branch Dieback of Cashew Caused by Lasiodiplodia theobromae in Brazil

Plant Disease ◽  
2002 ◽  
Vol 86 (5) ◽  
pp. 558-558 ◽  
Author(s):  
J. E. Cardoso ◽  
J. C. Vidal ◽  
A. A. dos Santos ◽  
F. C. O. Freire ◽  
F. M. P. Viana

Cashew nut (Anacardium occidentale) is one of the most important cash crops of northeastern Brazil. A new disease, named here as black branch dieback, caused by Lasiodiplodia theobromae, was observed causing serious damage on as many as 30% of the trees in some orchards in both coastal and inland semiarid cashew-growing areas of Ceará and Piauí states of Brazil, respectively. The disease symptoms are first observed as darkened, elongated lesions on stems near the branch apexes of herbaceous tissues. Gum exudation is common from lesions, which expand rapidly to affect the entire branch, leading to branch death. Diseased plants were collected, and L. theobromae was consistently isolated from canker tissues. Fresh mycelial disks of the fungus were used for artificial inoculation of healthy plants. Shoots of young cashew plants were inoculated on the apex by inserting a 3-mm plug taken from actively growing colonies on potato dextrose agar into an incision made with a sterile scalpel. Agar plugs with no mycelium were placed into incised plant shoots to serve as controls. Plants were incubated in a greenhouse at 28°C. Symptoms developed within 15 days after inoculation. Artificially inoculated plants showed symptoms similar to those that were naturally infected. L. theobromae was consistently reisolated from inoculated plants. The disease seems to occur throughout the year, but it spreads faster during the rainy season. A contagious disease pattern within the orchard was observed with a decreasing gradient from the orchard perimeter to the interior of the field, suggesting an external source of primary inoculum. All improved dwarf cashew clones were susceptible, but the newly released clone END-189 was the most susceptible. Black branch dieback may reduce tree growth, nut yield, and eventually cause plant death. Plant susceptibility is not related to its age however; only herbaceous tissues are vulnerable to natural infection. A similar disease on floral shoots of cashew caused by L. theobromae was reported by Olunloyo and Esuruoso in Nigeria (1). To our knowledge, this is the first report of L. theobromae causing branch dieback in cashew orchards in Brazil. Reference: (1) O. A. Olunloyo and O. F. Esuruoso. Plant Dis. 59:176, 1975.

Plant Disease ◽  
2013 ◽  
Vol 97 (6) ◽  
pp. 835-835 ◽  
Author(s):  
M. Catal ◽  
C. Ikten ◽  
E. Yol ◽  
R. Üstün ◽  
B. Uzun

Sesame (Sesamum indicum L.) is an important oilseed crops widely grown in the southern regions of Turkey. Sesame seeds are primarily used in production of tahini as well as a garnish on sweets and bakery products in the country. Sesame plants with phyllody disease symptoms have increasingly been observed in the fields of Antalya province since 2007. The disease incidence in these fields was found to range from 37 to 62% (2). Infected plants display a variety of the disease symptoms such as virescence, asymptomatic shoot proliferation, infertile flower formation, reduced leaf size, and thin and weak capsule development. Total genomic DNA was extracted from samples collected from symptomatic (10 plants) and asymptomatic healthy-looking plants (10 plants) using a CTAB method and amplified with universal primers P1/P7 and R16F2n/R16R2 in direct and nested PCR, respectively (1,3). Amplifications of the DNA from the symptomatic plants yielded a product of 1.8 kb in direct and 1.2 kb in nested PCR assays. No amplification was observed in symptomless plants of the same age and collected from the same fields. Amplicons were purified, cloned in a pTZ57R/T Vector, and sequenced using a Beckman Coulter 8000 CEQ Genetic Analysis System. Four aligned 16S rDNA sequences (1,845 bp) were found to be all identical and belonging to one species. One sequence was deposited in GenBank under the accession number KC139791. A BLAST similarity search revealed that the sequence shared 99% homology with the sequences of the members of 16SrIX group phytoplasmas, ‘Brassica rapa’ phyllody phytoplasma (HM559246.1) and Iranian Almond witches'-broom phytoplasma (DQ195209.1) available in GenBank. In addition, iPhyClassifier software (4) was employed to create a virtual RFLP profile. The analysis showed that the RFLP profile of the sesame phytoplasma 16S rDNA sequence is identical (a similarity coefficient of 1.00) to the profile of the 16Sr group IX phytoplasma reference sequence (Y16389). A phylogenetic tree was also constructed using the neighbor joining plot option of the Clustal X program. The sequence clustered together with 16SrIX group phytoplasmas. To our knowledge, this is the first report of a natural infection of sesame by a new phytoplasma species from the 16SrIX group in Turkey. References: (1) D. E. Gundersen and I.-M. Lee. Phytopathol. Mediterr. 35:144, 1996. (2) C. Ikten et al. Phytopathogenic Mollicutes 1:101, 2011. (3) C. D. Smart et al. Appl. Environ. Microbiol. 62:2988, 1996. (4) Y. Zhao et al. Int. J. Syst. Evol. Microbiol. 59:2582, 2009.


Plant Disease ◽  
2013 ◽  
Vol 97 (8) ◽  
pp. 1114-1114 ◽  
Author(s):  
D. Zhao ◽  
Y. B. Kang

Tree peony (Paeonia suffruticosa Andrews) is a perennial woody deciduous shrub native to China and famous for its beautiful flowers. Starting in early autumn 2010, blighted branches of tree peony were detected in the International Peony Garden in Luoyang. The disease incidence was greater than 10% and disease symptoms included bulb atrophy and twig and branch dieback. Pycnidia were embedded within the bark of diseased branches. They were small, black, ostiolate, and measured 145 to 275 × 140 to 251 μm. Pycnoconidia were single-celled, hyaline or sandy beige, rounded to ellipsoidal, and 3.9 to 10.3 × 2.3 to 7.0 μm. Pure cultures were obtained by plating the pycnoconidia on potato dextrose agar (PDA). In culture, the fungus produced a circular, white to pink colony with pyknotic and linter shaped aerial mycelium. Numerous pycnidia, initially brown and dark at maturity, were embedded in the mycelium, especially in the center of the colony, with a few of them scattered in the edge. The morphological characteristics were consistent with Phoma (2). The ITS1-5.8S-ITS2 region of three isolates were PCR amplified and sequenced with primers ITS1 and ITS4. Sequences (GenBank Accession No. JX885584) showed 99% identity with reference isolates of Peyronellaea glomerata (Corda) Goid (AB470906.1 and HQ380779.1) and Phoma glomerata (Corda) Wollenw. & Hochapfel (EU098115.1). These two species are synonyms (1). To test pathogenicity, nine healthy branches of 3-year-old potted tree peony plants were wound-inoculated with a PDA disk containing pycnidia from an actively growing colony of P. glomerata. Three control branches were inoculated with sterile PDA disks. Each inoculated branch was wrapped in a plastic bag and maintained in a greenhouse at 25 to 28°C. After 3 days, brown patches appeared on inoculated branches and extended by up to 1 cm. Pycnidia identical to those observed in the field and in storage appeared on all inoculated branches 7 days after inoculation. Control branches did not show symptoms. The pathogen was reisolated from inoculated branches, fulfilling Koch's postulates. P. glomerata was reported as the causal agent of withering of flowers and young shoots of grapevines in Yugoslavia (3). To our knowledge, P. glomerata and Botryosphaeria dothidea have always been reported together, causing branch wilting or dieback. To our knowledge, this is the first report of branch blight of tree peony caused by P. glomerata in China. References: (1) M. M. Aveskamp et al. Mycol. Soc. Am. 101:363, 2009. (2) G. H. Boerema et al. Studies in Mycology, 3, 1973. (3) A. Šaric-Sabadoš et al. Atti Ist. bot. Univ. Pavia 18:101, 1960.


Plant Disease ◽  
2012 ◽  
Vol 96 (10) ◽  
pp. 1579-1579 ◽  
Author(s):  
Z. W. Tan ◽  
C. S. Wang ◽  
G. L. Wang

Koelreuteria bipinnata var integrifoliola is becoming a popular urban green tree in Ningbo City, Zhejiang Province, China, because of its adaptation ability to local conditions, fast growth, and beautiful appearance. A survey conducted from 2007 to 2010 revealed serious bark cracking on greenbelt trees approximately 15 to 16 years old that had been transplanted 5 to 6 years ago. Bark cracks increased in size over time, extending into the phloem and leading to extensive areas of bark loss with discoloration of the underlying xylem. Symptomatic trees had fewer new shoots in spring; many wilted and died in summer. Root rot was not observed in the withered trees but large light brown lesions were observed on cross sections of the main stem, each with a dark brown outer margin. In a September 2009 survey, 95% of symptomatic trees had stem lesions more than 50 cm long. Pieces of xylem (2 × 2 × 1 mm thick) were obtained from the margin of lesions surface sterilized using 0.1% mercuric chloride for 30 s, washed in sterile distilled water, and placed on 2% potato dextrose agar (PDA) at 28°C for 2 days. The fungus was then isolated and 12 colonies were obtrained. Three isolates KL-1-2, KL-3-2, and KL-4-3 were incubated on 2% PDA at 28°C for 30 days to produce spores. On PDA, the colonies were circular or near circular with irregular gray edges turning black green or black. The fungus also produced abundant aerial hyphae that were villous, septate, and irregular branched. Conidia were elliptical (or rounded) and hyaline when immature, becoming dark brown and septate longitudinally when mature and ranged from 23.2 to 27.0 × 10.8 to 16.2 μm (average 25.3 × 13.6 μm), similar to Lasiodiplodia theobromae (Patouillard) Griffon =Botryodiplodia theobromae Pa.t, Botryosphaeria rhodina (Berkeley & Curtis) von Arx (2). DNA extraction directly from the mycelium of KL-1-2, KL-3-2, and KL-4-3 was performed after 10 days' growth on PDA (1). The identities of the three isolates were confirmed by ITS1-5.8S-ITS2 rDNA sequence (GenBank Accession Nos. JN681172, JQ894322, and JQ894323, respectively) analysis that showed 99%, 100%, and 100% sequence similarity to L. theobromae xsd08006 (Accession No. FJ478102), L. theobromae PD20 (Accession No. GU251120), and L. theobromae xsd08008 (Accession No. EU918707), respectively. Pathogenicity tests were performed on 20 five-year-old K. bipinnata var integrifoliola plants by placing mycelia plugs of isolate KL-1-2 (10 × 10 mm) on the main trunk after wounding with a metal needle. Control plants received PDA plugs without mycelium. After inoculation, humidity was maintained using wet absorbent cotton and PE wrap film. Stem bark and phloem cracking was observed after 60 days on 85% of inoculated plants; 30% of those trees also had xylem discoloration. Symptoms were similar to those with natural infection. Control plants remained symptomless. The same fungus was reisolated from the brown xylem of inoculated plants. To our knowledge, this is the first report of bark cracking of K. bipinnata var integrifoliola caused by L. theobromae in China. References: (1) M.-J. Côté et al. Plant Dis. 88:1219, 2004. (2) G. Fu et al. Australas. Plant Dis. Notes 2:75, 2007.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Farshid O Sirjani ◽  
Edwin E Lewis

Abstract A new dipterous pest is reported, for the first time, on commercial pistachios from Sirjan, Kerman province, Iran. The genus of the insect was determined to be Resseliella Seitner (Diptera: Cecidomyiidae). Adults are light brown to brown in color and 0.8–1.5 mm in length with females, generally, slightly larger than males. Females have an elongated ovipositor, which is characteristic of the genus. Larvae are orange in color, 2–3 mm in length in the later instars, feed under bark without inducing galls, and cause branch dieback on trees of various ages. Brown to black discolorations are observed on plant tissues under bark where the larvae feed. Infestations observed on current and the previous—year’s growths, ranged from 0.5 to 1.2 cm in diameter, and all located in outer branches. Dry leaves and fruit clusters on infested branches remain attached, which may be used to recognize infestation by the gall midge. Dark-colored, sunken spots with splits on the bark located at the base of the wilted sections of the shoots also are symptoms of Resseliella sp. larval activity. Species-level identification of the gall midge is currently underway.


2011 ◽  
Vol 11 (11) ◽  
pp. 1507-1509 ◽  
Author(s):  
Wissem Ghawar ◽  
Mohamed Ali Snoussi ◽  
Nabil Bel Haj Hamida ◽  
Aïcha Boukthir ◽  
Rihab Yazidi ◽  
...  

2013 ◽  
Vol 22 (1) ◽  
pp. 182-185 ◽  
Author(s):  
Nilo Fernandes Leça Júnior ◽  
Valter dos Anjos Almeida ◽  
Fábio Santos Carvalho ◽  
George Rego Albuquerque ◽  
Fabiana Lessa Silva

In order to verify the Trypanosoma cruzi infection in domestic domiciled dogs in a rural endemic area from the south region of the State of Bahia, Polymerase Chain Reaction (PCR) were performed using S35 and S36 primers in 272 dogs living in the district of Vila Operaria, in the municipality of Buerarema. All animals were clinically evaluated; 2.5 mL of blood were collected through venipuncture for the performance of molecular tests. None of these animals showed clinical signs of the illness and only two were identified with the DNA parasite. This result is the first report of natural infection by T. cruzi in domestic dogs in southern Bahia.


Plant Disease ◽  
2006 ◽  
Vol 90 (7) ◽  
pp. 973-973 ◽  
Author(s):  
N. A. Al-Saady ◽  
A. M. Al-Subhi ◽  
A. Al-Nabhani ◽  
A. J. Khan

Chickpea (Cicer arietinum), locally known as “Dungo”, is grown for legume and animal feed mainly in the interior region of Oman. During February 2006, survey samples of chickpea leaves from plants showing yellows disease symptoms that included phyllody and little leaf were collected from the Nizwa Region (175 km south of Muscat). Total nucleic acid was extracted from asymptomatic and symptomatic chickpea leaves using a cetyltrimethylammoniumbromide method with modifications (3). All leaf samples from eight symptomatic plants consistently tested positive using a polymerase chain reaction assay (PCR) with phytoplasma universal primers (P1/P7) that amplify a 1.8-kb phytoplasma rDNA product and followed by nested PCR with R16F2n/R16R2 primers yielding a product of 1.2 kb (2). No PCR products were evident when DNA extracted from healthy plants was used as template. Restriction fragment length polymorphism analysis of nested PCR products by separate digestion with Tru9I, HaeIII, HpaII, AluI, TaqI, HhaI, and RsaI restriction enzymes revealed that a phytoplasma belonging to group 16SrII peanut witches'-broom group (2) was associated with chickpea phyllody and little leaf disease in Oman. Restriction profiles of chickpea phytoplasma were identical with those of alfalfa witches'-broom phytoplasma, a known subgroup 16SrII-B strain (3). To our knowledge, this is the first report of phytoplasma infecting chickpea crops in Oman. References: (1) A. J. Khan et al. Phytopathology, 92:1038, 2002. (2). I.-M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998 (3) M. A. Saghai-Maroof et al. Proc. Natl. Acad. Sci. USA. 81:8014, 1984.


Plant Disease ◽  
2018 ◽  
Vol 102 (7) ◽  
pp. 1451 ◽  
Author(s):  
G. A. Díaz ◽  
B. A. Latorre ◽  
E. Ferrada ◽  
M. Gutiérrez ◽  
F. Bravo ◽  
...  

Plant Disease ◽  
2009 ◽  
Vol 93 (7) ◽  
pp. 762-762 ◽  
Author(s):  
R. K. Sampangi ◽  
C. Almeyda ◽  
K. L. Druffel ◽  
S. Krishna Mohan ◽  
C. C. Shock ◽  
...  

Penstemons are perennials that are grown for their attractive flowers in the United States. Penstemon species (P. acuminatus, P. deustus, and P. speciosus) are among the native forbs considered as a high priority for restoration of great basin rangelands. During the summer of 2008, symptoms of red spots and rings were observed on leaves of P. acuminatus (family Scrophulariaceae) in an experimental trial in Malheur County, Oregon where the seeds from several native forbs were multiplied for restoration of range plants in intermountain areas. These plants were cultivated as part of the Great Basin Native Plant Selection and Increase Project. Several native wildflower species are grown for seed production in these experimental plots. Plants showed red foliar ringspots and streaks late in the season. Fungal or bacterial infection was ruled out. Two tospoviruses, Impatiens necrotic spot virus and Tomato spotted wilt virus, and one nepovirus, Tomato ring spot virus, are known to infect penstemon (2,3). Recently, a strain of Turnip vein-clearing virus, referred to as Penstemon ringspot virus, was reported in penstemon from Minnesota (1). Symptomatic leaves from the penstemon plants were negative for these viruses when tested by ELISA or reverse transcription (RT)-PCR. However, samples were found to be positive for Cucumber mosaic virus (CMV) when tested by a commercially available kit (Agdia Inc., Elkhart, IN). To verify CMV infection, total nucleic acid extracts from the symptomatic areas of the leaves were prepared and used in RT-PCR. Primers specific to the RNA-3 of CMV were designed on the basis of CMV sequences available in GenBank. The primer pair consisted of CMV V166: 5′ CCA ACC TTT GTA GGG AGT GA 3′ and CMV C563: 5′ TAC ACG AGG ACG GCG TAC TT 3′. An amplicon of the expected size (400 bp) was obtained and cloned and sequenced. BLAST search of the GenBank for related sequences showed that the sequence obtained from penstemon was highly identical to several CMV sequences, with the highest identity (98%) with that of a sequence from Taiwan (GenBank No. D49496). CMV from infected penstemon was successfully transmitted by mechanical inoculation to cucumber seedlings. Infection of cucumber plants was confirmed by ELISA and RT-PCR. To our knowledge, this is the first report of CMV infection of P. acuminatus. With the ongoing efforts to revegetate the intermountain west with native forbs, there is a need for a comprehensive survey of pests and diseases affecting these plants. References: (1) B. E. Lockhart et al. Plant Dis. 92:725, 2008. (2) D. Louro. Acta Hortic. 431:99, 1996. (3) M. Navalinskiene et al. Trans. Estonian Agric. Univ. 209:140, 2000.


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