Ocular and oral lesions caused by Tacinga inamoena in sheep and goats in Northeast Brazil

ABSTRACT: Two outbreaks of traumatic injuries in goats and sheep associated with grazing and ingestion of the cactus Tacinga inamoena have recently been reported in the state of Paraíba, Brazil. In the first of these, which was detected in 2019 during a preliminary inspection of a herd of 70 animals, it was found that 15 showed certain ocular complications, and these animals were subjected to general physical and ophthalmic examinations. The clinical findings included excessive lacrimation, blepharitis, photophobia, corneal opacity, hyphema, corneal neovascularization, corneal ulcers, and adherence of gloquids to the bulbar conjunctiva and cornea. Large amounts of T. inamoena were found to be present in several areas in which these animals had been grazed and had been observed consuming the fruits of this plant. In the second outbreak during the following year, two sheep from a total of 100 animals were identified as having oral lesions associated with grazing in areas within which T. inamoena was growing. One of these animals was referred to a veterinary hospital, and on physical examination was found to show apathy, anorexia, a body score of 1.5, and the presence of gloquids within the fur. With respect to the oral cavity, halitosis, severe sialorrhea, extensive hemorrhagic ulcers, and painful tenderness on palpation were detected. Given the unfavorable prognosis, the sheep was subsequently euthanized. At necropsy, multifocal to coalescent plaques were detected on the upper and lower lips, oral mucosa, tongue, and hard and soft palates. These were generally elevated and firm and characterized by an irregular, ulcerated surface, sometimes crusty, with a yellow to light brown center and erythematous edges. The findings of this study highlight that the consumption of T. inamoena can cause serious oral and ophthalmic lesions in small ruminants in the northeastern semi-arid regions of Brazil, and can potentially contribute to substantial large economic losses. This problem tends to be exacerbated by the invasive behavior of T. Inamoena, particularly in areas in the process of environmental degradation.

First report of Colletotrichum siamense causing anthracnose on Erythrina crista-galli in China

Erythrina crista-galli L. (Fabaceae) is a popular ornamental plant in tropical and subtropical regions of South Asia. In October 2019, anthracnose-like lesions were observed on the leaves of E. crista-galli planted in Haikou, China. 5-30% of leaves were infected. At first, the circular spots of 1-2 mm in diameter were reddish-brown on the leaves, and then enlarged to circular, subcircular or irregular spots with reddish-brown center and surrounded by a diffuse yellow margin. Neighboring spots sometimes coalesced. Under continuously wet or humid conditions, the lesions expanded quickly, and became gray, subcircular or irregular spots covered by grayish-white mycelium and orange-pink conidial masses. Diseased leaves eventually fell off the trees. To identify the pathogen, diseased leaves were sampled from four gardens. Leaf tissues (5×5 mm) were cut from the margins of typical symptomatic lesions, surface-sterilized in 1% sodium hypochlorite for 1 min, plated on potato dextrose agar (PDA) medium, and incubated at 28.0±0.5℃ in the dark. Similar fungal colonies were obtained from all plated tissues after 3 days. The single-conidium colonies of all isolates were white to pale gray and cottony with visible orange conidial masses. Conidia were one-celled, aseptate, hyaline, straight, cylindrical to fusiform with obtuse ends, and ranged from 14.2-18.6 µm (16.4 µm)× 3.8-5.4 µm (4.7 µm) (n=100). After germination, conidia formed single, brown, oval or slightly irregular appressoria ranging from 8.0 to 11.8 μm (9.6 µm), and from 4.8 to 6.0 μm (5.4 µm). Sexual stage was absent. These characteristics of conidia and appressoria were matched with C. siamense belonging to the C. gloeosporioides complex (Prihastuti et al. 2009; Yang et al. 2009; Weir et al. 20012; Hu et al. 2015). To accurately identify the species, DNA was extracted from four purified isolates (JG-1, JG-3-1, SWS-1-3, SWS-2-1) （Fu et al. 2019）. The internal transcribed spacer of rDNA region (ITS), glyceraldehydes-3-phosphate dehydrogenase (GAPDH), calmodulin (CAL), actin (ACT) and chitin synthase (CHS) genes were amplified and sequenced. The nucleotide sequences were all deposited in GenBank (ITS: MT229427-MT229430, GAPDH: MT250821-MT250824, CAL: MT258893-MT258896, ACT: MT258897-MT258900 and CHS: MT258901-MT258904). Multi-locus phylogenetic analyses (ITS, GAPDH, CAL, ACT and CHS) (Weir et al. 2012) showed that the four isolates were clustered with C. siamense, which was in accordance with BLAST results. Pathogenicity tests of the four isolates were repeated three times on detached leaves (Ji et al. 2019). The conidial suspension (1×106 conidia/mL) was prepared using the conidia from 10-day-old cultures grown on PDA. Two 20-µL drops of conidial suspension were inoculated on non-wounded young healthy leaves, and each isolate was inoculated on 10 leaves. Two 20-µL drops of sterile water were inoculated on non-wounded young healthy leaves as control. The samples were maintained in containers at a relative humidity of 90± 5 per cent inside and 28℃ with a 12-h photoperiod. Gray, subcircular spots similar to the field disease symptoms were observed on the all inoculated leaves after 7 days, whereas no visible symptoms appeared on the non-inoculated leaves. The pathogen was re-isolated from inoculated leaves thus fulfilling Koch’s postulates. C. gloeosporioides has been previously reported as a pathogen causing leaf spot on Erythrina (E. indica var. picta, E. variegata var. orientalis) in Guam in 1983 and Brazil in 2012. (Russo et al. 1983; Oliveira et al. 2012). To our knowledge, this is the first report of C. siamense causing leaf spot of E. crista-galli in China.

Evaluating Host Resistance to Limit Colletotrichum coccodes on Onion

Leaf and neck anthracnose is incited by Colletotrichum coccodes (Wallr.) Hughes, a new foliar disease of onion (Allium cepa L.) in Michigan that has been observed in the state since 2010. Symptoms include elliptical lesions on the leaves, necks, or both that appear bleached with a pale salmon to dark brown center. To develop an effective integrated disease management strategy, field studies were conducted in 2011 and 2012 to evaluate 16 commercial onion cultivars for their susceptibility to the pathogen. The incidence and severity of anthracnose were evaluated weekly following inoculation. Onion cultivars differed significantly in disease severity and incidence; differences between years were also observed. ‘Hendrix’ had the lowest disease severity, whereas ‘Highlander’ and ‘Candy’ exhibited severe onion leaf and neck anthracnose symptoms. Using less susceptible onion cultivars combined with effective fungicides against C. coccodes may limit crop losses for Michigan growers.

Highlighted & Underlined

Providing students with healthier school lunches has a modest but significant effect on academic performance, according to a study published by the Brown Center Chalkboard blog. Roughly 20% of K-12 students are enrolled in language study, including American Sign Language, according to a report published by the American Councils for International Education. A new report, Why Rural Matters, suggests that rural students are facing nothing less than a national emergency.

Ocurrencia y propiedades de Xanthomonas campestris pv. phaseoli y xanthomonas pestolíticas, epifíticas en malezas

Populations of Xanthomonas campestris pv. phaseoli and other Xanthomonas occur in natural form la non symptomatic weeds. Sevently seven samples of twenty one weed species from fields Infested with common blight "Tizón común" In San Juan, Higuey, Constanza of the Dominkan Republic were evaluated. The isolationswere obtained by adding 10 ml of the buffer (12.5 mM K2PO4 + 10 mM Mg SO4, ph < 7.1). The pathogenicity tests were performed on the Dark Red Kidney bean, by inoculating plants, trifoliates and seed pods. To confirm the starch hydrolisis reaction with methyl violet and methyl green, an evaluation of the production of brown dye and thin layer chromatography for the Xanthomonadin pigment was made. Of the observed results, fourteen samples and eight species of weeds of X. campestris pv. phaseoli and 23 species of weeds of atypical Xanthomonas were found. The pathogenic isolations from leaf innoculum at two weeks the yellow zone had expanded and covered a wide area around the necrotic brown center. The bean seed pods inoculated with pathogenic isolates showed typical symptoms around ten days. All the pathogenic isolates on the leaves became pathogenic on the seed pods. None of the isolates of collected weeds after harvest. In the "Constanza" area showed any symptoms on the bean leaves. The weed samples collected from the common blight Infested fields had more pathogenic of isolates X. campestris pv. phaseolithan the samples taken from the outside ends of the fields or after harvest. We found eight weed species all belonging to six botanic families which might act as sympto-matic hosts suggests that other species could contain epiphitic X. campestris pv. phaseoli.

First Report of Blight Disease on Buxus Caused by Cylindrocladium buxicola in France

Cylindrocladium buxicola Henricot causes twig blight on Buxus spp., severe defoliation, and eventually death of plants, especially in young seedlings (1). The disease was first observed in the United Kingdom and New Zealand in the 1990s and recently, the fungus was detected in other European countries (1). In November 2006, box blight symptoms were observed in a Buxus sempervirens nursery located in the South West of France (La Reole). Since then, more diseased samples from other French sites, including forestry areas and ornamental garden nurseries, have been received, indicating that this disease is spreading. Symptomatic twig samples were sent for lab analysis and dark brown spots were observed on the leaves, sometimes coalescing to cover the entire leaf surface, with black streaks on the stems. Fungal fruiting structures were observed directly on the leaf surface and were examined with a stereomicroscope. Microscopic slides were then prepared by gently pressing a clear adhesive tape onto the surface covered by mycelium and spores, which was further stained with lactic acid and methyl blue. Cylindrical, straight, biseptate, hyaline conidia, 53.8 to 75.3 (64.4) × 4.4 to 5.2 (4.6) μm, were observed, sterile hyphae with terminal vesicles ended with a pointed apex, and conidiophores were penicilliate; all of those characters were consistent with C. buxicola (2). To support the diagnosis, fruiting structures were plated on malt agar media supplemented with 100 ppm of chloramphenicol. The pure culture obtained showed a whitish mycelium with a tan brown center that was in line with the original description of C. buxicola (2). DNA was extracted from the pure culture and the internal transcribed spacer (ITS) region was amplified by PCR using the ITS1-ITS4 primer pair (4). Nucleotide sequence was determined and deposited on GenBank (Accession No. JQ743502). BLAST analysis of the sequence showed 100% identity with all currently available C. buxicola ITS sequences, which confirmed our morphological diagnosis. To our knowledge, this is the first report of C. buxicola (teleomorph Calonectria pseudonaviculata) in France. The occurrence of this disease in France worries the nursery industry since losses can sometimes be dramatic as seen in United Kingdom, where the disease is widespread (3). References: (1) B. Henricot. The Plantsman 9:153, 2006. (2) B. Henricot and A. Culham. Mycologia 94:980, 2002. (3) B. Henricot et al. Plant Pathol. 49:805, 2000. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications, 1990.

Nuclear Magnetic Resonance Imaging Detects Internal Defects in Potatoes

Potatoes with hollow heart or brown center are considered to be of poor quality for both fresh and processing markets. A reliable nondestructive method, which can distinguish affected and normal potatoes, is described here. A Varian 4.7 Tesla, 33-cm horizontal-bore spectroscopy/imaging system was used to obtain nuclear magnetic resonance (NMR) images of potatoes. A two-dimensional multi-slice spin-echo imaging technique was used to acquire the cross-sectional images along the longitudinal direction. The echo time was 35 msec and the repetition time was 1.2 sec. A total of 13 slice images were taken for each potato. A one-dimensional projection technique was also performed to evaluate the possibility of using fast-scan method. The brown center showed high intensity in long echo scans due to its longer TL relaxation time. A suberin-like layer resembling the periderm developed on the cavity wall of hollow heart causing a tan or dark brown coloration. This cavity wall also appeared in high intensity on the image. The affected potatoes can easily be sorted out using this nondestructive NMR imaging technique.