Fruit Anthracnose on Cavendish bananas Caused by Colletotrichum fructicola in Guangxi, China.

Cavendish banana (Musa spp. AAA group) is one of the main fruit crops worldwide. It is widely planted in Guangdong, Hainan, Guangxi, Fujian and Yunnan provinces in southern China. In November 2020, banana fruits with anthracnose symptoms were collected from Dayu Town (N 23.17°, E 109.80°), Guigang City, and Chengjun Town (N 22.60°, E 110.00°), Yulin City, Guangxi Province, China, where the disease was found on about 70% of the banana plants, and on individual fruit, up to 10% of the surface was covered with symptoms. The symptoms initially began with rust-colored spots on the surface of the immature fruit, which gradually became sunken and cracked as the disease progressed. Small tissues (5×5 mm) from the pericarp at the junction of disease and health were surface-disinfected in 75% ethanol for 10 s, 2% sodium hypochlorite (NaClO) for 1 min, and washed three times in sterile water. Tissue pieces were placed on potato dextrose ager (PDA) and incubated at 25°C. Fifty-nine morphologically similar colonies were obtained after 5 days of incubation, with 100% isolation frequency. Of 59 isolates, GG1-3 isolated from Guigang City and YL4-2 isolated from Yulin City were selected as representative strains for intensive study. Mycelia were off-white for both isolates and conidia obtained from PDA were cylindrical, unicellular, hyaline and obtuse ends, with sizes of 11.5 ± 1.8×3.9 ± 0.8 µm (n=60) and 11.5 ± 1.6×4.1 ± 0.6 µm (n=60) for GG1-3 and YL4-2, respectively (Prihastuti et al. 2009). Genomic DNA was extracted from 7-day-old aerial mycelia using a DNAsecure Plant Kit (Tiangen Biotech, China). The internal transcribed spacer (ITS), the intergenic region of apn2 and MAT1-2-1 (ApMAT) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were amplified and sequenced (White et al. 1990; Silva et al.2012; Templeton et al. 1992). Sequences were deposited in GenBank (ITS, OR596961 to OR596962; GAPDH, OR661771 to OR661772; APMAT, OR661773 to OR661774) and showed 100% identities with the corresponding type strains sequences of C. fructicola. Phylogenetic tree was constructed with software raxmlGUI v.2.0.0 based on sequences of multiple loci (ITS, GAPDH and ApMAT) and Maximum Likelihood method. Phylogenetic analysis revealed that the two isolates and C. fructicola were clustered in the same clade, with 94% bootstrap support. According to morphology and phylogenetic analysis, the two isolates GG1-3 and YL4-2 were identified as C. fructicola. For pathogenicity tests, healthy fruits were surface sterilized with 75% ethanol followed by a wash with sterilized water. Five adjacent needle punctures in a 5-mm-diameter circle were made with a sterilized needle on healthy fruits, followed by inoculation with 20 µL of conidial suspension (106 spores/ml), and sterilized water was used as controls. All banana fruit were incubated in a humid chamber at 28°C. After 4 days, all inoculated fruits showed visible symptoms and had rust-colored spots on the margins, while control banana fruits remained symptomless. The fungus was isolated from the inoculated fruit and the isolates were found to match the morphological and molecular characteristics of the original isolates, confirming Koch's hypothesis. To our knowledge, this is the first report of fruit anthracnose on Cavendish bananas caused by C. fructicola in China. This study will provide valuable information for prevention and management of anthracnose on banana fruit.

Re-vitrectomy for recurrent retinal detachment in post-vitrectomy eyes of rhegmatogenous retinal detachment.

BACKGROUND: Recurrent retinal detachment (Re-RD) usually affects the prognosis of surgery for rhegmatogenous retinal detachment (RRD). Previous clinical studies of Re-RD were not specific. This study aimed to analyze the clinical characteristics of Re-RD in post-vitrectomy eyes with RRD and surgical outcomes after revitrectomy without combining it with retinectomy or scleral buckling. METHODS: This is a retrospective case series analyzed the ocular characteristics of 20 recurrent and contralateral eyes, evaluated the significance of the associations between variables before reoperation and the final best-corrected visual acuity (BCVA), and calculated the outcome of revitrectomy. RESULTS: Patients with phakic eyes, those undergoing only one surgery, and those with more than one break had better final BCVA. The final BCVA was negatively correlated with the axial length and positively correlated with the preoperative BCVA. Among the 12 eyes with no break detected before surgery, 11 (92%) were found to have a small crevice-like break beside the pigment scar of a large number of original laser spots. The single-operation complete retinal reattachment rate was 75%, the complete retinal reattachment rate was 80%, and the final incomplete retinal reattachment rate was 90%. The BCVA improved from 1.2 ± 0.6LogMAR (0.06 ± 0.25) before surgery to 0.8 ± 0.7LogMAR (0.15 ± 0.2) at the last follow-up. The BCVA of 16 patients with complete retinal reattachment improved from 1.0 ± 0.5LogMAR (0.1 ± 0.3) to 0.6 ± 0.4LogMAR (0.25 ± 0.4). In the contralateral eyes, 15% already had vision-damaging disease, and the incidence of eyesight-threating lesions was 5.9% during follow-up. CONCLUSIONS: Revitrectomy without retinectomy or scleral buckling can effectively treat Re-RD in post-vitrectomy eyes. In Re-RD patients with no definite retinal break detected preoperatively, the retinal hole usually shows small crevice-like changes alongside a large number of original laser pigment scars.

Wastewater leakage in West Texas revealed by satellite radar imagery and numerical modeling.

Wastewater, a byproduct of oil and gas production, is injected into disposal wells. Using Interferometric Synthetic Aperture Radar (InSAR) to observe ground deformation in the Ken Regan field, West Texas, we detected surface uplift that occurred near a wastewater disposal well from 2007 to 2011. High correlation between the observed deformation and the injection volume suggests that the uplift was caused by wastewater disposal in the well. Inverse elastic models were first used to calculate the injection depth and volume. Given the initial estimates of wastewater injection, forward poroelastic finite element models were applied to simulate stress/strain and displacement fields and to estimate the effective injection volume and depth, so as to ultimately understand the subsurface geomechanical processes and provide insight into the local hydrologic properties of the strata in the well location. Results from both elastic and poroelastic models indicate that the effective injection depth is much shallower than the depth reported to the Texas Railroad Commission (RRC). The most reasonable explanation is that the well was experiencing leakage due to casing failures and/or sealing problem(s). The Rustler Aquifer, within the zone of the effective injection depth, has been used as a source of freshwater for irrigation and livestock; wastewater leaked into this aquifer may possibly contaminate that freshwater. Our analysis that exploits remote sensing data and numerical models provides a clue as to understanding the subsurface hydrogeological process responding to the oil and gas activities and an indirect leakage monitoring method to supplement current infrequent leakage detection.