Incidence and control of black spot syndrome of tiger nut

Abstract

Tiger nut (Cyperus esculentum) is a very profitable crop in Valencia, Spain, but in the last years, part of the harvested tubers presents black spots in the skin making them unmarketable. Surveys performed in two consecutive years showed that about 10% of the tubers were severely affected by the black spot syndrome whose aetiology is unknown. Disease control procedures based on selection of tubers used as seed (seed tubers) or treatment with hot‐water and/or chemicals were assayed in greenhouse. These assays showed that that this syndrome had a negative impact on the germination rate, tuber size and yield. Selection of asymptomatic seed tubers reduced drastically the incidence of the black spot syndrome with respect to using seed tubers with severe symptoms (selection of healthy seed tubers was not possible because the causal agent is undetermined). Thermal treatment of seed tubers with severe symptoms reduced the number of unmarketable harvested tubers by half but was detrimental for the germination. Chemical treatments of seed tubers with severe symptoms decreased the incidence of the black spot syndrome about 40% for sodium hypochlorite and about 10% for hydrochloric acid, trisodium phosphate and the fungicide trioxystrobin.

Discovery and Diagnosis of a New Sobemovirus Infecting Cyperus esculentus Showing Leaf Yellow Mosaic and Dwarfism Using Small-RNA High Throughput Sequencing

“…The cultivation of C. esculentus and the elaboration of horchata have become substantial revenue sources for the county of Horta Nord in Valencia, Spain. However, some diseases have risen in the last decades, such as tuber rot [ 8 ] and leaf necrosis [ 9 ] produced by fungi and the black spot of unknown etiology [ 10 ]. These diseases have caused severe economic losses and threatened tuber production.…”

“…Transmission assays and/or epidemiological studies are necessary to know if XYDV is transmitted by tubers, mechanical wounding, and/or insects as other sobemoviruses [ 16 ]. In case XYDV is tuber-transmitted, in addition to the sanitary certification of imported tubers, other control measures should be tested, such as the selection of XYDV-free tubers, chemical and/or thermal disinfection, or in vitro culture [ 4 , 10 ]. The molecular techniques developed here are very sensitive and can be used to test the effectiveness of removing XYDV from tubers.…”

The Effects of Moisture Content and Loading Orientation on Some Physical and Mechanical Properties of Tiger Nut

“…Tiger nut, which is native to Africa and Mediterranean countries, is widely distributed in the Nile Valley of Egypt (Pascual et al, 2000). It can be eaten raw and is considered to have a sweet and delicious taste (Alvares et al, 2017), with freshly harvested tiger nut characteristically having a snow white flesh and a delicate fragrance. Its rich nutrition has resulted in its development into beverages, milk powder, as well as food targeted at infants, young children and the elderly (Rosello-Soto et al, 2018).…”

Comparison of viral infection risk between organic and conventional crops of tomato in Spain

“…survival analysis, nonparametric analysis, multivariate analyses, neural networks, meta-analysis and generalized linear models) and the choice of them is mainly determined by the nature of the response variable and/or the number and the nature of the covariates (Garret et al 2004). Bayesian modeling inference can provide a more appropriate framework to deal with complex models in comparison with traditional approaches (Gelman et al 2004), especially with the development of numerical methods for computing inference results (Held & Sabanés Bové 2014) Bayesian methodology has been applied to diverse aspects of phytopathology (Mila et al 2003, Alvares et al 2017, Lázaro et al 2016, 2017. In Bayesian inference, uncertainty about quantities of interest and experimental results is always expressed in probabilistic terms.…”