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Objective: was to select quinoa accessions as possible positive reaction differentials to mildew that identify the variability of Peronospora Variabilis Gaum as a pathogen collected in five departments and evaluated in Cusco. Material and methods: mildew samples were collected from the altiplano (Puno), inter-Andean valleys (Cusco, Apurímac, Ayacucho), and coast (Arequipa), obtaining 175 mildew samples. The installation of the experiment was with 100 accessions of quinoa from the Germplasm Bank of EEA Andenes in cultivated fields during two productive campaigns. For its evaluation, quinoa descriptors were used and agronomic characteristics, yield, reaction to mildew (P. Variabilis), ALJDPC (area under the disease growth curve), and saponin percentage were evaluated. In addition, virulence tests and severity evéduations were performed after inoculating quinoa accessions with mildew in the greenhouse. Results: the morphoagronomic evaluation allowed selecting the following genotypes cis possible differentials with a positive reaction to mildew: RR.GG.41 for isolates from Ayacucho, RR.GG.09 for isolates from Apurímac, RR.GG. 16 for isolates from Apurímac and Arequipa, RR. .GG.57 for isolates from Puno and Apurímac, RR.GG.26 for isolates from Ayacucho and Apurímac, RR.GG.38 for isolates from Cusco cind Arequipa RR.GG.43 for isolates from Puno cind Arequipa, RR. GG .76 for isolates from Cusco and Arequipa and the quinoa accessions RR.GG. 11, RR.GG.22, RR.GG.55, RR.GG.64 for the 142 isolates obtciined from the 175 samples of the five departments Conclusions: the identification of twelve possible differential plants allows knowing the variability of the pathogen in the coastal, inter-Andean, and high plateau valleys. [ABSTRACT FROM AUTHOR]

Quinoa crops in the Peruvian highlands are affected by mildew disease, which can cause losses of up to 90 % of production. The objective of this study was to evaluate the effect of strains of Trichoderma sp and efficient microorganisms (EM) in the control of mildew and yield of quinoa. In the experimental field of the International Potato Center (IPC) Camacani of the National University of the High Plateau of Puno department, in the agricultural campaign 2016-2017, there were sowed control seeds and others pelletized with eight treatments: four Trichoderma sp strains, three doses of EM (5 %, 10 %, and 15 %) and a mixture of Trichoderma sp and EM strains (15 %), later there were made four foliar applications of each one of the eight treatments to 1x107 ufc.ml-1, in each critical moment of the phenological cycle. It was determined the area under the curve of the disease progress (AUDPC) and the yield. All treatments applied significantly favored the reduction of the pathogen and crop yield. The most effective treatment in the reduction of mildew was Trichoderma sp TETQ-3 strain, followed by EM at 5 % with AUDPC of 586.19 and 586.44 respectively, which is equivalent to 53 % less than the control. In terms of yield, ME at 5 % increased production by 208 %, from 1256 kg/ha to 3872 kg/ha. The use of these microorganisms represents an alternative of sustainable use for the biocontrol of phytopathogens and growth promotion in quinoa crops. [ABSTRACT FROM AUTHOR]

Quinoa crop (Chenopodim quinoa Willd.) is native to the Peruvian Andes, nutritious food and it has become very important for agroexport. In Piura, the downy mildew disease appeared causing economic losses, were set as objectives: detect the primary inoculum, describe the symptoms and evaluate the effect of defense inductors in the control of downy mildew. The direct detection methodology was used to observe oospores, the treatments were; Biosar, 3Tac, Agromos + Soil set, Action FP/Pare, Metalosate and control, Area Under the Disease Progress Curve (ABCPE) was evaluated, comparisons of means were made of the Tukey test (α = 0.05). Oospores were detected in all the quinoa samples, being with greater number the var. INIA-altiplano with 96 and with lower var. passankalla with 8 oospores/100 units of seed. As a symptom, yellowish spots were observed on the upper side and gray sporulation on the underside of the leaves. The highest value of ABCPE was obtained by the control with 2,161.02; the lower values and that better controlled the mildew disease in quinoa, they were obtained with Action FP/Pare (0.5 / 0.5 L / 200L water) and Agromos + Soil set (0.25 + 0.25 L / 200 L water), with 939.8 and 1040.7 respectively. [ABSTRACT FROM AUTHOR]

In order to generate a new variety of quinoa for the northern highlands of Peru and contribute to the competitiveness of this andean grain, this research was carried out between 2013 and 2018. Phases of introduction and evaluation of germplasm, genetic improvement and advanced evaluation of promising materials were carried out. The first two phases carried out in INIA experimental fields and the third in farmer's fields. Phenotypic characteristics, physiological maturity, mildew reaction and grain yield were evaluated. Also, there was opinion of farmers. Quantitative data was analyzed using ANVA and Duncan's test. From the Genetic Compound A, introduced from the central highlands, the new variety of quinoa was generated, called INIA 437 Red of the North. It is accepted by the farmers of the research, It has white grain and semi-sweetness; purple in foliage and panicle; as well as outstanding characteristics of mildew tolerance and productivity, showing less damage to the disease and greater yield than the Witness, White of Junín variety; also It has greater profitability and productive stability than this; being suitable for cultivation in the study area. [ABSTRACT FROM AUTHOR]

The objective of this study was the species-level identification of the causal agent of the black mildew of mamoncillo (Melicoccus bijugatus) in Colombia using collections of black mildew of mamoncillo deposited at the Museo Micológico de la Universidad Nacional de Colombia Medellín (MMUNM). Observation of symptoms and signs, free-hand sections of structures, measurements, and photomicrographs were performed with a Boeco® stereoscope and a Carl Zeiss® Axiostar Plus microscope equipped with a Canon® PowerShot G5 digital camera. This fungus is characterized by foliar black spots up to five millimeters in diameter mostly on the adaxial leaf surface. Hyphae: dark brown, erect or sinuous; hyphopodia: opposite, scattered, arcuate; conidiogenous cell mixed with hyphopodia, usually opposite, ampulliform; mycelial setae: around perithecia, numerous, scattered, erect, with apex 1-2 dichotomous. Perithecia: scattered, verrucose, dark brown; asci unitunicate, evanescent; ascospores: ellipsoid, four-septated, constricted at the septa; cinnamon-brown. The morphological results allowed the identification of the causal agent of black mildew of mamoncillo as the fungus Meliola crucifera. [ABSTRACT FROM AUTHOR]

During the past years there has been an increase in the number of tomato greenhouse facilities in Michoacan. The expected high yield for some of these greenhouses has not been attained due mainly to the presence of tomato diseases, which in many cases, the identity of the pathogen is unknown. The objectives of this research were to determine the incidence and the etiology of the main diseases affecting greenhouse grown tomato in central Michoacan. Sampling was carried out in six commercial tomato greenhouses located in four municipalities from March to October 2007. The main diseases detected were wilting of young and mature plants, late blight, bacterial speck and powdery mildew. The identified pathogens were Phytophthora infestans, Oidiopsis taurica, Rhizoctonia spp., Fusarium oxysporum, Oidium neolycopersici and Pseudomonas syringae pv. tomato. Late blight caused by P. infestans and mildew caused by O. neolycopersici were the most important diseases detected due to the high disease incidence and severity. [ABSTRACT FROM AUTHOR]

The article presents a study on the appearance of the Podosphaera, a section of the Sphaerotheca xanthii, on the cucurbits in northern Sinaloa, Mexico. It is stated that the powdery mildew is one of the most important diseases in the cucurbits in the region. The literature notes of the Golovinomyces cichoracearum as the causal agent of the disease. The aim of the study is to identify and confirm the real cause of the disease. Results show that there is no occurrence of the Golovinomyces cichoracearum among the tested samples of the powdery mildew.