Research Projects

The objectives of this study were to identify the pathogen and evaluate the incidence and severity of the disease that affects bean crops in Tixtla, Guerrero, Mexico. For the identification, leaves with spots were collected for microscopy and pathogenicity tests. Regarding the incidence, a percentage of diseased plants in the field was obtained. About the severity, a scale of damage to the leaves was designed. The morphological characteristics of the pathogen corresponded to Uromyces phaseoli var. typica Arth. The damage was about 5% of plants that presented severity level 5 (with rust in 100% of leaves), 10% of plants with severity level 4 (75% of their leaves with rust), 15 % with level 3 (affected in 50% of leaves), and 20% presented level 2 (25% of leaves with rust), with the rest were healthy. The pathogen occurred on average in 50% of plants according to the incidence and severity of the disease determined in this region.

This experimental work was located in Mochitlán, Guerrero, Mexico. Its corn production in 2018 was 4,862 tons, being the most important for the area, and affected by both abiotic and biotic factors. Three randomly selected plots were worked, with 10 plants per plot to determine their growth in height, stem thickness, and fruit. For the detection and collection of pests, the plants were reviewed following a zig-zag sampling. The A7573 hybrid was planted with traditional tillage. The type of soil was feozem with pH 7.0 and clay texture. The climate was sub-humid semi-warm, with an average 22°C. Ecophysiological conditions resulted in a 10% decrease in stem and ear production between crops. The greatest pest corresponded to Spodoptera frugiperda (J.E. Smith) affecting 23% of plants with a 21% of severity in plant damage. Finally, abiotic factors influenced plant development and increased plague insects.

In Guerrero, 14730 ha of Radish (Raphanus sativus L.) were planted in autumn-winter with a production of 15,521 tons. In Tixtla, Guerrero, the radish yield is 8 tons per ha. Due to its economic importance in the region, this research was carried out with the objectives of knowing the cultural practices of radish cultivation and determining the factors that affect its yield. The incidence of pests in the field was determined following a completely random sampling. Insects were collected in flasks with 30% formaldehyde and identified in the laboratory with taxonomic keys. The main pests that attacked the crop were whitefly Bemisia sp (affecting 20% ​​of the plants), wireworm Agrotis sp (affecting 15%), and mealybug Planococcus sp (10%). Due to a water deficit, 10% of crops had a hard and fibrous texture. However, after farmers applied excess water to the dry crops, 15% of openings were produced, which lead to economic losses.

The aim of the research was to determine the growth of squash plants in different plots Tixtla de Guerrero, to see if there is difference in the germplasm and growth. The treatments were three plots, with ten repetitions each. The variables determined were: seedling emergence, length and diameter of stems, leaf area, length and weight of fruits flowers. The experimental design was completely randomized. The averages of the variables calculated in the three plots were: germination of 53%, stem length of 5 m, stem diameter of 2 cm, leaf area of 112 dm^2, length of the flowers of 10 cm, and weight of the fruits of 362 g. The variance analysis applied to the data obtained within and between the plots showed no significant difference, which manifested a similarity of behavior of the germplasm used between the plots.

Due to the economic importance of ball squash in Tepechicotlán, it was of interest to determine the diseases that affect it since they can affect its production. Three plots were chosen randomly for crop review in the sampling area at the 35th and 70th days of development. In each one, 100 plants were sampled following a zig-zag procedure to establish the incidence and severity of the disease in plants at both stages of development. Zucchini yellow mosaic virus (ZYMV) was detected in the pumpkin plants of the sampling area. The symptoms were yellowing, mottling, and frizzling of the leaves, followed by necrosis and defoliation with deformed fruits. Also, there was a considerable reduction of growth and productivity. At 35 days of development, crops were affected in 50% of the plots, with an average severity of 26%. At 70 days, the severity reached on average 50%, with the same incidence of 43%. Whitefly (Bemisia tabaci G.) was identified as transmitter of the ZYMV.

The sampling area is located in Tepechicotlán, where corn is grown and sold. It was of interest (due to its economic importance) to determine the diseases that affect it as they can affect its production. Three plots were sampled in two stages: at 45 and 90 days of corn crop development. In each plot and stage, 100 plants were sampled in a zig-zag procedure. In the sampling area, Maize Dwarf Mosaic Virus (MDMV) is transmitted by aphids of the genus Rhopalosiphum maidis (Fitch). The symptoms were foliar chlorosis, a reduction of growth, decrease in stem diameter, delay in maturity, and deformed cobs. At 45 days of crop growth, 33% of the plots were affected, with an average severity of 20%. At 90 days, severity reached an average of 40%, with the same incidence of 33%. Symptoms were identified in plants at both sampling stages, with a greater degree at the young plant stage. The affected plants had an approximately 55% decrease in vegetative and fruit production.