Thiamethoxam is a neonicotinoid with systemic and contact action, used in Mexico for the care of different traditional fruit crops, mainly in the cultivation of papaya. Soils of agroecosystems with papaya in the Gulf of Mexico area, the main producers of this fruit, are currently characterized as 45% of the producers organize papaya cultivation in rotation with watermelon at different sowing dates. The objective of this study was to determine the presence and concentration of thiamethoxam in soil and water during the rotation of papaya crop with watermelon culture in the central zone of Veracruz, Mexico. An analysis was carried out to know the management of thiamethoxam in different types of soil and in the region; and in an experimental plot. Soil and water samples were taken at different stages during the rotation of both crops. Those samples were taken systemically, starting with the watermelon culture cycle and then, during the phenological stages in the papaya crop cycle. Soil and water samples were analyzed using HPLC-UV equipment for its determination. The design was random blocks with six repetitions and the software used for data analysis was the Statistica 2007 program. Thiamethoxam was concentrated in amounts of ≥0.40 mg/L in 79% of the samples in water and ≥0.55 mg/kg in 75% of the samples in soil. The highest values of thiamethoxam in soil were in the stage of watermelon culture with 0.4 mg/kg and in the soil preparation of the papaya crop with concentrations of 0.8 mg/kg. Whereas irrigation water from the watermelon cultivation and the soil preparation for the papaya showed concentrations of 0.5 and 0.7 mg/L, respectively. The presence of thiamethoxam was identified in 100% of the samples analyzed in the stage of preparation of soil and water of the cultivation area, concluding a possible risk of residuality of thiamethoxam in fruits that exceed the maximum limits of tolerance established by the EPA, EFSA and FAO.

Mexico is one of the leading countries in avocado production worldwide and the most planted variety in Mexico is Hass. The state of Michoacán is the main avocado producer with 80% out of the total, followed by other states such as Jalisco and state of Mexico. In Veracruz there is an area planted in the central part of the state that needs to be characterized. The objective of this study was to typify the avocado producing zone in the high mountain zone of Veracruz, Mexico. The avocado producing area in the high mountains region, Veracruz is made up of the municipalities of Alpatlahua, Calcahualco, Coscomatepex and Ixhuatlan del café. A survey was applied to producers using a semi-structured questionnaire with open and closed questions. The information analysis was carried out systematically with descriptive and multivariate analysis of components and correspondence, in addition to parametric and non-parametric analysis of the data for some variables. The results obtained showed groups of small producers, composed of 80% men. Most producers are literated, and they devoted themselves to activities other than avocado cropping. The avocado producer has a tacit knowledge of the crop management from the plantation stage to the tree production. Producers have experience in management of other crops because they have the purpose of obtaining additional income from other activities.

Water contamination is a phenomenon of global concern resulting from human activities. Coliform bacteria reduce water quality and negatively affect public health. The pollution of surface and groundwater by coliform bacteria, including Escherichia coli , originate, in general, from point sources of pollution derived from human settlements, such as those located in Module I-1, Irrigation District 035, La Antigua, Veracruz, Mexico. The objective of this study was to assess the level of contamination of surface and groundwater by coliform bacteria and E. coli , as well as to identify point sources of water contamination by these bacteria in the sugarcane agroecosystem of Irrigation Module I-1, La Antigua. Sampling sites included deep wells, irrigation canals and natural streams near point sources of pollution. The determination of total coliform bacteria and E . coli were made in accordance with Mexican Standard NMX-AA-042-1987. Total coliform results revealed differences between groundwater (198.6 MPN/100 mL) and surface water concentrations (52,419.2 MPN/100 mL) (p < 0.05), and between irrigation water (76,501.1 MPN/100 mL) and concentrations in natural streams (28,337.3 MPN/100 mL). The highest concentration of E. coli was found in groundwater and surface water samples from the municipality of La Antigua. The primary sources of contamination are the discharges from drains and septic tanks. Total coliform values exceeded permissible limits established by NOM-127-SSA1-1994 that regulates the permissible water quality limits for human use and consumption. The presence of E. coli represents a significant public health risk.

The association of Persa lemon and coconut with annual crops contributes to the improvement of soil characteristics mainly in organic matter content by incorporating crop residues with an integrated management. The objective is to implement a system of corn and bean crops interspersed with Persa lemon and coconut palm fruit trees. The work was established in October 2017, in Hatillo, municipality of Antigua, Veracruz, with fruit trees of Persa lemon and coconut palm, in vines with the addition of organic fertilizers. Before the establishment was fertilized with 18 t. ha-1 of dry matter from sugar cane and then established the crops of Michigan bean, black Veracruz and H-520 corn, these crops were managed at different planting dates during the period 2018 and 2019. They were measured in fruit trees, plant height, stem diameter, number of leaves and branches, contribution of dry matter to the soil and soil analysis were performed on Persa lemon trees, coconut palm and annual crops. The results for Persa lemon show significant differences at 386 days, with respect to stem diameter, plant height, number of branches. With respect to the coconut palm, the diameter of stem presented significant differences from the 190 days, in the height of the palm the values were different to the 386 days. In the contribution of dry matter the black bean Veracruz, contributed greater amount to the soil with 8426 t/ha; the hybrid corn H-520 contributed greater amount of dry matter in the date of February 23, 2018 with 11333 t/ha. When analyzing the organic matter of the soil, a higher percentage was found in the intercropping system, surpassing the monoculture of sugar cane. The association of species allows to improve the agro ecological conditions in the management of the crops.

Objective: To know the variables of the reproductive component of materials for manual cross-pollination purposes, for which the search for sexual synchrony is emphasized. Design/methodology/approach: Four materials were analyzed, two with white pulp and two with red pulp, about which it is unknown if they present sexual self-incompatibility, and the synchrony in flowering is also unknown. The flowering phase and the variables that can shed light on its reproductive behavior were analyzed Results: It was found that the red materials present strong hercogamy, they cannot self-fertilize. There is also no floral synchrony, but there is closeness between the date of anthesis in a pitahaya with white pulp and a red one, which would allow promoting cross-pollination. Study limitations /implications: Hylocereus spp. is consumed in a large part of the world and has acquired a very strong importance since the industrial demand is increasing; however, several of the genotypes used in commercial production in Mexico show low fruit set compared to high floral emission, which is considered self-incompatibility. Findings/conclusions: The presence of hercogamy, stronger in the red-fleshed materials, indicates the existence of sexual self-incompatibility, explaining the fact that the materials emit a large number of flowers, but do not achieve fruit setting.

Papaya crops areas present phytosanitary problems since neonicotinoid pesticides are currently applied without efficient control methods. It is necessary to study insects behavior associated with this type of crop in response to the use of the neonicotinoid thiamethoxam. In order to know the efficiency of this insecticide, different doses were evaluated for the control of the type of insects referred to below. The study area was the locality of Mata Tambor in Cotaxtla, Veracruz, Mexico. Where a plot of papaya "Maradol" of 2,778 plants ha-1 was established, applying different doses of thiamethoxam during the process: T1) 0 kg/ha; T2) 0.3 kg/ha; T3) 0.4 kg/ha; and T4) 0.6 kg/ha. The variables were: insect population, gross mortality rate and the identification of pests that cause damage to the crop. No significant statistical differences were found in insect populations when applying those different doses. The mortality rate 16 days after applying thiamethoxam was higher in T3 at a dose of 0.4 kg/ha, this response is attributed to the fact that the insecticide achieved a residual effect on the culture. The use of T2 with a dose of 0.3 kg/ha in the crop became effective in pest control, generating a gross mortality rate of 241 individuals. Papaya cultivation can be associated with pests such as Bemisia tabaci, Myzus persicae, Frankliniella occidentalis and Toxotrypana curvicuada, which are the main vectors of virus in the culture.