Ciencias Agropecuarias

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Author: search.filters.author.Manobanda Moreta, Alexandra MaribelSubject: search.filters.subject.AGRONOMIA

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    Bioecología de Bactericera cockerelli (Sulc.) en el cultivo de papa (Solanum tuberosum L.) en las provincias de Tungurahua y Cotopaxi
    (2020-09) Manobanda Moreta, Alexandra Maribel; Vásquez Freytez, Carlos Luis
    The potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Psyllidae) is considered a pest in several solanaceous species, native to North America and currently it has become more relevant in recent years due to its capacity to invade in various geographical areas, its wide range of host plants and, mainly due to their ability to transmit pathogens to plants they feed on. Given that this species has been recently reported in the country, the present study evaluated the biology, geographic distribution and intra-plant distribution of B. cockerelli in potato crops in the provinces of Tungurahua and Cotopaxi. Biology was studied in potato leaves variety Super Chola under laboratory conditions (21.2 °C and 49.6% relative humidity). Additionally, samplings were carried out in 14 localities belonging to five cantons of the Tungurahua province (Ambato, Tisaleo, Mocha, Quero and Pelileo) and in five localities of the canton of Salcedo (Cotopaxi province). The life cycle of B. cockerelli showed an average total duration of 22.93 days with a mortality rate during the egg phase with 59.6%, while in the first and fourth nymphal instars only 4.25% of mortality was verified, respectively. Regarding geographical distribution, the plague was detected in cantons of Ambato and Píllaro (Tungurahua), in which the potato psyllid was found in 7 of 14 sampled localities, representing 50.0% of the areas considered in sampling. In canton of Salcedo (Cotopaxi), it was found in three of the five sampling locations, representing 60% of positive cases for the presence of the pest. This verified distribution in the sampled areas seems to be related to the height above sea level, since the species was not found in those locations with heights close to 3,000 meters above sea level. Regarding the intra-plant distribution, wide variability was observed in the spatial distribution in the different plant strata (upper, middle and lower), which suggests that the pest shows no preference to select the substrate for oviposition and feeding. The results obtained in the present investigation lay the foundations for thexv bioecological studies of B. cockerelli in the region, however, it is suggested that similar studies be carried out to evaluate other bioecological aspects of the pest.
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    Asociación del cultivo de girasol (Helianthus annuus L.) con cultivos atrayentes y su efecto en la entomofauna asociada en el sector Querochaca, cantón Cevallos, provincia de Tungurahua
    (2017) Manobanda Moreta, Alexandra Maribel; Vásquez, Carlos
    The objective of the research was to determine the effect of the association of the sunflower crop with attractive crops on the diversity and abundance of the entomofauna. Twelve samplings of the sunflower insects were made at 8:30; 11:30 and 14:30 h during four months by the use of entomological mesh. Insects were separated by morphotypes and later identified using taxonomic codes up to the family level and when possible up to the species level. Identifications of specimens of the orders Diptera and Hymenoptera were sent to the J.M Osorio-UCOB Entomological Museum (Venezuela). The different morphotypes were separated by their feeding habit in predators, phytophagous, parasitoids and pollinators. In addition, the Shannon-Wiener diversity index and the correlation between climatic parameters and insect diversity were calculated. A total of 379, 1065 and 396 insects were collected when sunflower seeded alone, in association with Vicia and Chinese cabbage respectively. In general, the composition of the entomofauna was similar in the three cropping systems in which it was found that the highest number of families collected corresponded to insects of predatory habit (11), phytophagous (5), pollinators (4) and parasitoid (2). The order with the greatest diversity of families was: Diptera (14), followed by Homoptera (3) and Hymenoptera (3), whereas only two families of Coleoptera and one of Hemiptera were collected. According to the Shannon-Wiener diversity index, maximum values of family diversity were observed when sunflower was maintained alone and in association with Vicia. A positive correlation was observed between insect numbers and temperature in sunflower + Vicia (r = 0.9144, p <0.00), sunflower + Chinese cabbage (r = 0.9548, p <0.00) and sunflower alone (r = 09204, p <0.00). In the same way a positive correlation was detected between the number of insects and the relative humidity. According to the results, sowing the sunflower with attractive crops could increase insect abundance, which could increase the degree of pollination of the crop, however, more detailed studies are required to establish its impact on productivity.