Modelo predictivo del impacto del cambio climático sobre la distribución y abundancia de una especie de noctuidae asociada con el cultivo de maiz (Zea mays)

Abstract

In Ecuador, the maize yield has shown a trend to decrease due to the effect of the misuse of seeds and the attack of pest insects, such as the fall armyworm (Spodoptera frugiperda), stem borer (Dialraca spp.) And the false meter (Mocis latipes); but there are also other potential secondary pests such as the earworm or earworm (Heliothis spp.), cutworms (Agrotis spp.). In the present study, an attempt to establish e relationship between the climatic parameters with the phenology of Agrotis sp. as well as its abundance and incidence in corn plantations. The biology of Agrotis sp. in maize leaves was studied under laboratory conditions. On the other hand, data about pest’s incidence and severity of damage, as well as the historical data from 2017 to 2019 on temperature, relative humidity and precipitation were subjected to a Principal Component Analysis. For this purpose, for each year, a matrix was constructed with the data of each of the variables temperature, relative humidity, precipitation, altitude, percentage of incidence and severity for each of the samplings carried out in each canton (201 in the 2017, 218 in 2018 and 263 in 2019). The results showed that the total development time (egg-adult) of Agrotis sp. reared on maize leaves took an average of 87.3 days, under temperatures that ranged from 18.5 °C during the egg stage and then it increased to 22.7 °C at the end of the development cycle (pupal phase). According to the Principal Component Analysis, the variability of the climatic data was explained by up to 76.81, 75.77 and 79.20% through the first three components from the data of 2017, 2018 and 2019, respectively. In the years 2018 and 2019, the first axis had a greater significance also for the variables precipitation and relative humidity, while the second axis was mainly explained by percentage of incidence and percentage of severity, indicating that the ordering of the given sampling points on the second axis, it was quite related to the incidence percentage and the severity percentage. Finally, rain, relative humidity and temperature showed a second-degree polynomial relationship with the severity and incidence of Agrotis sp. in corn plantations planted in the Sierra region during the years 2017-2019. This study constitutes a first approach to the study of the relationships between the climatic parameters and the populations of Agrotis sp. in corn. More extensive studies are required in other regions of Ecuador in order to achieve a better understanding of the climate-plant-pest dynamics.