Scientific Research and Essays

  • Abbreviation: Sci. Res. Essays
  • Language: English
  • ISSN: 1992-2248
  • DOI: 10.5897/SRE
  • Start Year: 2006
  • Published Articles: 2741

Article in Press

Path analysis for the evaluation of climate variables on Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) development phases in tomato crop

RUBENS PESSOA DE BARROS

The objective of this study was to evaluate the influence of climatic variables on the population dynamics of the tomato moth Tuta absoluta (Meyrick, 1917), (Lepidoptera:Gelechiidae) through correlations and path analysis, discovering their effects on the main variable in organic and conventional tomato crops (Solanum lycopersicum L.; Solanaceae). We studied the effects of the pheromone on insect phase sampling in two areas of agricultural interest with tomato cultivation in Alagoas, Northeast Brazil: latitude 09º81´76´´, longitude 36º59´42´´, during the agricultural years 2015-2017. The experimental design was completely randomized with two treatments (Delta traps) with 60 replicates. In the path analysis, the main variables were adults, eggs, caterpillars and mines. Precipitation, relative humidity, temperature, wind speed, and solar radiation were explanatory and correlated variables. Prior to path analysis, a multicollinearity diagnosis was performed to identify if the correlations between the explanatory variables would affect the path analysis result. In the experimental areas, throughout the study, the adult insect population accumulated a total of 6,623 insects in the conventional system, and 2,270 insects in the organic system, revealing that the insect has an endemic presence in Alagoas. In the path analysis we observed that rainfall, relative humidity, and solar radiation were the variables of greatest influence on the population dynamics with direct effects in the organic system with correlation coefficients r = 0.83, r = 0.52 and r = 0.45 respectively. The following variables showed negative correlations: wind r = -0.43, and temperature r = -0.19. In the conventional system r = 0.80, r = 0.43 and r = 0.41, for the same variables. The wind speed variable had a negative effect of r = -0.38, and the temperature had a negative effect of r = -0.13. We conclude that it is necessary to perform the path analysis to uncover the influence of climatic variables on the adult Tuta absoluta, and that estimates of the population dynamics will be more significant when considering the correlation with climatic variables. We observed that climatic conditions are variables conditioning the development of insect infestation in the tomato crops studied.

Keywords: integrated pest management