Resumo

VALDEZ-TORRES, J. Benigno; SOTO-LANDEROS, Federico; OSUNA-ENCISO, Tomás  e  BAEZ-SANUDO, M. Alonso. Phenological prediction models for white corn (Zea mays L.) and fall armyworm (Spodoptera frugiperda J.E. Smith). Agrociencia [online]. 2012, vol.46, n.4, pp.399-410. ISSN 2521-9766.

The loss of maize production in the world, attributed to pests and diseases, represents about 31 % in agriculture. and the main pest is the fall armyworm (Spodoptera frugiperda J. E. Smith). The objective of this study was to develop and evaluate phenological models for white maize and fall armyworm required to produce a strategy to prevent crop damage. To determine the threshold temperatures at each stage of development of the fall armyworm a growth chamber and a completely randomized one factor (temperature) experimental design were used, with 8, 10, 27, 38 and 40 °C. Quadratic polynomials were adjusted for the rate of development in terms of temperature and the following minimum and maximum threshold temperatures were mathematically determined: 8.7 and 39.8 °C. To study the phenological development of the crop and pest, two experimental plots with white maize (Pioneer 30P49^®) were established in the Valley of Culiacán, Sinaloa, Mexico; one in the 2008-2009 cycle and the other in that of 2009-2010. Both plots received the same agronomic management, without control of pests and diseases, and the phenological stages of the crop and pest were recorded. From the date of sowing, daily temperatures were recorded by a weather station installed at each plot. The stages of the crop and pest against accumulated degree days were adjusted by third-degree polynomials (R²> 95 %). These models were concurrently analyzed to determine the phenological stages (crop and pest) where the pest can cause crop damage.

Palavras-chave : modeling; forecasting; Zea maize L.; Spodoptera frugiperda J. E. Smith.

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