Resumo

SERRA, G.  e  TRUMPER, E.. Estimating the incidence of corn stem damage produced by Diatraea saccharalis (Lepidoptera: Crambidae) larva through assessment of external infestation signs. Agriscientia [online]. 2006, vol.23, n.1, pp.1-7. ISSN 1668-298X.

Diatraea saccharalis is economically the most important pest to corn crops in the Pampa region in Argentina. The tunneling produced by the larvae has negative consequences due to both physiological and mechanical damage (stem falling and ear dislodging). Losses caused by mechanical injuries increase as harvest is delayed, so one of the cultural methods to prevent them is to anticipate harvest. The objective of this work was to study the relationship between the number of bored internodes and the number of holes produced by large D. saccharalis larvae in the stem. The study was perfomed in Manfredi (Córdoba, Argentina) during the 1999/2000 growing season. It was carried out  using a split plot design with five planting dates and protection category (with and without insecticide) as treatments. Six models were evaluated  by means of linear and non linear regression. The percentage of stems broken below the ear ranged from 3.4 to 30%. The linear model provided a good description of the relationship between the number of bored internodes and the number of holes per plant (R² =0.95) and resulted in the best option for predictive purposes.

Palavras-chave : Diatraea saccharalis; Corn; Damage; Yield loss; Cultural management.

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