Determinación de ínstares larvales de Neoleucinodes elegantalis (Guenée) (Lepidoptera: Crambidae) desarrollandose en Solanum betaceum

The fruit borer Neoleucinodes elegantalis (Lepidoptera: Crambidae)is a quarantine pest that restricts the export processes of solanaceous fruits to the USA market. To develop mitigation measures against N. elegantalis, it is essential to know the number and duration of its larval stages. In the present study, we examined the larval growth inside the fruits of the tree tomato (Solanum betaceum). The evaluations of the diagnostic traits began when the newborn larvae emerged and continued through the final stage when the larvae left the fruit to pupate. As a food substrate of this stage, the fruits from the S. betaceum tree were supplied (experimental conditions: 22 ± 1°C and 68 ±2% RH). In an initial experiment, we measured three diagnostic traits of N. elegantalis, and selected the one with the least dispersion for further evaluation. In a second experiment, we used the chosen trait to determine the duration of the larval instars. We measured the selected one every 2 d, until larva emerged from the fruit to pupate. We analyzed the data by constructing frequency tables and histograms and estimating a regression model for the relationship between the measured trait and the proposed larval instars. In the study conditions, N. elegantalis completed four instars within a maximum time of 18 d. The coefficient of determination for the interaction between the measured diagnostic trait and larval stages of the fruit borer was high (R2 = 0.993) at the 95% confidence level.