Sublethal Effects on the Biological Development of Spodoptera frugiperda (Lepidoptera: Noctuidae) When Consuming Neem

Abstract

Objective: The Fall armyworm S. frugiperda was bred in laboratory and put under dose of watery extracts and
oil of seed of A. indica with the aim of determining and to quantify the alterations in the biological development
of larvae and pupae of caused by the consumption of A. indica and the doses in which the alterations happen.
Design/Methodology/Approach: Two experiments were development. In one eight doses were evaluated,
with watery extract of seed of A. indica in 4.0, 1.0, 0.7, 0.4, 0.1, 0.07, 0.04 and 0.01%. In the second the doses of
oil of A. indica were evaluated 0.16, 0.09, 0.02, 0.016, 0.009, 0.002, 0.0016 and 0.0009%. In both experiments
the variables were quantified: duration of the stage of larvae and pupae, survival of the larval stage and pupae,
survival of the larva stage and pupae and weight of pupae.
Results: The larvae prolonged their development in three days more than the witness when consuming watery
extract of A. indica; They reduced its survival like la rvae and pupa in 18 and 27.5% respectively. In Addition,
was reduced the weight of pupas. When consuming oil of A. indica, the larvae delayed their development from
three to 15 and 19 days more than the witness.
Study limitations/Implications: The study was carried out under laboratory conditions and in a single cycle;
it is desirable to repeat the study for more cycles and with different populations of fall armyworm.
Finding/Conclusions: The adverse effects in larvae were pronounced of three forms: 1) the duration of the
larval stage altered when staying the larvae by more days in that stage without changing pupae. 2) the survival
of the larval stage was reduced and 3) it decreased weight of pupa.