IMPACT OF DELTAMETHRIN ON ARTHROPOD PESTS AND PREDATORS IN A CORN FIELD

Abstract

In this research, the impact of deltamethrin, sprayed on the aerial part of cornplants, on pests and on predator arthopod populations was evaluated. The experimental designwas randomized blocks with four replicates. The insecticide (Decis 25 CE, 7.5 g. a. i./ha) wasapplied on the plant whorl when the corn plant reached 10 expanded leaves. Samples weretaken from 10 plants per plot, one day before, 7, 10, 14, 21 and 28 days after spraying, toevaluate population density or occurence of arthropods and the percentage of plants attackedby Spodoptera frugiperda. The insecticide controlled this pest infestation up to 7 days afterspraying and also significantly reduced population density of the leafhopper Dalbulus maidis.The insecticide did not affect negatively the complex of arthropod predators associated withthe aerial part of the corn plant. It showed selective toxicity, favoring both nymphs and adults ofDoru luteipes and of an unidentified group of ants and spiders. These results support the use of deltamethrin on integrated pest management programs of S. frugiperda on corn, specially inagroecossistems with high predator abundance.

Keywords

• Spodoptera frugiperda
• Zea mays
• natural enemies
• pyrethrins
• insecticide