Chemical control of corn leafhopper and incidence of corn stunting diseases caused by mollicutes

Abstract

The objective of this work was to verify the efficiency of maize seed treatment on Dalbulus maidis control, and its effect on corn stunting diseases incidence, at screenhouse and at field. Two experiments were carried out. In the experiment 1 ( screenhouse), maize seeds were treated with imidacloprid or with thiamethoxan. Healthy leafhoppers, phytoplasma infective leafhoppers, and spiroplasma infective leafhoppers were confined in plants. Efficiency of control, incidence of plants with corn stunting diseases, plant height, and grain production were evaluated. In the experiment 2 (field) imidacloprid and thiamethoxan were used for seed treatment and sprayed at 10 and 20 days after sowing. Corn stunting diseases incidence and grain production were evaluated. At screenhouse, the use of imidacloprid and thiamethoxan controlled the adults of D. maidis up to 50%, until the 30^th day, and reduced disease incidence and damage on growth and grain production of the infected plants exposed to the infective leafhoppers, two days after emergency. In field, redution on corn stunting diseases or increasing production due to seed treatments was not observed possibly because of the migratory flux of infective leaf hoppers.