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The corn leafhopper Dalbulus maidis (Hemiptera: Cicadellidae) is a specialist herbivore that attacks maize in the tropical and subtropical regions of the Americas. It is vector of three relevant plant pathogens being responsible for severe yield losses. Modern agriculture is dependent on the addition of fertilizers, especially nitrogen, which may influence the nutritional quality of the plants possibly with a subsequent increment of herbivorous insect populations. Through a field experiment, using a randomized design with four treatments with different levels of fertilization, we evaluated the effects of nitrogen fertilization in corn on the population levels of the vector D. maidis, on the incidence of the diseases transmitted by it, and on the levels of parasitism of the vectors’ eggs. The amount of nitrogen fertilizer used significantly influenced the density of the corn leafhopper and the parasitism by egg parasitoids, but not the incidence of the diseases transmitted by it. Two weeks after fertilization, the vector density was significantly higher in the highly fertilized treatment. The disease incidence was not directly linked with the level of fertilization, however, the symptoms of the diseases were much less evident in plants that received higher fertilization. Parasitism levels by egg parasitoids increased accordingly to the level of D. maidis populations. |
