On how nitrogen fertilization affects the host election and oviposition behavior of the corn stunt spiroplasma vector, Dalbulus maidis (Hemiptera: Cicadellidae)

Abstract

The corn leafhopper Dalbulus maidis (Hemiptera: Cicadellidae) is a serious maize pest widely distributed on the Americancontinent. This is the most common leafhopper feeding on corn crops in Argentina and Brazil, causing major economic lossesdue to its capability to transmit important pathogens, such as corn stunt spiroplasma, and considerably decreasing crop yield.One way to increase crop yield is to elevate fertilizing doses of nitrogen and phosphorus, although this could translate into anincrease in pest populations, since changes in host plant quality makes them more attractive to herbivorous insects, positivelyinfluencing their population dynamics. This study aims to assess the oviposition preference and the olfactory response of D.maidis to corn plants subject to three levels of nitrogen fertilization (100 ppm, 200 ppm and 300 ppm). Olfactory responsewas evaluated in a static-air four-way olfactometer using maize plants with different nitrogen fertilization levels as odorsources. Additionally, plants with different nitrogen fertilization levels were offered to females in a multiple-choice assay toassess their oviposition preference. The olfactory response of D. maidis was influenced by nitrogen fertilization, as femalesoriented toward plants treated with high fertilization levels. Similarly, oviposition preference assays showed that D. maidisfemales preferred to lay its egg in plants with high fertilization levels. The results herein reported could contribute to thedesign of integrated pest management strategies that promote balance between crop fertilization to improve yield and insectvector management.