Annual and geographical variations in the specific composition of jassids and their damage on cotton in Côte d'Ivoire

Abstract

The aim of this study is to highlight the diversity of leafhopper species and their impact on the cotton crop in Côte d'Ivoire. The collections made in 2021 allowed the identification of three species. Jacobiasca lybica is the most abundant, with proportions ranging from 73.3–93.3% depending on the site. The other two species are respectively Empoasca papayae (8.3%) and Jacobiella (= Empoasca) facialis (5%). In 2022, collections revealed the invasion of a new species, Amrasca biguttula, which became dominant with proportions of 90 to 100% depending on the site. Two other species J. lybica (2.7%) and J. facialis (1.3%) cohabit with A. biguttula. Thus, if the damage noted in 2021 was attributable to J. lybica, that observed in 2022 is essentially due to A. biguttula. The northeastern part of the cotton basin was the area most affected by attacks by these two new species. This zone seems to be favorable to the outbreak of leafhopper because of the low rainfall recorded in the localities. The results of the study reveal significant changes in the composition of leafhopper species in the cotton production areas of Côte d'Ivoire from one year to the next. This situation also explains the variations in damage levels. This raises the problem of adapting the phytosanitary protection programs applied by the producers.