Exploratory Survey of Lixus algirus L. (Coleoptera: Curculionidae) and Its Natural Enemies in Morocco

SIMPLE SUMMARY: Faba bean (Vicia faba L.) is one of the most important food legumes, and it is grown in Morocco under rainfed conditions. This crop is cultivated for use in both human food and animal feed and has a high protein content and nutritional value. The faba bean stem borer (Lixus algirus L.) is considered to be one of the major biotic stresses of faba beans in some Mediterranean areas, including Morocco. The aim of this study was to determine the distribution and abundance of L. algirus and its natural enemies in several Moroccan faba bean-growing regions. Among all the regions surveyed in this study, the Gharb and Saïs regions recorded the highest levels of damage by L. algirus. The conducted field surveys led to the identification of three parasitoids and one predator for possible use as biocontrol agents, among which the ectoparasitoid Chlorocytus lixi was the most dominant species. ABSTRACT: The stem borer weevil, Lixus algirus L. (Coleoptera: Curculionidae), causes severe damage to faba beans (Vicia faba L.) in Morocco. A survey was conducted to determine the distribution of L. algirus, its natural enemies, and the severity of damage it causes to faba beans in Morocco. A total of 16 and 27 stops were randomly selected and surveyed in the major faba bean-growing regions during the years 2017 and 2018, respectively. The Gharb region recorded the highest level of L. algirus infestation at 80% and 71.42% in 2017 and 2018, respectively, followed by the Saïs region at 58.75% and 36% in 2017 and 2018, respectively. Two egg parasitoids (Chlorocytus lixi and Anaphes longicornis), one egg predator (Orius sp.), and a larval parasitoid (Cyanopterobracon) were identified. The ectoparasitoid C. lixi was observed to be the most dominant species, with percentages of parasitism in the regions ranging between 35.75% and 70.49%. The larval parasitoid Cyanopterobracon was the second most abundant species, with percentages of parasitism ranging between 3.03% to 15.96%. Understanding the parasitoid complex of L. algirus in Morocco is necessary for the subsequent development of a biological control program.