The Maize Caterpillar Mythimna (= Leucania) loreyi (Duponchel, 1827) (Lepidoptera: Noctuidae): Identification, Distribution, Population Density and Damage in Tunisia

SIMPLE SUMMARY: Mythimna loreyi Duponchel (Noctuidae) is reported on several gramineous hosts worldwide. It attacks particularly maize and reduces yields significantly. It is a native species in East Asia and found in the Near and Middle East, Australia and Africa. Recently, this insect emerged in Tunisia. It was detected abundantly during surveys carried out as part of a research project on the invasive insect pest Spodoptera frugiperda threatening maize, sorghum and other cereal crops in Africa. This work carried out the first investigations on its morphological and molecular identification, distribution, population density and damage in Tunisia. Surveys were carried out in four regions in the north and south of Tunisia where mostly maize and sorghum were planted (Jendouba, Bizerte, Nabeul, Gabes). Morphological characterization was based on male genitalia. Molecular identification was determined based on mitochondrial cytochrome oxidase I sequences (mtCOI). Field-collected data included adult monitoring using traps, infestations, and incidence of the pest. Correlations with whether parameters were studied. Overall, our results indicated that M. loreyi was well established in all prospected areas in Tunisia. Therefore, a control program is needed to manage this pest. Additionally, the threat of this insect on strategic cereal crops in Tunisia (wheat) should be further investigated. ABSTRACT: Surveys were conducted during 2020 and 2021 to study the emerging lepidopteran pests inflicting cereals in Tunisia, with specific emphasis on maize and sorghum crops. A species was collected from traps placed in the Jendouba, Bizerte, Nabeul and Gabes regions. Thus, this study carried out first report on its identification, distribution, population density and damage. Results showed that M. loreyi was abundant in all prospected areas, with total adult captures reaching 4779 and 9499 moths on sorghum and maize, respectively, during 2020. Moreover, the mean infestation percentage reached its maximum during August at 31.05% and 20.69% for the Jendouba and Bizerte regions, respectively, while the highest infestations were observed in the Gabes and Nabeul regions during July, with respective mean values of 13.54% and 21.35%. In addition, results revealed that the highest pest incidence occurred in the Gabes region, with values of 11.1 ± 0.47 and 5.7 ± 0.48 during 2020 and 2021, respectively. Additionally, results pointed out that M. loreyi achieved two summer generations in the different localities of Tunisia. Overall, this study provides basic insights into the ecology and population biology of M. loreyi, which are required to establish an effective pest control program.