Identification and pathogenicity of bacteria in the Mediterranean corn borerSesamia nonagrioides Lefebvre (Lepidoptera: Noctuidae)

Abstract

IntroductionCorn is the largest grown cereal crop in the world with doubled grain yield per unit area compared to wheat and barley. Although corn production holds second place in Mediterranean agricultural production, there has been a sharp decline in this value due to infestation by the Mediterranean corn borer (Özcan, 2009). The Mediterranean corn borer, Sesamia nonagrioides (Lefebvre) (Lepidoptera: Noctuidae), is a major multivoltine pest of maize in Mediterranean countries (Tsitsipis, 1988;Alexandri and Tsitsipis, 1990). S. nonagrioides is a polyphagous species with a fairly wide range of host plants, including corn, sorghum, millet, rice, sugar cane, grasses, melon, asparagus, palms, and banana (Uygun and Kayapınar, 1993;Sannino et al., 2004). The population levels of this species, which has considerable potential to establish itself in an area and become abundant, may therefore depend on the abundance of these hosts (Eizaguirre and Fantinou, 2012). If insecticides are not applied, losses could rise to 100% in late and second crop production (Alexandri and Tsitsipis, 1990).Application of chemical insecticides against this harmful insect is recommended 2-3 times per growing season. However, yield losses could rise to 30% during seasons with severe insect outbreaks, even after 4-5 insecticide applications (Özcan, 2009). As well as causing significant maize crop losses, the insects reduce the nitrogen/protein content of grain by tunneling into the stem and cobs, where they are likely to interfere with the uptake of plant nutrients (Bayram, 2003). Furthermore, mycotoxigenic fungi associated with the pest often invade wound sites and can greatly depreciate the crop value (Avantaggiato et al., 2003). Although several control methods have been previously applied to this pest, damage is still pervasive. Chemical insecticides have been frequently used against it. While chemicals decrease pest population, they cause major threats to the environment and human health. Mechanical, cultural, and biological Abstract: Sesamia nonagrioides (Lep.: Noctuidae) is one of the most serious pests of corn in Turkey and other Mediterranean countries. Although various cultural, chemical, and biological methods are used to control this pest, its damage still continues in all Mediterranean countries. In this study, to find an effective bacterium that can be used as a biocontrol agent against S. nonagrioides, we isolated 15 bacteria from S. nonagrioides larvae and evaluated the larvicidal potency of all isolates on the pest. According to their morphological, physiological, biochemical, and molecular properties, the isolates were identified as Achromobacter insolitus (Sn1), Morganella morganii (Sn2), Klebsiella pneumoniae (Sn3), Citrobacter freundii (Sn4), Arthrobacter protophormiae (Sn5), Chryseobacterium indologenes (Sn6), Bacillus thuringiensis (Sn7), Bacillus safensis (Sn8), Bacillus thuringiensis (Sn9), Bacillus thuringiensis (Sn10), Klebsiella pneumoniae (Sn11), Staphylococcus sciuri (Sn12), Enterobacter kobei (Sn13), Serratia marce...

Culturable bacterial strains isolated from Bemisia tabaci (Gennadius, 1889) (Hemiptera: Aleyrodidae) populations of Adana and Mersin Provinces of Turkey and their entomopathogen characteristics

“…Microbacterium species interact with insects. Of these bacteria, Microbacterium testaceum and M. thalassium were isolated from Ostrinia nubilalis (Hübner, 1796) (Lepidoptera: Pyralidae) larvae, Microbacterium arborescens from Sesamia nonagrioides (Lefèbvre, 1827) (Lepidoptera: Noctuidae) and M. liquefaciens were isolated from Dendroctonus micans (Kugelann, 1794) (Coleoptera: Curculionidae) (Yaman et al, 2010;Secil et al, 2012;Eski et al, 2015). In the present study, Microbacterium sp.…”

“…Serratia marcescens, non-pathogenic at low-density, pass into hemocoel, multiply there and kill the insect in 1 to 3 d (Sikorowski et al, 2001). Serratia marcescens common in insects is commonly isolated from several pests of Lepidoptera and Coleoptera (Cakici et al, 2014;Eski et al, 2015;Pu & Hou, 2016;Bidari et al, 2018). However, there are no records on the isolation of this bacteria from the whiteflies.…”

Recent trends in management strategies for two major maize borers: Ostrinia nubilalis and Sesamia nonagrioides

“…Laboratory bioassays using pure Cry1Ab endotoxin from Bt to establish baseline susceptibility of O. nubilalis and S. nonagrioides have indicated that S. nonagrioides is at least as susceptible to this toxin as O. nubilalis (González-Núñez et al 2000). According to Eski et al (2015), Bt and B. safensis caused 93 and 80% mortality in S. nonagrioides larvae, respectively. However, the most widespread and successful application of Bt was achieved with the introduction of genetically engineered crops (see Bt technology and varietal resistance section).…”