~ 1122 ~ Journal of Entomology and Zoology Studies 2016; 4(4): 1122-1125 E-ISSN: 2320-7078 P-ISSN: 2349-6800 JEZS 2016; 4(4): 1122-1125 © 2016 JEZS Received: 23-05-2016 Accepted: 24-06-2016 Samira Hajialiloo Bonab MSc student, Department of Plant Protection, Ferdowsi University of Mashhad, Mashhad, Iran. Gholamhossein Moravvej Associate Professor, Department of Plant Protection, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran. Hussein Sadeghi Namaghi Professor, Department of Plant Protection, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran. Correspondence Gholamhossein Moravvej Associate Professor, Department of Plant Protection, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran. Comparative study on the efficacy of Bacillus thuringiensis var. tenebrionis and a neem based insecticide on adults and larvae of Xanthogaleruca luteola (Mull) (Col: Chyrsomelidae) in laboratory Conditions Samira Hajialiloo Bonab, Gholamhossein Moravvej and Hussein Sadeghi Namaghi Abstract The elm leaf beetle, Xanthogaleruca luteola (Müll). (Col: Chrysomelidae) is one of the most important pests on elm trees in Iran. Due to environmental issues of synthetic insecticides, biorational agents have been advised in control management programs of elm leaf beetle in urban green spaces. The susceptibility of adults and 3 rd instar larvae of this pest was evaluated to Bithiran ® (Bacillus thuringiensis var. tenebrionis) and NeemAzal ® -T/S (Neem based insecticide) using elm leaves dipped in aqueous insecticidal solutions. The mortality was recorded 24 h after treatment. The LC50 values for the third instar larvae and adults were respectively estimated to be 106.83 and 57.6 ppm for BT and 357.17 and 107.61 ppm for Neem. Bithiran ® was more effective against X. luteola larvae and adults when compared to NeemAzal ® -T/S. Further research on these biorational agents is recommended in field conditions before making any decision on their incorporation in control management programs. Keywords: Elm leaf beetle, Bithiran ® , NeemAzal ® –T/S 1. Introduction Among a series of urban pests, the elm leaf beetle Xanthogaleruca luteola (Müll) (Coleoptera: Chrysomelidae), as a defoliating insect, causes important damage on elm (Ulmus spp.) in farms and urban areas [1, 2] This pest was first recorded to be found in Iran in 1945 and it has become one of the most significant urban trees’ pests [3] . Both adults and larvae feed on the emergent leaves of the elm. The larvae skeletonize the leaves, destroying the tree's ability to achieve photosynthesis, adults beetle damage the foliage evidenced by a shot hole appearance in the leaves, and this damage continues throughout the growing period [4] . Repeated heavy infestation does not kill the tree outright, rather it usually weakens it, rendering it vulnerable to attack by insects and diseases. However, the beetle does transmit Dutch elm disease [2, 5] . Pesticides of biological origin have been intensively investigated for the past 30 years. An effort has been made to find an alternative to conventional insecticides. The alternative should be able to reduce health and environmental impacts [6] . There has been a worldwide interest in the development of alternative strategies, including the re-examination of using plant derivatives against agriculturally important insect pests. Plant derived materials are more readily biodegradable. Some have low toxicity to humans as well as natural enemies, and are more selective in action [7] . The application of such insecticides in urban areas holds special risks since most of them are not very selective, a realization that has led to the search for safe and environmentally friendly alternatives. Growing interest has been devoted to the development of control strategies with low environmental impact, such as botanical pesticides derived from naturally occurring plant compounds [8] and microbial agents, which are generally highly specific against target pests, thus facilitating the survival of beneficial insects in treated crops [9] . Among the most promising biological control agents, the entomopathogens such as viruses, bacteria and fungi provide a huge potential to control plant pests and diseases. The pesticide activity of these naturally occurring micro-organisms is mostly mediated by mechanisms highly specific to the target species, and typically based on modes of action, which are unique and usually not relevant to humans. Discovery of B. thuringiensis var.