Entomopathogenic Nematodes in Jordan: An Environmentally-Safe Alternative to Benefit Agriculture in Desert Systems
Investigators (most current known information)
As the world's food and fiber demand increases, stricter measures to protect and preserve our environment and natural resources need to be exercised. In this respect, development of sustainable management systems for preventing major economical agricultural losses must focus on strategies that limit production costs, enhance crop yields, and protect the environment. In relation to this last aspect, degradation of soils is a topic of particular concern. With the rapid worldwide degradation of soils, particularly in desert or semi-desert ecosystems, rational management urgently requires increased knowledge of the ecology of these soils, including knowledge of the diversity of the soil flora and fauna and their respective interactions. Nematodes and insects are among the most abundant faunal components of the soil. Several studies have shown the significance of nematodes as belowground herbivores (i.e., alter primary production by parasitism of roots) and in decomposition and mineralization processes (Anderson, 1981; Ingham et al., 1985; Griffiths, 1994), and as natural control agents of soil-dwelling insect pests (Gaugler and Kaya, 1990; Koppenhöffer, 2000) and plant-parasitic nematodes (LaMondia and Cowles, 2002; Perez and Lewis, 2002). In this last category, insect-parasitic and pathogenic nematodes are the most widely known and studied group of invertebrate parasitic nematodes. These nematodes have the potential to provide an environmentally-safe alternative to control insect pests in agricultural and forestry systems (Gaugler and Kaya, 1990; Kaya and Gaugler, 1993) and also for the control of insects pests of human and veterinary importance (Samish and Glazer, 2001). In this respect, the proposed research aims to isolate and identify the diversity of entomopathogenic nematodes (EPN) of soil-inhabiting insects and from cryptic habitats from arid and semiarid ecosystems in Jordan. Additionally, a selection of ecological/physiological parameters will be evaluated for future implementation of these nematodes as biological control agents against endemic insect pests in Jordan and other desert regions of the world.
Knowledge of the diversity and distribution of this group of nematodes will be valuable not only from a biodiversity standpoint, but also for future ecological and/or biocontrol studies as well as for bioprospecting and pharmaceutical applications. We hypothesized that the greatest diversity of these nematodes will be present in particular habitats that have high numbers and diversity of insects. We predict the discovery of a number of undescribed taxa with unique ecological traits such as heat and dehydration tolerance that will make these nematodes more suitable for their consideration as bio-insecticides in areas were drought and high temperatures prevail. Such traits can be utilized for improving efficacy of already existing strains either by conventional hybridization methods or by genetic engineering techniques (Burnell, 2002). We propose a scheme for sampling and isolation of EPN that will better assess the diversity of these nematodes in Jordan. For this purpose, a variety of sampling and isolation methods will be conducted by PI Al Banna and Jordanian collaborators, under the supervision of PI Stock. Identification of recovered taxa will be conducted by PI Stock on the basis of a combined morphological and molecular characterization as well as cross-hybridization tests. Training of Jordanian scientists in entomopathogenic nematology will be provided by PI Stock. A series of experiments will be conducted by both research teams to evaluate a range of ecological/physiological parameters for the recovered species/isolates. Ecological studies will involve the evaluation of physiological host range and the influence of selected abiotic factors (i.e., temperature, soil moisture) on the infectivity and reproduction of the recovered species/isolates. A live nematode culture collection will be established for future testing and implementation of the recovered species/isolates in biological control and/or IPM programs against agricultural insect pests. Results from these studies will be published in peer-review journals. Additionally we will include a published web-based descriptive manual with an interactive identification system to all taxa encountered in this study.
In addition to developing a deeper understanding of the diversity, biology and ecology of insect pathogenic nematodes, the present study will also provide an important tool for the identification of species and isolates for registration, quarantine, and proprietary protection purposes. Consequently, we expect these results will be immediately useful to other researchers interested in conservation of biotic diversity and in applying this knowledge to nonchemical and nontoxic pest control programs in desert and semidesert habitats.
Stock, S. P., L. Al Banna, A. Mahsneh, R. Darwish, and A. Katbeth. 2007. “Assessment of ecological traits of four Jordan-native Entomopathogenic nematodes isolates.” (In preparation and to be submitted to Biological Control )
Stock, S. P., L. Al Banna, A. Mahsneh, R. Darwish, and A. Katbeth. 2007. “Biogeography and diversity of entomopathogenic nematodes in Jordan.” (Submitted to Journal of Invertebrate Pathology ).
Stock, S. P., L. Al Banna, R. Darwish, A. Katbeh, A. Mahasneh, and W. Nasr. 2007. Diversity of entomopathogenic nematodes (Steinernematidae, Heterorhabditidae) in Jordan. To be presented at: 40th annual meeting society for invertebrate pathology . 12-17 August 2007. Quebec Canada.
Al Banna, L., R. Darwish, A. Katbeh, and S. P. Stock. 2005. Survey and Assessment of Entomopathogenic Nematodes (Steinernematidae, Heterorhabditidae) in Jordan. Presented at: Asia-Pacific congress of entomology. 18-21 October 2005. Jeju Island, South Korea.