Browsing by Author "Lewis, Edwin E."

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    Conspecific and heterospecific pheromones stimulate dispersal of entomopathogenic nematodes during quiescence
    (Nature Portfolio, 2020-03-18) Kaplan, Fatma; Gentil, Abigail Perret; Giurintano, Julie; Stevens, Glen; Schiller, Karl C.; Mirti, Amaleah; Sampson, Edith; Torres, Cedric; Sun, Jiayi; Lewis, Edwin E.; Ilan, David Shapiro; Erdoğan, Hilal; Bursa Uludağ Üniversitesi/Ziraat Fakültesi/Biyosistem Mühendisliği.; 0000-0002-0387-2600; AAP-5834-2020; 57216199216
    Ascaroside pheromones stimulate dispersal, a key nematode behavior to find a new food source. Ascarosides produced by entomopathogenic nematodes (EPNs) drive infective juvenile (IJ) emergence from consumed cadavers and dispersal in soil. Without ascarosides from host cadavers, Steinernema feltiae (EPN) reduce dispersal substantially. To determine whether other Steinernema spp. exhibit the same behavior, we compared S. feltiae and S. carpocapsae IJs without host cadaver pheromones. Unlike S. feltiae, S. carpocapsae IJs continued to disperse. However, S. carpocapsae IJs exhibited a temperature-dependent quiescent period. The IJ quiescent period increased at ≤20 °C but did not appear at ≥25 °C. Consistent with this, S. carpocapsae IJ quiescence increased from 30 min to 24 h at ≤20 °C over 60 days. The quiescent period was overcome by dispersal pheromone extracts of their own, other Steinernema spp. and Heterorhabditis spp. Furthermore, S. carpocapsae IJ ambush foraging associated behaviors (tail standing, waving, and jumping) were unaffected by the absence or presence of host cadaver pheromones. For S. feltiae, IJ dispersal declined at all temperatures tested. Understanding the interaction between foraging strategies and pheromone signals will help uncover molecular mechanisms of host seeking, pathogenicity and practical applications to improve the EPN’s efficacy as biocontrol agents.
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    Entomopathogenic nematode dispensing robot: Nemabot
    (Elsevier, 2021-02-14) Erdoğan, Hilal; Ünal, Halil; Lewis, Edwin E.; ERDOĞAN, HİLAL; ÜNAL, HALİL; Bursa Uludağ Üniversitesi/Ziraat Fakültesi/Biyosistem Mühendisliği Bölümü; 0000-0002-0387-2600; AAP-5834-2020; IHS-3745-2023
    Entomopathogenic nematodes (EPN) are obligate endoparasites of many insect species and they are important biocontrol agents. Application strategies that improve precision and reduce labor would increase their potential in many cropping systems. We developed a unique robotic system to apply EPNs to a surface area precisely. The robotic system picks up EPNs from a suspension in a reservoir with a peristaltic pump and transfers them to an exact point with an exact amount. Four suspensions were prepared with four concentrations of EPNs; 0.1, 0.2, 0.4 and 0.8 g of commercial EPN product per 2 L of water. All suspensions were applied in three different amounts of water (25, 50 and 100 mL per application). In total, 12 different applications were conducted with the robot. Conical falcon centrifuge tubes were used to collect applied EPNs. Five samples (10 ?l) were taken from collected 25, 50 and 100 mL EPN suspensions and the average nematode number in the samples were scaled to the whole suspension. Results of the experiments showed that all robot applications, except 25 mL?0.1 g dose, were not significantly different from those of the control treatment, application with a pipette.. Thus, the robotic system has been found to make consistent applications.