Behaviour and Population Dynamics of Entomopathogenic Nematodes Following Application

Comparison of virulence, reproductive potential, and persistence among local Heterorhabditis indica populations for the control of Temnorhynchus baal (Reiche & Saulcy) (Coleoptera: Scarabaeidae) in Egypt

“…Initially, since a nematode population comprises individuals that inhabit a specific unit of substratum (Caveness 1964), the primary thrust was to examine the novel populations herein to look for any new nematode strain which is a subgroup within a species differing in one or more of such significant traits as virulence and reproductive potential within the third instar larvae of T. baal, and/or persistence from the rest of the species. Significant beneficial traits have been recorded to differ among strains within an EPN species, e.g., virulence (Griffin 2015;Baiocchi et al 2017), reproductive potential (Testa and Shields 2017; Abd-Elgawad 2017a), persistence (Shields 2015), and environmental tolerance (Somasekhar et al 2002). Therefore, studies to estimate fitness and quality of nematodes reared in T. baal such as measuring nematode viability (percentage of emerged living infective juveniles), infectivity (power to invade), reproductive capacity (yield per insect), and virulence (power to kill) (Abd-Elgawad et al 2012) could upgrade the grub biocontrol.…”

Conditioning the entomopathogenic nematodes Steinernema carpocapsae and Heterorhabditis megidis by pre-application storage improves efficacy against black vine weevil, Otiorhynchus sulcatus (Coleoptera: Curculionidae) at low and moderate temperatures

“…Differences in susceptibility of O. sulcatus instars to EPN seem to vary both depending on nematode species and on test conditions (bioassay, pot, field) (Georgis and Poinar, 1984;Long et al, 2000;van Tol and Raupp, 2005). While the early instars may be more susceptible to species such as S. kraussei, they may be more difficult to find in more complex field conditions, due to both their smaller physical size (Lola-Luz et al, 2005) and smaller ''active space" of stimuli (Griffin, 2015).…”

Transmission Success of Entomopathogenic Nematodes Used in Pest Control

“…To increase their chances of finding a suitable host, IJs employ a variety of strategies, and two types of model can be used to help conceptualize this [ 108 ]. Hierarchical models, developed for other parasites, divide the transmission process into a set of steps that may include dispersal, host-habitat location, host location and host acceptance, with each phase (phases are not necessarily distinct) characterized by responses to specific stimuli [ 108 , 109 ]. While each of these processes is studied in EPNs, the temporal phasing of them has received less attention, but we can assume that rapidly after their emergence from an insect host or their application as biocontrol agents, IJs move away in an initial dispersal phase characterized by random movements as well as potential responses to environmental signals that might bring them to their hosts’ habitat [ 109 ].…”

“…Ascaroside #9 accumulated in nematode-infected cadavers and in bioassays caused S. feltiae IJs to become more active and move away from the source location [ 58 ]. Once in the host’s habitat, nematodes rely on different types of signals, mostly chemicals [ 110 ] (although vibrations or temperature gradients might also be used [ 111 , 112 , 113 ]), bringing them to the area of the habitat that is modified by the presence of the host (host’s “active space”) [ 109 ], and ultimately to the host itself.…”