Comparison of pheromone trap design and lures for Spodoptera frugiperda in Togo and genetic characterization of moths caught

Abstract

Fall armyworm, Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae), is a pest of grain and vegetable crops endemic to the Western Hemisphere that has recently become widespread in sub-Saharan Africa and has appeared in India. An important tool for monitoring S. frugiperda in the USA is pheromone trapping, which would be of value for use with African populations. Field experiments were conducted in Togo (West Africa) to compare capture of male fall armyworm using three commercially available pheromone lures and three trap designs. The objectives were to identify optimum trap 9 lure combinations with respect to sensitivity, specificity, and cost. Almost 400 moths were captured during the experiment. Differences were found in the number of S. frugiperda moths captured in the various trap designs and with the three pheromone lures, and in the number of non-target moths captured with each lure. The merits of each trap 9 lure combination are discussed with respect to use in Africa. A nearly equal number of COI-CS (161) and COI-RS (158) moths was captured with no differences found in COI marker proportions among traps or lures. However, the diagnostic rice strain marker Tpi was rarely found. Overall, the genetic characterization of the pheromone trap collections indicated a consistent distribution of genetic markers from 2016 to 2017, suggesting a population at or near equilibrium.

Sexual communication of Spodoptera frugiperda from West Africa: Adaptation of an invasive species and implications for pest management

“…As we sampled only a small proportion of both field populations (Benin n = 88 individuals and Nigeria n = 96 individuals), we cannot exclude that rice-strain specimens might be present in these regions and genotype specific sexual communication differences may exist in Benin, Nigeria or other African countries. In general, American lures have been successfully used to catch FAW males in Africa, although high numbers of non-target moths, some of which have similar appearance as FAW and might not be distinguished by local farmers 13 , highlight the need for more specific pheromone formulations. Analysis of the composition of American lures showed that lures like "L105A" from Scentry Biologicals, Inc. (Billings, Montana), the "FAW" lure from Trécé, Inc. (Adair, Oklahoma), and the "Scenturion Fall Armyworm Lure" from Suterra LLC (Bend, Oregon) contain Z11-16:Ac 36 , a compound not detected by the male antennae in EAG experiments with populations from America 18,37 and Africa (Table 1).…”

“…The fact that some American lures contain extremely high percentages of Z7-12:Ac, i.e. the "FAW" lure from Trécé releases almost 30% Z7-12:Ac, the "L105A" and "L976" lures from Scentry Biologicals around 10% Z7-12:Ac, and the "Scenturion Fall Armyworm Lure" circa 8% Z7-12:Ac 13 , could explain the attraction of non-target moths like Leucania loreyi to traps baited with FAW lures 13 . The results of our study showed that Z9-14:Ac, Z7-12:Ac, and Z9-12:Ac are the most promising candidates that should be used to formulate FAW lures, as only these three compound are present within the female gland and evoked EAG responses larger than the control stimuli ( Figs.…”

“…monitoring with pheromone traps to determine timing of pesticide application 9,10 , mass trapping to reduce population densities 11 , and mating disruption with high pheromone concentrations to disturb the mate finding process 12 . In Africa, monitoring with pheromone traps (baited with American lures) is currently used to assess infestation levels 13,14 and preliminary field trials are performed to evaluate the efficiency of mating disruption 5 . The key component in these control methods is the sex pheromone of FAW females.…”

Oviposition preferences, Bt susceptibilities, and tissue feeding of fall armyworm (Lepidoptera: Noctuidae) host strains

“…Populations in the Americas migrate into eastern and central North America from overwintering grounds over the course of several generations 2,8–11 . The migration course depends on host plant availability and weather patterns, 2,8–10 and routes can be tracked via pheromone traps 12–14 and mitochondrial haplotyping 11,15–17 . Fall armyworm are newly invasive into the Eastern hemisphere, making accurate management information vital.…”

Fall‐armyworm invasion, control practices and resistance breeding in Sub‐Saharan Africa

“…The traps attract, trap, and kill male moths, but they do not sufficiently reduce the male moth population to disrupt mating, hence they should not be used for FAW control purposes (FAO, 2019b), but rather only for monitoring and forecasting. Effective monitoring and forecasting can only be achieved with highly specific cost‐effective lures that exclude non‐target species, otherwise low specificity leads to overestimation of infestation levels and false movement patterns (Meagher et al., 2019). Lures are synthetic compounds that mimic natural pheromones and these are put in traps to attract the moths (FAO, 2018d; Knodel et al., 1995).…”