Comparing Performance of Synthetic Sex Attractants and a Semisynthetic Bisexual Lure in Orthosia and Conistra Species (Lepidoptera: Noctuidae)

The performance of a semisynthetic bisexual lure (SBL, containing isoamyl alcohol, acetic acid and red wine) previously found attractive for a number of noctuids was compared with that of the respective synthetic sex attractants of Orthosia cerasi ( = stabilis ), O. cruda , O. gothica , O. incerta , Anorthoa munda and Conistra vaccini . The respective sex attractants performed significantly better in the Orthosia spp. than the SBL lure, which, although regularly catching low numbers of both females and males, did not differ significantly from zero catch in unbaited control traps. On the other hand, the SBL lure performed as well as the sex attractant in C. vaccini . Sizeable catches of C. rubiginea , C. rubiginosa and C. erythrocephala were also recorded in traps with the SBL lure. The SBL lure can prove to be a useful tool in ecological and faunistical studies of Conistra and related hibernating Xylenini species.

The larvae of species of the noctuid genus Orthosia feed on leaves of various trees in late spring/early summer, and some species are known to cause damages to orchard and forest trees as well (Cayrol, 1966). Adults have a single flight period per year, in early spring (March, April, according to climatic conditions). Sex attractants have been described among the pest Orthosia in Europe for Orthosia cruda (Denis et Schiffermüller, 1775), Orthosia incerta (Hufnagel, 1766), Orthosia gothica (Linnaeus, 1758), Orthosia cerasi (Fabricius, 1775) (= stabilis (Denis et Schiffermüller, 1775)) and Anorthoa munda (Denis et Schiffermüller, 1775) (Booij and Voerman, 1984;Tóth et al., 1992Tóth et al., , 1993, and traps baited with these are available for detection and monitoring. However, sex attractant baited traps will catch only males. Traps capable of capturing females could provide more useful data for monitoring of population dynamics. For example, data on captured females give information on the female flight pattern, by dissection of females we obtain data on *Corresponding author; e-mail: szanyi.szabolcs@agr.unideb.hu the timing of fertilisation and oviposition, and thus these surveys could result in more precise pest control decisions (Wall, 1989;Witzgall et al., 2010).
A female-targeted noctuid feeding attractant containing isoamyl alcohol plus acetic acid has been described in North America (Landolt, 2000) and this lure proved to be attractive also on European noctuids as well (Tóth et al., 2010). Recently, we managed to increase the effect of this known synthetic attractant by the addition of natural ingredients such as wine extracts or wine, and this improved semisynthetic bisexual lure (SBL) attracted more than a hundred noctuid species (both females and males) in field tests in Hungary and Transcarpathia (Nagy et al., 2014Szanyi et al., 2015;Tóth et al., 2015). A considerable number of species attracted belonged to the subfamily Hadeninae, including Orthosia species. Therefore, it appeared to be worthwhile to test this semisynthetic bisexual lure for attractancy on pest Orthosia species as well.
This present research was undertaken to compare the activity of the SBL lure with that of the respective synthetic sex attractants of some Orthosia spp. We were encouraged to embark on such a study, since in a preliminary experiment in 2012 traps baited with the mixture of iso-amyl alcohol plus acetic acid captured 97 Orthosia specimens (O. cerasi: 28%, O. cruda 33%, O. gothica: 8%, O. incerta: 15% and A. munda: 16%) while unbaited traps caught a single O. cerasi. (Tóth et al., unpublished). Similarly, the capture of three specimens of Orthosia hibisci (Guenée, 1852) has been reported in traps with the same lure composition in a screening test in Alaska (Landolt et al., 2007).
Data on other noctuids being on the wing in early spring (i.e. hibernated Conistra spp.) are also presented.

Field tests
Tests were conducted in a mixed oak forest at the Julianna major Experimental Station of the Plant Protection Institute of the Centre for Agricultural Research, Hungarian Academy of Sciences (PPI CAR HAS, Budapest, Hungary) using accepted methods in trapping experiments of the same nature (Roelofs and Cardé, 1977). Traps were arranged in a large circle, in random order, separated by 8-10 m. Traps were inspected at some days' intervals (preferably twice weekly), when captured insects were recorded and removed. At the same time traps were moved one position forward in the circle to minimize positional effects.
The catch data from field trapping tests were transformed using √(x+0.5) (Roelofs and Cardé, 1977) and analyzed by repeated measure ANOVA. If the ANOVA yielded significance, then treatment means were separated by the Student-Newman-Keuls test. If one of the treatments caught no insects, the Bonferroni-Dunn test was used to compare mean catches in other treatments with zero catch. All statistical procedures were conducted using the software packages StatView® v4.01 and SuperANOVA® v1.11 (Abacus Concepts, Berkeley, CA, USA).

Traps
In the tests, funnel traps CSALOMON® VARL were used. These traps have routinely been used for trapping several moth species of larger size (Tóth et al., 2000(Tóth et al., , 2010Subchev et al., 2004); photos of the trap can be viewed at www.csalomontraps.com. For killing captured insects, a small piece (1×1 cm) of a household anti-moth insecticide strip (Chemotox® SaraLee, Temana Intl. Ltd, Slouth, UK; active ingredient 15% dichlorvos) was placed into the catch container of traps.

Baits
The SBL lure tested was the same as described earlier , with the active ingredients of isoamyl alcohol, acetic acid and red wine (1:1:1).

Discussion
In both years of the study the population density of Orthosia spp. appeared to be very low, as evidenced by the relatively low catches of all spp. in traps with their respective sex attractants (pls refer to catch figures in Tóth et al., 1992Tóth et al., , 1993. In such circumstances the performance of the sex attractants in all spp. exceeded that of the SBL lure in the present study. We conclude that the activity of the SBL lure (if any) does not reach the level of practical applicability. Consequently, despite the fact that among the SBL catches females were also represented, the SBL lure cannot be recommended for use in detection and monitoring for agricultural or forestry purposes.
On the other hand, the SBL lure showed surprisingly high attractivity in C. vaccini, performing at a similar level as its sex attractant. Sizeable catches were recorded, especially in the second year also from other Conistra spp., so SBL appears to be a strong attractant for Conistra.  In this comparative study we included only the sex attractant of C. vaccini. Although a sex attractant consisting of (Z)-11-hexadecenyl acetate and (Z)-11-hexadeceal has been described also for C. rubiginea (Subchev et al., 1986), in numerous field tests of our own of various mixtures of these two compounds we never observed catches of more than a handful of specimens from this species (Tóth et al., unpublished), so we felt that the sex attractant has not been sufficiently optimized. Conistra species are not regarded as pests, so probably the activity of the SBL lure cannot be exploited for agricultural or forestry applications, however, it can prove to be useful in ecological and faunistical studies for this group of insects, as already evidenced in a large number of other noctuid taxa (Nagy et al., 2014Szanyi et al., 2015).
Other noctuids (E. transversa, S. libatrix and L. ornitopus) in the catch of traps with the SBL lure in this study are typical species in tests performed in the course of the summer season (Nagy et al., 2014Szanyi et al., 2015).
The strikingly low attractivity of synthetic lures on Orthosia species vs. the high efficiency in capturing of hibernated Conistra and related Xylenini species (Eupsilia spp., Litophane spp.) can be explained that the freshly emerged Orthosia species are mostly feeding on amenta of willow (Salix) species.
Isoamyl alcohol, the major synthetic component of the SBL lure was originally identified from fermenting liquids and is thought to affect noctuids which prefer to feed on such fermenting sources (Landolt, 2000). Another group of synthetic feeding attractants is based on floral compounds like phenylacetaldehyde (Cantelo and Jacobson, 1979;Creighton et al., 1973). Phenylacetaldehyde-based lures attract predominantly such noctuids (Plusiinae and Melicleptriinae mainly) which prefer flowers for feeding source (Landolt et al., 2001(Landolt et al., , 2006Tóth et al., 2010). Since Orthosia spp. adults are frequently observed to feed on catkins, the flowers of willow trees, it may show perspectives to test phenylacetaldehyde-based attractants for this group of pests in future assays.