Orientation Disruption of messoria (: ) Males with Synthetic Sex Attractant Components: Field and Flight Tunnel Studies

P. PALANISWAMY, E. W. UNDERHILL AND M. D. CHISHOLM National Research Council of Canada, Prairie Regional Laboratory, Saskatoon,Saskatchewan, Canada S7N OW9

Environ. Entomol. 13: 36-40 (1984) Downloaded from https://academic.oup.com/ee/article/13/1/36/2480252 by guest on 29 September 2021 ABSTRACT Disruption of orientation of Euxoa messoria male to traps baited with a synthetic sex attractant or virgin females was studied under two field designs. In both designs, the atmosphere in the test sites was permeated with (Z)-ll-hexadecenyl acetate (Zll-16:Ac), (Z)-7-hexadecenylacetate (Z7-16:Ac),and (Z)-9-hexadecenylacetate (Z9-16:Ac), each compound singly or as a ternary blend. In 81-m' test plots, effective (>89%) disori- entation of males occurred, using the blend or Zll-16:Ac alone; Z7-16:Ac and Z9-16:Ac, tested singly, were ineffective. In the other test sites, where the disruptants were released from rubber septa in close proximity to the monitoring trap, disorientation resulted from both the blend and Z7-16:Acalone; Zll-16:Ac was ineffective under these conditions. Studies of male behavioral responses to these components in a flight tunnel showed that Zll-16:Ac is a long-range attractant whereas Z7-16:Acprimarily effects close-range flight and landing. No behavioral effect could be attributed to Z9-16:Ac.Results of flight tunnel responses and visual observations of field test sites accounted for the disruption results obtained.

THE DARKSIDED CUTWORM, Euxoa messoria (Har- ments, trace quantities seemed to enhance the ris), is widely distributed through North America, power of the published binary lure. occurring from coast to coast in southern Canada We report here the effect of air permeation with and as far south as Tennessee and California Zl1-16:Ac, Z7-16:Ac, and Z9-16:Ac on E. messorta (Hardwick 1970). The larvae are pests of several male orientation to female- and sex attractant- garden and annual crops (Beirne 1971). E. mes- baited monitoring traps in small-plot field tests. soria is particularly known as a pest of tobacco, on The behavioral responses by males to these com- which it is considered to be the most destructive ponents in a flight tunnel are also reported. of several cutworm pests (Cheng 1971). Pest management programs for the darksided Materials and Methods cutworm integrating a variety of techniques are needed to supplement the use of insecticides. . Adult darksided cutworm females, Cheng (1977, 1981) has studied the possible role which were used to bait field traps, were reared of parasites. Another potential method is the use in the laboratory. Newly hatched larvae were of behavior-modifying chemicals that disrupt sex- placed on cut leaves of rye, Secaie cereaie, for ca. ual communication between adult moths and sup- 10 days and then transferred singly to l-oz (ca. press mating (Kydonieus and Beroza 1982). Before 30-ml) diet cups containing a modified wheat germ the use of behavior-modifying chemicals for large- diet (Shorey and Hale 1965). The culture was scale mating suppression, small-plot male disori- maintained at 22°C under a photoperiod of LD entation studies are recommended (Roelofs and 17:7. Pupae were sexed and stored separately until Novak 1981). Although disorientation studies do adult emergence. Male moths used for behavioral not test for mating suppression, they are an effec- studies in the flight tunnel were field collected, tive method of screening potential compounds, using cone-orifice traps similar to model 3 de- blends, and concentrations. Potential disruptants scribed by Steck and Bailey (1978) and baited with of E. messoria male orientation include (Z)-l1- Zl1-16:Ac (200 ~g) + Z7-16:Ac (10 ~g) + Z9-16: hexadecenyl acetate (Zl1-16:Ac) and (Z)-7-hex- Ac (0.2 ~g). The insects were held in the laboratory adecenyl acetate (Z7-16:Ac), components of a sex at 22° C, 70% relative humidity (RH), for at least attractant for this species (Struble et al. 1977). The 2 days before experimentation to permit their re- most abundant compound in the attractant, Zl1- covery from any possible habituating effects of the 16:Ac, has been identified in ovipositor extracts of trap lure. adult females (Underhill, unpublished data). We Chemicals and Traps. Hexadecen-l-ols were considered (Z)-9-hexadecenyl acetate (Z9-16:Ac) synthesized by recognized procedures, purified by also as a potential disruptant, because in field tests argentation chromatography, and acetylated with conducted before these disorientation experi- acetic anhydride (Chisholm et al. 1980). Assayed

36 February 1984 PALANISWAMY ET AL.: DISRUPTION OF E. messoria SEX ATTRACTION 37 by capillary gas chromatography (GC), each was ment of wing fanning. Males that failed to show >98% pure and contained no detectable positional wing fanning within 3 min after sample introduc- or geometrical isomers, nor any functional group tion were considered nonresponsive and were dis- analogs such as free alcohols. Red rubber septa carded. Each was tested only once, and all (Arthur H. Thomas no. 8753-D22), impregnated were discarded at the end of each day. Visual ob- via 1% solutions in hexane, were used as disruptant servations of each moth's behavior were spoken releasers and trap lures. Release rates of hexadec- into a cassette recorder, and the data were tran- enyl acetates from rubber septa were calculated scribed later. (Butler and McDonough 1979), using 730 days for In this report, moths were considered to have their half-life. Cone-orifice traps were used initiated plume-oriented flight if they followed the throughout. Monitoring traps were baited with plume for at least 10 cm from the point of release. either Zll-16:Ac (200 ILg) + Z7-16:Ac (10 ILg) + Plume-oriented flight refers to continued upwind Downloaded from https://academic.oup.com/ee/article/13/1/36/2480252 by guest on 29 September 2021 Z9-16:Ac (0.2ILg) or with three virgin females held flight in the plume or to hovering and looping within a wire screen cage. Traps were inspected flights in the plume area but without upwind prog- daily, and new females were added as required. ress. Plume-oriented flight was considered termi- In this report the word "disruptant" is used to nated when the moth left the plume area and did denote test chemicals employed to disrupt the ori- not reorient in the plume. entation of male moths to traps baited with syn- Statistical Analyses. In field disruption experi- thetic chemical lures or live female moths. ments, sets of treatments were set out for varying Field Designs. Two experimental designs were times during the flight period. Data within a set employed to assess disorientation of males to mon- were transformed to \IX + 0.5 and analyzed by itoring traps. In one design, 16 stakes 1.5 m high an analysis of variance test and significant differ- were set in a square grid (4 by 4) to form a test ences among means were determined by Duncan's plot 81 m2• A rubber septum attached near the top multiple range test. Flight tunnel tests were done of each stake was used to release potential disrup- on several days, and each day 30 to 40 males were tants in the test plot. An additional stake, centered exposed to different treatments in varying number in the test plot, carried a monitoring trap at a and in random order. Only the three-component height of 1.5 m. In the other design, termed "close- treatment, namely, Zll-16:Ac (20 /-lg)+ Z7-16:Ac range disruption," disruptants were released from (5 /-lg)+ Z9-16:Ac (0.1 /-lg), was tested every day eight septa which were equally spaced in a hori- and x2 comparisons indicated no significant day- zontal circle around the axis through the trap en- to-day variations in any of the responses examined. try holes. The extent of male orientation disrup- The data from all testing days were combined, and tion was assessed by comparing the number of the percentages were transformed (arcsin y'X). The males captured in disruptant test sites and in check significance of treatment effects was compared by plots which contained similarly baited traps. Tests x2 analysis, and the means were compared by were done in cereal crop fields, and all test sites Duncan's multiple range test, using a pooled bi- and check plots were separated from others by at nomial error variance (Palaniswamy et al. 1983). least 150 m. Treatment effects on transformed latency data (In Field Observations. The nocturnal flight behav- X) and plume-oriented flight termination data were ior of E. messoria in the close-range disruption compared by Duncan's multiple range test using plots was studied by using night viewing devices the error mean square from one-way analysis of (Varo model 9876 and Javelin model 221). Obser- variance. vations were made on several nights, and each treatment plot was observed for a total of ca. 45 Results and Discussion min. Flight Tunnel. The flight tunnel has been de- The relative attractancy of the synthetic lure scribed in detail previously (Palaniswamy et al. and virgin female moths for target males was tested 1983). All flight tunnel assays were done 1 to 3 h before the disorientation experiments. In a test into scotophase. The tunnel, illuminated by flu- replicated three times, traps baited with the syn- orescent lights (0.1 lux) had a laminar air flow of thetic lure and with females captured 88 and 54 25 cm sec-·I. At the start of the test, a cylindrical E. messoria males, respectively. These captures are wire screen cage (7 cm in diameter by 12 cm long) not significantly different and are in close agree- containing a male moth was positioned on a dis- ment with earlier data (Struble et al. 1977). posable stand near the origin at the downwind end Orientation disruption of darksided cutworm of the tunnel and in the path of the chemical males to female-baited and sex attractant-baited plume. The position of the plume had been pre- traps in 81-m2 treatment plots is summarized in viously established, using titanium tetrachloride. Table 1. When the three-component blend was re- After a 3-min base-line period, if the moth re- leased at rates of 1.59 and 4.77 /-lg per plot per mained calm, a rubber septum impregnated with day, there was >89% disruption of male orienta- chemicals was positioned 190 cm upwind from the tion to sex attractant- and female-baited traps. Plots point of moth release. Responding insects were re- permeated with Zll-16:Ac alone also effected up leased from their cage ca. 30 sec after commence- to 89% male disorientation, but neither Z7-16:Ac 38 ENVIRONMENTAL ENTOMOLOGY Vol. 13, no. 1

Table 1. Disruption of E. messoria male orientation in 81-m' test plots

Disruptant % Test· Release rate Trap bait" Males ca ught" Composition ("g/septum) Disruption' ("g/p]ot per day) A Ternary blend' (315) 4.77 S 9c 95 Ternary blend' (lOS) 1.59 S 18c 90 Ternary blend' (31) 0.47 S 46b 74 Check (no disruptant) S 176a B Zll-16:Ac (100) LSI S 56b 77 Z7-16:Ac (100) LSI S 179a 26 Z9-16:Ac (100) LSI S 200a 18

Check (no disruptant) S 243a Downloaded from https://academic.oup.com/ee/article/13/1/36/2480252 by guest on 29 September 2021 C Zll-16:Ac (300) 4.55 S 12c 89 Z7-16:Ac (300) 4.55 S 94b 13 Z9-16:Ac (300) 4.55 S 13]a 0 Check (no disruptant) S 108ab D Ternary blend' (105) 1.59 F 4b 89 Zll-16:Ac (l00) 1.51 F 4b 89 Check (no disruptant) F 37a

• Each test replicated three times: (A) 5-10 September 1980; (B) 29 August-5 September 1980; (e) 25-29 August 1980; (D) 31 August-8 September 1981. • S = ZlI-16:Ac (200 "g) + Z7-16:Ac (10 "g) + Z9-16:Ac (0.2 "g); F ~ 3 E. messorla femalE's per trap. o Values in separate tests followed by the same letters do not differ at the 5% level. (catch in untreated area) - (catch in disruptant area) d Percent disruption = catch in untreated area x 100.

'Ternary disruptant blend contained Zll-16:Ac: Z7-16:Ac: Z9-16:Ac = 100:5:0.1.

nor Z9-16:Ac was effective in disrupting male ori- entation were >92%. Releasers of Z7-16:Ac, when entation in these plots. similarly deployed (test F), also disrupted male The effect of releasing disruptants close to mon- orientation and disruption increased as the releas- itoring traps is shown in Table 2. When septa re- ers were placed closer to the monitoring traps. leasing the ternary blend (test E) were placed 0.3, When Z7-16:Ac was released at 0.38 /Lg per site 1, and 2 m from the trap, reductions in male ori- per day, the extent of male disorientation to traps

Table 2. Close-rangedisruption of E. messoria male orientation

Disruptant Distance Trap Males % Tl"sl" Release rate Composition ("g/septum) (em) from bail'" caught' Disruption' ("g/ plot per day) trap'

E Ternary blend! (210) 1.59 30 S ]b 98 Ternary blend! (210) 1.59 100 S 4b 92 Ternary bll"ndf (2]0) 1.59 200 S 4b 92 Check (no disruptan!) S 15]a F Z7-16:Ac (50) 0.38 30 S 48b 84 Z7-16:Ac (50) 0.38 100 S 161ab 45 Z7-16:Ac (50) 0.38 200 S 250a 14 Check (no disruptant) S 292a G Z7-16:Ac (5) 0.04 30 S 30a 44 Z7-16:Ac (50) 0.38 30 S lOb 81 Z7-16:Ac (200) 1.52 30 S Oc 100 Check (no disruptant) S 54a H Z7-16:Ac (50) 0.38 30 F 9b 76 Check (no disruptant) F 37a ZlI-16:Ac (5) 0.04 30 S 43a 0 Zll-16:Ac (50) 0.38 30 S 36ab 0 ZlI-16:Ac (200) 1.52 30 S 12b 60 Check (no disruptant) 30ab

• Each test replicated three times: (E) 5-16 September 1980; (F) 19-26 August 1981; (Gl 10-12 September 1980; (H) 3] August- 8 September 1981; (1) 16-22 September 1980. 'Eight septa containing disruptants encircled the monitoring trap; distance (em) septa w••re separated from trap center. oS = Zll-16:Ac (200 "g) + Z7-16:Ac (l0 "g) + Z9-16:Ac (0.2 "g); F = 3 E. messoria females per trap. 'Values in separate tests followed by the same letters do not differ at the 5% level. . . (catch in untreated area) - (catch in disruptant area) d • Percent lsruphon = catch in untreated area x 100.

!Ternary disruptant blend = Zll-16:Ac: Z7-16:Ac: Z9-16:Ac = 100:5:0.1. February 1984 PALANISWAMY ET AL.: DISHUPTION OF E. messoria SEX ATTRACTION 39

Table 3. Flight tunnel behavioral responses of E. messoria males to Zll.16:Ac, individually and in combination with Z7.16:Ac and Z9·16:Ac

Lure No. of males % Plume-oriented Plume-oriented % Wing fanning % Landingd composition (Ilg) tested Bight initiation'" Bight termination'" Zll-16:Ac (2) 32 78c 68b 138ab 0 Zll-16:Ac (20) 43 88abc 79ab 143ab 7 Zll-16:Ac (200) 22 100a 82ab 117b 0 Zll-16:Ac (20) + Z7-16:Ac (5) 23 100a 87ab 169ab 65 Zll-16:Ac (20) + Z7-16:Ac (5) + Z9-16:Ac (0.1) 70 96ab 91ab 155a 67 Zll-16:Ac (200) + Downloaded from https://academic.oup.com/ee/article/13/1/36/2480252 by guest on 29 September 2021 Z7-16:Ac (10) 27 81bc 90ab 124b 45 Zll-16:Ac (200) + Z7-16:Ac (10) + Z9-16:Ac (0.2) 17 100a 94a 136ab 50

• Values followed by thl" same letters in the same column do not differ at the 5% level. • Pl"rcentage based on the number of moths which fanned. 'Ml"an distance (em) from release 10int. d Pl"rcl"ntage based on the number of mot s which initiated plume-oriented Bight. baited with the synthetic lure (test F) and females moths made wide lateral excursions in their ap- (test II) was similar. Zl1-16:Ac appeared to have proach to the trap, apparently crossing the Zl1- little or no disruptive effect on male orientation. 16:Ac plumes but not being attracted at close range To clarify the basis for the differences in ori- to the sources. Therefore, little disruption of male entation disruption which occurred in response to orientation occurred at close-range sites using Zl1- single components when tested under the two ex- 16:Ac. In contrast, up to 89% disorientation (Table perimental designs, we studied male behavioral 1) occurred with Zl1-16:Ac alone in the 81-m2 responses to the components in a flight tunnel. plots. On the basis of male responses to this com- There was no response to Z7-16:Ac alone at loads ponent in flight tunnel tests, we conclude that dis- of 5, 20, and 200 ~g per septum (n = a minimum orientation occurred through confusion and was of 8 for each concentration). Males responded rap- due to the competitive long-range attraction of idly to Zl1-16:Ac with wing fanning and engaged males to Zl1-16:Ac emanating from both the dis- in upwind flight (Table 3); however, most termi- ruptant releasers and the monitoring trap bait. nated their plume-oriented upwind flight without When Z7-16:Ac was tested alone in the close-range landing on the source. These results indicated that sites, disruption occurred at the three doses tested, Zll-16:Ac alone is capable of eliciting long-range but the cause of disruption may have differed based attraction. By using blends of Zl1-16:Ac + Z7-16: on the amounts of Z7-16:Ac employed. At 5 ~g per Ac, the wing fanning activation response was sim- septum, 63% of the approaching moths exhibited ilar to that caused by Zll-16:Ac alone, but the plume-oriented flight to the releasers (Table 4), number of males which landed on the source in- creased significantly. This indicates that Z7-16:Ac primarily influences continuation of plume-orient- ed flight at close range and initiation of landing. Table 4. Field observations at night of moths respond- ing to disruptant sources at close range" Changes in the ratio and dose of these two com- ponents (Table 3) resulted in no observable differ- % Plume- % No. of ences in male responses, and no behavioral re- oriented Landing Disruptant moths ap- Bight to on dis- sponse could be attributed to additions of Z9-16: (Ilg/septum) proaching disruptant ruptant Ac. site' septa'·d septad Observations of moth behavior near close-range disruptant sites were conducted at night (Table 4). Z7-16:Ac (5) 24 63 33 Z7-16:Ac (50) 19 58 16 At sites where the ternary blend was released, 81 % Z7-16:Ac (200) 10 10 0 of moths observed exhibited plume-oriented flight Zll-16:Ac (50) 28 18 7 to the disruptant releasers surrounding the moni- Zll-16:Ac (200) 15 13 0 toring traps. This indicates that competitive at- Zll-16:Ac (200) + Z7-16:Ac (10) + traction of the releaser sources for the male moths Z9-16:Ac (0.2) 42 81 57 (confusion) was the cause of their disorientation both at these sites and in the 81-m2 plots (Table 1) • The site consisted of a trap containing the three-component lure surrounded by eight disruptant septa at 30 em from the bait. when the blend was released. Of the moths ob- • Includes all moths seen Bying upwind towards the site within served at sites where Zll-16:Ac was released (Ta- 2 m. ble 4), less than 20% exhibited plume-oriented flight 'Includes those moths exhibiting plume-oriented Bight to any of the disruptant sources within 20 em downwind. toward the disruptant septa. Most of the observed d Percentage based on number of moths approaching site. 40 ENVIRONMENTAL ENTOMOLOGY Vol. 13, no. 1 and hence disruption appeared to be due to com- sex pheromones: evaporation rates of acetates from petitive attraction of releasers (confusion). Al- natural rubber septa. J. Chern. Eco!. 5: 825-837. though complete disruption was obtained by using Cheng, H. H. 1971. Assessment of tobacco losses 200 /Lg per septum, it did not appear to be as a caused by the darksided cutworm, Euxoa messoria result of confusion. Here it was noted that the (Lepidoptera: Noctuidae) Delhi, Ontario. Can. Ento- mo!. 103: 534-541. number of moths approaching the site was less 1977. Insect parasites of the darksided cutworm, Eu- than at the lower dose treatments and only 1 of xoa messoria (Lepidoptera: Noctuidae) in Ontario. the 10 moths observed exhibited plume-oriented Ibid. 109: 137-142. flight to the disruptant septa. Not capable of elic- 1981. Additional hymenopterous parasites newly re- iting long-range attraction, Z7-16:Ac caused no corded from the darksided cutworm, Euxoa messo- disruption in the 81-m2 plots, where competition ria (Lepidoptera: Noctuidae) in Ontario. Ibid. 113: Downloaded from https://academic.oup.com/ee/article/13/1/36/2480252 by guest on 29 September 2021 of sources was minimal. 773-774. . Based on the data obtained from small-plot (81- Chisholm, M. D., W. Sieck, and E. W. Underhill. m2) disorientation tests and flight tunnel behavior- 1980. Effects of additional double bonds on some olefinic moth sex attractants. J. Chern. Eco!. 6: 203- al responses, blends of Zll-16:Ac Z7-16:Ac, or + 212. Zll-16:Ac alone, show potential for E. messoria Hardwick, D. F. 1970. The genus Euxoa (Lepidop- mating disruption and can be recommended for tera: Noctuidae) in North America. I. Subgenera larger-scale tests. Z7-16:Ac, although capable of Orosagrotis, Longivesica, Chorizagrotis, Pleonecto- disrupting male orientation when in close prox- poda, and Crassivesica. Mem. Entomo!. Soc. Can. 67. imity to the attractant source, appears to offer con- 177 pp. siderably less potential as a mating disruptant. Al- Kydonieus, A. F., and M. Beroza. 1982. Insect though addition of Z9-16:Ac to lures containing suppression with controlled release pheromone sys- tems. Vo!. I and II. CRC Press, Boca Raton, Fla. Zll-16:Ac + Z7-16:Ac resulted in increased cap- Palaniswamy, P., E. W. Underhill, W. F. Sieck, and ture of in field tests carried out before E. messoria M. D. Chisholm. 1983. Responses of male red- the work reported here, these results could not be backed cutworm, Euxoa ochrogaster (Lepidoptera: confirmed; Z9-16:Ac did not increase the attrac- Noctuidae), to sex pheromone components in a lIight tiveness of the binary blend, nor did it cause ap- tunne!. Environ. Entomo!. 12: 748-752. preciable disruption of male orientation. Roelofs, W. L., and M. A. Novak. 1981. Small-plot disorientation tests for screening potential disrup- tants, pp. 229-242. In E. R. Mitchell [ed.], Manage- Acknowledgment ment of insect pests with semiochemicals. Plenum Press, New York. We thank S. Peesker, B. K. Bailey, and G. Beckett for Shorey, H. H., and R. L. Hale. 1965. Mass-rearing technical assistance, and the Department of Crop Sci- of the larvae of nine noctuid species on a simple ence, University of Saskatchewan, for provision of test sites. We also thank H. H. Cheng, Agriculture Canada, artificial medium. J. Econ. Entomo!. 58: 522-524. Delhi, Ontario, for supplying E. messoria eggs and for Sieck, W. F., and B. K. Bailey. 1978. Pheromone advice on rearing. traps for moths: evaluation of cone trap designs and design parameters. Environ. Entomo!. 7: 449-455. Struble, D. L., G. E. Swailes, and G. L. Ayre. 1977. References Cited A sex attractant for males of the darksided cutworm, Euxoa messoria (Lepidoptera: Noctuidae). Can. Beirne, B. P. 1971. Pest insects of annual crop plants Entomo!. 109: 975-980. in Canada. I. Lepidoptera. II. Diptera. III. Coleop- tera. Mem. Entomo!. Soc. Can. 78. 124 pp. Note; NRCC No. 21329. Received for publication 13 Butler, L. I., and L. M. McDonough. 1979. Insect May 1983; accepted 29 August 1983.