Rubber Septum Dispensers Research Articles

Identification of the Sex Pheromone of the Asparagus Moth, Parahypopta Caestrum (Lepidoptera, Cossidae)

Chemical, electrophysiological, and field trapping experiments were carried out to identify the female-produced sex pheromone of the asparagus moth, Parahypopta caestrum, a very serious pests of asparagus cultivations in southern Europe. Gas chromatography coupled with mass spectrometry and electroantennogram detection (GC-MS-EAD) analysis of hexane and solid-phase microextraction (SPME) extracts of sex pheromone glands of calling females consistently detected four compounds eliciting EAG responses in male moth antennae. According to their GC retention times, mass spectra, and comparative EAG analyses with reference standards, these EAD-active compounds were identified as (Z)-9-tetradecenol (Z9-14:OH), (Z)-5-tetradecenyl acetate (Z5-14:Ac), (Z)-7-tetradecenyl acetate (Z7-14:Ac), and (Z)-9-tetradecenyl acetate (Z9-14:Ac), respectively. In the SPME extracts from the head-space of individual abdominal tips, Z9-14:Ac, Z5-14:Ac, Z7-14:Ac, and Z9:14 OH were detected in the ratio of 82:9:5:4. In EAG dose-response experiments, Z9-14:Ac was the strongest antennal stimulant at different doses tested. In field trapping experiments, Z9-14:Ac, Z7-14:Ac, and Z5-14:Ac proven to be essential for male attraction and a their 85:5:10 blend loaded onto green rubber septum dispensers was significantly more effective than single-, two-, and any other three-component blend of these compounds. The addition of Z9-14:OH to the optimal blend resulted in a significant reduction of male catches. The attractive blend here identified allowed for an effective and accurate monitoring of P. caestrum flight activity in southern Italy.

Performance of polyethylene tubes as pheromone lures for the sorghum plant bug, Stenotus rubrovittatus (Hemiptera: Heteroptera: Miridae)

The sorghum plant bug, Stenotus rubrovittatus (Matsumura) (Hemiptera: Heteroptera: Miridae), is a pest that infests rice in many regions of Japan. Three sex attractant pheromone components—hexyl butyrate, (E)-2-hexenyl butyrate, and (E)-4-oxo-2-hexenal—were identified in S. rubrovittatus. Because the longevity of a synthetic rubber septum dispenser is not sufficient for it to be an effective S. rubrovittatus pheromone lure, the performances of an alternative pheromone dispenser—a polyethylene tube—was examined. Hexyl butyrate and (E)-2-hexenyl butyrate are essential components of S. rubrovittatus male attraction, and the application of (E)-4-oxo-2-hexenal strongly enhanced the attractiveness of such “tube-type” lures. A 5:1:10 blend of hexyl butyrate, (E)-2-hexenyl butyrate, and (E)-4-oxo-2-hexenal was found to be the best blend ratio for male attraction in the tube-type lures. Tube-type lures attracted more males than rubber lures. Furthermore, the attractiveness of the tube-type lures was maintained for more than 28 days in the field. These results suggest that tube-type lures made of polyethylene plastic are suitable for monitoring S. rubrovittatus in fields.

Sex Pheromone Dispenser Type and Trap Design Affect Capture of Dogwood Borer

Using a ternary sex pheromone blend [86:6:6 v:v:v (Z,Z)-3,13-octadecadienyl acetate: (E,Z)-2,13-octadecadienyl acetate: (Z,E)-3,13-octadecadienyl acetate], we tested the effect of dispenser type and trap design for capture of dogwood borer (DWB), Synanthedon scitula Harris (Lepidoptera: Sesiidae) in apple orchards in West Virginia, Virginia, and North Carolina. Wing-style sticky traps baited with polyethylene vial pheromone dispensers captured more male DWB over the first 2 months than traps baited with rubber septum pheromone dispensers. However, catches in vial-baited traps decreased considerably after the first 2 months, possibly due to the antagonistic effect of 3,5-di-tert-butyl-4-hydroxy acetophenone that diffused from the polyethylene vials. By contrast, traps baited with rubber septum dispensers captured DWB males for at least 6 months; over the last four months of the flight season, catches in traps baited with a rubber septum were greater than those in traps baited with a vial dispenser. Therefore, the rubber septum dispenser is recommended for season-long monitoring of DWB. A release-rate study, using laboratory and field-aged dispensers, demonstrated that desorption of DWB sex pheromone from polyethylene vial or rubber septum dispensers followed first order kinetics, with half-lives of 1.6 and 10.7 months, respectively. Several trap designs, including wing-and delta-style sticky traps, and white and green "bucket-style" traps, baited with rubber septum dispensers were compared in commercial apple orchards for catch of DWB. Bucket traps caught more moths when moth populations were high, because the sticky surfaces of the 1C and delta traps likely became saturated. However, among the commercially available traps tested, no particular design gave consistently higher catches. Further work is needed to explore capture mechanisms and maintenance needs of different trap types.

(3Z,6Z,9Z,12Z,15Z)‐pentacosapentaene and (9Z,11E)‐tetradecadienyl acetate: sex pheromone of the spruce coneworm Dioryctria abietella (Lepidoptera: Pyralidae)

AbstractThe spruce coneworm, Dioryctria abietella Denis & Schiffermüller (Lepidoptera: Pyralidae), is a major pest in spruce seed orchards in Europe. Initial work on its pheromone ecology reported significant attraction of males to (9Z,11E)‐tetradecadienyl acetate (9Z,11E‐14:OAc), but this compound appeared to be a very weak attractant in field trials. In this study, we show that a second female‐produced compound, the polyunsaturated long‐chain hydrocarbon (3Z,6Z,9Z,12Z,15Z)‐pentacosapentaene (C25 pentaene), is a strong synergist to 9Z,11E‐14:OAc, and that both compounds are needed for significant attraction of males. In field‐trapping experiments, the highest catches were obtained with high amounts of pentaene added to the acetate (acetate:pentaene ratio from 1 : 10 to 1 : 30) and the highest doses (1–3 mg per rubber septum dispenser) were the most attractive. Two potential behavioural synergists, (Z)‐9‐tetradecenyl acetate and (9Z,12E)‐tetradecadienyl acetate, turned out to be behavioural antagonists and both reduced trap catch of D. abietella in a dose‐dependent way when added individually to the binary blend. The recent discovery of the C25 pentaene as a pheromone component of D. abietella, as well as of three North American congeners, suggests that the use of a mixture of so‐called type I and type II pheromone compounds is a widespread motif of sexual communication within the genus. The identification of a highly attractive sex pheromone will help in developing efficient strategies for monitoring and control of D. abietella populations in European spruce seed orchards.

MONITORING OF CHESTNUT MOTHS BY INTRA- AND INTERSPECIFIC SEMIOCHEMICALS

The effectiveness of synthetic sex attractants and a compound of plant origin, ethyl-(E,Z)-2,4-decadienoate, to monitor the flight activity of the chestnut moths Pammene fasciana, Cydia fagiglandana and Cydia splendana in southern Italy was evaluated. Field trapping tests were carried out from the end of June to the end of September during 2006 and 2007 in two chestnut orchards. In both years, pagoda traps were baited with rubber septum dispensers loaded with 1 mg of synthetic sex attractants of one of the three species or with 40 mg of ethyl-(E,Z)-2,4-decadienoate. In 2007, Pherocon IIB traps baited with the sex attractant blend of P. fasciana or ethyl-(E,Z)-2,4-decadienoate were also used. In both years, pheromone traps captured a high number of P. fasciana males, a fair number of C. fagiglandana males and no male of C. splendana. The pattern of weekly catches by pheromone traps showed a peak of flight activity between the second and third decade of July and a smaller one at the end of August for P. fasciana and between the second and third decade of August for C. fagiglandana, without substantial variations among trapping sites. Traps baited with ethyl-(E,Z)-2,4-decadienoate allowed for capturing conspicuous numbers of P. fasciana males and females and the pattern of flight activity as monitored by this compound was similar to that by the sex pheromone blend. Failure to capture C. splendana males could be due to a lack of attractiveness of the sex attractant blend used but also to a low presence of this pest, as suggested by visual fruit samplings carried out at the harvest. Captures of female chestnut moths by ethyl-(E,Z)-2,4-decadienoate are of practical interest since they could be used for a more rational application of control means.

Efficacy of the pear ester as a monitoring tool for codling moth Cydia pomonella (Lepidoptera: Tortricidae) in New Zealand apple orchards

The behavioural response of both sexes of codling moth, Cydia pomonella to the pear-derived kairomone (ethyl (2E,4Z)-2,4-decadienoate), codling moth sex pheromone (E,E-8,10-dodecadien-1-ol), and sex pheromone combined with the pear derived kairomone loaded into red rubber septum were investigated in trapping experiments in New Zealand apple orchards. A range of 0.01-10.0 mg of pheromone loading in rubber septum dispensers was tested and the highest catch of males was in traps baited with 1.0 mg. No dose response in trap catch of males was seen in traps baited with different amounts of pear-derived kairomone (0.01-10.0 mg). The number of females caught was significantly affected by the amount of pear derived kairomone used to bait traps, with the highest catch obtained at 10 mg loading. The attractiveness of sex pheromone was not enhanced by the addition of the kairomone either when used in the same bait or in a separate bait. The mean number of males captured in traps was reduced by 44% when the pheromone and kairomone were combined at ratio of 1:1 (0.1 mg pheromone: 0.1 mg kairomone) in separate sources. Kairomone baited traps showed some potential for monitoring the flight activity of female C. pomonella in apple orchards in two locations (Canterbury and Hawke's Bay). However, the number of male moths caught was low as compared to the number of male moths caught in pheromone-baited traps, and therefore the sex pheromone should continue to be used for monitoring male activity.

Optimization of pheromone lure and trap design for monitoring the fir coneworm, Dioryctria abietivorella

AbstractThe major components of the sex pheromone of Dioryctria abietivorella (Groté) (Lepidoptera: Pyralidae) were recently identified as (9Z,11E)‐tetradecadien‐1‐yl acetate (9Z,11E‐14:Ac) and a polyunsaturated, long‐chain hydrocarbon (3Z,6Z,9Z,12Z,15Z)‐pentacosapentaene (C25 pentaene). The optimal ratio of these components and the role of potential minor components were not fully determined in the initial short report on the pheromone's identification. We tested different ratios of the two major components loaded into grey halobutyl rubber septum dispensers, placed in sticky traps deployed in conifer breeding arboreta. The optimal ratio of the two components was 200 µg 9Z,11E‐14:Ac to 2000 µg C25 pentaene. (Z)‐9‐Tetradecen‐1‐yl acetate, which had been identified previously in female pheromone gland extracts, and five other potential minor pheromone components, were tested individually as additions to the optimized two‐component lure blend. None of the ternary blends were more attractive than the optimized two‐component blend, at the ratios tested. Two lure adjuvants, a UV stabilizer (Sumisorb 300) and the antioxidant butylated hydroxytoluene, added individually or together, did not affect the attractiveness of the optimized lure blend. The Pherotech diamond sticky trap baited with the optimized lure blend was the most effective trap design among eight types of sticky trap and a bucket style trap that were tested. Traps baited with synthetic lures were as attractive as traps baited with virgin female moths. The optimized two‐component lure blend in the Pherotech diamond trap is recommended for monitoring fir coneworm infestations. The availability of an effective synthetic pheromone opens the possibility for control tactics using mating disruption or attract‐and‐kill techniques.

Female sex pheromone of Sesamia cretica: chemical and behavioural evidence for a three‐component blend

AbstractThe female‐produced sex pheromone of the Durra stem borer, Sesamia cretica (Lederer) (Lepidoptera: Noctuidae), had been previously characterized as a 75:25 blend of (Z)‐9‐tetradecenol (Z9‐14:OH) and (Z)‐9‐tetradecenyl acetate (Z9‐14:OAc) based on field trapping experiments. The low attraction of this blend in the field led us to further investigate the sex pheromone of this pest. Coupled gas chromatography with electroantennographic detection (GC‐EAD) analysis of female pheromone gland extracts consistently revealed three EAD‐active compounds. According to their GC retention times, mass spectra, and comparative EAG analyses with authentic standards, two of these compounds were found to be the previously reported components Z9‐14:OH and Z9‐14:OAc, whereas a third compound was identified as (Z)‐11‐hexadecenol (Z11‐16:OH). In wind tunnel experiments, the highest male responses were elicited by ratios of Z9‐14:OH, Z9‐14:OAc, and Z11‐16:OH, ranging from 90:1:9 to 90:5:5. In field tests, the 90:1:9 ratio of the blend loaded onto rubber septum dispensers was significantly more effective than single‐component, two‐component, and any other ratio of the three‐component blend. The greater effectiveness of this blend resulted in a more accurate detection of S. cretica flight activity compared with the previously reported two‐component blend.

Interference with the mate‐finding communication system of the Chinese tortrix Cydia trasias (Lep., Olethreutidae) using synthetic sex pheromones

Abstract: Interference with the mate‐finding communication system of Cydia trasias (Meyrick) using sex pheromone dispensers (60% E8,E10‐dodecadienyl acetate and 40% E8,E10‐dodecadien‐1‐ol, 0.5 mg/dispenser) was investigated in three plots of the Chinese scholar‐tree, Sophora japonica L., in Beijing, China, in 2000. Treatments were evaluated by pheromone‐baited traps, caged virgin females, pupating and hibernating populations on tree trunks, and assessment of larval damage in petioles and seed pods. Six to eight natural rubber septum dispensers were placed in each tree at the pheromone‐treated plots at three separate periods: at the beginning of overwintering generation flight, the first‐ and the second‐generation flights. Application of pheromone dispensers reduced the incidence of mating of virgin females in treated plots relative to those in the control plots. Pheromone‐baited trap catches were lowered on average by 96%, suggesting a high level of disruption. Average larval density on tree trunks was significantly lower in the pheromone‐treated plots than in the untreated control plots. The mean percentage of Chinese scholar‐tree petioles infested with first‐ and second‐generation larvae, and seed pods infested with third‐generation larvae was significantly greater in untreated control plots than in pheromone‐treatment plots. These results suggest that disruption of pheromone‐based communication in C. trasias is prospective, with synthetic sex pheromone on trees in urban environments.

Pheromone Trapping ofSynanthedon tipuliformis(Lepidoptera: Sesiidae) in Washington Red Currants

Abstract Collections of volatiles, ovipositor extracts, and electoantennography showed the sex pheromone of female currant borer moths, Synanthedon tipuliformis (Clerck), from Washington to be a 2-component (100:3) blend of (E,Z) -2, 13-octadecadienyl acetate and (E,Z) -3, 13-octadecadienyl acetate. Pheromone-baited sticky traps (rubber septa dispensers) captured male S. tipuliformis at one abandoned and two commercial red currant sites (one treated with insecticide, one untreated) in south central Washington from 19 May to 16 August 2000. Peak catches occurred during late May and June with up to 200–300 moths/trap/wk. Lowest numbers (overall mean: 4.8 ± 0.9 moths/trap/visit) were recorded at the insecticide-treated site and largest numbers (39.6 ± 5.5 moths/trap/visit) occurred at the untreated, commercial site.

Relationship between sex pheromone elicited behaviour and response of single olfactory receptor neurones in a wind tunnel

Responses from pheromone-specific receptor neurones in male Agrotis segetum (Denis & Schiffermuller) (Lepidoptera: Noctuidae) were recorded in a laboratory wind tunnel. Stimuli were: (1) rubber septum dispensers loaded with single components or a four-component pheromone blend, (2) excised glands from female A. segetum, (3) constrained A. segetum females with extruded glands. Dose-response curves for three neurone-types with different specificity were established. The neurones were specifically tuned to respond to either one of the two pheromone components (Z)-5-decenyl acetate and (Z)-7-dodecenyl acetate, or to the behavioural antagonist (Z)-5-decenol. In parallel, a behavioural dose-response curve with males flying upwind to a four-component pheromone blend was established. There was a clear correlation between behavioural arrestment of upwind flight and maximum spiking activity in ZS-10:OAc-specific neurones. The pheromone release rates of individual females and synthetic dispensers were compared. A load of 50-200 ng of ZS-10:OAc on a rubber septum elicited approximately the same neural response as one female gland.

Field Tests of Synthetic Sex Pheromone of the Apple Leafminer Moth, Phyllonorycter ringoniella

The apple leafminer moth, Phyllonorycter ringoniella, is becoming a more serious insect pest on apple trees with four to five generations a year in Korea. In order to devise a forecasting method for more accurate estimation of their numbers and development timing, the sex attractant was studied. Various ratios, from 10:0 to 0:10, of the two components, (Z)-10-tetradecenyl acetate (Z10–14:Ac) and (E,Z)-4,10-tetradecadienyl acetate (E4,Z10–14:Ac), identified from the sex pheromone gland (Jung and Boo, 1997), were tested for attractivity in terms of behavioral response (taxis, approach, and landing) against P. ringoniella males in a wind tunnel. The lure with Z10–14:Ac/E4,Z10–14:Ac in a ratio of 4:6 elicited the highest response in two (taxis and approach) measurement categories. For eliciting landing behavior, the two blends of 5:5 and 4:6 were best. The single component, Z10–14:Ac, elicited taxis behavior, but a combination of two chemicals was needed for eliciting all three behaviors. In the field, male attraction to various lure mixtures in Pherocon IC traps was usually greater than attraction to virgin females. The best field activity was in the lure baited with a 4:6 ratio of Z10–14:Ac and E4,Z10–14:Ac. Similar results were obtained from tests conducted in a net house. This optimum ratio for attracting P. ringoniella males in Korea is different from those reported in Japan (10:3) or China (7:3 to 6:4). The isomer E10–14:Ac neither improved nor depressed the number of catches when added at up to 10% of the total mixture to lures of the two components in the 4:6 ratio. The attractivity of the lures increased with higher amounts of the pheromones, up to 10 μg in the wind-tunnel experiment and 5 mg in the apple orchard. The number of males captured was not significantly different among traps installed at 0.3, 1.5, or 2 m above the ground, or among wing, delta, or water traps. A rubber septum dispenser impregnated with 1 mg of the 4:6 mixture maintained its field attractivity for up to eight weeks.

Effect of Bait on Capture of Heliothis virescens Males (Lepidoptera: Noctuidae) in Two Different Traps

Identification of pheromone components for the tobacco budworm, Heliothis virescens (F.), (Roelofs et al. 1974, Tumlinson et al. 1975, Klun et al. 1980) in conjunction with the development of the wire cone trap (Hartstack et al. 1979, 1980) have presented opportunities for the development of a pheromone-based trapping system. In insect pest management programs, a durable, inexpensive, easily serviced, and sensitive trap is desirable. The high cost and bulk of the wire cone trap essentially eliminates its use for all but experimental purposes. A commercial version of the wire cone trap, the Scentry Heliothis cone (Scentry, Inc., Buckeye, AZ), is available, but it also is unwieldy and expensive. The possibility of using a different trap, the inexpensive and easy to handle bucket trap, was investigated in this study. An important aspect of H. virescens trapping is the development of a suitable pheromone dispenser. For H. virescens, initial evaluations of a laminated plastic dispenser were made by Hendricks et al. (1977); later evaluations were reported by Hartstack et al. (1980) and Zvirgzdins & Henneberry (1983). Comparisons of laminated plastic and rubber septum dispensers under desert conditions were reported by Flint et al. (1979). They found that the rubber septa were very effective dispensers and lasted for a longer period of time than laminated plastic dispensers. Polyvinyl-chloride (PVC) substrates for dispensing the pheromone of H. virescens have been developed and evaluated by Hendricks (1982, 1983) and Hendricks et al. (1987) and were reported to be more effective than other dispensers tested. Further evaluations of the Ramaswamy, PVC and Flint dispensers were conducted by Lopez et al. (1987). The objective of the present study was to evaluate the effectiveness of cone and bucket traps for capturing H. virescens males when combined with different pheromone dispensing systems. Therefore, the commonly used bait dispensers for H. virescens-the laminated plastic Hercon dispensers (Hercon Laboratories, Inc., South Plainfield, NJ) and the Biolure membrane dispenser (Consep Membranes, Inc., Bend, OR)-were compared with other available dispensers in cone and bucket traps. Scentry cone traps (test 1) and International Pheromones bucket traps (test 2) (Great Lakes IPM, Vestaburg, MI) were positioned 100 m apart and 1 m above ground level in a N-S direction in fallowed fields near Gainesville, FL. The tests were conducted in late September-early October 1989 during a period of relatively low H. virescens moth population. The test area was heavily populated with Desmodium tortuosum (Swartz) de Candolle, an important weed host for H. virescens (Jackson & Mitchell 1984). The traps were baited with different commercial lures (BioLure and Hercon 2or 7-components) or septa (Israeli-Maavit, Tel Aviv, Israel; A. H. Thomas No. 1780J07, Swedesboro, NJ; Wheaton no. 224091, Millville, NJ) prepared locally by Laboratory personnel. Load ratios for the experimental lures (1 mg total/septum) were: tetradecenal, 3%; (Z)-9-tetradecenal, 5%; hexadecanal, 8%; (Z)-7-hexadecenal, 1%; (Z)-9-hexadecenal, 1%; and (Z)-11-hexadecenal, 82%. All synthetic compounds used on the septa formulations were obtained from commercial sources and were analyzed on both capillary and GC

Selection of pheromone trap and attractant dispenser load to monitor black army cutworm,Actebia fennica

Catch rates of black army cutworm moths,Actebia fennica (Lepidoptera: Noctuidae), were determined for different types of traps and different dispenser loads of sex attractant. Of the five traps tested, highest catch (35 males/per night) was obtained with Uni-Traps, whereas Pherocon 1CP, Delta and Hara traps rapidly became saturated at 9, 6, and 11 males/per night, respectively. Multi-Pher traps, like the Uni-Traps, have a covered vertical cone with a large collecting bucket but only catch about 1/3 of the number of moths (9 males/per night) as the Uni-Traps, thus reducing potential saturation. Red rubber septa loaded with 500 μg of attractant blend gave a consistent catch for at least 60 days; 1000 and 2000 μg loadings lasted for a minimum of 90 days. Polyvinylchloride and red rubber septa dispensers containing 100 μg of attractant had similar catch rates, which decreased rapidly with age. Based on these trap and lure-loading experiments, Multi-Pher traps baited with 1000 μg of attractant in a red rubber septum were selected for future calibration studies between catch density and population fluctuations on susceptible sites. Two years of monitoring results also are reported.

Identification of sex pheromone components of darksided cutworm,Euxoa messoria, and modification of sex attractant blend for adult males

Eleven "pheromone-like" compounds were identified in excised abdomen tip extracts of calling adult females of darksided cutworm,Euxoa messoria (Harris). The essential pheromone components were (Z)-7- and (Z)-11-hexadecenyl acetates in a ratio of 1∶40, which agreed with an attractant blend developed empirically by field testing the attractancies of synthetic blends. The pheromone component, (Z)-11-hexadecenol, improved the attraction of darksided cutworm males whereas the components (Z)-9-tetradecenyl acetate and (Z)-7-dodecenyl acetate inhibited their attraction. The other "pheromone-like" compounds identified in the female extracts had no obvious effect on the attraction of darksided cutworm males. Three compounds that functioned as parapheromones when substituted for (Z)-7-hexadecenyl acetate in the two-component blend were (Z)-7-pentadecenyl, (Z)-7-tetradecenyl, and (Z)-7-tridecenyl acetates. (Z)-11-hexadecenal was not detected in the female extracts, but it had a synergistic effect on the attraction of darksided cutworm moths and inhibited the attraction of male moths of a nontarget species,Helotropha reniformis (Grote). As a trap bait for monitoring purposes, we recommend a four-component blend of (Z)-7-hexadecenyl acetate, (Z)-11-hexadecenyl acetate, (Z)-11-hexadecenol, and (Z)-11-hexadecenal at 12.5, 500, 1, and 10 μg/red rubber septum dispenser containing 5 μg of antioxidant 2,6-tert-butyl-4-methyl phenol. This blend is effective under field conditions for at least six weeks.

Pheromone Trapping System for the Velvetbean Caterpillar (Lepidoptera: Noctuidae)1

A system was developed for monitoring adult populations of the velvetbean caterpillar (VBC), Anticarsia gemmatalis Hübner, using pheromone-baited traps. A bucket-style trap that contained a small piece of insecticide strip to kill captured moths was the most effective of two trap designs evaluated. Bucket traps baited with rubber septa lures and impregnated with a total of 0.5 mg VBC pheromone [a 40:60 blend of (Z, Z, Z)-3,6,9-eicosatriene and (Z, Z, Z)-3,6,9-heneicosatriene] were most effective when positioned just above the canopy of the soybean crop. There was a positive relationship between quantity of pheromone loaded on rubber septa dispensers (range, 0.02–0.5 mg each) and number of male VBC moths captured in bucket traps; peak moth captures were recorded at the 0.5-mg load. Conversely, the number of VBC caught in traps baited with pheromone dosages ranging from 0.5 to 10 mg pheromone per septum declined rapidly from the optimum dosage (0.5 mg). Decline in moth captures at the higher dosage levels apparently was due to too high a release rate of one or both of the pheromone components. A method also is described for rapidly estimating moth captures in bucket traps.

Field Evaluation of Commercial Pheromone Formulations and Traps Using a More Effective Sex Pheromone Blend for the Fall Armyworm (Lepidoptera: Noctuidae)1

A four-component blend of the recently identified sex pheromone for the fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith), was formulated in different commercial dispensing systems (rubber septa, microtubules, polyvials, plastic laminates) and fieldtested against wild moths at Gainesville, Fla., and in Guadeloupe, French West Indies. A pheromone blend that consisted of (percentage by weight) (Z)-7-dodecen-l-ol acetate (Z7-12:AC), (0.45%), (Z)-9-dodecen-l-ol acetate (0.25%), (Z)-9-tetradecen-l-ol acetate (Z9-14:AC) (81.61%), and (Z)-ll-hexadecen-l-ol acetate (17.69%) was highly effective as a lure for the FAW when formulated at 2 mg total pheromone blend in rubber septa, polyvials, or microtubules. Rubber septa dispensers that contained the four-component pheromone blend (2 mg) remained highly attractive to male FAW for up to 2 weeks in the field. The Hartstack 75–50 cm screenwire cone trap and the International Pheromones (IP) moth trap were both effective tools for capturing large numbers of FAW males. The IP moth trap baited with the four-component pheromone blend (2 mg) on rubber septa dispensers has been used to capture FAW moths over a wide geographic area ranging from French Guiana to Canada, thus demonstrating the usefulness of this combination for survey purposes. A two-component pheromone blend consisting (percentage by weight) of 0.58% Z7-12: AC and 99.42% Z9-14: AC on rubber septa dispensers (2 mg total blend) also was highly effective as a lure for FAW males. Although it was not tested over the same range as the four-component blend, data presented here and elsewhere suggest that the two-component blend could be substituted for the four-component pheromone blend for survey purposes.

A four-component pheromone blend for optimum attraction of redbacked cutworm males,Euxoa ochrogaster (Guen�e)

Four acetates,Z-5-decenyl acetate,Z-5-,Z-7-, andZ-9-dodecenyl acetates, in microgram ratios of 1∶200∶2∶1 or 1∶200∶6∶2 were excellent, specific sex pheromone blends for capturing male redbacked cutworm moths in cone traps. Blends in ratios of 1∶200∶2∶1 and 2∶200∶2∶1 at 1000 μg/ rubber septum dispenser remained highly effective for 6 weeks under field conditions. The essential minor components,Z-5-decenyl,Z-7-, andZ-9-dodecenyl acetates, became inhibitory at concentrations of about 10% in the blends, and this may be an important general phenomenon in lepidopteran pheromones. Blends involving a parapheromone,Z-5-undecenyl acetate, withZ-5-,Z-7-, andZ-9-dodecenyl acetate, in microgram ratios of 8∶200∶2∶1 or 20∶200∶6∶2 were also excellent specific attractants for this species. TheZ-8-dodecenyl acetate had no obvious effect on the attraction of the redbacked cutworm males.