Journal of Chemical Ecology, Vol. 8, No. 2, 1982

C O M P O U N D S M O D I F Y I N G THE ACTIVITY OF TWO SEX A T T R A C T A N T S FOR MALES OF THE PEA MOTH, Cydia nigricana (F.)

A.R. GREENWAY,

C. W A L L , a n d J . N . P E R R Y

Rothamsted Experimental Station, Harpenden, Herts. AL5 2JQ, U.K. (Received April 27, 1981; revised June 29, 1981)

Abstraet--(E)-10-Dodecen-l-yl acetate (E10-12:Ac) and (E,E)-8,10-dodecadien-l-yl acetate (E,E8,10-12:Ac) are sex attractants for males of the pea moth, Cydia nigricana (F.). Thirty-two structurally related compounds with chain lengths of 9-14 carbon atoms were exposed with E10-12:Ac or E, E8,10-12:Ac in traps in the field to investigate their influence on the activity of the attractants. Only alchols and acetates unsaturated at C-8, -9, or -10 greatly influenced moth captures. (Z) and (E)-8-dodecen-l-ol were weak synergists for E10-12:Ac but no synergists for E, E8,10-12:Ac were found. (Z) and (E)-8-d odecen- l-yl acetate and (E, E)-8,10-d odecadien- 1-ol inhibited both E10-12:Ac and E, E8,10-12:Ac while (E)-10-dodecen-l-ol, 10-dodecyn-l-ol, (Z) and (E)-9-dodecen-l-yl acetate, (Z)-10-dodecen-l-yl acetate, and undecyl acetate inhibited only the former attractant. Key Words--Pea moth, Cydia nigrieana (F.), Lepidoptera, Olethreutidae, sex attractant, (E)-10-dodecen-l-yl acetate, (E,E)-8,10-dodecadien-l-yl acetate, inhibitor, synergist, lure.

INTRODUCTION M a l e s o f the pea m o t h , Cydia nigricana (F.) ( L e p i d o p t e r a : T o r t r i c i d a e ) , are a t t r a c t e d b y ( E , E ) - 8 , 1 0 - d o d e c a d i e n - l - o l (E, E 8 , 1 0 - 1 2 : O H ) (Lewis et al., 1975), ( E ) - 1 0 - d o d e c e n - l - y l a c e t a t e ( E 1 0 - 1 2 : A c ) a n d ( E , E ) - 8 , 1 0 - d o d e c a d i e n 1-yl acetate (E, E 8 , 1 0 - 1 2 : A c ) ( W a l l et al., 1976), E, E 8 , 1 0 - 1 2 : O H is the sex p h e r o m o n e of the closely r e l a t e d c o d l i n g m o t h , Cydia p o m o n e l l a (L.) ( R o e l o f s et al., 1971; B e r o z a et al., 1974), a n d is a w e a k a t t r a c t a n t for pea m o t h ( W a l l et al., 1976). T h e r e l a t e d acetate, E, E 8 , 1 0 - 1 2 : A c , has b e e n i d e n t i f i e d as 397 0098-0331 / 82/0200-0397503.00[0 9 1982 Plenum Publishing Corporation

398

GREENWAY ET AL.

the pea moth female sex pheromone and is the most potent attractant when fresh, but it is rapidly degraded to an inhibitor (Greenway and Wall, 1980, 1981). El0-12:Ac, while not as attractive as E, E8,10-12:Ac, can be formulated as lures which are stable for several months in the field and suitable for practical monitoring of pea moth populations (Wall and Greenway, 1981). In field tests, Wall et al. (1976) showed that simultaneous evaporation of certain related compounds could either synergize or inhibit the attractiveness of E, E8,10-12: OH for pea moth, so it was of interest to investigate the effects of such compounds on the activity of the two more potent attractants. Such phenomena are well known in other moth species, for example in Argyrotaenia velutinana (Walker) (Roelofs and Comeau, 1971), Adoxophyes orana (Fischer von Roslerstamm) (Voerman et al., 1974), and Ostrinia nubilalis (Hubner) (Klun and Robinson, 1972) and, in A. orana, pheromone communication between the sexes could be disrupted by inhibitors (Minks et at., 1976). Synergists might be valuable for mass trapping or in population monitoring, especially to increase trap catches in sparse populations and to enhance the competitiveness of lures in dense populations. The structure of behaviorally active compounds, whether attractants, synergists, or inhibitors, is significant in the wider context of the mechanisms underlying sex-pheromone perception in insects. They provide the opportunity to investigate these mechanisms at both the electrophysiological and behavioral levels. In fact, E, E8,10-12:OH can act both as an attractant, when on its own, and as an inhibitor of both E10-12:Ac and E, E8,10-12:Ac (Wall et al., 1976), and an explanation for this effect would be of considerable interest. It is also useful to know whether any compounds which might occur as impurities in the synthetic attractants modify their activity so that appropriate synthetic routes can be chosen and specific impurities removed if necessary.

M E T H O D S AND MATERIALS

Chemical Formulation. Attractant lures were prepared by applying E 10-

12:Ac (10 3/.tg) or E, E8,10-12:Ac (102/~g) in redistilled dichloromethane (t02 tzl) to rubber serum stoppers (Greenway and Wall, 1981). Test chemicals (commercial or synthesized here) were purified to at least 98% and formulated in the same way in separate rubber stoppers (for amounts see Tables 1 and 2). The solvent was allowed to evaporate while the attractant or test chemical was absorbed, and the dosed stoppers were then stored in screw-cap glass bottles in the dark at - 1 5 ~ less than 14 days before use. Field Tests. Experiments were done on farms in east and southeast England, in pea fields or in wheat fields after peas. Triangular aluminum traps (Lewis and Macaulay, 1976) with removable inserts coated with Tangletrap

399

ATTRACTANTS OF PEA MOTH

(The Tanglefoot Company, Grand Rapids, Michigan) were placed on stands at crop height in wheat or on the ground in peas. Each trap contained an attractant lure, either alone or with a test chemical; the rubber stoppers were suspended within the traps. In the earlier experiments (Table 1), test chemicals (up to 9 per experiment) at a 1:1 ratio with either E10-12:Ac or E, E8,1012:Ac were evaluated for their effects upon the activity of the attractants. Chemicals which showed a large modifying effect were tested further at lower doses with ratios of 1:10 and 1:100 to the appropriate attractant (Table 2). Traps were examined regularly, usually each morning before the flight period; captured moths were counted and removed, and the sticky inserts replaced if necessary. In the earlier experiments (Table 1), traps were set out in rows (blocks) and treatments assigned to traps randomly within each block; the distance between traps within blocks was never less than 20 m. Treatments involving attractants alone were replicated thrice within each block. At least three blocks were used, either simultaneously at different positions in the same field or sequentially at the same position. In later experiments (Table 2), Latinsquare designs (Perry et al., 1980) were used after interactions between attractant traps for pea moth had been shown to be significant (Wall and Perry 1978). This involved allocating each of the t treatments to one of t sites, usually at least 150 m apart within a locality. After each trapping period (usually one or two days), the treatments were reallocated to sites so that after t trapping periods each treatment had occupied each site once; standard randomization procedures were used. Transformation of the data to natural logarithms aided additivity and equalized error variance. An analysis of variance of the transformed counts was done for each experiment. Since the effects of individual chemicals were usually tested in experiments with several other compounds, some values within the same column of Tables 1 and 2 are not statistically independent. RESULTS AND DISCUSSION

The results of experiments in which all of the test chemicals were evaluated at a 1:1 ratio with either E10-12:Ac or E, E8,10-12:Ac were expressed as the mean logarithmically transformed catch per trap for "attractant + test chemical" minus the corresponding value for the attractant alone (Table 1). Compounds were evaluated either because they showed substantial EAG activity (Wall et al., 1976), were structurally related to active compounds, or were potential impurities in the synthetic attractants. Some of the chemicals (Nos. 4, 7-11, 13, 22-26, and 28) had already been tested in traps on their own without any evidence of attractive properties (Wall et al., 1976), and of those tested alone in these experiments (12, 16, 17, 19-21, 27, 30-32) only (E,E)-8, 10-dodccadienal (32), attracted moths.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Test Chemical

9 : OH 10 :OH 11 : OH 12 : OH 13 :OH 14 :OH 10-11 :OH Z8-12:OH E8-12:OH Z9-12 :OH E9-12 :OH Z10-12 :OH E l 0 - 1 2 :OH 10YNE-12 : OH E, E8,10-12 :OH 9 :Ac 10:Ae 11 :Ac 12 :Ac 13 :Ac 14 :Ac 10-11 :Ac Z8-12:Ac E8-12:Ac Z9-12:Ac

Abbreviation

-3.376 -1.667 -2.683

-0.401 -0.352 -0.286 0.180

-0. 716

0.336 -0.090

-1.073 -0. 776 -2.604

-0.071 0.120 0.350

0.401 0.562

-0.596 -0.447 - 0.078 0.205 -0.002 -0.276 -0.104

E l 0 - 1 2 : Ac

-0.594

-2.508 -2.874

0.364 0.357 0.350 0.385 0.062 0.352

-3.032

-0.078 -0.288 0.389 -0.553 0.371 0.626 0.023

- 0.097

E, E 8 , 1 0 - 1 2 :Ac

Attractancy a with

ATTRACTANCY OF MALE C. n i g r i c a n a TO TRAPS CONTAINING E 1 0 - 1 2 : A c OR E, E 8 , 1 0 - 1 2 : A c AND AN EQUAL AMOUNT OF TEST CHEMICAL

Nonanol Decanol Undecanol Dodecanol Tfidecanol Tetradecanol 10-Undecen-l-ol (Z)-8-Dodeeen-l-ol (E)-8-Dodecen-l-ol (Z)-9-Dodecen-l-ol (E)-9-Dodecen-l-ol (Z)-10-Dodecen-l-ol (E)-10-Dodecen-l-ol 10-Dodecyn-l-ol (E,E)-8,10-Dodeeadien-l-ol Nonylacetate Decyl acetate Undecyl acetate Dodecyl acetate Tridecyl acetate Tetradecyl acetate 10-Undecen-l-yl acetate (Z)-8-Dodecen-l-yl acetate (E)-8-Dodecen-l-yl acetate (Z)-9-Dodecen-l-yl acetate

No. Name

TABLE 1.

:Z

4~

E9-12 : Ac Z10-12:Ac 11-12:Ac 10YNE-12:Ac Z10-12 :ALD E l 0 - 1 2 :ALD E, E8,10-12 :ALD -0.631

0.106 -0.543 0.048 -0.136 -0.419

-4.621

-0.279 -0.175 0.065 0.230 0.044 -0.249 0.099

aResults are expressed as the mean loge (catch per trap) for "attractant + test chemical" minus the corresponding value for the attractant. To convert such a difference, d, to a percentage increase in catch, p, due to test chemical, use: p = (e d - 1) • 100 (a negative value o f p indicates a percentage decrease in catch). Figures in italics indicate treatments (attractant + test chemical) whose catch was found to be significantly different at the 5% level from that of E10-12 :Ac (or E, E8,10-12 :Ac) after an analysis of variance. This implies that the corresponding chemicals are synergists (positive values) or inhibitors (negative values).

26 (E)-9-Dodecen-l-yl acetate 27 (Z)-10-Dodecen-l-yl acetate 28 ll-Dodecen-l-yl acetate 29 10-Dodecyn-l-yl acetate 30 (Z)-10-Dodecenal 31 (E)-10-Dodecenal 32 (E,E)-8,10-Dodecadienal

4~

Abbreviation

10YNE-12 :OH

11 :Ac

Z8-12:Ac

18

23

15 E, E8,10-12 : OH

14

13 E10-12 :OH

2 E8-12 :OH

1 Z8-12 :OH

No.

Test chemical

10 10 2 10 3

1

10 10 2 10 3 10 2 10 3

1

10 2 10 3 10 2 10 3 10 2 10 3 10 2 10 3

(ug)

Dose

2.121

3.716 3.376

1.930 0

3. 585

2.121 3. 629

3.150

3. 585

3.376

3.376

3. 933

Attractant alone

1.879

2.869

1.025

1.250 0

2.809

2.303

3.937

4.333

Attractant + test chemical

Mean log catch

E 1 0 - 1 2 : Ac (103 t~g)

0.348 0.351 0.216

0.268

0.572 0.348 0.281

0.268

0.216

0.216

0.141

SED

12 12 24

24

2 12 12

24

24

24

24

af

3.857

5. 655 3.336

3.850

3.336

3.857 5. 655 3.033

2.554

3.336

3.336

3.336

4. 741 O.829

2.904

3.429 3.910 0

2.577

3.963

3.049

3.258

Attractant alone

Mean log catch

0.097 0.167 0.414

0.414

0.097 0.167 0.552

0.458

0.414

0.414

0.414

SED

E, E 8 , 1 0 - 1 2 :Ac(102 #g)

Attractant + test chemical

Attractant

TABLE 2. MEAN LOG CATCHES OF MALE C. nigricana IN TRAPS C O N T A I N I N G E 1 0 - 1 2 : A c OR E , E 8 , 1 0 - 1 2 : A c AND D I F F E R E N T AMOUNTS OF TEST CHEMICAL a

6 6 24

24

6 6 8

24

24

24

24

af

t~

,


>

>

>

404

GREENWAY ET AL.

Table 2 shows the effects of various proportions (1 : 1, 1 : I0, or 1 : 100) of each of the test chemicals shown to be behaviorally active in Table 1 on the activity of the attractants. Some standard errors are relatively high, either due to a patchy distribution of responding insects (Taylor et al., 1978) or, more probably, as the result of trap interactions (Wall and Perry, 1978). The later experiments, using Latin-square designs to allow for these sources of variability, are more efficient so that differences between treatments are easier to detect (Perry et al., 1980). Table 1 shows that none of the compounds synergized E, ES,IO-12:Ac, although Z 8-12: OH and E8-12: OH (8 and 9) synergized E 10-12: Ac weakly. However, several compounds inhibited one or both attractants: E10-12:Ac was inhibited strongly (attractancy reduced by >80%) by E, E8,10-12:OH (15), Z8-12:Ac (23), E8-12:Ac (24), Z9-12:Ac (25), and Z10-12:Ac (27), while E10-12:OH (13), 10YNE-12:OH (14), l l : A c (18), and E9-12:Ac (26) were less effective inhibitors. E, E8,10-12:Ac was inhibited strongly by E, E8,10-12:OH (15), Z8-12:Ac (23), and E8-12:Ac (24). No other compounds, except E, E8,10-12:ALD (32, see above), had any obvious effects upon moth captures. These results are similar to those obtained with other Lepidoptera (Arn et al., 1974; Voerman et al., 1974) in that compounds which influence sex pheromone perception have common structural features. In some caes, e.g., A. velutinana (Roelofs and Comeau, 1971) and Pectinophora gossypiella (Saunders) (Beroza et al., 1971, McLaughlin et al., 1972), straightchain saturated compounds had synergistic or inhibitory properties and 12:Ac was later found to be a pheromone component in A. velutinana (Roelofs et at., 1975) but only 1 l:Ac (18) of the saturated compounds had any effect on pea moth behavior. Figure 1 shows the structural formulae of compounds with synergistic or inhibitory activities for comparison with those of the attractants, E 10-12:Ac and E, E8,10-12:Ac. Both polar (alcohol) and less polar (acetate) classes of compounds contain both attractants and inhibitors as well as inactive compounds and, in the range of saturated compounds studied (C9-C14) no peak of activity was obvious at an optimum carbon number (i.e., correlated with volatility). Thus, the effects are determined by factors other than simple physical properties. Preliminary attempts to correlate activity with the presence and position of functional groups has led to some tentative conclusions about the influence of these structural features: (1) All but one (11 :Ac, 18) of the behaviorally active compounds are unsaturated. (2) There are more active acetates than alcohols. (3) Olefinic unsaturation is generally more important than acetylenic. (4) The position of double bonds appears to be influential but not in a clear-cut way. (5) A terminal methyl group (absent in 10-1 I:OH and 10-I l:Ac) is-essential for activity. The complexity of the mode of action is also illustrated by comparing

ATTRACTANTS OF PEA MOTH

405

No.

Compound

28

E 1 0 - 1 2 = Ac E,E8,10-12 : AC

31

? ~

Syncrgists 1 2

Z8 - 12 = OH E 8 - 1 2 = OH

13 14

E l 0 - 12 : OH 10YNE- 12 :OH

~-~"~'.~'OH /v~.~v---~.-~H

Inhibitors

15

FIG.

E,E8,10-

12 ~

OH

18

11 : AC

23

Z8-12 = Ac

24

E8-12 : Ac

25

Z 9 - 1 2 , Ac

26 27

E9-12 : Ac Z10-12 : Ac

-~"'~-~"oH ~ " ~ o -

-

M H

~,. ~ < , - v ~ . / ~ o

1. Structures of E10-12:Ac and E,E8,10-12:Ac and their synergists and inhibitors.

these results (Table 1) with those of Wall et al. (1976) where E, E8,10-12:OH was the attractant, since this clearly shows that the behavioral activity of a given secondary compound depends on the attractant used. Z8-12:Ac (23) and E8-12:Ac (24) are two of the most powerful inhibitors (apart from E, E8,10-12:OH) of both E l 0 - 1 2 : A c and E, E8,10-12:Ac but had no effect on the attractiveness of E, E8,10-12:OH; similarly Z9-12:Ac (25) and E9-12:Ac (26) inhibited E10-12:Ac and E, E8,10-12:OH but did not affect E, E8,1012:Ac. Also, E10-12:OH (13) inhibited E10-12:Ac but synergized E, E8,1012:OH while E8-12:OH(9) had the opposite effect. Further field tests (Table 2) investigated the effects of lower ratios (1: I 0 and 1:100) of those compounds which were strong inhibitors at 1:1 with either E10-12:Ac or E, E8,10-12:Ac. E, E8,10-12:OH(15), Z8-12:Ac (23), Z 9 12:Ac(25), and ZI0-12:Ac(27) were very inhibitory at l:l with E10-12:Ac, and E8-12:Ac(24) was only slightly less effective (Table 1). At lower proportions (Table 2), E, E8,10-12:OH and Z9-12:Ac retained considerable inhibitory power but the others lost activity--Z10-12:Ac at l:10 and Z 8 12:Ac and E8-12:Ac at 1:100. Similarly, E, E8,10-12:OH, Z8-12:Ac, and E8-12:Ac, at 1:1 with E, E8,10-12:Ac nearly inhibited all moth captures and were also active at l:10, but only E, E8, I 0-12: OH was still inhibitory at l:100 and then only weakly (Table 2). E10-12:OH(13), IOYNE-12:OH(14), E, E8,10-12:OH(15), and Z1012:Ac(27) are possible impurities in the synthetic attractants as precursors or potential side products and, because of this, their inhibitory effects might be significant. However, in practice, they are either unlikely to occur in amounts

406

GREENWAY ET AL.

sufficient to affect the potency of the attractant, as for E 10-12:OH, 1 0 Y N E 12:OH, or Z10-12:Ac in E10-12:Ac, or are easily removed by chromatography in the case of E, E8,10-12:OH in E, E8,10-12:Ac. The mode of action of the inhibitors and other active compounds described in this paper is not clear. The weight of evidence in Lepidoptera favors the idea of different receptor cell types responding differently to various compounds (Priesner, 1980; Boekh, 1980) rather than competition for the same receptor site (Roelofs and Comeau, 1971) and this is consistent with the complexity of the relationships between structure and activity discussed above. However, it may be significant that E, E8,10-12:Ac, the most potent pea moth attractant, was influenced by fewer compounds than was E l 0 12:Ac; perhaps these two attractants interact with the same receptor site and the stronger stimulus from the former is less easily modified by the action of secondary compounds. In some respects, the sex pheromone receptor system in C. nigricana seems to contrast with that in C. pomonella. Males of the latter species possess a receptor cell type for E, E8,10-12:Ac which is a strong behavioral inhibitor (Hathaway et al., 1974, 1979; George et al., 1975), although not present in the female sex pheromone, in addition to one for E, E8,10-12:OH, the natural pheromone (Preiss and Priesner, 1978). Also, as noted above, 11 :Ac(18) is the only saturated inhibitor of a pea moth attractant while 11:OH inhibits the codling moth pheromone (Hathaway et al., 1974). Thus, certain compounds structurally related to the pea moth sex attractants can influence their attractancy in the field; most of these are unsaturated at C-8, -9, or-10 and elicit large EAG responses. The effects range from mild synergism to strong inhibition and provide chemicals with which to investigate further the action of such compounds at the electrophysiological and behavioral levels. Acknowledgments--We are grateful to many colleagues for technical assistance. We also thank the National Research Development Corporation for their interest; some of the data in this paper are included in U.K. patent 1,548,920.

REFERENCES ARN, H., SCHWARZ,C., LIMACttER, H., and MANI, E., 1974. Sex attractant inhibitors of the codling moth Laspeyresia pomonella L. Experientia 30:1142-1144. BEROZA, M., SXATEN, R.T., and BIERL, B.A. 1971. Tetradecyl acetate and related compounds as inhibitors of attraction of the pink bollworm m o t h for the sex lure hexalure. J. Econ. Entomol. 64:580-582. BEROZA, M., B1ERL, B.A., and MOFFITT, H.R. 1974. Sex pheromones: (E,E)-8,10-dodecadien1-ol in the codling moth. Science 183:89-90.

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BOEKH, J. 1980. Neural mechanisms of odour detection and odour discrimination in the insect olfactory pathway, pp. 367-374, in M. Sherwood (ed.). Insect Neurobiology and Pesticide Action. Proceedings of a conference of the Society of Chemical Industry, University of York, September 1979. GEORGE, D.A, McDoNOUGH, L.M., HATHAWAY,D.O., and MOFFITT, H.R. 1975. Inhibitors of sexual attraction of male codling moths. Environ. Entomol. 4:606-608. GREENWAY,A.R., and WALL,C. 1980. Rep. Rothamsted Exp. Sta. 1979, Pt. 1, 117. GREENWAY,A.R., and WALL,C. 198 l. Attractant lures for males of the pea moth, Cydia nigricana (F.), containing (E)-10-dodecen-l-yl acetate and (E,E)-8,10-dodecadien-l-yl acetate. J. Chem. Ecol. 7:563-573. HATHAWAY, D.O., McGOVERN, T.P., BEROZA, M., MOFFITT, H.R., MCDoNOUGH, L.M., and BUTT, B.A. 1974. An inhibitor of sexual attraction of male codling moths to a synthetic sex pheromone and virgin females in traps. Environ. Entomol. 3:522-524. HATHAWAY, D.O., McDoNOUGH, L.M., GEORGE, D.A., and MOFFITT, H.R. 1979. Antipheromone of the codling moth: potential for control by air permeation. Environ. Entomol. 8:318-321. KLUN, J.A., and ROBINSON,J.F. 1972. Olfactory discrimination in the European corn borer and several pheromonally analogous moths. Ann. Entomol. Soc. Am. 65:1337-1340. LEWIS, T., WALL, C., MACAULAY,E.D.M., and GREENWAY,A.R. 1975. The behavioral basis of a pheromone monitoring system for pea moth. Cydia nigricana. Ann. Appl. Biol. 80: 257-274. LEwis, T., and MACAULAY,E.D.M. 1976. Design and elevation of sex attractant traps for pea moth, Cydia nigricana (Steph.), and the effect of plume shape on catches. Ecol. Entomol. 1:175-187. McLAUGHLIN,J.R., GASTON,L.K., SHOREY,H.H., HUMMEL,H.E., and STEWART,F.D. 1972. Sex pheromones of Lepidoptera, XXXll I. Evaluation of the disruptive effect of tetradecyl acetate on sex pheromone communication in Pectinophora gossypiella. J. Econ. Entomol. 65:1592-1593. MINKS, A.K., VOERMAN,S., and KLUN,J.A. 1976. Disruption of pheromone comunication with micro-encapsulated antipheromones against Adoxophyes orana. Entomol. Exp. AppL 20:163-169. PERRY, J.N., WALL,C., and GREENWAY,A.R. (1980) The use of Latin square designs in field experiments involving insect sex attractants. Ecol. Entomol. 5:385-396. PREISS, R., and PR1ESNER, E. 1978. Neue Laborverfahren zur Wirksamekeitsbestimmung yon Lockstoffen und Lockstoff-Inhibitoren beim Apfelwickler Laspeyresia pomonella (L.). Mitt. Dtsch. Ges. Allg. Angew. Entomol. 1:166-169. PRIESNER,E. 1980. Sensory encoding of pheromone signals and related stimuli in male moths, pp. 359-366, in M. Sherwood (ed.). Insect Neurobiology and Pesticide Action. Proceedings of a conference of the Society of Chemical Industry. University of York, September 1979. ROELOFS,W.L. and COMEAU,A. 1971. Sex pheromone perception: synergists and inhibitors for the red-banded leaf roller attractant, J. Insect Physiol. 17:435-449. ROELOFS, W.L. COMEAU,A., HILL, A., and MIL1CEVIC, G. 1971. Sex attractant of the codling moth: characterization with electroantennogram technique. Science 174:297-299. ROELOFS,W.L., HILL,A.S., and CARDE,R. 1975. Sex pheromone components of the redbanded leafroller, Argyrotaenia velutinana (Lepidoptera, Tortricidae). J. Chem. EcoL 1:83-89. TAYLOR, L.R., WoIWOn, I.P., and PERRY,J.N. 1978, The density-dependenceof spatial behavior and the rarity of randomness. J. Anita. Ecol. 47:383-406. VOERMAN,S., MINKS, A.K., and Houx, N.W.H. 1974. Sex pheromones of summerfruit tortrix moth, Adoxophyes orana: Investigations on compounds modifying their attractancy. Environ. Entomol. 3:701-704.

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WALL,C., and GREENWAY,A.R. 1981. An attractant lure for use in pheromone monitoring traps for the pea moth, Cydia nigricana (F.). Plant Pathol. 30:73-76. WALL,C., and PERRY, J.N. 1978, Interactions between pheromone traps for the pea moth Cydia nigricana (F.). Entomol Exp. Appl. 24:155-162. WALL,C., GREENWAY,A.R., and BURT, P.E. 1976. Electroantennographic and field responses of the pea moth, Cydia nigricana, to sex attractants and related compounds. Physiol. Entomol. 1:151-157.

Compounds modifying the activity of two sex attractants for males of the pea moth,Cydia nigricana (F.).

(E)-10-Dodecen-1-yl acetate (E10-12∶Ac) and (E,E)-8,10-dodecadien-1-ylacetate (E,E8,10-12∶Ac) are sex attractants for males of the pea moth,Cydia nigr...
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