Monitoring and mass-trapping methodologies using pheromones: the lesser date moth Batrachedra amydraula.

The lesser date moth (LDM) Batrachedra amydraula is a significant pest of date palm fruits. Previously, detection and monitoring of the pest was inaccurate due to high costs of sampling with lifting machines. We report a practical system for detection and monitoring of LDM based on pheromone traps and relevant models. Dose-response experiments with LDM pheromone traps indicated a 1 mg lure is optimal for monitoring. Delta traps with adhesive covering their entire inner surface gave the highest captures while trap colour was unimportant. Sampling pheromone traps throughout the night indicated male flight began at 1:00-2:00 and reached a peak 2 h before sunrise. Monitoring traps exposed all year long in Israel revealed three generations with different abundance. Trapping transects in a date plantation indicated interference from a monitoring trap became minimal at distances >27 m away. Inter-trap distances closer than this may lower efficiency of monitoring and mass trapping in control programs. Our estimate of the circular effective attraction radius (EARc) of a 1 mg delta trap for LDM (3.43 m) shows this bait is among the most attractive compared with baits for other insects. We developed encounter-rate equations with the pheromone trap EARc to model the interplay between population levels, trap density and captures that are useful for detection of invasive LDM and its control by mass trapping. The integrated methodologies are applicable to many pest species.

A common mode of attraction of larvae and adults of insect predators to the sex pheromone of their prey (Hemiptera: Matsucoccidae).

The attraction of several adult predators, genera Elatophilus, Hemerobius and Sympherobius, to the sex pheromones of pine bast scales, Matsucoccus Cockerell, has already been demonstrated. Here, the hypothesis that the larvae of these predators are similarly attracted to the host prey sex pheromone is tested. The response of predators was tested in field trials using pine tree arenas baited with the sex pheromones of M. josephi Bodenheimer & Harpaz, M. feytaudi Ducasse and M. matsumurae Kuwana. Experiments were conducted in Israel in stands of Pinus halepensis infested by M. josephi and in Portugal in stands of P. pinaster infested by M. feytaudi, respectively. The selectivity of larvae for the three sex pheromones was tested in Petri dish arenas in the laboratory. In the field, the larval stages exhibited similar modes of attraction to those of the conspecific adults: Elatophilus hebraicus Pericart in Aleppo pine forest, E. crassicornis Reuter and Hemerobius stigma Stephens in the maritime pine forests. Laboratory choice tests confirmed the kairomonal selectivity of larvae. Both forest and laboratory tests demonstrated the response of a coccinellid of the genus Rhyzobius to the sex pheromones of M. feytaudi and M. matsumurae. A unique chemical communication system among several taxa of predators of Matsucoccus spp. was highlighted that may be attributed to their coevolution on a geological time scale.

Sex pheromone of the citrus mealybug Planococcus citri: synthesis and optimization of trap parameters.

A simple synthesis of the pheromone of the citrus mealybug, Planococcus citri (Risso) (Hemiptera: Pseudococcidae), has been developed. Various factors affecting capture of males have been assessed to optimize the trap design and to develop a lure with high efficacy and longevity. Male capture was the same with the racemic and chiral pheromone; technical pheromone (85% purity) was statistically as attractive as pure pheromone (97%). A special formulation was used to determine the actual release rate of the pheromone under field conditions as related to male capture. Generally, plate traps caught more males than delta traps, and large traps caught more than small ones. The effects of aging on the performance of three types of rubber dispensers were evaluated. It was found that the American dispenser displayed the most consistent trapping performance and could be used for monitoring for at least 16 wk with a load of 200 microg of pheromone. The dose-response of the males to sex pheromone was tested within the range of 25-1,600 microg.

Synthesis and biological activity of the four stereoisomers of 4-methyl-3-heptanol: main component of the aggregation pheromone of Scolytus amygdali.

Stereoisomers of 4-methyl-3-heptanol are major components of aggregation pheromones of bark beetles and trail pheromones of ants. Recently, (3S,4S)-4-methyl-3-heptanol (I) has been tentatively identified as the main component of the aggregation pheromone of the almond bark beetle, Scolytus amygdali (Coleoptera: Scolytidae). The four stereoisomers of 4-methyl-3-heptanol were prepared and bioassayed. Key steps included preparation of chiral 4-methyl-3-heptanones using SAMP and RAMP reagents, reduction to the corresponding alcohols, and stereospecific transesterification with vinyl acetate with lipase AK catalysis. In field tests, only (3S,4S)-4-methyl-3-heptanol attracted beetles in combination with the synergist (3S,4S)-4-methyl-3-hexanol, whereas (3R,4S)- and (3R,4R)-4-methyl-3-heptanols were inhibitory.

Synthesis and structure-activity relationship of diene modified analogs of Matsucoccus sex pheromones.

The biological activity of the Matsucoccus spp. sex pheromones and diene modified analogs has been tested in forests of Israel and Portugal in order to explore the structure-activity relationship of the pine bast scale pheromone/kairomone system. The response of the adult predatory bugs, Elatophilus hebraicus and E. crassicornis and of the brown lacewing, Hemerobius stigma is more selective than that of the conspecific Matsucoccus males. The removal of the terminal methyl group from the diene terminus of both pheromones 1 and 2 eliminates all kairomonal activity but retains moderate pheromonal activity. Addition of a methyl group to the diene terminus of pheromones 1 and 2 sustains full pheromonal and kairomonal activities of the Elatophilus spp. but eliminates entirely the kairomonal activity of H. stigma. Subtle designed alterations in the structure of the diene group, typical of all Matsucoccus pheromones, change the mode of the kairomonal activity markedly.

Sex pheromone of the vine mealybug, Planococcus ficus in Israel: occurrence of a second component in a mass-reared population.

Two pheromonal components were detected in airborne collections from the vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) mass-reared on potato sprouts. The compounds were identified as (S)-lavandulyl senecioate (I) and (S)-lavandulyl isovalerate (II) by GC and GC-MS by comparison with synthetic standards. Chiral GC analysis on a cyclodextrin column established their chirality. Compound I was identified recently as the sex pheromone of P. ficus in California. The attraction of vine mealybug males to both components I and II was demonstrated in a Petri dish bioassay and in a flight assay in the rearing chamber. Indoors, both compounds displayed a similar level of attractiveness to the mass-reared males. However, trials in a vineyard indicated that feral males were attracted only to compound I. Reanalysis of the airborne pheromone indicated that laboratory first generation daughters of females that were collected in the vineyard produce only (S)-lavandulyl senecioate (I). The relative amount of (S)-lavandulyl isovalerate (II) increased gradually in each subsequent generation of P. ficus reared on potatoes. These findings indicate that feral P. ficus mealybugs produce and respond only to (S)-lavandulyl senecioate (I), whereas mealybugs that were reared in the laboratory on potato sprouts produce and respond to both (S)-lavandulyl senecioate (I) and (S)-lavandulyl isovalerate (II).

Quantitative GC analysis of secondary alcohol pheromones: determination of release rate of red palm weevil, Rhynchophorus ferrugineus, pheromone from lures.

Aliphatic secondary alcohols are components of several aggregation pheromones of important beetle and weevil pests. Some of these pheromones are used frequently for the monitoring and mass trapping of the relevant insects. We encountered severe difficulties in direct GC quantitative analysis of these compounds. Therefore, we developed a simple GC analysis of secondary alcohols convening them to trifluoroacetyl derivatives and using secondary alcohol acetates as internal standards. This method was applied for the quantitative analysis of several secondary alcohols, including the aggregation pheromone components of the almond bark beetle and the red palm weevil. The release rate of the latter pheromone from commercial lures was also determined.

Pheromonal and kairomonal activities can be separated: synthesis and bioactivity studies of pine bast scale sex pheromones and their analogues.

New syntheses were achieved to secure matsuone (1), the pheromone of the pine scale Matsucoccus matsumurae, that of M. feytaudi (2), and that of M. josephi (3). Five analogues (4-8) of 1, 2, and 3 were synthesized and their bioactivities studied. The pheromone analogue 7 showed relatively strong pheromonal activity toward M. josephi, while it was inactive as a kairomone toward the predator Elatophilus hebraicus. Similarly, analogue 8 acted as a pheromone for M. feytaudi, but it did not attract any of its local predators. The M. feytaudi pheromone 2 exhibited strong kairomonal activity toward E. hebraicus, but was not active as a pheromone mimic to attract M. josephi.

Antennal response and field attraction of the predator Elatophilus hebraicus (Hemiptera: Anthocoridae) to sex pheromones and analogues of three Matsucoccus spp. (Homoptera: Matsucoccidae).

The predator Elatophilus hebraicus is closely associated with its prey, the pine bast scale, Matsucoccus josephi, and utilizes the M. josephi sex pheromone as a kairomone. Kairomonal activity of E. hebraicus was studied by GC-EAD and field bioassays. The sex pheromone of M. josephi [2E,5R,6E,8E)-5,7-dimethyl-2,6,8-decatrien-4-one [(R)-E-M.j.] elicited a strong EAD response and attracted large numbers of the predator. The sex pheromone of two allopatric Matsucoccus spp., Matsucoccus feytaudi, (3S,7R,8E,10E)-3,7,9-trimethyl-8,10-dodecadien-6-one [(S,R)-E-M.f.] and Matcucossus matsumurae, (2E, 4E,6R,10R)-4,6,10,12-tetramethyl-2,4-tridecadien-7-one [(R,R)-E-M.m.], were also EAD-active and attracted significant numbers of E. hebraicus in the forest. Increasing the lure load of (S,R)-E-M.f. and (R,R)-E-M.m., in order to compensate for their lower volatility relative to (R)-E-M.j., resulted in similar attraction of E. hebraicus to each of the three pheromones. Other Matsucoccus pheromone stereoisomers displayed no behavioral activity. There was a significant difference in the activity of sex pheromone analogues, (6E/Z,8E)-5,7-dimethyl-6,8-decadien-4-one (52% E + 48% Z, ANLG 1) and (6E/Z,8E)-2,4,6-trimethyl- 1,6,8-nonatrien-3-one (60% E + 40% Z, ANLG 2). The (E) isomer of ANLG 1 evoked a strong EAD response from E. hebraicus and the mixture of E/Z ANLG 1 attracted the predator in moderate numbers, whereas ANLG 2 was inactive both in EAD and field tests. Conversely, M. josephi males were not attracted to M. feytaudi and M. matsumurae pheromones or pheromone analogues. Cross-activity of E. hebraicus to M. feytaudi and M. matsumurae pheromones may be based on structural similarity of the compounds. Alternatively, E. hebraicus may respond specifically to the pheromones of two allopatric Matsucoccus spp. If true, kairomonal attraction of E. hebraicus to these pheromones may have evolved during speciation of Matsucoccidae and may have been preserved despite the allopatry of M. josephi, M feytaudi and matsumurae.

Outdoor attractancy of males ofMatsucoccus josephi (Homoptera: Matsucoccidae) andElatophilus hebraicus (Hemiptera: Anthocoridae) to synthetic female sex pheromone ofMatsucoccus josephi.

The active component of the sex pheromone ofMatsucoccus josephi is (2E,6E,8E)-5,7-dimethyl-2,6,8-decatrien-4-one; the chemical is also a powerful kairomone of adult males and females of the bugElatophilus hebraicus the principal predator ofM. josephi. The presence of theZ isomer (2E,6Z,8E)-5,7-dimethyl-2,6,8-decatrien-4-one does not interfere with the attractancy of the activeE component forM. josephi males or the bug. Our results show a clear dose-response between trap catch ofM. josephi males andE. hebraicus. Conversely, increasing amounts of theZ isomer in the mixture did not affect the attraction of the scale insect males or the bug. The catch ofM. josephi males did not differ significantly among traps of different color, and was significantly higher with traps attached to the tree trunk than those suspended between trees. Comparison of the catch ofM. josephi among the three forests and between pine species suggests that the level of infestation ofPinus halepepsis andPinus brutia ssp.brutia is similar, despite the fact that the latter pine is resistant to the scale insect. Both sexes ofE. hebraicus were trapped in much lower numbers at the more infested sites. This may be related to interference with the activity ofE. hebraicus due to deterioration and drying of parts of the tree crowns and heavy colonization by generalist predators in injured trees.

Chirality of israeli pine bast scale,Matsucoccus josephi (homoptera: Matsucoccidae) sex pheromone.

The absolute configuration of the sex pheromone of the Israeli pine bast scale,Matsucoccus josephi, was determined as (2E,5R,6E,8E)-5,7-dimethyl-2,6,8-decatrien-4-one, designated here asR-E with 10% (2E,5S,6E,8E)-5,7-dimethyl-2,6,8-decatrien-4-one, designated asS-E. The chirality of the quantitatively minorZ isomer was (2E,5R,6Z,8E)-5,7-dimethyl-2,6,8-decatrien-4-one (R-Z). Chiral assignments were made by comparative gas chromatographic (GC) analysis of naturalM. josephi pheromone with stereoselectively synthesized stereoisomers on a chiral Cyclodex-B column, which separated the enantiomers with baseline resolution. In gas chromatographic-electroantennographic detection (GC-EAD) analysis of the racemicZ andE isomers, the latter elicited the stronger antennal response by maleM. josephi. In GC-EAD of all four stereoisomers, employing the chiral column,R-E was the most active stereoisomer. In field testsR-E attracted 10 times more males ofM. josephi than didS-E. The racemicE/Z pheromone mixture, containing all four stereoisomers in approximately equal amounts, attracted as many maleM. josephi as did an equivalent amount ofR-E, indicating that the other stereoisomers are not inhibitory. The same keto-diene moiety with the same chiral center and configuration in all three known Matsucoccidae sex pheromones implies a common biosynthetic pathway and phylogenetic relationship.

Immunochemical and biological analysis of pheromone biosynthesis activating neuropeptide in Heliothis peltigera.

This study describes the preparation and characterization of a highly specific antiserum to Helicoverpa zea pheromone biosynthesis activating neuropeptide (Hez-PBAN), and the use of this antiserum, in an enzyme linked immunosorbent assay (ELISA), to determine: a) the content of endogenous PBAN in head extracts of male and female Heliothis peltigera; b) the level of PBAN at different developmental stages; and c) the content of PBAN in four different moth species. Cross-reactivity studies revealed that the antiserum is directed mainly toward the N-terminal region of the neuropeptide, and that it exhibits similar binding affinities toward the oxidized and reduced forms of PBAN. Analysis of PBAN content in head extracts of male and female H. peltigera, at scotophase, revealed the presence of 4.97 and 4.58 pmol, respectively, in 3-day-old moths, and 5.33 and 4.78 pmol, respectively, in 7-day-old moths. The similarity in the content of PBAN at both ages and sexes was in accordance with the amount of pheromonotropic activity in these extracts which stimulated pheromone biosynthesis to a similar level. Analysis of PBAN-like immunoreactivity (IR) in head extracts of H. peltigera larvae and pupae demonstrated the existence of the neuropeptide in the 4th larval instar and continued to increase as a function of development. No IR could be detected in the first three larval instars. The larval and pupal extracts also exerted pheromonotropic activity which followed a similar pattern. The activity in these extracts, however, was considerably lower than that found in adult male and female heads. IR was also detected in head extracts of three other Noctuidae moths: Helicoverpa armigera, Cornutiplusia circumflexa and Spodoptera littoralis, indicating a high degree of chemical and structural similarity of PBAN in these moths.

Role of sex pheromone components in behavioral reproductive isolation betweenAutographa gamma (L.) and eitherTrichoplusia ni (Hübner) ORChrysodeixis chalcites (Esp.) (Lepidoptera: Noctuidae: Plusiinae).

The composition of theAutographa gamma sex pheromone was reexamined and only (Z)-7-dodecenyl acetate and (Z)-7-dodecenol were identified by capillary GC, GC-MS, and dimethyl disulfide derivatization and subsequent GC-MS analysis. The fatty acid content of the pheromone glands was also studied, and a series of saturated and unsaturated acids was identified. However, most of the related pheromonal compounds were not detected. The male response to the pheromone components was studied in a flight tunnel and compared with the response to calling females. The best synthetic baits evoked a response similar to that observed to the virgin females, but males spent significantly more time at calling females than at the synthetic baits. The preferred synthetic baits consisted of (Z)-7-dodecenyl acetate alone or of a blend with 5% (Z)-7-dodecenol. Increasing the relative amount of the alcohol caused a gradual reduction in male response, particularly in the last steps of the courtship sequence. The addition of the minor sex pheromone components of the sympatric Plusiinae species,Trichoplusia ni andChrysodeixis chalcites, to theA. gamma pheromone was also investigated in the flight tunnel. Some of these components exhibited a significantly antagonistic effect on theA. gamma male courtship behavior. The most potent antagonists were (Z)-5-dodecenyl acetate and (Z)-9-tetradecenyl acetate. The response ofA. gamma andT. ni males to conspecific and heterospecific females was also compared in the flight tunnel. WhereasA. gamma males were attracted only to their conspecific females, a small percentage ofT. ni males were also attracted toA. gamma females and 11% performed the whole courtship sequence.

Female sex pheromone of oriental tobacco budworm,Helicoverpa assulta (Guenee) (Lepidoptera: Noctuidae): Identification and field testing.

Analysis of ovipositor washings from virgin femaleHelicoverpa assulta (Guenée) (Lepidoptere: Noctuidae) from Korea by gas chromatography (GC) linked to electroantennography and GC linked to mass spectrometry resulted in the identification of nine compounds, hexadecanal, (Z)-9-hexadecenal, (Z)-11-hexadecenal, hexadecyl acetate, (Z)-9-hexadecenyl acetate, (Z)-11-hexadecenyl acetate, hexadecan-l-ol, (Z)-9-hexadecen-l-ol, and (Z)-11-hexadecen-1-ol. However, ovipositor washings from females from Thailand contained mainly the 16-carbon aldehydes with very small amounts of (Z)-9-hexadecenyl acetate. Field tests conducted in Korea, China, and Thailand indicated that a binary blend of (Z)-9-hexadecenal and (Z)-11-hexadecenal was sufficient for attraction, although the most attractive ratio of compounds varied with location. In Korea a 20∶1 blend of compounds was the most attractive, while in Thailand a 7.5∶1 blend was most attractive. In China both blends of hexadecenal isomers were equally attractive. Addition of the hexadecenyl acetates to the 20∶1 blend of hexadecenals in the ratio of 1∶3.3 increased the trap catch of maleH. assulta compared to lures containing the aldehydes alone in Korea but reduced trap catch in China. Addition of the hexadecenyl acetates to the 7.5∶1 blend of hexadecenals had no significant effect on trap catch in Thailand or China compared to the aldehydes alone. The addition of the 16-carbon alcohols to the aldehydes had a significantly inhibitory effect in all three countries, suggesting they are not pheromone components. Taken together these results indicate thatH. assulta is polymorphic with at least two populations responding to different sex pheromones.

Sexual behavior ofMatsucoccus josephi (Homoptera: Margarodidae) : Asynchronous adult male emergence and release of female sex pheromone.

The daily emergence patterns ofMatsucoccus josephi adults and third-instar male larvae raised on artificially infested saplings ofPinus halepensis were determined. A single peak of emergence was found for adult males between 0300 and 0500 hr. Adult females emerged throughout the day, with maximum emergence between 0500 and 0700 hr. Two daily emergence periods were observed in third-instar male larvae, one between 0300 and 0900 hr and the other between 1700 and 2100 hr. Airborne pheromone emitted by adult virgin females was collected using a flow system. No significant differences were recorded in the attraction of the male to crude pheromone collected at different times of day. A single female, virgin or half an hour after mating, was sufficient to attract the males in an olfactometer system. From minor differences in pheromone release throughout the day, and from the lesser degree of attraction by females half an hour after mating, it is assumed that there is no mechanism controlling the daily release of the female sex pheromone. Reduction of pheromone emission after mating is suggested.

Identification of sex pheromone component of spruce budmothZeiraphera canadensis.

The analyses of virgin female sex pheromone gland extracts by gas chromatography (GC), GC-electroantennographic detection (GC-EAD) and GC-mass spectrometry (GC-MS) followed by field-trapping experiments, have identified (E)-9-tetradecenyl acetate (E9-14:Ac) as the primary sex pheromone component of the spruce budmoth,Zeiraphera canadensis. Dosages of 1.0-100.0 [Symbol: see text]g ofE9-14:Ac impregnated in rubber septa provide effective trap baits.

Female sex pheromone components ofHeliothis peltigera (Lepidoptera: Noctuidae) : Chemical identification from gland extracts and male response.

Ten compounds were found in the sex pheromone glands ofHeliothis peltigera (Schiff) and identified as tetradecenal, (Z)-9-tetradecenal, (Z)-9-tetradecenol, (Z)-9-tetradecenyl acetate, hexadecanal, (Z)-7-hiexadecenal, (Z)-9-hexadecenal, (Z)-11-hexadecenal, (Z)-11-hexadecenol, and (Z)-11-hexadecenyl acetate. Behavioral tests in a wind tunnel and subsequent trapping studies conducted in the field indicated that (Z)-11-hexadecenal and (Z)-9-tetradecenal are the main pheromone components ofH. peltigera. Addition of (Z)-11-hexadecenol to the binary blend did not enhance the capture of males ofH. peltigera, but it decreased the number of males of the sympatricH. armigera. Rubber septa impregnated with a mixture of 2 mg (Z)-11-hexadecenal + 1 mg (Z)-9-tetradecenal + 0.6 mg (Z)-11-hexadecenol are recommended for monitoringH. peltigera.

Synthesis and field bioassay of some analogs of sex pheromone of citrus mealybug,Planococcus citri (Risso).

A series of structural analogs of (s+)-cis-(1R)-3-isopropenyl-2,2-dimethylcyclobutanemethanol acetate, sex pheromone of the citrus mealybug,Planococcus citri (Risso), was synthesized. The analogs were tested in a field bioassay in order to determine the structure-activity relationships of the pheromone. All changes in structure reduced the activity of the test compounds, to various degrees. The most active analog tested was the homolog (+)-cis-(1R)-3-isopropenyl-2,2-dimethylcyclobutaneethanol acetate (IV), whose activity, at a higher dosage, was comparable to that of the pheromone. The alcohol (+)-cis-(1R)-3-isopropenyl-2,2-dimethylcyclobutanemethanol was tested in mixtures with the pheromone and found to be neither an inhibitor nor a Synergist. The results show that all functional groups of the pheromone molecule are essential for optimal biological activity.

Identification of sex pheromone components from pheromone gland volatiles of the tomato looper,Plusia chalcites (Esp.).

The sex pheromone glands ofPlusia chalcites release, dodecyl acetate, (Z)-7-dodecenyl acetate, (Z)-9-dodecenyl acetate, 11-dodecenyl acetate, (Z)-8-tridecenyl acetate, and (Z)-9-tetradecenyl acetate. A combination of capillary GC, GC-MS, and dimethyl disulfide derivatization enabled a rigorous identification of all these compounds, some of which were previously found in gland extracts. Bioassays in a flight tunnel showed that a ternary blend of (Z)-7-dodecenyl acetate, (Z)-9-dodecenyl acetate, and (Z)-9-tetradecenyl acetate elicited directed flights from 85 to 100% of the males tested and elicited copulation attempts, at the end of the flights, from 44 to 74% of the males tested. This blend was equal in activity to the natural gland extract. Addition of the other acetates had only a slight influence on the activity of this mixture. Substitution of either (Z)-9-dodecenyl acetate or (Z)-9-tetradecenyl acetate in this blend by 11-dodecenyl acetate gave two ternary mixtures which also elicited high levels of courtship activity, almost as high as that of the original blend. Addition of (Z)-7-dodecenyl alcohol inhibited almost totally the flight activity of males.

Double-bond location in monounsaturated fatty acids by dimethyl disulfide derivatization and mass spectrometry: Application to analysis of fatty acids in pheromone glands of four lepidoptera.

A rapid analytical procedure for the determination of the position of double bonds in mixtures of monounsaturated fatty acid methyl esters has been developed. The method is based on direct capillary GC-MS-EI analysis of dimethyl disulfide adducts. The procedure was applied to mixtures of monounsaturated fatty esters from pheromone gland extracts of three tortricids from theChoristoneura genus,C. fumiferana, C. occidentalis, andC. pinus pinus, and one noctuid from the Plusiinae subfamily,Plusia chalcites. A correlation was found between the known major pheromone components in the four species with the corresponding fatty acids. Some of the additional fatty acids may be precursors to as yet unidentified minor pheromone components, present in extremely small quantities, in these species.