Potato Tuberworm Moth Research Articles

Oviposition Deterrents in Larval Frass of Potato Tuberworm Moth, Phthorimaea operculella (Lepidoptera: Gelechiidae).

The potato tuberworm moth (PTM) Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) is one of the most damaging pests of potato Solanum tuberosum L. in warm temperate and subtropical areas. Our previous experiment showed that extracts of larval frass of PTM deterred oviposition of conspecific females. In this study, we investigated the identification of chemicals in larval frass that were influencing the oviposition of PTM by behavioral bioassays and electroantennography analysis in the laboratory. Frass was collected from third and fourth instar larvae and combined analysis of gas chromatography coupled with electroantennography (GC-EAD) of dichloromethane extracts showed that eight compounds from larval frass extracts elicited repeatable antennal responses from mated females. Seven EAD-active compounds in frass volatile extract were identified by gas chromatography-mass spectrometry (GC-MS) as linoleic acid, octadecanoic acid, tricosane, pentacosane, heptacosane, nonacosane, and cholesterol. Oviposition bioassays indicated that frass extracts had a deterrent effect on egg laying, the deterrent activity increased with the concentration of frass extracts, and the threshold value for statistical significance in oviposition deterrence was in the range of 20-200mg frass per cage. Linoleic acid, pentacosane, heptacosane, nonacosane, and cholesterol in larval frass volatiles were found to play a key role in repelling oviposition in a dose-dependent manner. We suggest that the bioactive compounds in larval frass are responsible for repelling oviposition of PTM, and n-alkanes, especially pentacosane, strongly deter oviposition and may be considered as a potential oviposition deterrent for potential applications.

Antennal mechanosensors mediate sex pheromone‐induced upwind orientation in the potato tuberworm moth

AbstractMales of the potato tuberworm moth Phthorimaea operculella (Lepidoptera: Gelechiidae) locate conspecific females by a series of short and straight flights, or ‘hops’. On the floor of a wind tunnel, P. operculella can change their heading angles in response to wind direction shift, suggesting that they detect wind direction and orient upwind when on the ground. It is unlikely that they navigate in wind by vision‐induced optomotor anemotaxis as in many flying moths. To investigate the mechanism of wind direction detection in this species, their orientation behaviour in response to pheromone pulses is observed in a wind tunnel. Intact male moths orient upwind even in complete darkness. After the flagellum of one antenna is amputated, male moths still successfully orient upwind. However, they fail to head upwind when the basal segments of both of their antennae are immobilized with glue. The ability to surge upwind is restored by removing the glue from the antennae. Thus, the results of the present study indicate that males of P. operculella orient upwind in response to mechanoreceptive cues from mechanosensory organs on their antennae. In Lepidoptera, two distinct anemotactic mechanisms of different sensory modalities appear to coexist: optomotor anemotaxis when airborne and the aim‐then‐shoot anemotactic system mediated by antennal mechanoreception when on the ground.

Aim‐then‐shoot anemotaxis involved in the hopping approach of potato tuberworm moth Phthorimaea operculella toward a sex pheromone source

AbstractMale moths locate conspecific females by pheromone‐induced upwind flight maintained by detecting a visual flow, termed optomotor anemotaxis. Their behavioural pattern is characterized by an upwind surge in response to a pheromone stimulus and crosswind casting after odour loss, which is considered to be reset and restarted on receipt of another pheromone pulse. However, pheromone‐stimulated males of the potato tuberworm moth Phthorimaea operculella exhibit a series of short and straight intermittent flights, or hops, when moving upwind. It is unclear whether they navigate by employing the same behavioural pattern and wind detection mechanism as that used by flying moths. To analyze odour‐modulated anemotaxis in male potato tuberworm moths, a flat wind tunnel is constructed to give regular odour stimuli to an insect regardless of its location. Moths are subjected to pheromone pulses of different frequencies to test whether they show a behavioural pattern that is reset and restarted by a pheromone pulse. Moths on the ground are also subjected to crosswind shear to examine their detection of wind direction. Path analyses reveal that males surge upwind when they receive a pheromone pulse and exhibit casting by successive hops when they lose odour. This behavioural pattern appears to be similar to that of flying moths. When the direction of the airflow is switched orthogonally, males adjust their course angle accordingly when they are on the ground. It is suggested that, instead of optomotor anemotaxis, this ‘aim‐then‐shoot’ system aids the detection of wind direction, possibly by mechanosensory means.

Differential Attractiveness of Potato Tuber Volatiles to Phthorimaea operculella (Gelechiidae) and the Predator Orius insidiosus (Anthocoridae)

The behavioral responses of the potato tuberworm moth Phthorimaea operculella and the polyphagous predator Orius insidiosus to volatiles emanating from exposed tubers were studied by four-arm olfactometer bioassays. Mated females of P. operculella distinguished volatiles released by intact potato tubers from volatiles damaged mechanically or by conspecific larvae. Volatiles from intact potato tubers were attractive to them. On the other hand, unmated females of P. operculella did not respond to tuber volatiles. Adults of O. insidiosus were attracted to volatiles from tubers damaged by P. operculella larvae, but did not respond to intact or mechanically damaged tubers. Methyl jasmonate (MeJA) was the only compound identified from the headspace of potato tubers (GC-MS of direct headspace sampling). The amount varied with the type of induction, being 0.001 +/- 0.0003 ng g(-1) in tissues of intact fresh tubers, 0.002 +/- 0.0007 ng g(-1) in mechanically damaged tubers, and showing a six- to tenfold increase in P. operculella damaged tubers (0.090 +/- 0.006 ng g(-1)). Behavioral bioassays with synthetic MeJA confirmed that the response of the insects is dependent on MeJA concentration. Mated females of P. operculella showed the highest response at 0.001 ng g(-1) (concentration released by intact tubers), whereas O. insidiosus showed the highest response, between 0.01 and 0.05 ng g(-1), which is close to the concentration released by P. operculella damaged tubers. Based on these results, we postulate that P. operculella and O. insidiosus have adapted their responses to plant volatiles differently, enabling them to locate suitable hosts or prey.

Comparison of the Sex Pheromone System between Japanese and Thai Populations of the Potato Tuberworm Moth, Phthorimaea operculella (Lepidoptera: Gelechiidae)

Comparison of the Sex Pheromone System between Japanese and Thai Populations of the Potato Tuberworm Moth, Phthorimaea operculella (Lepidoptera: Gelechiidae)

Effect of temperature on biosynthesis of sex pheromone components in potato tuberworm moth,Phthorimaea operculella (Lepidoptera: Gelechiidae)

Rearing temperature modified the sex pheromone component ratio in the potato tuberworm moth,Phthorimaea operculella. This phenomenon seemed to be induced with ambient temperature by differences in timing and speed of biosynthesis between two pheromone components. (E,Z,Z)-4,7,10-Tridecatrienyl acetate (triene) was mainly synthesized during the pupal period, while most of (E,Z)-4,7-tridecadienyl acetate (diene) was synthesized during a short period just after emergence. Therefore, the ratio of triene in a newly emerging adult was relatively high at all temperatures although the amount of triene was relatively low at 35°C. On the other hand, the synthetic rate of accumulation of diene was clearly modified by ambient temperature. Biosynthesis of diene at 15°C was very low in the first two days and high in the third day. Consequently, a titer of the diene component at 15°C became approximately equivalent to that at 25°C one day later.

Effect of rearing temperature on pheromone component ratio in potato tuberworm moth,Phthorimaea operculella, (Lepidoptera: Gelechiidae)

The ratio of two components in the sex pheromone of the potato tuberworm moth,Phthorimaea operculella, was influenced by the rearing temperature. The percentage of the (E,Z,Z)-4,7,10-tridecatrienyl acetate dropped as the rearing temperature was raised. The total amount of the pheromone did not change parallel with the change of ratio. The critical period sensitive to temperature seemed to be the pupal stage. Temperature in the larval stage may also influence the ratio slightly. The biological significance of the phenomenon was also discussed.

Variability in pheromone composition and periodicity of pheromone titer in potato tuberworm moth,Phthorimaea operculella (Lepidoptera: Gelechiidae)

The ratios and quantities of the pheromone components, (E,Z)-4,7-tridecadien-1-yl acetate (diene) and (E,Z,Z)-4,7.10-tridecatrien-1-yl acetate (triene), in the glands of individual female potato tuberworm moths (Phthorimaea operculella) originating from the United States (California) and Japan (Nagoya) were analyzed by gas chromatography. Quantities of glandextracted pheromone components of Nagoya females fluctuated in a periodic fashion during the photoperiod. Maximal titers coincided with the onset of scotophase (and calling), then gradually declined to minimal levels soon after lights-on. The average daily pheromone quantities decreased significantly as females aged. Both populations exhibited considerable variation in the ratio of the two components. The proportions of triene in the blend ranged from 27% to 88% (triene -X = 56 ± 13% SD; CV = 23%) for California females and from 16% to 71% (42 ± 13%; CV = 31%) for Nagoya females. Nagoya females also stored significantly higher amounts of pheromone in their glands (8.6 ± 3.9 ng) than did California females (2.7 ± 1.4). The differences between the populations, while substantial, would probably not be sufficient to impart a barrier to panmixis, given the wide range of component ratios favored by the males.

Pattern of pheromone-oriented flight in male potato tuberworm moths

The pheromone-oriented flight of maleP. operculella was observed under field conditions. Eighty percent or more of the flights were shorter than 1 m. Thus the approach of males of this species to a distant pheromone source is composed of a chain of short flights. The pattern of the flights changed when the males came within about 1 m of the lure, with a decrease of flight speed and an increased tortuosity. This probably facilitates eventual location of the female by a male. Only a few males succeeded in arriving at the high-dose lures. Males did not succeed in arriving at the lure when it was 70 cm above the ground: this was confirmed by a trap test; however, the flight pattern consisted of a chain of short flights even in these cases. The adaptive significance of this flight pattern is discussed.

ChemInform Abstract: Allylation of Grignard Reagents: Its Application for the Synthesis of (4E,7Z)‐4,7‐Tridecadienyl Acetate, a Sex Pheromone of Potato Tuberworm Moth.

AbstractThe results of the reaction between the chlorobutene (II) and the Grignard compound (III) depend on the solvents.

Allylation of Grignard Reagents: Its Application for the Synthesis of (4E, 7Z)-4,7-Tridecadienyl Acetate, A Sex Pheromone of Potato Tuberworm Moth

Abstract Alkylmagnesium halides have been found to react with (Z)-4-benzyloxy-1-chloro-2-butene in presence of HMPA to produce a rearranged product 3-alkyl-4-benzyloxy-1-butene, while in absence of HMPA a normal product (Z)-1-alkyl-4-benzyloxy-2-butene resulted as the predominant product. Latter product has been utilized for the synthesis of (4E, 7Z)-4,7-tridecadienyl acetate, a sex pheromone of potato tuberworm moth.

ジャガイモガ性フェロモン構成成分の最適混合比

ジャガイモガ性フェロモン構成成分の最適混合比

Allozyme Variation in Laboratory-reared and Field-collected Potato Tuberworm Moth (Lepidoptera: Gelechiidae)

Inheritance patterns of mannose phosphate dehydrogenase (MPI), phosphoglucose isomerase (PGI), and isocitrate dehydrogenase (IDH) were investigated in the potato tuberworm moth, Phthorimaea operculella (Zeller), using starch gel electrophoresis. IDH and PGI are each controlled by two codominant alleles and MPI by three codominant alleles and all three loci are autosomal and unlinked to one another. IDH and PGI are dimeric proteins and MPI is monomeric. Comparison of a laboratory and a field population revealed lower variability in the former. Neither population was in Hardy-Weinberg equilibrium at the MPI locus.

Temporal pattern of female calling behaviour of the potato tuberworm moth Phthorimaea operculella (Zeller) (Lepid., Gelechiidae)

AbstractVirgin females of the potato tuberworm moth, Phthorimaea operculella (Zeller), called sporadically throughout the scotophase of a 13L:11D photoregime, but somewhat more intensely during the second half. Freshly emerged, one, two and three day post‐emergence moths were similar in respect of the total percentage of females calling, time of initiation of calling, total time spent calling, average duration of calling bouts and number of calling bouts per dark period. The presence of the host plant (potato tubers) did not alter the calling behaviour of two day old females. No calling activity was observed during the light period.ZusammenfassungÜber das zeitliche Muster des weiblichen Lockverhaltens bei der Kartoffelmotte Phthorimaea operculella (Zell.), (Lepid., Gelechiidae)Unbegattete Weibchen von P. operculella sandten sporadisch während der Skotophase der 13L:11D Photoperiode Pheromone aus, jedoch etwas stärker in der zweiten Hälfte. Frisch geschlüpfte 1–3 Tage alte Motten verhielten sich bezüglich der Gesamtquote lockender Weibchen sowie des Beginns, der Gesamtdauer, der mittleren Dauer und der Zahl der Lockphasen pro Dunkelperiode ähnlich. Die Anwesenheit von Wirtspflanzen (Kartoffelknollen) veränderte bei zwei Tage alten Weibchen das Lockverhalten nicht. Während der Lichtperiode wurde keine Lockaktivität beobachtet.

Role of pheromone components in evoking behavioral responses from male potato tuberworm moth,Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae)

Responses of the male potato tuberworm moth,Phthorimaea operculella (Zeller), to two sex pheromone components and female crude extract were studied. Both in a wind tunnel and the field, males were better able to locate a source consisting of a 1∶1 mixture of (E,Z)-4,7-tridecadien-1-yl acetate and (E,Z,Z)-4,7,10-tridecatrien-1-yl acetate than a source consisting of the triene alone. The addition of the diene increased the time spent in the vicinity of the pheromone source, time spent on the source itself, and also increased the average number of visits to the source per individual when compared to the triene alone. The triene elicited high levels of locomotor activity and may play a major role in eliciting earlier (long-range) steps in the behavioral sequence of sexually activated moths. The diene appeared to influence later (short-range) behavior. The behavioral responses of males to a 1∶1 mixture of the diene and triene were similar to those elicited by female crude extract.

New stereocontrolled approach to some insect pheromones via silicon-directed beckmann fragmentation

Abstract The major components of sex pheromones of potato tuberworm moth and Douglas fir tussock moth have been synthesized via the regio- and stereo-controlled Beckmann fragmentation assisted by trimethylsilyl group.

Preliminary results with sex pheromones to trap potato tuber worm moths in Saudi Arabia

A mixture of sex pheromone PTM1 (trans-4,cis-7-tridecadien-1-ol acetate) and PTM2 (trans-4,cis-7,cis-10-tridecatrien-1-ol acetate) on rubber cap dispensers was used to attract adult male tuber moths to water pan traps. Correlation analysis of daily catches made over a 61-day period showed that temperature and relative humidity accounted for 20.5% and 1.4% respectively of catch variability. Further studies are needed to reveal any major components of the 78% residual variability.

Seasonal Patterns of Potato Tuberworm Moth Abundance as Determined by Pheromone Trapping 1

Potato tuberworm moth population was monitored using water pan traps with rubber septa, impregnated with trans-4, cis-7-tridecadienyl acetate, in a 12-ha field in which 4 successive potato plantings were made over a 2 yr period. Tuberworm moth populations were directly related to the presence of potato foliage in successive crops and were annually highest in the spring plantings. Spring populations increased as the crop matured and decreased when vines were killed and potatoes were harvested. Following harvest, moth activity remained low until the late-summer planting emerged and, even with available host material, the late-summer planting did not support a high tuberworm population. After harvest of the late summer crop, the tuberworm population remained low until the next spring crop emerged.

Synthesis of the two components of the sex pheromone system of the potato tuberworm moth,Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) and field experience with them

Male potato tuberworm moths are attracted by a mixture oftrans-4,cis-7-tridecadien-1-ol acetate andtrans-4,cis-7,cis-10-tridecatrien-1-ol acetate. The synthesis of both compounds is described. Overall yields were 14.4 and 9.5% after distillation. The products were purified by liquid chromatography. Mixtures of these compounds in several ratios and quantities were tested in potato fields in Australia, Peru, and Cyprus. The largest catches were obtained from water pan traps baited with rubber sleeve stoppers containing both components in ratios varying between 1∶9 and 9∶1. The stoppers were attractive over a period of several months even under hot weather conditions.

Elucidation of the sex pheromone system of the potato tuberworm moth,Phthorimaea operculella (Zeller) (Lepidoptera, Gelechiidae): a short review

Recent research, reviewed here, of the pheromone system of the potato tuberworm moth has led to the isolation, identification, and synthesis of its components.trans-4,cis-7-tridecadien-l-ol acetate (PTM 1) andtrans-4,cis-7,cis-10-tridecatrien-l-ol acetate (PTM 2), mixtures of which are much more attractive in the field than 2 virgin female moths or each compound on its own.