Heinrich Arn

Sex pheromone of European corn borer. - Ostrinia nubilalis: Polymorphism in various laboratory and field strains

Sex gland extracts ofOstrinia nubilalis females collected in the wild or laboratory-reared from Switzerland, Italy, and Hungary were analyzed. Individuals collected in the north of Switzerland contained (Z)- and (E)-11-tetradecenyl acetate at the approximate ratio of 97∶3 (Z type), in accordance with field responses of males and previous findings. On the other hand, females from a laboratory culture derived from field collections made in the same area and reared for four to five generations contained theZ andE isomers at ratios of ca. 3∶97 and 35∶65, respectively. In the south, one of the eight wild females analyzed was of theZ type and the rest intermediate, whereas males were predominantly trapped with blends of the two isomers containing 60 to 97E. In a laboratory culture reared for one to two generations from corn borers collected in Hungary, three of nine females were of the intermediate type and the restZ. Small amounts of (Z)-11-hexadecenyl acetate were detected in female glands of theE strain; however, no effect of this compound could be observed in the field.

Feeding response of Aphis pomi, Myzus persicae, and Amphorophora agathonica to phlorizin

Abstract Phlorizin, a phenolic compound present only in the apple genus, Malus , was found to be neutral as a probing stimulus to Aphis pomi , an apple feeder, but was a probing deterrent to the non-apple feeding aphids, Myzus persicae and Amphorophora agathonica . Phlorizin was an ingestion deterrent to all three species although the threshold was lower for A. pomi . Apple can be utilized as a host by A. pomi since it feeds in the phloem which appears not to contain phlorizin.

Characterization of pheromone blend for grapevine moth, Lobesia botrana by using flight track recording

The behavioral responses of Lobesia botrana males to calling females, pheromone gland extracts, and synthetic sex pheromones were recorded in a wind tunnel. Gland extracts and synthetic pheromones were released from a pheromone evaporator. The numbers of males reaching the source and their flight tracks in response to calling females and pheromone gland extracts were compared to those of synthetic blends. Upwind flights to natural sex pheromone were straighter and faster than to a three-component blend of (E)-7,(Z)-9-dodecadienyl acetate (E7,Z9–12:Ac), (E)-7,(Z)-9-dodecadien-1-ol (E7,Z9–12:OH), and (Z)-9-docecenyl acetate (Z9–12:Ac) (100:20:5). The optimum ratio of E7,Z9–12:OH and Z9–12:Ac to E7,Z9–12:Ac was found to be 5% and 1%, respectively. An additional seven compounds identified in the sex pheromone gland were investigated for their biological activity. Two unsaturated acetates, i.e., (E)-9-dodecenyl acetate (E9–12:Ac) and Δ11-dodecenyl acetate (Δ11–12:Ac), increased the number of males reaching the source as well as straightness, linear velocity, and decreased the track angle of upwind flight. Optimum response was obtained by releasing 10 pg/min E7,Z9–12:Ac in a mixture with 0.5 pg/min E7,Z9–12:OH, 0.1 pg/min Z9–12:Ac, 0.1 pg/min E9– 12:Ac and 1 pg/min Δ11-12–Ac. The saturated acetates previously identified in the female glands were biologically inactive.

Sex pheromone blends of three tortricid pests in European vineyards

Abstract The sex pheromone glands of the three most important tortricids of European vineyards, Eupoecilia ambiguella Hbn., Sparganothis pilleriana Den. and Schiff. and Lobesia botrana Den. and Schiff., have been chemically investigated and found to contain up to 15 different straight-chain acetates and alcohols. Behavioural observations in the wind tunnel and field trapping demonstrate that in each species at least three female-produced components are involved in male attraction.

Effects of dodecyl acetate andZ-10-tridecenyl acetate on attraction ofEupoecilia ambiguella males to the main sex pheromone component,Z-9-Dodecenyl acetate

Attraction ofE. ambiguella males toZ-9-dodecenyl acetate (Z9-12∶Ac), alone and in combination with dodecyl acetate (12∶Ac) orZ-10-tridecenyl acetate (Z10-13∶Ac) was tested in both wind-tunnel and field experiments. In the laboratory, response toZ9-12∶Ac reached a distinct dosage optimum at which attraction was nearly as good as to live females. Addition of 12∶Ac, a minor component of female glands and effluvia, had no effect at low doses ofZ9-12∶Ac and only marginally improved attraction at the optimum. However, inclusion of 12∶Ac with an overdose ofZ9-12∶ Ac fully restored activity. In the field,Z9-12∶Ac alone was not very attractive at any dose; catches markedly increased by adding 12∶Ac and climbed with increasing dose of each compound up to 10 mg. Optimum ratio ofZ9-12∶Ac to 12∶Ac was 1∶1 to 1∶5. Another compound,Z10-13∶Ac, had the same effect as 12∶Ac in the laboratory and the field but was effective at a lower dose. In the field, inclusion of the synergist permits use of high cap loads to attract more males, perhaps from greater distances.

Sex pheromone ofEupoecilia ambiguella female: Analysis and male response to ternary blend.

Sex gland extracts and washes ofEupoecilia ambiguella contain 10–20 ng/female of the primary sex pheromone componentZ-9-dodecenyl acetate (Z9–12∶Ac), accompanied by a number of related compounds. These areE-9-dodecenyl acetate (E9–12∶Ac),Z-9-dodecen-1-ol (Z9–12∶OH), saturated acetates of 12, 16, 18, and 20 carbons, and traces of a doubly unsaturated acetate, tentatively identified as a 9,11-dodecadienyl acetate. Octadecyl acetate predominates among the pheromone-related components, making up 1–2, occasionally 20–30 times the amount ofZ9–12∶Ac. The same compounds were also found in field-collected females and in effluvia.Z-9-Undecenyl acetate, which is a male attractant on its own, was also found in a sample of female effluvia. A hierarchy is observed in the ethological function of the pheromone components.Z9–12∶Ac is an attractant forE. ambiguella males. Dodecyl acetate (12∶Ac) is not attractive on its own but augments male catch when added to the main attractant. Addition of 18∶Ac augments attraction only when bothZ9–12∶Ac and 12∶Ac are present. Windtunnel tests demonstrate that 18∶Ac also raises the disorientation threshold, as previously shown for 12∶Ac. Other compounds, with the possible exception of additional saturated acetates, had either no effect on trap catch or, in the case ofE9–12∶Ac,Z9–12∶OH, andE-9,11-dodecadienyl acetate, were inhibitory above a certain level. A blend of roughly equal parts ofZ9–12∶Ac, 12∶Ac, and 18∶Ac provides the best attractant blend forE. ambiguella known to date.

A computer-controlled video system for real-time recording of insect flight in three dimensions.

A computer-controlled video system for real-time recording of insect flight in three dimensions is described. The flight paths of moths were recorded in a flight tunnel using two CCD cameras placed adjacent to each other at angles of 45 and 135° to the flight tunnel axis and separated by a distance of 120 cm. They were connected to two 28-level gray-scale frame grabbers via two external synchronizers. The two-dimensional coordinates of the flying insect were obtained from the two cameras at 40-ms intervals and transferred to host computer for processing and monitor for real-time display. Due to speed limitation in the image acquisition hardware, construction of the three-dimensional file was carried off-line. The flying insect was rendered as a dark spot in a bright background using a homogeneous light source. As the insect enters into the field of view of the two cameras, the light distribution changes, and the frame grabber detects only those variation in the light distribution which results from a flying insect. The target insect can be as small as 3 pixels and can be tracked in a stereoscopic field of view 60 cm long and 50 cm high. A method was developed that allowed for scalar scoring of various pheromone sources to assess their attractiveness using vector flight parameters. This method was applied successfully for optimization of pheromone blend of the grapevine moth, Lobesia botrana.

A DOUBLE‐LABEL CHOICE‐TEST FOR THE SIMULTANEOUS DETERMINATION OF DIET PREFERENCE AND INGESTION BY THE APHID AMPHOROPHORA AGATHONICA1

Tritium and calcium‐45 were used to label selectively the two diets offered in choice‐tests to Amphorophora agathonica. Radioassay of the aphids in a liquid scintillation counter gave quantitative information on the liquid uptake from each diet. With this technique, preferences for certain sucrose concentrations and for a complex diet could be demonstrated which were not apparent from the feeding rates in no‐choice experiments. The deterrency levels of crude extracts of resistant and susceptible raspberry varieties were established with a small number of individual aphids.

Determination of release rates of pheromone dispensers by air sampling with C-18 bonded silica

Release rates of pheromones from commercial dispensers for mating disruption inLobesia botrana andCydia pomonella have been measured by sampling an air stream with C-18 bonded silica (Sep-Pak cartridges) followed by extraction and gas chromatographic analysis. The flow chamber is made from inexpensive materials that can be replaced when contaminated. The results correspond with those obtained by gravimetry; the method supplies additional information on the composition of the airborne material.

Field activity of sex pheromone components of Peribatodes rhomboidaria

M. T6th 1, G. Sz6cs 1, W. Francke 2, P. M. Guerin 3, H. Arn 3 & A. Schmid 4 1plant Protection Institute, Hungarian Academy of Sciences, Budapest, P f 102, H-1525, Hungary; 2Department of Organic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, D-2000, Hamburg, FRG; 3Swiss Federal Research Station, Wiidenswil, CH-8820, Switzerland; 4Station Cantonale de Protection des Plantes, Chateauneuf s. Sion, CH-1950, Switzerland