Glenn Peter Svensson

Currant, and in particular blackcurrant, Ribes nigrum , is widely grown in Europe. It is the host of a number of pest insects, but their occurrence and the damage they cause vary geographically. In northern Europe, three lepidopteran species, the currant shoot borer ( Lampronia capitella ), the currant clearwing ( Synanthedon tipuliformis ), and the currant bud moth ( Euhyponomeutoides albithoracellus ), are particularly damaging and sometimes cause decreased plant vigour and drastic yield losses. With fewer insecticides approved for use and with an increased interest in organic production of currants, the need for alternative methods to control these moths is urgent. We here applied pheromone‐based mating disruption in small and sometimes well isolated plantations in Finland, Norway and Sweden against the three pests using 15–25 g of active ingredients and 300 dispensers per ha. A strong trap shutdown effect, up to 100%, was recorded for the currant clearwing and the currant bud moth, but no effect on the most widespread species, the currant shoot borer, was noted. After 1 year of treatment, however, it was not possible to detect any significant effect on the damage level or on the future adult population size of the pests. We conclude that for the currant clearwing and the currant bud moth, mating disruption is likely to work with higher pheromone doses or modified dispenser density, whereas the reason behind the lack of effect on the currant shoot borer needs to be addressed by new experiments and observations of behaviour.

The currant bud moth, Euhyponomeutoides albithoracellus , the currant shoot borer, Lampronia capitella and the currant clearwing, Synanthedon tipuliformis , are destructive pests on currants in the Nordic countries, but detailed information about their relative abundance in commercial crop fields is lacking. We used pheromone‐baited monitoring traps to analyse the presence and flight period of the three species in 28 commercial black currant fields in Finland, Norway and Sweden during 4 years. We also estimated moth‐induced damage in the same fields and analysed within‐ and between‐generation relationships of catches and damage to find patterns to predict current and future pest pressures. At least two of the species were found at all sites. The shoot borer was the most widespread and abundant species, followed by the clearwing, which was relatively common at all sites except in northern Sweden, whereas the bud moth was not detected at all in Norway and southern Sweden. Geographic variation in flight phenology was observed for both the shoot borer and the clearwing. We found a significant positive correlation in all between‐year analyses of damage and in most between‐year analyses of catches, but a less consistent pattern when relating catches to damage within and between generations. Combining catch and damage data may be a useful tool to predict future overall infestation levels of the three pests in black currant fields in the Nordic countries.

BACKGROUND: The strawberry tortrix, Acleris comariana (Lepidoptera: Tortricidae), is a destructive pest of strawberry in Denmark and southern Sweden. The efficacy of pheromone‐based communication disruption of the species was examined in crop fields in southern Sweden. Due to the high cost of purchasing or synthesizing the pheromone (E)‐11,13‐tetradecadienal, lower quantities were applied per ha compared to similar mating disruption studies on other tortricid pests.RESULTS: When treating 1 ha within fields with 14 or 1.4 g of pheromone and using rubber septa as dispensers, trap catches were reduced by ≥98% versus control areas. When treating whole fields with 0.45–0.90 g/ha and using 1 g SPLAT droplets as dispensers, the effect on trap catch was less pronounced (63–95% reduction vs control fields). A corresponding reduction in larval numbers following the treatment was not achieved. Additional experiments revealed that males are more attracted to SPLAT droplets compared to trap lures, and aggregate near SPLAT droplets, indicating that low catches in traps were due to induced allopatry, a form of competitive disruption. In addition, female‐baited traps were outcompeted when placed close to septum‐baited traps. Pest densities were high, and the lack of control effect could be attributed to high encounter rates between the sexes despite the female competitive disadvantage, making mating disruption less efficient.CONCLUSION: Our data show the potential for pheromone‐based control of A. comariana as part of integrated pest management, but the method needs optimization regarding density and strength of dispensers and ways to reduce the initial density of the pest to levels where competitive mechanisms of mating disruption can be efficient. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Regeneration of Norway spruce, Picea abies, forests is to a large extent depending on the production of seeds from high quality plus trees in orchards. However, the seed yield is variable and unpredictable due to weather, pest insects and diseases. Thus, more knowledge is needed to improve planning of harvest and mitigation of pests and diseases to secure future forest regeneration. In this study, we used pheromone traps and cone inventory to document the phenology and population trends of three important lepidopteran seed and cone consumers, viz. the spruce seed moth, Cydia strobilella, the spruce coneworm, Dioryctria abietella and the cloaked pug, Eupithecia abietaria, in six south Swedish orchards over 6 years. The flight period of C. strobilella was concentrated in May, whereas D. abietella had an extended flight period from May to October, and E. abietaria mainly flew in June and early July. Population densities measured by trap catch and cone density fluctuated between years and orchards, despite these were located within 74 km of each other. For C. strobilella, but not for D. abietella, there was a significant relationship between the number of males captured per trap and the number of larvae per ha or the proportion of infested cones in the subsequent generation. No significant relationships occurred between larval density and trap catch the following year (within generation) for any of the species. Notably, the trap catches were high also after years almost void of breeding material, that is, cones. Our results indicate that we still lack information on several parameters essential for reliable predictions of population trends, such as prolonged diapause, winter survival and the presence and abundance of natural enemies.

The poplar moth, Leucoptera sinuella (Lepidoptera: Lyonetiidae), is widely distributed across Europe, Asia, and parts of Africa. It was first identified in Chile in 2015 and has since become a significant pest in the agricultural sector. Additionally, economic losses are further aggravated by the presence of L. sinuella pupae in nearby fruit orchards. This study investigated the presence of a male-produced sex pheromone in L. sinuella, focusing on the hairpencil (HP) glands, which are known as dissemination structures for male pheromones in lepidopterans. Male HP glands were solvent-extracted and analyzed by gas chromatography–mass spectrometry. Chemical microderivatization and comparisons of mass spectra and retention indices of natural compounds with synthetic standards led to the identification of two compounds: (Z)-3-decenyl hexanoate (the major component) and (Z)-3-decen-1-ol (a minor component). Although electrophysiological assays did not show detectable antennal responses to (Z)-3-decenyl hexanoate, behavioral bioassays demonstrated its role as a short-range courtship signal in L. sinuella. Males with ablated hairpencils exhibited significantly reduced courtship success compared to controls; however, exposure of females to synthetic (Z)-3-decenyl hexanoate or HP extract restored male courtship success. To our knowledge, (Z)-3-decenyl hexanoate has not been previously reported as a sex pheromone component in any insect species, making this discovery an intriguing addition to the diversity of chemical communication in insects.

BACKGROUND: The sugarcane borer Diatraea saccharalis (Lepidoptera) is a key pest on sugarcane and other grasses in the Americas. Biological control as well as insecticide treatments are used for pest management, but economic losses are still significant. The use of female sex pheromones for mating disruption or mass trapping in pest management could be established for this species, provided that economical production of pheromone is available.RESULTS: Combining in vivo labelling studies, differential expression analysis of transcriptome data and functional characterisation of insect genes in a yeast expression system, we reveal the biosynthetic pathway and identify the desaturase and reductase enzymes involved in the biosynthesis of the main pheromone component (9Z,11E)‐hexadecadienal, and minor components hexadecanal, (9Z)‐hexadecenal and (11Z)‐hexadecenal. We next demonstrate heterologous production of the corresponding alcohols of the pheromone components, by expressing multiple steps of the biosynthetic pathway in yeast.CONCLUSION: Elucidation of the genetic basis of sex pheromone biosynthesis in D. saccharalis, and heterologous expression in yeast, paves the way for biotechnological production of the pheromone compounds needed for pheromone‐based pest management of this species. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The currant bud moth Euhyponomeutoides albithoracellus is a destructive pest in black currant orchards in Northern Sweden and Finland. The larvae feed on the buds, and at high densities, the species can cause severe yield losses. Sex pheromone components of the bud moth were identified via solvent extraction of excised female pheromone glands, analyses by gas chromatography with electroantennographic detection and gas chromatography–mass spectrometry and field trapping experiments. Antennae of males responded strongly and consistently to two compounds in extracts, identified as (E)‐11‐tetradecenyl acetate and (Z)‐11‐tetradecenyl acetate. Weaker and less consistent responses were observed to the corresponding alcohols, (E)‐11‐tetradecenol and (Z)‐11‐tetradecenol, and tetradecyl acetate. Field tests showed strong attraction of bud moth males to a 1:1 blend of (E)‐11‐tetradecenyl acetate and (Z)‐11‐tetradecenyl acetate. Adding the alcohols to the binary acetate blend reduced trap catches drastically, whereas tetradecyl acetate had no statistically significant impact on male attraction when added to that binary blend. Finally, testing different compositions of the binary acetate blend revealed highest catch in traps baited with a 25:75 or 50:50 ratio of the E:Z acetate isomers. The identification of sex pheromone components of the bud moth contributes to developing sustainable control of this pest via monitoring and mating disruption with sex pheromone.