Attract, reward and disrupt: combining habitat manipulation and semiochemicals to enhance pest control in apple orchards

Agricultural intensification entails negative effects on natural enemy populations and the pest regulation services they provide. Habitat manipulation holds potential to control pests with less negative effects on the environment than conventional methods. This can be achieved by the establishment of non-crop vegetation to support natural enemies and disfavour pests. Synthetic semiochemicals possess the capability of affecting arthropods behaviour and can be combined with habitat manipulation to increase pest control. In this thesis I examine how biological control is affected in high (conventional) and low (organic) intensity apple production systems and how habitat manipulation with and without semiochemicals can be used to enhance biological pest control. The intensity of management had a strong effect on the natural enemy community and their pest control potential. Organic apple orchards were able to support a higher number and diversity of natural enemies and presented a higher suppression of sentinel Dysaphis plantaginea colonies than integrated pest management orchards. The natural enemies which were most affected by management were predatory heteroptera with many species almost exclusively found in organic orchards. D. plantaginea, establishes a mutualism with ants as a protection strategy against natural enemies. By introducing bean plants infested with Aphis fabae, ants (Lasius niger) were diverted from D. plantaginea colonies, leaving them exposed to predation. The possibility to attract natural enemies with synthetic herbivore induced plant volatiles (HIPVs) was tested in apple and barley. In both crops the HIPVs were able to attract green lacewings (Chrysoperla carnea s.l.) over four weeks. Significant increases in oviposition and larval abundance was recorded compared to the control as well as a higher reduction in two species of cereal aphids. When HIPVs were deployed along flower strips, the attraction of natural enemies including Miridae was enhanced. The combination of HIPVs, flower strips and mating disruption suppressed populations of lepidopteran pests below that of flower strips + mating disruption or mating disruption alone under a three-year study

Konceptuell modell Övervakningsmetoder för naturliga fiender i relation till skadegörarförekomst, biologi och metodernas styrkor och svagheter

A poster showing the relationship between major pests, key natural enemies and monitoring methods for natural enemies over a growing season. Based on field research in south Swedish apple orchards over several years

Attract, reward and disrupt: responses of pests and natural enemies to combinations of habitat manipulation and semiochemicals in organic apple

The widespread use of pesticides along with the simplification of the landscape has had undesirable effects on agroecosystems, such as the loss of biodiversity and the associated ecosystem service biological control. How current production systems can be remodelled to allow for a re-establishment of biological pest control, while preserving productivity, is a major challenge. Here, we tested whether a combination of tools could augment or synergize biological control of insect pests in apple (Malus domestica), comprised of a tortricid pest complex, a geometrid pest complex and the rosy apple aphid. The tools aimed at disrupting mating behaviour of multiple pest species (multispecies mating disruption, "Disrupt", MMD), attracting natural enemies (a blend of herbivory-induced volatiles, "Attract", A), or providing refuge and rewards for a diverse insect community (perennial flower strip, "Reward", R) over a 3-year period. Suction samples were consistently richer in generalist predators but not in parasitoids when multiple tools including MMD + A + R or MMD + A were employed. In addition, lepidopteran pest levels were significantly lower in these plots than in MMD or MMD + R at the end of the 3-year experiment. This was, however, not reflected in survival of artificially established aphid colonies. Our data indicates that multiple, complementary tools can greatly enhance natural enemy level, but also that long-term implementation is needed to fully realize the augmentatory or synergistic potential of complementary components and restore biological control as an ecosystem service of practical relevance

Praktiska erfarenheter med blomsterremsor i äppelodling från forskning & praktik

Power point presentation about practical experiences regarding flower strips and monitoring of natural enemies in Swedish apple orchards. Co-presented by researchers and farmers at a Horticultural conference in Linköpling Sweden. The language is mixed Swedish and English

Jakten på idémetoder : Bland böcker, bloggar och bröderna Härén

Syfte Syftet är att belysa och lyfta fram olika metoder som hjälper människor att bli skickligare på att ta fram nya idéer. Frågeställning Måste vi vänta på att äpplet ska falla ner i huvudet på oss för att vi ska få bra idéer, eller finns det några metoder som kan hjälpa oss att ta fram idéer på löpande band? Dessa två frågor är drivkraften i vår jakt genom böcker, bloggar och bröderna Härén. Böckerna beskriver kreativitet och hur människor kan göra för att bli mer kreativ. Men hur tillämpar bloggare kreativitet i verkligheten? Vad säger Fredrik och Teo Härén angående kreativitet och idémetoder? Resultat Kreativitet uppkommer genom att göra saker på nya sätt eller att vi gör nya saker vi inte prövat på förut. Alla människor är kreativa, men vissa är det mer eller mindre. För att upprätthålla kreativiteten bör vi tillämpa de metoder som finns och vi bör göra det ofta, om inte dagligen

Outsourcing eller Business Process Outsourcing : En jämförande studie

Denna studie behandlar de två koncepten outsourcing och business process outsourcing samt möjligheter och risker med nämnda koncept. Genom studier av ämnena business process outsourcing samt traditionell outsourcing har författarna påträffat sådan information som indikerar och tydliggör sådant som i litteraturen uppfattas som centralt då det kommer till möjligheter och risker då med de båda koncepten. Syftet med studien är att beskriva dessa koncept och jämföra dess risker och möjligheter. Någon förförståelse av det studerade området har inte författarna. Med anledning av att leverantörerna av ovanstående tjänster inte haft möjlighet att delge författarna vilka deras kunder är har studien begränsats till skriven litteratur samt leverantörernas uppfattning om risker och möjligheter med dessa tjänster. Studien är utformad dels med en deduktiv metod vilket inneburit litteraturstudier, samt med en kvalitativ metod som inneburit tre djupintervjuer. Genom att studera outsourcing- och BPO-branschen har författarna kommit fram till tre respondenter vilka anses representativa och väl anpassade för studien, då dessa levererar båda ovan nämnda former av tjänster. Arbetets teoridel är strukturerad på ett tydligt sätt som belyser risker och möjligheter med de båda koncepten, samt en kortare förklaring av faktorer som påverkar valet om att köpa in dessa tjänster eller ej. I empirin ställs frågor baserade på vad teorin menar är risker och möjligheter med de båda koncepten. Här redovisas också de svar författarna erhållit från respondenterna. Då det gäller att jämföra de båda koncepten är slutsatsen att det kan göras på två olika sätt. Delvis genom att jämföra riskerna och möjligheterna och dels genom att jämföra strukturen på de olika koncepten. Studiens slutsats är att riskerna och möjligheterna med de båda koncepten liknar varandra och flertalet av de identifierade är helt identiska

Data from: Organic management in apple orchards: higher impacts on biological control than on pollination

1. Intensive agricultural management negatively affects both natural enemies of pests and pollinators. Such management also has the potential to adversely affect the ecosystem services that these communities confer. Organic management has been proposed as an alternative method to mitigate such problems by restoring the services provided by arthropod communities. 2. We evaluated the effect of organic management on two ecosystem services provided by arthropods in apple orchards: pollination and biological control. We used relative decrease in colonies to assess biological control of the major apple aphid pest, and measured pollination through fruit set, number of seeds per apple and pollinator visitation. Additionally, we monitored the organisms responsible for pollination and biological control services and established the impact of pollination on apple quality. 3. Our results show a strong effect of organic management on biological control and on the temporal dynamic of natural enemy-pest interactions. Parameters such as aphid colony suppression, first and repeated occurrence of natural enemies, natural enemy species evenness and natural enemy abundance were significantly higher in organic compared to conventional orchards. Predatory bugs were the natural enemies best-affected by organic management and played a key role in early predation of aphids preventing colony growth. 4. In this instance, pollination was not influenced by organic management. It is likely due to the temporal scale at which this service is delivered, a scale that differs greatly from biological control, combined with differences in the dispersal capacity of the organisms involved. Fruit weight, calcium, potassium and magnesium content were positively affected by pollination success. 5. Synthesis and applications. We found that organic management in apple orchards preserves the local natural enemy community, and specifically predatory bug populations, essential for early aphid colony suppression. Our results suggest that, in conventional orchards, local management options that decrease or even eliminate pesticide use early in the season would increase the biological control of aphids. This would lead to reduction in apple damage at harvest. Our results on pollination success indicate that the implementation of organic management at orchard scale does not enhance pollination services for apple growers

Organic management in apple orchards: higher impacts on biological control than on pollination

Intensive agricultural management negatively affects both natural enemies of pests and pollinators. Such management also has the potential to adversely affect the ecosystem services that these communities confer. Organic management has been proposed as an alternative method to mitigate such problems by restoring the services provided by arthropod communities. We evaluated the effect of organic management on two ecosystem services provided by arthropods in apple orchards: pollination and biological control. We used relative decrease in colonies to assess biological control of the major apple aphid pest, and measured pollination through fruit set, number of seeds per apple and pollinator visitation. Additionally, we monitored the organisms responsible for pollination and biological control services and established the impact of pollination on apple quality. Our results show a strong effect of organic management on biological control and on the temporal dynamic of natural enemy–pest interactions. Parameters such as aphid colony suppression, first and repeated occurrence of natural enemies, natural enemy species evenness and natural enemy abundance were significantly higher in organic compared to conventional orchards. Predatory bugs were the natural enemies best‐affected by organic management and played a key role in early predation of aphids preventing colony growth. In this instance, pollination was not influenced by organic management. It is likely due to the temporal scale at which this service is delivered, a scale that differs greatly from biological control, combined with differences in the dispersal capacity of the organisms involved. Fruit weight, calcium, potassium and magnesium content were positively affected by pollination success. Synthesis and applications. We found that organic management in apple orchards preserves the local natural enemy community, and specifically predatory bug populations, essential for early aphid colony suppression. Our results suggest that, in conventional orchards, local management options that decrease or even eliminate pesticide use early in the season would increase the biological control of aphids. This would lead to reduction in apple damage at harvest. Our results on pollination success indicate that the implementation of organic management at orchard scale does not enhance pollination services for apple growers

Aphid-infested beans divert ant attendance from the rosy apple aphid in apple-bean intercropping

Ecological intensification of cropping systems aims at restoring multi-functionality while supporting current productivity levels. Intercropping is a form of ecological intensification involving ecological processes beneficial to farmers that do not take place in monocultures. Thus, it represents a practical approach to decrease the use of synthetic inputs such as insecticides in cultivated systems. Whereas insecticide reduction via intercropping-facilitated suppression of aphids is reported in literature, the majority of published studies focussed on herbaceous crops. Thus, the effect of intercropping on aphid populations of cultivated trees remains largely unaddressed. In this study we hypothesized that intercropping a specific companion plant within perennial crops would divert ant attendance from an aphid attacking the crop to another aphid feeding on the newly introduced plant, reducing aphid damage on the crop. We tested our hypothesis in the system of apple (Malus domestica Borkhausen), the rosy apple aphid (Dysaphis plantaginea Passerini) and the black garden ant (Lasius niger L.). Bean plants (Vicia faba) with the black bean aphid (Aphis fabae Scopoli) were intercropped within apple trees inoculated with D. plantaginea. We measured ant attendance, aphid development and survival as well as honeydew composition on both plant species through semi-field and field experiments. The majority of ants chose to attend A. fabae over D. plantaginea in the semi-field experiment with potted plants. In the orchard, a larger majority of scouts were scored on A. fabae over D. plantaginea. A higher number of D. plantaginea colonies remained active in the apple control, whilst they were almost eradicated by intercropping. Although chemical analyses of honeydew disclosed differences in the carbohydrate and amino acid profiles between aphid species, the difference in honeydew composition did not explain the preference for A. fabae. Ants did not discriminate between the two honeydew mimics both in laboratory and field bioassays. Our results showed the potential of intercropping apple trees with beans as a method to reduce ant attendance and thus colony survival. We propose that intercropping represents a bottom-up approach towards ecological intensification of perennial crops. Together with other ecosystem-based measures such as habitat management, intercropping should be considered when planning ecosystem redesign to increase biological control of pests

Recruiting on the Spot: A Biodegradable Formulation for Lacewings to Trigger Biological Control of Aphids

Upon herbivory, plants release herbivore-induced plant volatiles (HIPVs), which induce chemical defenses in the plant as well as recruit natural enemies. However, whether synthetic HIPVs can be employed to enhance biological control in a cultivated crop in the field is yet to be explored. Here we show that a biodegradable formulation loaded with induced and food-signaling volatiles can selectively recruit the common green lacewing, Chrysoperla carnea, and reduce pest population under field conditions. In apple orchards, the new formulation attracted lacewing adults over a 4-week period, which correlated well with independent assessments of the longevity of the slow-release matrix measured through chemical analyses. In barley, lacewing eggs and larvae were significantly more abundant in treated plots, whereas a significant reduction of two aphid species was measured (98.9% and 93.6% of population reduction, for Sitobion avenae and Rhopalosiphum padi, respectively). Results show the potential for semiochemical-based targeted recruitment of lacewings to enhance biological control of aphids in a field setting. Further research should enhance selective recruitment by rewarding attracted natural enemies and by optimizing the application technique