In the spring, apple orchards are susceptible to freeze damage. Various approaches to orchard protection have been used in the past. Overhead sprinkling for bloom delay has been effective in extending to a later period in the spring the freeze hardiness of apple buds. Thus, protection against a late spring freeze is obtained. Previous research has not been conducted to determine optimum sprinkling times in the spring, the most effective threshold temperature, the amount of water needed to provide adequate bud protection, and the daily length of sprinkling time. A 2-year investigation was conducted with the objective of obtaining basic information to help in system design and the operational aspects of overhead sprinkling. The experiment was designed to determine the effectiveness of a system sprinkling beginning at the end of rest and at Celsius growing degree hour accumulations relating to stages bud development. The evaluation of limited and unlimited water use and the relation to bloom delay was obtained. The two sprinkler types studied were umbrella and impact. On the umbrella sprinklers, four cycling times (1/2, 1/3, 1/4, and 1/6 time) and three threshold temperatures (7, 10, and 13 C) were tested. On the impact sprinkler, three nozzle sizes (4.0, 3.6, and 2.8 mm) were evaluated. The investigation answered many questions, the most important of which were: (1) when only limited bloom delay is needed, more freeze protection can be obtained by sprinkling in the early spring than in the late spring; (2) bloom delay can be regulated by terminating sprinkling at different stages of bud development; (3) to obtain maximum delay, sprinkling should begin at the end of rest and a low threshold temperature for sprinkling should be used for sprinkler initiation; (4) when limited delay is required, greater efficiency of water use can be obtained by lowering the threshold temperature and lowering the application rate.

<p> The radiation balance of a dwarf apple orchard was evaluated. Results compared favourably with those for a single apple tree in an earlier investigation. Reflection, heating and longwave exchange coefficients were analysed. </p> <p> Transmitted global radiation was measured with moving and stationary sensors. Coefficients for the partitioning of incident global radiation were calculated. A relationship between photosynthetically active radiation and global radiation was established. Coefficients for the partitioning of incident photosynthetically active radiation were obtained and compared to the global radiation components. A problem associated with the measurement of transmitted radiation is discussed briefly. </p> / Thesis / Master of Science (MSc)

Identifying the resources that limit bee populations is essential both for bee conservation and pollination management in agroecosystems. Land-use change typically leads to decreased habitat availability for wild pollinators including loss of nesting habitat, which is an essential but often-overlooked resource for wild bees. Cavity-nesting bees, such as many Osmia spp. (Hymenoptera: Megachilidae), occupy holes in wood or reeds to build their nests; due to their nesting habits, they are frequently scarce in agricultural settings, although, under the right circumstances, these bees can be ideal pollinators of apple and other orchard crops. Artificial nesting structures (“bee hotels”, “trap nests”, or “nest boxes”) are used to study cavity-nesting bees and have been posited as solutions for promoting bee conservation. To evaluate the effects of additional nesting habitat on the local abundance of Osmia spp., and on bees more generally, artificial nesting structures for cavity-nesting bees were installed at 24 sites in apple orchards around Ottawa in 2021 and 2022. Each site had two treatments: one with nest boxes, and one without (control). Transect walks were conducted to measure overall bee contact (including contact by Osmia spp.) with apple blossoms and, after the end of apple bloom, with flowers in the undergrowth and/or in shrubs. Numbers of apple buds and developing fruit were also recorded. Osmia spp. and overall bee numbers were both significantly higher in the treatment with nest boxes (44% and 15% higher, respectively, in 2021, and 113% and 47% higher, respectively, in 2022); however, there was no difference in fruit set (apple count/bud count) between the two treatments. Thus, nest boxes seem to locally increase Osmia spp. numbers as well as total bee numbers, but they have no apparent effect on apple yield, likely because apple production was not pollinator limited in the years of this study. These findings suggest that bee populations in apple orchards are limited by nesting resources, which has important implications for orchard management practices and bee conservation policy.

L'intérêt des prédateurs généralistes dans la lutte biologique par conservation est peu étudié en verger de pommiers. Cette thèse visait à déterminer le rôle de prédateurs généralistes invertébrés (principalement carabes et araignées) et vertébrés (mésanges et chauves souris) dans le contrôle de trois ravageurs clés du pommier et de définir les éléments paysagers qui leur sont favorables. Pour cela, nous avons effectué des suivis de populations dans des vergers en agriculture biologique et nous les avons associés à des mesures de prédation des ravageurs par analyse moléculaire des contenus stomacaux et faeces des prédateurs à l'aide d'amorces spécifiques développées à cet effet. Nous montrons que les ravageurs sont consommés dès leur apparition dans les vergers, notamment les pucerons par les araignées de la frondaison, ce qui suggère que ces prédateurs ont un potentiel de régulation important. De plus une complémentarité temporelle semble exister entre araignées et carabes dans le contrôle des tordeuses. L'influence des éléments paysagers intra et extra verger diffère selon les taxa de prédateurs considérés. Ce dernier résultat suggère des compromis dans les aménagements à réaliser pour favoriser leur action et la nécessité d'une meilleure compréhension de leur écologie. / Generalist predators have been merely studied in conservation biological control studies in apple orchards. This work aimed to determine the potential of invertebrate (arthropods, mainly carabids and spiders) and vertebrate (great tits and bats) predators at suppressing three key apple pests and then to devise which landscape features are beneficial to them. For this purpose, we monitored pest and predator populations in organic apple orchards of southeastern France and related their abundance and diversity to measures of pest predation using molecular gut content and faeces analysis with specific primers designed for this purpose. We found that pests were consumed as soon as they arrived in the orchard, in particular aphid by canopy spiders, indicating that these predators are likely to be efficient. We also observed some temporal complementarity in predation of tortricids by spiders and carabids. Finally, the influence of landscape features within and surrounding the orchards was different for the different studied taxa suggesting the need for compromises in orchard management for enhancing natural enemy populations and for a better consideration of the ecology of these predators.

Made available in DSpace on 2016-12-08T16:44:39Z (GMT). No. of bitstreams: 1 PGPV11MA082.pdf: 598754 bytes, checksum: 43c782069b53e20aa6e95ab94d5ad243 (MD5) Previous issue date: 2011-05-30 / The South American fruit fly, Anastrepha fraterculus (Wiedermann, 1830) (Diptera: Tephritidae), is an important pest in temperate fruit production in Brazil. In apple orchards the insect causes damage to immature fruit, as well as fruits in the final stages of maturation. Control is done through broad spectrum application of phosphate insecticides or with toxic baits; both of which are facing increasing restrictions and limitations in their use. Unfortunately, there are few alternatives to control the South American fruit fly in orchard cultivations. This study compares toxic baits formulations containing a new insecticide, spinosad, to two commercially available baits: Biofruit® + Malathion and Success 0,02 CB®. The experiments were conducted in laboratory with adult A. fraterculus to assess their feeding responses, as well as the durability of each formulation under exposure to radiation and rain. The formulations tested were: a) ANA 01 - (23,0% SPLAT® + 24,2% attractant + 0,1% spinosad), b) ANA 02 - (40,0% SPLAT® + 24,2% attractant + 0,1% spinosad), c) ANA 03 - (49,0% SPLAT® + 24,2% attractant + 0,1% spinosad), d) ANA 04 - (49,0% SPLAT® + 20,2% attractant (less 4% from protein) + 0,1% spinosad), e) ANA 05 - (49,0% SPLAT® + 20,2% attractant (less 4% of sources of carbohydrate) + 0,1% spinosad), f ) Success 0,02 CB® - (attractant + spinosad), g) Malathion 1000 CE (0,15%) + hydrolyzed protein (Biofruit® 3%), and h) control using distilled water only. The efficacy of the formulations containing spinosad (ANA 02 and ANA 03) was equivalent to the commercial standards (Success 0,02 CB® and Biofruit® + Malathion) in terms of feeding responses at 96 hours after delivery of treatments. The ANA 03 and Success 0,02 CB® formulations showed greater resistance to solar radiation compared to the other treatments at 35 days after delivery, resulting in 48% fly mortality. For tests of formulation rain-fastness, all ANA treatments tested were more persistent during 20 mm and 50 mm of rainfall compared to the commercial standard formulations. The ANA 01 and Biofruit® + Malathion® formulations resulted in 50% fly mortality in the shortest amount of time; 6.61 hours and 8.71 hours respectively. The formulations that took the longest to achieve 50% mortality were ANA 03 (15,68 hours) and ANA 04 (15,50 hours). The restriction of protein attractant in the formulations reduced the fly response more so than restricting carbohydrates. The ANA 03 formulation was highly efficient in the control of A. fraterculus, equivalent to Success 0,02 CB® in both feeding responses and resistance to solar radiation, and outperforming all other treatments in terms of rain-fastness. In a second experiment this toxic bait was applied in two organic apple orchards (Gala) in São Joaquim, SC, to evaluate its impact on South American fruit fly populations. The test was conducted during two growing seasons 2009-10 and 2010-11, beginning at the end of thinning when fruits measured 20 mm in diameter, and continued until harvest. The ANA 03 formulation was distributed in the borders on natural vegetation and reapplied every two weeks. Sampling of captured adults was measured weekly in McPhail traps with torula yeast attractant. Damage evaluations were performed at the beginning of the harvest. Application of ANA 03 reduced the South American fruit fly populations by 74,24% and 66,21% in the first and second seasons respectively, when compared with the control fields. Even with a population reduction, the fruit damage did not differ significantly between treatments: ANA 03 (18,31% ±6,72) and control (30,99% ±8,01) in the first season. In the following year, the reduction in fruit damage was significantly different in the treated area (79,67% ±5,83) compared to the control (96,60% ±1,37). The toxic bait formulation ANA 03 has a significant impact on reducing A. fraterculus populations; however, it does not prevent flies from migrating into orchards / A mosca-das-frutas sul-americana Anastrepha fraterculus (Wiedemann, 1830) (Diptera:Tephritidae) é uma das pragas de maior importância para a fruticultura de clima temperado no Brasil. Na cultura de macieira o inseto causa danos em frutos imaturos, bem como nos estádios finais de maturação. O controle do inseto é feito através de aplicações inseticidas fosforados em cobertura ou com iscas tóxicas, sendo que poucas alternativas de manejo existem na cultura. Porém o uso de fosforados vem sofrendo restrições progressivas e a busca de novos inseticidas é uma necessidade premente. Este trabalho comparou a eficiência de formulações de iscas tóxicas contendo o inseticida espinosade com dois padrões comerciais Biofrut®+ Malathion e Success 0,02 CB®. As avaliações foram realizadas em laboratório com adultos de A. fraterculus quanto à resposta alimentar dos insetos, resistência dos tratamentos a radiação solar e à chuva. As formulações testadas foram: a) ANA 01 - (SPLAT® 23,00% + atrativo M7 24,20% + espinosade 0,1%); b) ANA 02 (SPLAT® 40,00% + atrativo M7 24,20% + espinosade 0,1%); c) ANA 03 (SPLAT® 49,00% + atrativo M7 24,20% + espinosade 0,1%); d) ANA 04 (SPLAT® 49,00% + atrativo M7 20,20% menos 4% de fontes proteicas + espinosade 0,1%); e) ANA 05 (SPLAT® 49,00% + atrativo M7 20,20% menos 4% de fontes de carboidrato (açúcar) + espinosade 0,1%); f) Success 0,02 CB® - (atrativos + espinosade); g) Malathion 1000 CE (0,15%) + proteína hidrolisada (Biofruit® 3%) e h) Testemunha água destilada. A eficiência das novas formulações contendo espinosade (ANA 02 e ANA 03) foram equivalentes aos padrões comerciais (Success 0,02 CB® e Biofruit®+ Malathion) quanto a resposta alimentar em 96 HAF (horas após o fornecimento dos tratamentos). Para os testes de resistência à irradiação solar as formulações ANA 03 e Success 0,02 CB® foram superiores aos demais tratamentos 35 DAF (dias após o fornecimento). Quanto ao efeito da chuva observou-se que as formulações ANA foram superiores aos demais tratamentos tanto para lâminas de 20 mm, como de 50 mm de chuvas. As iscas tóxicas ANA 01 e Biofruit®+ Malathion apresentaram os menores valores de TL (tempo letal) 50 com 6,61 e 8,71 horas respectivamente. Os maiores valores de TL50 foram registrados para as formulações ANA 03 (15,68 horas) e ANA 04 (15,50 horas). A restrição de atrativos proteicos nas iscas tóxicas reduz a resposta alimentar dos insetos com maior intensidade que a de carboidratos (açúcares). A formulação ANA 03 apresentou alta capacidade no controle de Anastrepha fraterculus sendo equivalente a isca comercial Success 0,02 CB® nos testes de resposta alimentar e resistência a radiação. Nos testes com chuva simulada, o tratamento ANA 03 foi superior aos demais tratamentos. Esta formulação foi utilizada em pomares orgânicos de macieira na região de São Joaquim, SC para avaliação do efeito de aplicações da isca na borda do pomar sobre populações da mosca-das-frutas. As avaliações foram conduzidas durante duas safras (2009/2010 e 2010/2011), com aplicações iniciadas após o fim do raleio - frutos com até 20 mm de diâmetro e conduzidas até a colheita da cultivar Gala. A isca foi distribuída nas plantas espontâneas da periferia dos pomares e reaplicada quinzenalmente. A amostragem de adultos foi feita semanalmente com armadilhas McPhail e atrativo torula. As avaliações de danos em frutos foram feitas em plantas marcadas no início da colheita. As aplicações reduziram as populações de adultos da mosca-das-frutas capturados nas armadilhas em 74,24% e 66,21% na primeira e segunda safra respectivamente, em comparação com a área testemunha. Mesmo com a redução nos níveis populacionais, os danos em frutos não diferenciaram significativamente entre os tratamentos com isca (18,31%±6,72) e testemunha (30,99%±8,01) na primeira safra. No segundo ano a redução de danos foi significativa na área tratada (79,67%±5,83) em comparação com a testemunha (96,60%±1,37). Conclui-se que a isca tóxica ANA 03 tem efeito sobre as populações do inseto, mas não impede o acesso das moscas-das-frutas às áreas de produção resultando em danos significativos nos frutos

This study investigated understorey management in Canterbury, New Zealand, apple orchards for the enhancement of populations of Dolichogenidea tasmanica (Cameron) (Braconidae) for leafroller (Lepidoptera: Tortricidae) biological control. The first objective was to determine the influence of understorey plants on the abundance of D. tasmanica and leafroller parasitism, and to investigate the mechanisms behind this influence. The second was to determine the most suitable understorey plants in terms of their ability to enhance parasitoid abundance, leafroller parasitism, parasitoid longevity, parasitoid fecundity and its ability to not benefit leafroller. Results from three consecutive field trials showed that buckwheat (Fagopyrum esculentum Moench), coriander (Coriandrum sativum L.), alyssum (Lobularia maritima (L.) Desv), and, to a lesser extent, broad bean (Vicia faba L.), enhanced parasitoid abundance and leafroller parasitism. The mechanisms behind the effects of understorey plants had previously been unexplored. However, results here showed that it was the flowers or the buckwheat that 'attracted' the parasitoid to the plant and not the shelter, aphids or microclimate that the plant may also provide. Providing flowering plants in the orchard understorey also increased immigration of parasitoids and enhanced parasitoids and enhanced parasitoid longevity and fecundity in the laboratory. In contrast, the understorey plants had no influence on the female:male ratio of D. tasmanica. Although coriander enhanced leafroller parasitism three-fold in field experiments compared with controls, it failed to enhance the longevity of both sexes of D. tasmanica in the laboratory compared with water-only. Broad bean significantly enhanced parasitoid abundance three-fold and significantly increased parasitism from 0% to 75% compared with the controls on one leafroller release date. However, laboratory trials showed that of male D. tasmancia but it did not enhance female longevity. Also, female D. tasmanica foraging on broad bean produced a total of only three parasitoid cocoons, but this result was based on an overall 6.5% survival of larvae to pupae or to parasitoid cocoon. Furthermore, results suggested that extrafloral nectar secretion decreased as the plants matured. Phacelia (Phacelia tanacetifolia Benth.) did not significantly enhance parasitism rate in the field compared with controls, and numbers of D. tasmanica captured by suction sampling were significantly lower in phacelia treatments compared with alyssum, buckwheat and control plots. Also, laboratory experiments showed that survival of D. tasmanica on phacelia flowers was equivalent to that on water-only and significantly lower than on buckwheat. These results suggest that phacelia does not provide nectar to D. tasmanica, only pollen, and therefore is not a suitable understorey plant for D. tasmanica enhancement in orchards. Buckwheat and alyssum showed the most potential as understorey plants for the enhancement of natural enemies. Buckwheat not only increased numbers of D. tasmanica seven-fold, but also increased numbers of beneficial lacewings (Micromus tasmaniae (Walker)) and hover flies (Syrphidae) captured on yellow sticky traps compared with the controls. It significantly increased leafroller parasitism by D. tasmanica from 0% to 86% compared with the controls (on one date only), and in the laboratory enhanced D. tasmanica longevity and increased fecundity compared with water-only. Similarly, alyssum significantly increased parasitism rate compared with controls, and two-fold more D. tasmanica were suction sampled in these plots compared with controls. It also enhanced longevity of both sexes of D. tasmanica compared with water, and showed the most favourable characteristics in terms of being of no benefit to leafrollers. This is because it was not preferred over apple by leafroller larvae and when they were forced to feed on it, it caused high mortality (94.3%) and low pupal weight (15 mg). Furthermore, alyssum did not enhance the number of fertile eggs produced by adult leafrollers compared with water only. However, further research is required to address the overall effect of buckwheat and alyssum on crop production and orchard management, including effects on fruit yield and quality, frost risk, disease incidence, soil quality, weeds and other pests. Also, research into the ability of these plants to survive in the orchard with little maintenance, and into the optimal sowing rates, would be useful. Sampling natural populations of leafroller within each treatment showed that damage from leafrollers and the number of leafroller larvae were respectively 20.3% and 29.3% lower in the flowering treatments compared with the controls. Furthermore, field trials showed up to a six-fold increase in leafroller pupae in controls compared with buckwheat and alyssum. This suggests that increasing leafroller parasitism rate from understorey management in orchards will translate into lower pest populations, although neither larval numbers/damage nor pupal numbers differed significantly between treatments. Trapping D. tasmanica at a gradient of distances showed that this parasitoid travels into rows adjacent to buckwheat plots, indicating that growers may be able to sow flowering plants in every second or third row of the orchard, and still enhance leafroller biocontrol while minimising the adverse effects of a cover crop. Sowing buckwheat and alyssum in orchard understoreys may enhance biological control of apple pests in organic apple production and reduce the number of insect growth regulators applied in IFP programmes. However, the challenge still remains to investigate whether conservation biological control can reduce leafroller populations below economic thresholds.

This study investigated understorey management in Canterbury, New Zealand, apple orchards for the enhancement of populations of Dolichogenidea tasmanica (Cameron) (Braconidae) for leafroller (Lepidoptera: Tortricidae) biological control. The first objective was to determine the influence of understorey plants on the abundance of D. tasmanica and leafroller parasitism, and to investigate the mechanisms behind this influence. The second was to determine the most suitable understorey plants in terms of their ability to enhance parasitoid abundance, leafroller parasitism, parasitoid longevity, parasitoid fecundity and its ability to not benefit leafroller. Results from three consecutive field trials showed that buckwheat (Fagopyrum esculentum Moench), coriander (Coriandrum sativum L.), alyssum (Lobularia maritima (L.) Desv), and, to a lesser extent, broad bean (Vicia faba L.), enhanced parasitoid abundance and leafroller parasitism. The mechanisms behind the effects of understorey plants had previously been unexplored. However, results here showed that it was the flowers or the buckwheat that 'attracted' the parasitoid to the plant and not the shelter, aphids or microclimate that the plant may also provide. Providing flowering plants in the orchard understorey also increased immigration of parasitoids and enhanced parasitoids and enhanced parasitoid longevity and fecundity in the laboratory. In contrast, the understorey plants had no influence on the female:male ratio of D. tasmanica. Although coriander enhanced leafroller parasitism three-fold in field experiments compared with controls, it failed to enhance the longevity of both sexes of D. tasmanica in the laboratory compared with water-only. Broad bean significantly enhanced parasitoid abundance three-fold and significantly increased parasitism from 0% to 75% compared with the controls on one leafroller release date. However, laboratory trials showed that of male D. tasmancia but it did not enhance female longevity. Also, female D. tasmanica foraging on broad bean produced a total of only three parasitoid cocoons, but this result was based on an overall 6.5% survival of larvae to pupae or to parasitoid cocoon. Furthermore, results suggested that extrafloral nectar secretion decreased as the plants matured. Phacelia (Phacelia tanacetifolia Benth.) did not significantly enhance parasitism rate in the field compared with controls, and numbers of D. tasmanica captured by suction sampling were significantly lower in phacelia treatments compared with alyssum, buckwheat and control plots. Also, laboratory experiments showed that survival of D. tasmanica on phacelia flowers was equivalent to that on water-only and significantly lower than on buckwheat. These results suggest that phacelia does not provide nectar to D. tasmanica, only pollen, and therefore is not a suitable understorey plant for D. tasmanica enhancement in orchards. Buckwheat and alyssum showed the most potential as understorey plants for the enhancement of natural enemies. Buckwheat not only increased numbers of D. tasmanica seven-fold, but also increased numbers of beneficial lacewings (Micromus tasmaniae (Walker)) and hover flies (Syrphidae) captured on yellow sticky traps compared with the controls. It significantly increased leafroller parasitism by D. tasmanica from 0% to 86% compared with the controls (on one date only), and in the laboratory enhanced D. tasmanica longevity and increased fecundity compared with water-only. Similarly, alyssum significantly increased parasitism rate compared with controls, and two-fold more D. tasmanica were suction sampled in these plots compared with controls. It also enhanced longevity of both sexes of D. tasmanica compared with water, and showed the most favourable characteristics in terms of being of no benefit to leafrollers. This is because it was not preferred over apple by leafroller larvae and when they were forced to feed on it, it caused high mortality (94.3%) and low pupal weight (15 mg). Furthermore, alyssum did not enhance the number of fertile eggs produced by adult leafrollers compared with water only. However, further research is required to address the overall effect of buckwheat and alyssum on crop production and orchard management, including effects on fruit yield and quality, frost risk, disease incidence, soil quality, weeds and other pests. Also, research into the ability of these plants to survive in the orchard with little maintenance, and into the optimal sowing rates, would be useful. Sampling natural populations of leafroller within each treatment showed that damage from leafrollers and the number of leafroller larvae were respectively 20.3% and 29.3% lower in the flowering treatments compared with the controls. Furthermore, field trials showed up to a six-fold increase in leafroller pupae in controls compared with buckwheat and alyssum. This suggests that increasing leafroller parasitism rate from understorey management in orchards will translate into lower pest populations, although neither larval numbers/damage nor pupal numbers differed significantly between treatments. Trapping D. tasmanica at a gradient of distances showed that this parasitoid travels into rows adjacent to buckwheat plots, indicating that growers may be able to sow flowering plants in every second or third row of the orchard, and still enhance leafroller biocontrol while minimising the adverse effects of a cover crop. Sowing buckwheat and alyssum in orchard understoreys may enhance biological control of apple pests in organic apple production and reduce the number of insect growth regulators applied in IFP programmes. However, the challenge still remains to investigate whether conservation biological control can reduce leafroller populations below economic thresholds.