Pome Fruit Orchards Research Articles

Application of sulfur-based products reduces Halyomorpha halys infestation and damage in pome fruit orchards.

The brown marmorated stink bug, Halyomorpha halys (Stål, 1855) (Hemiptera: Pentatomidae) is an invasive pest that causes economic damage on crops, decreasing fruit yield and quality. Conventional insecticides are frequently used to reduce infestations, but these are often with a limited residual effect, besides being costly and detrimental to nontarget organisms and the environment. In integrated pest management, novel strategies against H. halys are proposed, such as the use of alternative substances with an effect on insect behaviour and mobility. As one of the oldest multi-site fungicides applied against fungal pathogens and as an insecticide and acaricide to control scales and mites, sulfur is proposed here to reduce H. halys infestation in fruit orchards. Field experiments were performed to evaluate the effect of repeated wettable sulfur applications on H. halys in apple and pear orchards. Sulfur-induced plant phytotoxicity effects and quanti-qualitative parameters on apple fruits were also recorded. Halyomorpha halys infestation was significantly reduced in sulfur-treated compared to untreated pears and apples. Furthermore, sulfur sprays reduced fruit damage caused by H. halys. Besides, sulfur-mediated phytotoxicity such as symptoms on leaves and fruit drop were not observed. Fruit quality was not influenced by sulfur treatments. Wettable sulfur seems to be a promising formulation given the low phytotoxicity, considering the technical aspects for an effective use of sulfur-based products to counteract H. halys in pome fruit orchards. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Peculiarities of bacteriosis development in agrocenosis of pome fruit orchards

Goal. Was to determine ssources of bacterium diseases of pome fruits in agrocenoses and their seasonal development study and factors, which impacts on plants defeating level.
 Methods. Field (route, selective and continuous studies) and laboratory (extracting pure bacterium cultures, determining pathogenicity, identifying through the sum of morpho-cultural and their physiological and biochemical features).
 Results. There were determined the defeating peculiarities of pome fruits by bacteriosis defeating on pome fruits during the investigation in 2011—2015 and 2021—2023. Their causative agents was conformed by bacterium extraction from plant material. The most intensive bacterial necrosis happened in spring, during the period of juice intensive movement, when the tree is the most favorable to defeating. The defeating observed only on some shoots in summer (to 5% from the volume of tree crown), but the cancer development continued on the trunk’s bark. The first symptoms of fire blight observed during blossoming and at the beginning of fruit setting. The full picture opened during the shoots’ active growth. The shoots` defeating level was in the scope of 3—12% and only on some trees reached 15—18%. The fire blight strong defeat (to 55% of crown tree) observed in 2015 through the mass propagation pear-tree psylla. New fire blight sources were not identified in Chernivtsi region in 2021—2023.There were only presence of bacterial necrosis causative agent.
 Conclusions. The bacteriosis defeating determined and researched in plantations Chernivtsi and Vinnytsia regions. The highest fire blight defeating level (to 55% of crown) connected with mass propagations of pear-tree psylla. It is the main pathogen carrier. The bacterium necroses defeating depends upon the weather conditions of weather period and following the necessary level of agrotechnical measures. The investigation scheme for pome fruits bacteriosis determined developed with phenological phases terms considerations and periods of the most plants susceptibility to phytopathogens defeating.

Early Detection of Potential Infestation by Capnodis tenebrionis (L.) (Coleoptera: Buprestidae), in Stone and Pome Fruit Orchards, Using Multispectral Data from a UAV

Wood-boring insect pests pose a significant threat to orchards, potentially leading to tree mortality. In the initial stages of infestation, no visible symptoms are apparent, but as infestations progress, rapid and widespread symptoms emerge, resulting in accelerated tree decline. Therefore, the timely detection of early wood-boring insect symptoms is critical for effective pest control, necessitating advanced methods such as remote sensing. In this study, remote sensing is utilized to identify the early symptoms of peach flatheaded root borer (PFRB) infestation in trees. A multispectral sensor attached to a UAV captures aerial imagery data from stone fruit and pome fruit orchards. These data undergo processing in photogrammetric and GIS programs, where NDVI, NDRE, and the tree crown area are computed. On-site observations confirm PFRB infestations. Various machine-learning models, including logistic regression (LR), artificial neural network (NN), random forest (RF), and extreme gradient boosting (XGBoost), are compared using mean NDVI values, mean NDRE values, crown area, mean temperature, and mean relative humidity. Mean NDVI values emerge as the most crucial factor for predicting PFRB infestation across all machine-learning models. The XGBoost model proves the most effective, achieving an accuracy of 0.85, with marginal variations from the other tested models.

Turning a Pest into a Natural Enemy: Removing Earwigs from Stone Fruit and Releasing Them in Pome Fruit Enhances Pest Control.

The European earwig Forficula auricularia (L.) (Dermaptera: Forficulidae) is an omnivorous insect that is considered a minor pest of stone fruit and a key predator of pests in pome fruit orchards. In many pome fruit orchards, earwigs are absent or in low abundance due to broad-spectrum spray programs and the slow recolonization rate of earwigs. Orchards in transition to organic or "selective" conventional programs often struggle to achieve effective levels of biological control, and thus, may benefit from inoculating earwigs to expedite their re-establishment. In a two-year study, we evaluated the potential for mass trapping earwigs from stone fruit using rolled cardboard traps to reduce fruit damage and provide earwigs for augmentation in pome fruit. We also tested whether a single mass release or five releases (on alternating weeks) of the same total number of earwigs in apples and pears reduced pests relative to plots where no releases occurred. Mass trapping did not decrease earwig abundance or substantially reduce fruit damage in stone fruit orchards. However, trapping was an efficient method for providing earwigs for augmentation. Earwig abundances were only increased in orchards where earwigs were previously low or absent; however, multiple orchards with varying prior levels of earwigs exhibited reductions in key pests (woolly apple aphid and pear psylla). For some other pests evaluated, plots with mass releases of earwigs had a slight trend in overall lower pest density when compared with control plots. A strategy for moving earwigs out of stone fruit orchards and into pome fruit orchards could be an effective method for augmenting orchard predator populations.

Aquatic Risks at the Landscape Scale: A Case Study for Pyrethroid Use in Pome Fruit Orchards in Belgium.

Procedures for environmental risk assessment for pesticides are under continuous development and subject to debate, especially at higher tier levels. Spatiotemporal dynamics of both pesticide exposure and effects at the landscape scale are largely ignored, which is a major flaw of the current risk assessment system. Furthermore, concrete guidance on risk assessment at landscape scales in the regulatory context is lacking. In this regard, we present an integrated modular simulation model system that includes spatiotemporally explicit simulation of pesticide application, fate, and effects on aquatic organisms. As a case study, the landscape model was applied to the Rummen, a river catchment in Belgium with a high density of pome fruit orchards. The application of a pyrethroid to pome fruit and the corresponding drift deposition on surface water and fate dynamics were simulated. Risk to aquatic organisms was quantified using a toxicokinetic/toxicodynamic model for individual survival at different levels of spatial aggregation, ranging from the catchment scale to individual stream segments. Although the derivation of landscape-scale risk assessment end points from model outputs is straightforward, a dialogue within the community, building on concrete examples as provided by this case study, is urgently needed in order to decide on the appropriate end points and on the definition of representative landscape scenarios for use in risk assessment.

An Overview of Pest and Disease Occurrence in Organic Pome Fruit Orchards in Europe and on the Implementation of Practices for Their Control

There is limited data regarding the specific problems faced by organic fruit growers when dealing with plant protection, particularly at a European Union level, though some general knowledge about pest and disease incidence can be found. Such information is crucial to improve the efficacy of a targeted knowledge transfer to organic fruit growers and advisors aiming at an increased adoption of innovative practices. A survey was thus carried out in seventeen European countries (16 EU member states and Switzerland), within the framework of the EU-funded project BIOFRUITNET, aiming at filling this knowledge gap also in terms of research needs. A questionnaire including a section about general aspects of orchard management (functional biodiversity, fertilization management, varietal/rootstock selection) and a section specifically dedicated to pest and disease occurrence and management in organic orchards was utilized to interview about 250 professionals (farmers and advisors), 155 of which were involved in pome fruits (including apple and pear) production. The analysis of the answers related to plant protection pointed out a varied situation about pest and disease occurrence in apple and pear orchards across Europe, though related to the zonal location of the respondent. However, more than 50% of respondents generally considered just few among the most damaging ones, normally co-occurring in the orchards. Interestingly, regardless of the respondents’ nationality or zonal location, more pests than diseases were indicated as relevant agents threatening organic pome fruits production. Nevertheless, only few measures promoting functional biodiversity in the orchards resulted in being broadly implemented in all regions. The analysis of the data underlines the strong demand for the development of a toolbox of measures that can be integrated successfully into the general orchard management strategy including the successful enhancement of functional or general biodiversity.

BIOLOGICAL CONTROL OF CODLING MOTH, CYDIA POMONELLA (L.) IN APPLE ORCHARDS OF BULGARIA USING GINKO® DISPENSERS

The codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), is a significant pest of pome fruit and walnut orchards worldwide and it is a particular problem in Bulgaria. Codling moth resistance to many insecticides has been recently detected in Bulgaria. Codling moth (CM) mating disruption with Ginko® dispensers was evaluated in four successive years from 2019 to 2022 as part of an anti-resistance strategy. In an isolated 3 ha apple orchard in the Plovdiv district of South-Central Bulgaria, close to the town of Perushtitsa, field tests were conducted for the control of the codling moth (CM), C. pomonella, via mating disruption (MD) using pheromone Ginko® dispensers. The pheromone dispensers were hung in the upper third of tree canopies with a density of 500 dispensers/ha before CM flight started. Dynamics of CM flights was monitored by pheromone traps installed in the trial plot and in a conventionally treated reference orchard. Two types of baits were used in the traps: PHEROCON® CM L2–codlemone lures and PHEROCON® CM DA COMBO-P + AA lures (Trécé Inc., USA) in the orchards for mating disruption. The PHEROCON® CM L2 lures were changed at 4-week intervals and PHEROCON® CM DA COMBO-P + AA lures at 8-week intervals. PHEROCON® VI Delta sticky traps baited with PHEROCON CM DA COMBO- P + AA lures and standard CM L2 caps were installed, for comparison, in a reference orchard located in the Plovdiv region. Fruit infestation was periodically assessed till the harvest time. In both years fruit damage remained lower till late July and increased slightly only in August. At harvest, fruit damage remained below 1%. It was obvious that mating disruption could be useful strategy for the control of codling moth in Bulgarian apple orchards, specifically when the plot is isolated from external sources of infestation and the population density of the pest is low.

Fire blight resistance, irrigation and conducive wet weather improve Erwinia amylovora winter survival in cankers.

Erwinia amylovora causes fire blight, a disease responsible for enormous economic losses in the pome fruit-producing areas where it is present. Despite the abundant research on fire blight, information about E. amylovora population dynamics and survival in fire blight cankers and the plant defense responses to this pathogen in the infected bark are limited. In our study, we obtained fire blight cankers in apple, pear, and Asian pear cultivars showing differing resistance to the disease by shoot inoculation with E. amylovora. We collected cankers from irrigated and non-irrigated trees every 3 months in two independent field experiments and analyzed samples by viability digital PCR. We also assessed the expression of pathogenicity-related (PR) genes in the bark of selected apple and Asian pear cultivars. A logistic regression analysis revealed the impact of environmental and host factors on E. amylovora detection rates in cankers. The chances of detecting live E. amylovora cells in cankers increased significantly in those collected from irrigated trees, in July, and/or during an experiment performed in a year with an expected average rainfall when compared to samples from non-irrigated trees, collected in January, and/or during an experiment performed under environmental conditions dominated by drought. We found a positive correlation between the pathogen detection rates in cankers and the host resistance to fire blight that might be explained by lower E. amylovora survival rates in more damaged tissues of susceptible hosts. The genes PR-1, PR-2, PR-5, and PR-8 were induced in the bark surrounding apple and Asian pear fire blight cankers. Our study, involving the analysis of more than 800 canker samples, provides new knowledge about the fire blight disease cycle and lays the foundation for improved fire blight management and eradication strategies in pome fruit orchards.

A Synthetic Blend of Fruit and Live Yeast Odours Shows Promise for Trapping Mated Female Queensland Fruit Fly, Bactrocera tryoni, in the Field.

Tephritid fruit flies are major horticultural pests of fruit and vegetable crops. Developing an odour lure that can attract mated female flies under field conditions has presented a major challenge to chemical ecologists around the globe. We have designed a new lure to attract female Queensland fruit fly, Bactrocera tryoni, based on the knowledge that this pest tephritid is attracted not only to odours from ripening fruits, but also to odours of symbiotic (gut-associated) yeasts on which the larvae feed. Initial field trials screened four volatile mixtures, each containing a base mix of three, short-chain "fruit ripening" esters and differing in the addition of long-chain "fruity" esters and / or alcohols produced by live yeasts. Results demonstrated that the lure formulated from short-chain esters and live yeast alcohols attracted the most female flies, with significantly higher catches than an odourless control trap, and a protein-baited trap. As electrophysiological studies exploring peripheral responses in tephritids to alcohols associated with fermentation have not been extensively investigated, we conducted this work on both the antennae and maxillary palps, and discovered that three yeast alcohols were detected by both sensory organs. Performance trials conducted in pome fruit and stone fruit orchards evaluated the six-component blend of short-chain ester and live yeast alcohol lure against a commercially available synthetic fruit-odour lure and a protein-based lure. In the apple orchard, the new lure caught significantly more female flies, and in particular mated females, compared to the commercially available lures. In the stone fruit orchard, while the new lure again caught the most mated female flies compared to the other lures, differences were not significant. The visual stimulus (trap design) used had a significant effect on capture, with a Ladd trap (red sphere on a yellow panel) being considerably more effective than the other traps. We discuss the implications of this study, including why the degree of effectiveness of the new lure might have differed among the test orchards (citrus, apple, stonefruit), and why yeast odours might increase attractiveness to "ripening fruit" volatile blends under field conditions.

In vitro and in vivo activity of chemical fungicides and a biofungicide for the control of wood diseases caused by botryosphaeriales fungi in apple and pear

Dieback and canker disease caused by species of Botryosphaeriales affect the productivity of pome fruit orchards. In this study, we evaluated the efficacy of fungicides and biofungicide for controlling canker and dieback diseases in apple and pear using in vitro and field trials. Isolates of Diplodia seriata, D. mutila, and Dothiorella omnivora from apple, and of D. seriata and Aplosporella aquifolii from pear were used. Cercobin® (thiophanate-methyl), followed by Bellis® (pyraclostrobin + boscalid), and Nativo® (tebuconazole + trifloxystrobin) inhibited mycelial growth, conidial germination and pycnidia formation in vitro in all fungal isolates. T. harzianum produced mycelial growth inhibition and mycoparasitism in dual culture assays. Thiophanate-methyl and T. harzianum fully inhibited pycnidia production, while pyraclostrobin + boscalid and tebuconazole + trifloxystrobin were most effective against conidia germination. In the orchard assays, protective sprays of the fungicides on pruning wounds reduced incidence by up to 20%, while T. harzianum and tebuconazole + trifloxystrobin reduced the lesion severity up 37 and 41%, respectively. This study represents the first evaluation of fungicides and biofungicide effectiveness for the control of canker and dieback diseases of apples and pears in Argentina.

Winter activity of Clubiona spiders and their potential for pest control

Winter-active arthropod predators (like vegetation-dwelling spiders) significantly suppress pest populations during winter in pome fruit orchards in Central Europe. Clubiona spiders are very abundant in orchards and have been observed to be active during winter. Here, we performed laboratory experiments to assess the movement and predation activity of clubionids at low temperatures. In addition, we also assessed prey survival (psyllids and crickets). We revealed that Clubiona spiders actively moved even at a temperature below 0 °C. Pest prey (Cacopsylla sp.) was able to survive at low temperatures, but crickets died at 3 and -1 °C. Overall Clubiona activity was very low but present during the whole observation period of five days. The predation activity of Clubiona declined with lower temperatures for both cricket and pest (Cacopsylla sp.) prey. Nevertheless, 44% and 25% of Clubiona individuals captured and consumed psyllid and cricket prey, respectively, even at the lowest temperature of −1 °C. Our results show that Clubiona spiders are active predators at low temperatures and, therefore, should contribute to the suppression of overwintering pest populations.

Interactions of predatory coccinellids (Coleoptera: Coccinellidae) and aphids (Hemiptera: Aphididae) in pome and stone fruit orchards of Çanakkale Province

This study revealed the tritrophic interactions of predatory coccinellids-host aphids-host plants on pome and stone fruit trees and herbaceous plants in fruit orchards of Çanakkale Province, Turkey. Field sampling was done during the spring and summer seasons in 2020 and 2021. Twelve predatory species belonging to eight genera from the family Coccinellidae (Coleoptera) were found interacting with eleven host aphids from the family Aphididae (Hemiptera) on eight host plants. A total of 33 tritrophic interactions of predatory coccinellids-host aphids-host plants were revealed on the pome and stone fruit orchards in the Çanakkale Province. From the predators, Harmonia axyridis (Pallas) associated with seven aphids was the most common coccinellid, followed by Oenopia conglobata (L.) which was associated with six aphids. From the aphids, Brachycaudus helichrysi (Kaltenbach) was the most common species; it was associated with ten different predatory coccinellids. Also, from the host plants, the highest number of the interactions of predatory coccinellids-host aphids were revealed on Cydonia oblonga Mill. (Rosaceae) and Prunus domestica L. (Rosaceae) in the pome and stone fruit orchards of Çanakkale Province. As a result, it is considered that the tritrophic interactions of predatory coccinellids-host aphids-host plants should be better understood to increase the success of biological control of pest aphids on the fruit orchards.

Determination of thrips (Thysanoptera) fauna on stone and pome fruit trees in Balıkesir province, Turkey

This study was carried out to identify species belonging to Thysanoptera in stone and pome fruit orchards in the districts (Balya, Bandırma, Bigadiç, Burhaniye, Dursunbey, Erdek, Gönen, Havran, Kepsut and Manyas) of Balıkesir Province, Turkey in 2018 and 2019. The survey revealed 32 Thysanoptera (thrips) species. Thrips were examined in 9900 flowers, leaves, and fruits from 198 orchards during the research. The most widespread (total number of samples) and abundant (total number of individuals) species were: Taeniothrips inconsequens (Uzel) (Thripidae: Thysanoptera) (158 specimens- 2922 individuals), Haplothrips reuteri (Karny) (Phlaeothripidae: Thysanoptera) (76- 529), Thrips meridionalis (Priesner) (55- 359) and Thrips minutissimus Linnaeus (21- 209) (Thripidae: Thysanoptera). The highest number of thrips specimens were detected from cherry (Prunus avium L.), followed by apple (Malus domestica L.), peach (Prunus persica Batsch), and plum (Prunus domestica L.) trees. Ta. inconsequens predominated the thrips fauna on peach and cherry. H. reuteri was the most abundant species on pear. Thrips were found in 41.94% of flowers, while they were detected in 1.83% and 1.16% of fruit and leaves. This study was designed to fill the gaps in the data such as diversity in plant species associated, spatial distribution on plant parts, and temporal distribution in relation to phenological periods.

Habitat niches suggest that non-crop habitat types differ in quality as source habitats for Central European agrobiont spiders

Non-crop habitats in agricultural landscapes may differ in their potential to serve as source habitats for natural enemies. To determine this potential for different habitat types, it is crucial to understand habitat preferences and the habitat niche width of natural enemies. In addition, populations of natural enemies are affected by management practices depending on their preferences for habitat strata. Here we analysed agrobiont spider preferences (very common species in arable fields) for different microhabitats (ground, herbaceous, and shrub strata) and non-crop habitats (agroecosystems, forests, scrub, meadows, steppe, and wetlands). We compared guild-specific preferences of cursorial and web-building spiders that inhabit pome fruit orchards and cereal fields using two databases on Central European spider preferences. The majority of agrobiont spiders showed a moderate niche width. Agrobiont spiders from orchards preferred the shrub stratum while spiders from cereal fields preferred the ground and herbaceous strata across habitats. Agrobiont spiders primarily utilized non-crop habitats that were structurally similar to a particular agroecosystem: spiders from orchards utilized mostly woody vegetation while spiders from cereal fields utilized mostly meadows. Moreover, cursorial and web-building spider species from cereal fields differed in their preferences for different non-crop habitats. The results highlight that non-crop habitats have different potential as sources of agrobiont spiders. The composition of non-crop habitats in agricultural landscapes may affect the functional composition and pest control potential of spider communities. Further studies focusing on the effects that landscapes have on natural enemies in local agroecosystem need to account for the identity of non-crop habitats.

Automation and robotics in the cultivation of pome fruit: Where do we stand today?

AbstractThe cultivation of apples and pears in orchards consists of several tasks that still demand much human labor. The cost of this skilled labor increases while the number of competent seasonal workers becomes insufficient. These facts are a threat to the fruit industry. To find a solution, this paper addresses current as well as future automation possibilities for the main orchard tasks as a profitable alternative to human labor. Besides an activity research in pome fruit orchards, this paper contains an overall review of the research and developments that have been performed to automate each major activity (e.g., pruning, thinning, spraying, harvesting and mobile navigating) in the cultivation of pome fruit. These tasks are individually evaluated on feasibility and profitability of the developed automations. Finally, this paper concludes that, despite the large amount of research, almost no fully automated and cost‐efficient solution has been developed. A possible option to increase the viability of the prototypes might be the simplification of the tree structures, and consequently the orchard architecture, to make it “robot‐ready.” Another option in this perspective is combining several techniques, for accomplishing individual tasks, in one multipurpose robot platform. As a result, the usability and efficiency of the robot increases.

Conservation value of pome fruit orchards for overwintering birds in southeastern France

Bird survival in winter relies on the availability of key population resources such as food, shelter and resting sites. In annual crops, intensive crop management has been shown to affect bird communities through a reduction in winter resources, but much less is known about perennial crops. In this study, we performed bird surveys in 30 orchards for two years to investigate how abundance, species richness and evenness in wintering bird communities were affected by the availability of unharvested fruits in pome fruit orchards and of fruiting ivy in surrounding hedgerows. We further investigated how these resources depend on orchard management. We observed 41 bird species overall, among which 13 were of conservation concern. Bird abundance was mainly driven by the number of unharvested fruits and to a lesser extent by the number of ivy bearing trees. Bird species richness was primarily driven by the number of ivy bearing trees. This result was consistent with analyses at the species level, indicating that the occurrence of seven species (Sylvia atricapilla, Parus caeruleus, Parus major, Erithacus rubecula, Turdus iliacus, Turdus merula, and Turdus philomelos) was significantly dependent on the number of ivy-bearing trees. Interestingly, compared to organic orchards, non-organic (conventional and integrated) orchards had significantly more unharvested apples because of the absence of prophylactic measures against pests, thus providing wintering birds with more available resources. Our study supports the conservation value of commercial pome fruit orchards for Palearctic bird species overwintering in Southern Europe.

Fire Blight Monitoring in Pear Orchards by Unmanned Airborne Vehicles (UAV) Systems Carrying Spectral Sensors

Controlling fire blight in pear production areas depends strongly on regular visual inspections of pome fruit orchards, nurseries and other hosts of Erwinia amylovora. In addition, these inspections play an essential role in delineating fire blight free production areas, which has important implications for fruit export. However, visual monitoring is labor intensive and time consuming. As a potential alternative, the performance of spectral sensors on unmanned airborne vehicles (UAV) or drones was evaluated, since this allows the monitoring of larger areas compared to the current field inspections. Unlike more traditional remote sensing platforms such as manned aircrafts and satellites, UAVs offer a higher flexibility and an extremely high level of detail. In this project, a UAV platform carrying a hyperspectral COSI-cam camera was used to map a heavily infected pear orchard. The hyperspectral data were used to assess which wavebands contain information on fire blight infections. In this study, wavelengths 611 nm and 784 nm were found appropriate to detect symptoms associated with fire blight. Vegetation indices that allow to discriminate between healthy and infected trees were identified, too. This manuscript highlights the potential use of the UAV methodology in fire blight detection and remaining difficulties that still need to be overcome for the technique to become fully operational in practice.

Control of Anthonomus spp. weevils in IPM pome fruit orchards

Since the withdrawal of broad spectrum insecticides like carbamates and organophosphates and the restricted use of neonicotinoids, weevils have become an increasing problem in pome fruit in Belgium. In particular, the apple blossom weevil Anthonomus pomorum and the pear bud weevil Anthonomus pyri (syn. A. cinctus or A. piri), that used to be secondary pests, have developed into important pests for many apple and pear growers, respectively. Recently, also the pear blossom weevil Anthonomus spilotus was found to be present in several pear orchards in Belgium, causing considerable damage. Here we present an overview of recent monitoring data, field and laboratory trials, executed in the Belgian fruit growing area near Sint-Truiden. Laboratory trials on A. pyri indicated a high direct contact activity as well as a high indirect residual contact activity of the neonicotinoid insecticides thiacloprid and acetamiprid, while the anthranilic diamide insecticide cyantraniliprole reached only good control activity after exposure of the A. pyri weevils to spray residue on leaves. In a field trial, application of thiacloprid and cyantraliprole targeting the active A. pyri weevils in autumn also resulted in very high control efficacies, leaving opportunities for a successful combination of those insecticides with biological control by the parasitoid Scambus pomorum. This opens perspectives for control strategies in line with sustainable integrated pest management (IPM) principles.

Effects of Ground Cover Management on Biotic Communities, Ecosystem Services and Disservices in Organic Deciduous Fruit Orchards in South Africa

Organic orchards may have higher biodiversity and levels of ecosystem services compared to conventionally managed orchards. However, it is not well understood how management decisions within organic orchards alter biotic communities and ecosystem service levels. The simultaneous provision of individual ecosystem services and mitigation of disservices is crucial for organic growers who cannot replace natural regulatory processes by artificial inputs. This study addresses one of the major constraints for organic fruit production in South Africa, namely the availability of strategies for pest control and nutrient management in soils. A field experiment was established to study the impact of a treatment with dead organic mulch compared to controls on the composition of biotic communities, the simultaneous provision of ecosystem services, and the mitigation of disservices in organic pome fruit orchards in the Western Cape Province. Mulching did not significantly reduce weed cover or alter the taxonomic composition of weed communities, but affected soil organisms. Mulched subplots had significantly higher densities of Collembola and phytophagous nematodes and lower microbial activity and woodlice numbers. Independent of mulch treatment, both orchard type (conventional: apricot & organic: apricot, peach, plum and quince) and weed cover had pronounced effects on the composition of biotic communities and associated ecosystem service and disservice potentials. The community composition of plants, microbes and web-building spiders differed significantly between organically and conventionally managed plots. The composition of communities and levels of ecosystem service and disservice potentials also differed significantly between organic orchards of different fruit type. The two potential pest groups (phytophagous nematodes and arthropods) were most abundant in peach subplots with high weed cover and tree age and least abundant in conventionally managed apricot plots. These results emphasize the crucial importance to consider weed-microbe-animal interactions when developing management practices in organic orchards. Management decisions in organic orchards hold the potential to affect biotic communities to the benefit of pest control and soil nutrient services, but can also result in unexpected detrimental effects on ecosystem services.

Multitemporal Chlorophyll Mapping in Pome Fruit Orchards from Remotely Piloted Aircraft Systems

Early and precise spatio-temporal monitoring of tree vitality is key for steering management decisions in pome fruit orchards. Spaceborne remote sensing instruments face a tradeoff between spatial and spectral resolution, while manned aircraft sensor-platform systems are very expensive. In order to address the shortcomings of these platforms, this study investigates the potential of Remotely Piloted Aircraft Systems (RPAS) to facilitate rapid, low cost, and flexible chlorophyll monitoring. Due to the complexity of orchard scenery a robust chlorophyll retrieval model on RPAS level has not yet been developed. In this study, specific focus therefore lies on evaluating the sensitivity of retrieval models to confounding factors. For this study, multispectral and hyperspectral imagery was collected over pome fruit orchards. Sensitivities of both univariate and multivariate retrieval models were demonstrated under different species, phenology, shade, and illumination scenes. Results illustrate that multivariate models have a significantly higher accuracy than univariate models as the former provide accuracies for the canopy chlorophyll content retrieval of R2 = 0.80 and Relative Root Mean Square Error (RRMSE) = 12% for the hyperspectral sensor. Random forest regression on multispectral imagery (R2 > 0.9 for May, June, July, and August, and R2 = 0.5 for October) and hyperspectral imagery (0.6 < R2 < 0.9) led to satisfactory high and consistent accuracies for all months.