Search Results (21)

Evaluating cultivar susceptibility to biotic stressors in apple orchards is essential for selecting genotypes adapted to local conditions and for designing effective plant protection strategies. This study conducted a comparative assessment of five apple cultivars (‘Florina’, ‘Jonathan’, ‘Golden Delicious’, ‘Pinova’, and ‘Idared’) in response to major fungal diseases (Venturia inaequalis, Podosphaera leucotricha, and Monilinia spp.) and insect pests (Eriosoma lanigerum, Quadraspidiotus perniciosus, Anthonomus pomorum, Aphis spp., and Cydia pomonella). The cultivars were monitored over a five-year period in six orchards located in Central Transylvania, Romania. Significant differences in phytosanitary behavior were recorded among cultivars and locations. ‘Florina’ consistently showed the highest tolerance to pathogens and pests across all sites and years, while ‘Jonathan’ and ‘Golden Delicious’ proved highly susceptible, particularly to apple scab, powdery mildew, aphids, and codling moth. Pest incidence was strongly influenced by temperature, while disease occurrence was more closely linked to precipitation patterns. Heritability analysis indicated that genetic factors played a substantial role in shaping cultivar responses to most biotic stressors. The integrated approach to cultivar–location–pathogen and pest interactions offers practical insights for optimizing orchard protection strategies under variable ecological conditions. Full article

The woolly apple aphid—WAA (Eriosoma lanigerum Hausmann, 1802) poses a significant threat to intensive apple production. Given the limitations of conventional synthetic pesticides, there is an urgent need for effective and sustainable pest management strategies. Botanical extracts derived from plants with insecticidal properties mitigating aphid populations without adverse environmental impacts are scarce where WAA is concerned. Thus, the pertinent study aimed to investigate the aphicidal potential of Koelreuteria paniculata seed ethanolic extract (derived from the seed coat) and mechanically extracted oil (derived from the seed itself). At concentrations of 2.5% and 5%, both solutions expressed undeniable insecticidal potential, providing absolute (100%; oil) or significant (86–100%; ethanolic extract) mortality rates both in vivo and in vitro. Predominant phenolic compounds determined in the ethanolic extract were gallic and protocatechuic acids and three derivates—p-coumaric, quercetin, and luteolin acid derivates—contributing to more than 90% of the total phenolic content, while phenolic compounds were not detected in the oil, indicating activity of different active compounds. Although deriving from different seed parts and distinct extraction methods, both ethanolic extract and oil exhibited significant aphicidal effects against WAA. The integration of botanical extracts from invasive species into pest management practices supports ecological balance and sustainable agricultural productivity, fostering a healthier environment and more resilient agricultural systems. Full article

To date, apple orchards are among the most treated crops in Europe with up to 35 chemical treatments per year. Combining control methods that reduce the number of pesticide treatments is essential for agriculture and more respectful of the environment, and the use of predatory insects such as earwigs may be valuable to achieve this goal. European earwigs, Forficula auricularia (Dermaptera: Forficulidae) are considered beneficial insects in apple orchards where they can feed on many pests like aphids. The aim of this study was to investigate the potential impact of orchards’ insecticide treatments on resistance-associated molecular processes in natural populations of earwigs. Because very few molecular data are presently available on earwigs, our first goal was to identify earwig resistance-associated genes and potential mutations. Using earwigs from organic, integrated pest management or conventional orchards, we identified mutations in acetylcholinesterase 2, α1 and β2 nicotinic acetylcholine receptors. In addition, the expression level of these targets and of some essential detoxification genes were monitored using RT-qPCR. Unexpectedly, earwigs collected in organic orchards showed the highest expression for acetylcholinesterase 2. Four cytochromes P450, one esterase and one glutathione S-transferases were over-expressed in earwigs exposed to various management strategies in orchards. This first study on resistance-associated genes in Forficula auricularia paves the way for future experimental studies aimed at better understanding the potential competition between natural enemies in apple orchards in order to optimize the efficiency of biocontrol. Full article

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. Full article

Nature-based solutions, such as biological control, can strongly contribute to reducing the use of plant protection products. In our study, we assessed the effect of augmentative releases of the European earwig (Forficula auricularia) to control the woolly apple aphid (Eriosoma lanigerum), a worldwide pest that causes serious damage to apple trees. The trials were carried out in two organic apple orchards located in Catalonia (NE Spain) from 2017 to 2020. Two treatments were compared: with vs. without earwig release. For the treatment, 30 earwigs per tree were released by means of a corrugated cardboard shelter. These releases were performed once per season and were repeated every year. We periodically assessed the length of the woolly apple aphid colonies, the number of colonies per tree, the percentage of aphids parasitized by Aphelinus mali, and the number of earwigs per shelter. Our results showed that earwig releases reduced the length of the colonies, but this effect was noticeable only for the second year onwards. Moreover, we found that those releases were compatible with A. mali. Overall, we demonstrated the positive impact of earwig releases on the woolly apple aphid control and the importance of considering time on augmentative biological control strategies. Full article

The influence of different semi-natural surroundings adjacent to apple orchards on the occurrence of predatory syrphids and biological control of Aphis pomi Deg. and Dysaphis plantaginea Pass. was compared. Two methods of catching hoverflies were used: yellow traps to collect the adults and hand picking to get the larvae from aphid colonies. A total of 1029 Syrphidae (26 species belonging to 14 genera) of subfamily Syrphinae were collected in Moericke traps from apple orchards and their boundaries. At all sites, a much greater number of hoverflies was collected in the surroundings (638 specimens) than in the orchards (391 specimens). In apple orchards, 134 syrphids belonging to 10 species were reared from A. pomi and D. plantaginea colonies. In both cases, the dominants were Episyrphus balteatus (Deg.) Eupeodes corollae (Fabr.), Syrphus vitripennis Meig. and S. scripta (L.), suggesting that hoverflies are attracted by plants flowering in semi-natural habitats in the vicinity of the orchard, and they then migrate to the orchard and reduce the aphid colonies. The results confirmed the positive influence of natural surroundings on the conservation of aphid predators. Full article

Predaceous ladybeetles are highly polyphagous predators that ingest supplementary food from flowering plants. Flowering plants widely grown in agroecosystems can sustain multiple natural enemies of agricultural pests, and the pollen and nectar resources from flowering plants may have a positive role in natural enemies. Cnidium monnieri (L.) Cusson, an annual herb with many flowers, blooms from May to July. C. monnieri can support several predatory natural enemies, and the addition of C. monnieri strips increases the density of Harmonia axyridis (Pallas) and improves the biological control of apple aphids in an apple orchard. H. axyridis is also the most important natural enemy in wheat aphid biocontrol and is attracted to healthy and aphid-infested C. monnieri plants. In addition, adult Propylaea japonica Thunberg survives significantly longer on C. monnieri flowers than on a water-only diet. In this study, a laboratory experiment was conducted to assess (i) the effect of nutritional supplements derived from C. monnieri flowers on the development and reproduction of H. axyridis under a wheat aphids-only diet; (ii) the effect of C. monnieri flowers on H. axyridis adult reproduction performance. We compared the larval durations, survival, weight, adult longevity, and reproduction of H. axyridis reared on wheat aphids-only and aphids plus C. monnieri flower diets. The results showed that H. axyridis larvae reared on aphids plus flowers had significantly greater weights and survival rates, shorter larval durations, and produced 1.62 times more eggs than those reared on wheat aphids-only diets. H. axyridis adults ingesting a C. monnieri flowers plus an aphid diet increased egg production 1.44 times compared to the aphids-only diet. Our study demonstrates that C. monnieri flowers as a supplementary food positively affect the survival, development, and reproduction performance of H. axyridis. Full article

To date, direct interactions between pests and natural enemies are often considered in biocontrol programs. Recently there has been an increase of evidence for the importance of third-party mediated indirect interactions in determining the population dynamics of insects. Predicting the strength of such interactions remains a central challenge in biocontrol assessments. Here, two field experiments were performed in two years to investigate to which extent Dysaphis plantaginea Passerini, Aphis pomi De Geer, and Myzus cerasi Fabricius might indirectly interact through shared natural enemies and ants. We first studied the population dynamics of target insects in isolated orchards of apples and cherries. Secondly, we investigated how the spatial coexistence of aphid-infested cherries can indirectly affect the population dynamics of apple aphids via natural enemies and ants. In the first experiment, nine parasitoid species were recorded on apple and cherry aphids, among them were three species in common. Six predatory families were found on cherry and apple aphids, while only one ant species, Lasius niger L., was found associating with these aphids. In the second experiment, temporal variation in the natural enemy-mediated apparent competition between M. cerasi and apple aphids was found. The cherry aphid is likely to be an important source of natural enemies that attack apple aphids early in the season. Significantly reduced numbers of ants associating with apple aphids in the intercropping habitat were found. Our results emphasize the importance of considering indirect interactions in the designing of pest management strategies. Full article

The systematic and long-term use of pesticides in fruit plantations leads to the formation of resistant pest populations. The purpose of this work was to evaluate the effectiveness of the use of entomophages and acariphages for the protection of apple orchards. Against the dominant pest Cydia pomonella (Linnaeus), Habrobracon hebetor (Say) was used, which was caught in the Krasnodar Territory using cassettes with caterpillars attractive to H. hebetor. To determine the most genetically high-quality population, an RAPD analysis was carried out from three Russian (Krasnodar, Stavropol, and Belgorod) and one Kazakh (Shymkent) populations of H. hebetor, which revealed a high level of DNA polymorphism and genetic diversity in the studied geographical populations of the cities of Krasnodar and Stavropol. The efficiency of the captured Krasnodar population of H. hebetor against C. pomonella was about 75%. To regulate the number of aphids Aphis pomi De Geer and Tetraneura caerulescens (Pass.), breeding reserves of the aphidophages Harmonia axyridis Pallas, Leis dimidiata Fabr., Cycloneda sangvinea L., and Aphidius colemani Vier. were established. The biological efficiency of the developed technique was 82.8–88.6%. The release of the acariphages Amblyseius andersoni (Chant) and Metaseiulus occidentalis (Nesb.) on the apple tree showed effectiveness from 80 to 90% against Tetranychus urticae Koch and Panonychus ulmi (Koch). To study the possibility of simultaneous use of entomophages and insecticides, experiments were carried out to study the sensitivity of H. hebetor and H. axiridis to insecticides. When H. hebetor cocoons were treated with Insegar^® and Atabron^®, the ectoparasitoid emergence values were 98.4% and 100%, respectively. The survival of adult H. axiridis treated with Madex twin^®, Atabron^®, and Koragen^® on the fifth day was 97.3%, 89.6%, and 81.9%, respectively. Based on the data obtained, it can be argued that it is possible to create favorable conditions for entomophages, which effectively regulate pest numbers in apple orchards. Full article

Citrullus colocynthis L. is a wild watermelon, commonly named bitter melon or bitter apple, that naturally grows in arid regions of India among other hot arid areas of the world. Its non-edible fruits contain certain phytochemicals of therapeutic and nutraceutical value. The effectiveness of biopesticide formulations that are known to possess insecticidal properties was tested. This is the first botanical pesticide formulation developed from C. colocynthis, named “Thar Jaivik 41 EC”. The phytochemicals of C. colocynthis seed were identified using GC-MS/MS, and a total of 59 constituents were identified, of which seven have significant insecticidal properties: n-hexadecanoic acid; octadecanoic acid; dotriacontance; 9, 12-octadecadienoic acid (Z,Z); 9, 12-octadecadienoic acid (Z,Z)-, methyl ester; 6-octadecenoic acid, methyl ester; and hexatriacontane. Among the different levels of tested concentrations, “Thar Jaivik 41 EC” was found most effective at 3 mL L⁻¹ for managing various insect pests such as pod borer (Helicoverpa armigera) and aphid (Toxoptera citricida) through repellent, deterrent, antifeeding action and by causing respiration abnormalities. Moreover, it caused the least harm to natural enemies such as coccinellids at this concentration. The phytotoxicity response of “Thar Jaivik 41 EC” on tested crops revealed that it is highly safe for plants, showing no toxicity symptoms when applied at higher doses than the recommended one (3 mL L⁻¹). Integration of the “Thar Jaivik 41 EC” formulation in agriculture would help to safeguard farmers’ benefits, such as reduced pest levels, improved food safety and quality of products, which would allow them to fetch higher prices, as well as provide intangible benefits to the consumers and environment. Full article

Grafting cultivars onto rootstocks is a widely used practice by the apple industry predominantly aimed at faster fruit bearing. Using high-throughput sequencing, we revealed the presence of recently described viral agents, namely apple hammerhead viroid (AHVd), apple luteovirus 1 (ALV-1), and citrus concave gum-associated virus (CCGaV), in germplasm collections and production orchards in the Czech Republic and Hungary. The HTS results were validated with RT-(q)PCR, and Northern blotting techniques. To obtain further insight about the presence of these agents, RT-PCR based surveys were carried out and showed their widespread presence alone or in mixed infections. The pathogens were present both in production areas and in feral samples. In addition, rootstock-to-scion transmission of ALV-1 and CCGaV was confirmed using commercial rootstock materials. Phylogenetic relationships based on partial sequences of distinct variants were also investigated. Furthermore, the rosy apple aphid was found to be ALV-1-positive, suggesting that it might be a potential vector of the virus. Full article

Diversifying agroecosystems through habitat management inside or outside production fields can provide alternative hosts and/or prey for natural enemies. In semi-natural habitats, parasitoids may find alternative host-plant complexes (HPC) that could allow their development when pest hosts are scarce in the field. However, morphological and physiological differences between alternative and targeted HPCs could affect the preference and fitness of the parasitoids, possibly altering their efficacy in regulating pests. In the present study, we examined two Aphelinus mali parasitoid populations developing on Eriosoma lanigerum from two host plants (Malus domestica-apple trees and Pyracantha coccinea). We hypothesized that A. mali from both HPCs will show different life history traits and behaviors because primary and alternative host-plants are known to induce variations in parasitoid biological performance. Our findings indicate that A. mali originating from E. lanigerum on P. coccinea parasitized more aphids and are smaller than those originating from E. lanigerum on apple. Furthermore, these parasitoids did not significantly vary their ability to attack and oviposit apple E. lanigerum, suggesting that P. coccinea could function as a suitable banker plant for A. mali. We discuss the potential use of P. coccinea in conservation biological control of E. lanigerum in apple orchards. Full article

Testing fluctuating rather than constant temperatures is likely to produce more realistic datasets, as they are ecologically more similar to what arthropods experience in nature. In this study, we evaluated the impact of three constant thermal regimes (7, 12, and 17 °C) and one fluctuating thermal regime (7–17 °C with a mean of 12 °C) on fitness indicators in the rosy apple aphid Dysaphis plantaginea, a major pest of apple orchards, and the parasitoid Aphidius matricariae, one of its natural enemies used in mass release biological control strategies. For some—but not all—traits, the fluctuating 7–17 °C regime was beneficial to insects compared to the constant 12 °C regime. Both aphid and parasitoid development times were shortened under the fluctuating regime, and there was a clear trend towards an increased longevity under the fluctuating regime. The fecundity, mass, and size were affected by the mean temperature, but only the mass of aphids was higher at 7–17 °C than at a constant 12 °C. Parasitism rates, but not emergence rates, were higher under the fluctuating regime than under the constant 12 °C regime. Results are discussed within the framework of insect thermal ecology and Jensen’s inequality. We conclude that incorporating thermal fluctuations in ecological studies could allow for the more accurate consideration of how temperature affects host–parasitoid interactions and insect responses to temperature change over time. Full article

The woolly apple aphid Eriosoma lanigerum (Homoptera: Aphidiae) is an important pest in apple orchards worldwide. Since the withdrawal or restricted use of certain broad-spectrum insecticides, E. lanigerum has become one of the most severe pests in apple growing areas across Western Europe. At present, effective limitation of woolly aphid populations relies on a good synergy between chemical control treatments and biological suppression by beneficial arthropods, especially by its main specific natural enemy, the parasitoid Aphelinus mali (Hymenoptera: Aphelinidae). To develop a knowledge-based decision support system, detailed monitoring data of both species were collected in the field (region of Sint-Truiden, Belgium) for a period of ten years (2010–2020). Aphelinus mali flights were monitored in the field, starting before flowering until the end of the second-generation flight at minimum. The seasonal occurrence of the most important management stages of E. lanigerum, e.g., start of wool production or activity on aerial parts in spring and migration of crawlers from colonies towards flower clusters or shoots, were thoroughly monitored. All obtained data were compared with historical and literature data and analysed in a population dynamics phenological model. Our outcomes showed that the emergence of first-generation A. mali adults (critical for the first parasitation activity and the basis for following A. mali generations in the continuation of the season) can be accurately predicted by the developed model. Hence, this information can be utilized to avoid insecticide sprayings with detrimental side effects at this particular moment as demonstrated by the outcomes of a field trial. In addition, the start of migration of E. lanigerum crawlers towards flower clusters or shoots is accurately predicted by the model. In conclusion, our results demonstrate that the model can be used as decision support system for the optimal timing of control treatments in order to achieve effective control of E. lanigerum with maximal biological suppression by its main natural enemy. Full article

BACKGROUND: Larvae of the minute aphidophagous Scymnus nubilus Mulsant (Coleoptera: Coccinellidae) are common predators in apple orchards, covered by a wax layer that might act as a defense mechanism against natural enemies. However, the costs and benefits of protection conferred by wax remain to be assessed. We tested the following hypothesis: there is a trade-off in wax producing ladybeetles between the protection conferred by wax cover and the physiological or behavioral costs associated with its production. We predict that: (1) wax production is an efficient defensive mechanism (against intraguild predation), (2) wax production is associated with detrimental physiological (growth, reproduction) or behavioral effects (behavioral compensation: increased biomass consumption). RESULTS: Tests were carried out in the laboratory with wax and waxless larvae of S. nubilus, with and without lacewing larvae of Chrysoperla agilis (Neuroptera: Chrysopidae) being used as a potential intraguild predator of the coccinellid. Waxless individuals were more susceptible to intraguild predation by lacewing larvae. Adults originating from waxless larvae were lighter than the ones originating from wax larvae, suggesting a metabolic cost resulting from a constant need of wax production. Body-weight gain and conversion efficiency were lower in waxless larvae. Biomass consumption was similar, showing that waxless larvae did not compensate for the physiological cost by eating more aphid biomass. CONCLUSION: The results indicate the potential existence of a trade-off between growth and protection associated with wax production. Full article