THE INFLUENCE OF DIFFERENT PHYTOPROTECTION SYSTEMS ON ENTOMOFAGE FAUNA IN APPLE PLANTATION

The paper presents data on the diversity of entomophagous fauna in an ecologically managed apple plantation, as well as aspects regarding the differences found in the structure of the entomophagous complex in three variants of phytoprotection technologies: "Ecological", "Biotechnical" and "Chemical standard". The study was carried out during the years 2019-2020, at the Research Institute for Fruit Growing Pitesti, in a plot aged 12 years. The evaluations were performed both in the field, visually and in the laboratory, at binocular magnifier. As a result of this study, a number of 6 species of predatory insects were identified: Chrysopa carnea, Coccinella septempunctata, Adalia decempunctata, Anthocoris sp., Phytoseiulus persimilis and Aphidoletes aphidimyza, were mainly from the Orders Mesostigmata, Coleoptera, Neuroptera, Diptera and Hemiptera.

Myzus persicae Management through Combined Use of Beneficial Insects and Thiacloprid in Pepper Seedlings

Excessive insecticide application has posed a threat to pollinators and has also increased insecticide resistance of Myzus persicae Sulzer. Therefore, it is urgent to develop an economical and effective strategy, especially for greenhouse vegetables. Firstly, we selected a neonicotinoid insecticide that is specifically fatal to M. persicae but relatively safe to predators and bumblebees by laboratory toxicity tests and risk assessments. Then, we tested the effectiveness of the neonicotinoid insecticide under different temperature conditions. According to the LC50 values and the hazard quotients, thiacloprid met the requirements. Greenhouse trails indicated that thiacloprid was quite efficient, while control dropped to 80% without the application of thiacloprid. As for biological control, Harmonia axyridis effectively controlled 90% of aphids with thiacloprid or not. However, Aphidoletes aphidimyza performed better above 20 °C. Our results indicated that it is cost-effective to control M. persicae with A. aphidimyza in suitable temperature conditions and H. axyridis was more effective at low temperatures. Practically, thiacloprid could be used either as an emergency option to control aphids’ abundance alone or in combination with natural enemies.

Aphid alarm pheromone alters larval behaviour of the predatory gall midge, Aphidoletes aphidimyza and decreases intraguild predation by anthocorid bug, Orius laevigatus

Intraguild predation is the killing and consuming of a heterospecific competitor that uses similar resources as the prey, and also benefit from preying on each other. We investigated the foraging behaviour of the gallmidge, Aphidoletes aphidimyza, a predator of aphids used for biological control that is also the intraguild prey for most other aphid natural enemies. We focus on how aphid alarm pheromone can alter the behaviour of the gallmidge, and predation by the anthocorid bug Orius laevigatus (O. laevigatus). We hypothesised that gallmidges would respond to the presence of (E)-β-farnesene (EBF) by leaving the host plant. Since feeding by Aphidoletes gallmidge larvae does not induce EBF emission by aphids, this emission indicates the presence of an intraguild predator. We found that gallmidge larvae reduced their foraging activities and left the plant earlier when exposed to EBF, particularly when aphids were also present. Contrastingly, gallmidge females did not change the time visiting plants when exposed to EBF, but lay more eggs on plants that had a higher aphid density. Lastly, EBF reduced the number of attacks of the intraguild predator, O. laevigatus, on gallmidge larvae, potentially because more gallmidges stopped aphid feeding and moved off the plant at which point O. laevigatus predated on aphids. Our work highlights the importance of understanding how intraguild predation can influence the behaviour of potential biological control agents and the impact on pest control services when other natural enemies are also present.

Sexual dimorphism and sex pheromone detection in Aphidoletes aphidimyza

Sexual dimorphism, particularly at the level of sensory and locomotor organs, is usually attributed to sexual selection. Antennae are notably developed in males of species that need to detect a sex pheromone at low concentration or at long distance. In addition to their role in intrasexual selection, antennae can be seen as important ornaments in intersexual selection. Antennae of Aphidoletes aphidimyza are clearly sexually dimorphic (males have longer antennae than females, with highly developed sensilla) while females emit a sex pheromone for mating. Males with longer and more symmetrical antennae than others could be more successful in reaching the source of sex pheromone, especially if they can fly properly. A morphometric study was first conducted, to apprehend the variability of antennae, wings and tibias in lab conditions. The length of the antennae of male A. aphidimyza is impressive and the right antenna is longer than the left antenna. Secondly, choice experiments were conducted in a Y-shaped olfactometer with males of A. aphidimyza facing the sex pheromone. The relationship between choice patterns and morphology of males was then studied, but no link was found between the morphology of males and their behaviour while exposed to the sex pheromone, although males were indeed attracted by the olfactometer arm containing the sex pheromone.