The age of tomato plants affects the development of Macrosiphum euphorbiae (Thomas, 1878) (Hemiptera) colonies

We tested the hypothesis that the intensity and duration of Macrosiphum euphorbiae infestations in tomato depend on both the age (phenological stage) of the host plant and the initial number of aphids present in the colony. We compared the effects of three initial levels of infestation and two phenological stages of the plant (pre-flowering and flowering stages) on infestation curves. The position of the infestation peak over time was significantly affected by the plant phenological phase. Populations of M. euphorbiae reached the highest peak of abundance on plants infested at the pre-flowering stage compared to those subsequently infested. Within a phenological phase, the maximum abundance also varied according to the initial aphid density on the plant. The implications concerning the management of the pest in the field are briefly discusse

Effects of Trichoderma harzianum Strain T22 on the Arthropod Community Associated with Tomato Plants and on the Crop Performance in an Experimental Field

Fungi belonging to the genus Trichoderma have received much attention in recent years due to their beneficial effects on crop health and their use as pest control agents. Trichoderma activates direct plant defenses against phytophagous arthropods and reinforces indirect plant defense through the attraction of predators. Although the plant defenses against insect herbivores were demonstrated in laboratory experiments, little attention has been paid to the use of Trichoderma spp. in open field conditions. In the present study, we investigated the effects of the inoculation of the commercial Trichoderma harzianum strain T22 on the arthropod community associated with tomato plants and on the crop performance in an experimental field located in South Italy. Our results showed that inoculation with T. harzianum could alter the arthropod community and reduce the abundance of specific pests under field conditions with respect to the sampling period. The present study also confirmed the beneficial effect of T. harzianum against plant pathogens and on tomato fruit. The complex tomato–arthropod–microorganism interactions that occurred in the field are discussed to enrich our current information on the possibilities of using Trichoderma as a green alternative agent in agriculture

Effects of Below-Ground Microbial Biostimulant Trichoderma harzianum on Diseases, Insect Community, and Plant Performance in Cucurbita pepo L. under Open Field Conditions

Agrochemicals are generally used in agriculture to maximize yields and product quality, but their overuse can cause environmental pollution and human health problems. To reduce the off-farm input of chemicals, numerous biostimulant products based on beneficial symbiont plant fungi are receiving a great deal of attention. The evolution of plant diseases and the performance of insects are influenced by plant chemical defences, both of which are, in turn, influenced by below-ground symbionts. Direct and indirect plant defences mediated by belowground symbionts against plant diseases and insect herbivores were demonstrated in greenhouses experiments. However, little attention has been paid to the use of Trichoderma under open field conditions, and no data are available for zucchini (Cucurbita pepo L.) plants in the field. To determine the effects of a commercial Trichoderma harzianum strain T22 on plant viruses, powdery mildew, the arthropod community, and on the agronomic performance associated with zucchini plants, an experiment was conducted in 2022 under open field conditions in South Italy. Our results indicate that T. harzianum T22 makes zucchini plants more attractive to aphids and to Hymenoptera parasitoid but failed to control zucchini pathogens. The complex plant–disease–arthropod–microorganism interactions that occurred in the field during the entire plant cycle are discussed to enrich our current information on the possibilities of using these microorganisms as a green alternative in agriculture

aphidophaga 13

Introduction: Chemoreception is the main mechanism used by insects to communicate both intra-species and inter-species, and to interact with their environment. The specialized organs for this function are sensilla, mainly located on the antennae, but also on tarsis, palpi and genitalia. At the molecular level, it is essential the role of OBPs that solubilize and carry the odorant molecules towards the specific receptors. In the aphid parasitoid Aphidius ervi (Hymenoptera: Braconidae), host acceptance is based on the perception of specific kairomones present on the aphid cuticula and cornicle secretions. Methods: Antennal sensilla of A. ervi were investigated using both SEM (Scanning Electron Microscopy) and TEM (Transmission Electron Microscopy). The proteic profile of Aphidiuservi has been determined by working on the construction and annotation of de novo transcriptome, using the specific bioinformatic tool Blast2Go. Results: At least two type of putative olfactory sensilla were found, one of the “placoidea” and the other of the “grooved peg” type. The first type is the most abundant and was found on most of the antennomeres evenly distributed on the whole surface. The groveed peg occurs only on the distal part of some antennomeres. The analysis of the transcriptome allowed us to identify the transcripts which mediate olfactory perception, in particular several OBPs and other molecules that were identified and characterized. Conclusions: The study of the molecular basis of olfaction, by the identification of OBPs, provides useful information to better understand OBPs functioning and their interaction with odorant molecules. Then, it will be possible to test different compounds in order to determine their effects on A.ervi behaviour, and their applicability in aphids’ biological control