Black truffle, Tuber melanosporum Vittad., production is increasing due to an improvement in cultivation management and to the demand for this highly appreciated fungus. However, this intensification of truffle cultivation has led to the appearance of problems related to pest incidence. Specifically, the truffle beetle, Leiodes cinnamomeus (Panzer, 1793) (Coleoptera: Leiodidae), causes significant losses in black truffle marketability. However, its biology is still poorly known, and no effective agro-ecological methods exist to mitigate its damage to the truffles. This study aimed at assessing the population dynamics of L. cinnamomeus over four seasons (2019-2023) in an orchard located in NE Spain and relating these dynamics to weather variables and damage to truffle fruit bodies. Moreover, we described the diversity of arthropods captured in the traps in search of potential natural enemies of this beetle. The maximum population peak was observed in November, except for a single season in which it occurred in December. Moreover, the sex ratio was balanced (0.54 on average), but it varied over the growing season and among years. Significant and positive relationships of the population density of truffle beetles with air temperature and relative humidity were observed. The number of beetles per trap and day was strongly linked to heat accumulation. Finally, the Carabid Percus (Pseudopercus) patruelis (L. Daufour, 1820) was identified as a natural enemy of L. cinnamomeus. These results could be used in the future for monitoring and predicting truffle beetle populations.

BackgroundEnergy flows in most food chains in the agroecosystem are crowned with beneficial natural enemies including different species of predatory and parasitic insects, birds and animals. They are utilized in organic and IPM cotton production to replace the conventional insecticides usually applied in cotton production.ResultsNatural populations of six coccinellids, five staphylinids and two carabids (Coleoptera), three anthocorids and three reduviids (Heteroptera), five syrphids (Diptera, three labidurids (Dermaptera), two chrysopids (Neuroptera) and one thripid (Thysanoptera) species were manipulated in Egyptian clover to aggregate in seed production stripes (stripe technique) adjacent to and across the cotton fields during April-May, 2022. These 30 predatory species represent 112 energy flow routes in food chains preying on tetranychid mites, aphids, thrips, whiteflies and cotton leaf worm attacking cotton plants during vegetative growth stage beginning from April to May 2022. High populations of these predators develop along the clover season (November-May) on different pests where no insecticide applications occur. They aggregate in the flowering clover stripes left for seed production feeding on nectar, pollens and remaining pests. By dryness of the clover stripes, populations of all these predatory species abandon the clover, migrating outwards into the adjacent cotton or corn fields showing an excellent high protection against cotton pests suppressing their populations far away under the level of economic threshold damage during vegetative growth stage. Dressing cotton seeds with Bacillus amyloliquefaciens as antagonist protects the seedlings from soil-borne diseases. Insect pheromone traps detected the first appearance of the pink bollworm, Pectinophora gossypiella (Saund.) moths, the cotton bolls are attacked also by the spiny bollworm, Earias insulana (Boisd.). The egg parasitoid Trichogramma evanescens (West.) was released in 6 successive releases to guide the energy flow in favor of the parasitoid by getting it from egg contents of these two pests, which resulted in high protection of cotton bolls. This study aims better understanding of biodiversity and the routes of energy flow among the complex net of food chains governing the bio-dynamics in the Egyptian agroecosystem, which enabled the development of the present strategy to completely abandon application of the conventional insecticides and chemical fertilization for organic cotton production in Egypt.ConclusionThe study is an approach contributing to improvement of the agroecosystem and production of healthy crops.

Heavy metal contamination represents a critical global environmental concern. The movement of heavy metals through the food chain inevitably subjects insect natural enemies to heavy metal stress, leading to various adverse effects. This review assesses the risks posed by heavy metal exposure to insect natural enemies, evaluates how such exposure impacts their pest control efficacy, and investigates the mechanisms affecting their fitness. Heavy metals transfer and accumulate from soil to plants, then to herbivorous insects, and ultimately to their natural enemies, impeding growth, development, and reproduction of insect natural enemies. Typically, diminished growth and reproduction directly compromise the pest control efficacy of these natural enemies. Nonetheless, within tolerable limits, increased feeding may occur as these natural enemies strive to meet the energy demands for detoxification, potentially enhancing their pest control capabilities. The production of reactive oxygen species and oxidative damage caused by heavy metals in insect natural enemies, combined with disrupted energy metabolism in host insects, are key factors contributing to the reduced fitness of insect natural enemies. In summary, heavy metal pollution emerges as a significant abiotic factor adversely impacting the pest control performance of these beneficial insects.

Lablab (Lablab purpureus L.) is an important food and livestock feed legume that can also enhance soil fertility. However, its production is limited by insect pests, notably the black bean aphid (Aphis fabae). The present field study was conducted to determine the difference in the contribution of lablab genotypes and natural field margin vegetation (FMV) to the abundance and diversity of natural enemies and the damage, incidence, and abundance of bean aphids. Eighteen lablab genotypes were planted in the presence or absence of FMV in a randomized complete block design experiment replicated four times. Data on aphid abundance, incidence, and severity of damage were collected at four growth stages of the crop. Lablab genotypes significantly influenced aphid incidence, suggesting some level of tolerance to aphid colonization. Findings showed that lablab genotypes were a significant influence on natural enemy species richness with no statistical difference for abundance and natural enemy species diversity. However, the genotypes did not vary significantly in their influence on the number of aphid natural enemies. FMV was associated with low bean aphid damage. Overall, the presence or absence of FMV did not influence the number of natural enemies caught on the crop. This concurs with recent work that shows a similar number of natural enemies with field margin plants but may reflect the reduced number of pest insects. Cropping seasons influenced aphid abundance and damage severity, with the populations developing at the early stages of lablab development and decreasing as the crop advanced. This pattern was similar both in the presence or absence of FMV. The findings of this study highlight the important contribution of crop genotype together with the presence of field margin species in the regulation of aphids and their natural enemies in lablab.