Survey on the aphid communities in Northern Italy open field tomato crops

Aphids are phytophagous insects that damage a wide range of plant species and may act as vectors of several pathogens, including Cucumber Mosaic Virus (CMV). CMV seriously affects tomato crops but, although earlier studies have described CMV in northern Italy, little is known about the aphid species in the area that could be involved in its transmission in tomato fields. This three-year survey (2021-2023) focused on monitoring aphid populations in open field tomato crops in the northern Italian provinces of Piacenza, Cremona and Mantua. Sampling included both tomato plants and nearby weeds like Solanum nigrum, Convolvulus arvensis, Abutilon theophrasti or crop like Medicago sativa, which may serve as CMV reservoirs. DNA barcoding of the COI gene, along with morphological analysis where necessary, was used to identify the aphids. A total of 28 aphid taxa were identified from the collected samples, and 89.8% of all identified samples were known CMV vectors. Aphis fabae and Macrosiphum euphorbiae were the most frequently identified species. The greatest number of aphid specimens and species diversity were recorded during the first sampling of each year, whereas the highest sampling diversity was recorded in Piacenza. The current study provides a comprehensive qualitative assessment of the diverse aphid species associated with open field tomato crops in one of the most important districts for their cultivation in Italy.