Rodent bark gnawing is common during winter in times of low or unavailable food supply. During the growing season, it is a rare phenomenon, but can occur due to low food supply and/or poor food quality resulting from climatic influence. We evaluated this unusual damage of apple tree (Malus domestica) orchards by rodents in two localities in the Czech Republic. In 2019, 24% of trees in the orchard in Brno were gnawed by the common vole (Microtus arvalis) population. Damage in the Holovousy orchard by water vole (Arvicola amphibius) was inspected in 2020 and showed that 15% of trees were damaged with massive root gnawing. These findings were compared with gnawing in forest beech plantations in 2019, with up to 13% of trees damaged. Three rodent species (Microtus agrestis, M. arvalis and Clethrionomys glareolus) participated in the damage. Detailed description of the various vole species’ damage in vegetation period, which somehow differs from winter time damage, may help in the future in early recognition and early application of plant protection in times when this phenomenon may reappear.

The mitochondrial genomes of two vector psyllids of the ‘Candidatus Phytoplasma mali’, Cacopsylla picta and C. melanoneura, were sequenced using high-throughput sequencing on the Illumina platform. The main objective of the study was to describe their mitogenome and characterize their genetic variability and the potential changes in the context of the observed global warming. The four complete sequences for C. picta, 14,801 bp and 14,802 bp in length, two complete and one partial sequence for C. melanoneura, ranging from 14,879 bp to 14,881 bp in length, were obtained for the first time for these European apple psyllids. The detected intraspecies mtDNA identity was highly similar (99.85–99.98%), the identity’s similarity with other Cacopsylla species varied between 79.79 and 86.64%. The mitogenomes showed a typical mitochondrial DNA structure with 13 protein-coding genes, 2 rRNA genes and 22 tRNA genes; the presence of CGGA motif in the ND1-trnS2 junction was detected in both species. Phylogenetic analysis placed both species in close relationship with C. burckhardti within the Cacopsylla clade-I O group. The analysis of complete mitogenomes and of partial COI sequences of fifty-two Cacopsylla individuals showed a high homogeneity of genotypes over 15 years and among the different localities in the Czech Republic.

Specimens of the plum seed wasp, Eurytoma schreineri Schreiner, 1908 (Hymenoptera: Eurytomidae), collected in the Czech Republic were found to be parasitized by an unidentified species of Pyemotes Amerling, 1861 (Acari: Pyemotidae) very close to or identical to P. herfsi. Out of 526 collected wasps, 24.14% were parasitized, primarily as larvae (21.48%). Infected larvae and pupae of the plum seed wasp were covered by spherical, physogastric females of the genus Pyemotes. Genus identification was based on sequence similarity analysis of the nuclear 18S rDNA region, amplified from DNA isolated from the mites. This is the first record of pyemotid mite parasitisim on the plum seed wasp, E. schreineri, and the first report of natural infection of an insect by these mites in the Czech Republic.

Eurytoma schreineri is a new invasive pest in the Czech Republic and may pose a risk in other European countries. Fruit damage caused by E. schreineri results in premature fruit drop, sometimes up to 90%. This study is the first to test the attractiveness of differently coloured sticky traps as a monitoring tool to determine presence, abundance, and timing of treatments against adults. We also evaluated efficacy of insecticides allowed in integrated pest management (IPM). Laboratory and field trials demonstrated that yellow sticky traps were the most attractive. Spinosad proved to be the most effective insecticide under both laboratory and orchard conditions, reducing infestation to 22.2% compared to 79.2% in untreated orchards. These findings provide new knowledge on pest monitoring and control strategies and will support fruit growers in developing effective IPM systems against E. schreineri.