Revision of the genus Pseudobryobia McGregor, 1950 (Acari, Tetranychidae)

The species of the tetranychid mite genus Pseudobryobia are revised mainly based on data published in the literature. Following a survey of the classification history of the genus, emphasizing the changes that occurred in the morphological characters used in its definition, we briefly discuss their relative importance for the genus delimitation. As a result, we provide amended diagnoses for the genera Pseudobryobia and Bryobia and transfer 7 species from Pseudobryobia to Bryobia. Species belonging to the genus Pseudobryobia bear two setae on coxisternal plate II, one pair of tenent hairs on all the empodia and are distributed in the Nearctic biogeographic zone. Conversely, some species previously assigned to the genus Pseudobryobia bear one seta on coxisternal plate II, two rows of tenent hairs on empodia II-IV, and are recorded in the Palearctic and Afrotropical biogeographic zones. These species are transferred to the genus Bryobia. The following nomenclature changes resulting from the revision are proposed: B. (Bryobiopsis) abbatielloi new combination, B. (B.) anacantha reinstated combination, B. (Allobia) bucharica reinstated combination, B. (B.) eurotiae reinstated combination, B. (A.) japonica reinstated combination, B. (B.) neoephedrae new combination, B. (A.) nikitensis reinstated combination. We recognise six subgenera for Bryobia, as previously considered by other authors, and also treat Nuciforaella Vacante (1983) as a junior synonym of Bryobia (Allobia) Livshits and Mitrofanov, 1971. A key to the species of Pseudobryobia is also provided.

The tetranychid mites (Acari: Tetranychidae) of Kenya and a redescription of the species Peltanobia erasmusi Meyer (Acari: Tetranychidae) based on males

This paper reports 18 tetranychid mite species (Acari: Tetranychidae) from various plant hosts in Kenya. Four species of these belong to the subfamily Bryobiinae and the other 14 belong to the subfamily Tetranychinae. Eight of the mite species identified belong to the genera Bryobia, Petrobia, Peltanobia, Paraplonobia, Duplanychus, Eutetranychus and Mixonychus and are being reported for the first time in Kenya while the other ten had already been reported before. The paper provides a list of these species and their brief descriptions as well as a redescription of Peltanobia erasmusi Meyer (Acari: Tetranychidae) to include male characters that were not included in the original description.

Ladybeetles as Predators of Pest and Predacious Mites in Citrus

The acceptability of Panonychus citri (McGregor) (Tetranychidae) as prey for adults and larvae of four coccinellid species, Cycloneda sanguinea L., Exochomus childreni Mulsant, Harmonia axyridis Pallas, and Olla v-nigrum (Mulsant), was evaluated. Also, three beneficial predacious species, Euseius mesembrinus (Dean), Iphiseiodes quadripilis (Banks) and an Amblyseius sp. (Phytoseiidae), were evaluated for their acceptability as prey for H. axyridis adults. Adult females and early larval stages of C. sanguinea, E. childreni, H. axyridis, and O. v-nigrum readily consumed adult P. citri females when these were presented on leaf disk arenas in Petri dishes. The most voracious mite predator was H. axyridis. Adult female H. axyridis consumed an average of 15.14 ± 1.9 female P. citri in 24 h, and first-instar larvae consumed 6.1 ± 0.7 in 60 min. Only H. axyridis was tested with predaceous mites as prey. First-instar H. axyridis larvae consumed one or two adult Amblyseius sp. in three out of eight trials, and a single E. mesembrinus female. No I. quadripilis females were eaten by H. axyridis larvae. Adult female H. axyridis did not consume adult female phytoseiids of any species under similar conditions. If predacious phytoseiids are generally unacceptable as prey for coccinellids while P. citri is selectively consumed, then coccinellid predation would likely have a net beneficial effect in contributing to suppression of tetranychid mite populations in citrus.