Tetranychus marianae McGregor, 1950 (Acari: Tetranychidae) in Piper (Piperaceae) species in the state of Pará, Brazil

This study reports the occurrence of the phytophagous mite Tetranychus marianae McGregor, 1950 (Tetranychidae), in species of the genus Piper (P. hispidum Sw., P. marginatum Jacq., P. montealegreanum Yunk., P. peltatum L., P. reticulatum L., and P. tuberculatum Jacq.) (Piperaceae) and the predator mite Amblyseius tamatavensis Blommers, 1974 (Phytoseiidae), in species and cultivars of Piper nigrum L., from the Piperaceae collection of Embrapa Amazônia Oriental in Belém, Pará.

Relationships between the Pathogen Erysiphe alphitoides, the Phytophagous Mite Schizotetranychus garmani (Acari: Tetranychidae) and the Predatory Mite Euseius finlandicus (Acari: Phytoseiidae) in Oak

Food webs on forest trees include plant pathogens, arthropods, and their natural enemies. To increase the understanding of the impact of a plant pathogen on herbivore-natural enemy interactions, we studied the powdery mildew fungus Erysiphe alphitoides, the phytophagous mite Schizotetranychus garmani, and the predatory and mycophagous mite Euseius finlandicus in pedunculate oak (Quercus robur) leaves. In June, July and August of 2016, we assessed the severity of powdery mildew, mite population density and adult female mite size in 30 trees in three forests near Belgrade, Serbia. In August, the infection severity of E. alphitoides related positively to the population density of S. garmani and negatively to the body size of S. garmani females. Throughout the vegetative season, the infection severity of E. alphitoides related positively to the population density of E. finlandicus but not to its body size. The effect of E. alphitoides on the population density and adult size of S. garmani was not mediated by the population density of E. finlandicus, and vice versa. Interactions were consistent in all forests and varied with the summer month. Our findings indicate that E. alphitoides can influence the average body size and population densities of prey and predatory mites studied, irrespective of predator-prey relationships.

POPULATION FLUCTUATION OF Tetranychus urticae (ACARI: TETRANYCHIDAE) IN DIFFERENT CHRYSANTHEMUM VARIETIES IN GREENHOUSES

This research aimed at verifying the population fluctuation of the phytophagous spider mite Tetranychus urticae in four chrysanthemum (Chrysanthemum morifolium Ramat: Asteraceae) cultivars: Convington (Yellow - CVT), Kalamazoo (White - KLZ), White diamond (Cream - WD) and Royal Time (Pink - RT). Samples were taken every two weeks during two production cycles (March to April and August to October). In each sampling, leaves from 20 chrysanthemum plants were collected from each cultivar, one apical and one basal (40 leaves/cultivar sample). A total of 583 T. urticae individuals were collected, 41.9 % of the individuals in WD, 38.0 % in KLZ, 15.1 % in RT and 5.0 % in CVT. There were no significant differences in the populational density among the evaluated varieties (p > 0.05). Thus, the results indicated no significant differences in plant susceptibility to the phytophagous mite, suggesting that the four varieties are equally adapted to avoid T. urticae attack.

Two New Records for Spider Mite Fauna of Turkey, Tetranychus kanzawai Kishida and Eotetranychus rubiphilus Reck (Trombidiformes: Tetranychidae)

Two new spider mites, Tetranychus kanzawai Kishida and Eotetranychus rubiphilus Reck (Trombidiformes: Tetranychidae) were recorded for Turkish phytophagous mite fauna. While E. rubiphilus was obtained from Prunus domestica L. and Prunus cerasus L. (Rosaceae), T. kanzawai was found only on P. domestica in different municipalities of Ordu province, Turkey.

Panonychus citri (MacGregor) (Tetranychidae) and Eriophyes medicaginis K. (Eriophyidae): Two important phytophagous mites recorded for the first time in Greece

Panonychus cirri (MacGregor) one of the most important phytophagous mites in many parts of the world, has been collected from citrus trees in various localities of county Preveza, Heperos, Greece. This mite has been, possibly, introduced to Greece via Albania. Another phytophagous mite, Eriophyes medicaginis Keifer, well known to cause witches’ broom on alfalfa, has been collected from Medicago saliva L. in the counties Attiki and Boiotia of central Greece. In a two year study on arthropods associated with alfalfa at the Kopafs region of Boiotia, E. medicaginis was found to be constant and recedent in both years. High population densities were observed during the period mid-September to mid-March.