Abundance and distribution of <Emphasis Type="Italic">Microdispus lambi</Emphasis> (Acari: Microdispidae) in Spanish mushroom crops

The myceliophagous mite Microdispus lambi has become a veritable plague since 1996, when it was first observed in Spanish mushroom crops, and is now causing substantial economic losses, particulary in spring and summer. This study looks at seasonal variation of the pest, its distribution on commercial farms and the population development during the crop cycle of the common white mushroom, Agaricus bisporus. Over a period of 18 months, 24 consecutive mushroom crop cycles were monitored and a total of 24 spawn and 960 substrate samples were analysed. We found that it is usually the substrates in the growing rooms that are infested, most commonly the compost. In many cases, the pest can be detected when the first ‘flush’—i.e., mushroom growth surge, with weekly periodicity—is harvested, although damage does not become evident until the third flush. Mites were detected at the back of the mushroom growing room and, to a lesser extent, near the access door.     

Modelling the potential distribution of the invasive tomato red spider mite, <Emphasis Type="Italic">Tetranychus evansi</Emphasis> (Acari: Tetranychidae)

Predicting the potential geographical distribution of a species is particularly important for pests with strong invasive abilities. Tetranychus evansi Baker & Pritchard, possibly native to South America, is a spider mite pest of solanaceous crops. This mite is considered an invasive species in Africa and Europe. A CLIMEX model was developed to predict its global distribution. The model results fitted the known records of T. evansi except for some records in dry locations. Dryness as well as excess moisture stresses play important roles in limiting the spread of the mite in the tropics. In North America and Eurasia its potential distribution appears to be essentially limited by cold stress. Detailed potential distribution maps are provided for T. evansi in the Mediterranean Basin and in Japan. These two regions correspond to climatic borders for the species. Mite establishment in these areas can be explained by their relatively mild winters. The Mediterranean region is also the main area where tomato is grown in open fields in Europe and where the pest represents a threat. According to the model, the whole Mediterranean region has the potential to be extensively colonized by the mite. Wide expansion of the mite to new areas in Africa is also predicted. Agricultural issues highlighted by the modelled distribution of the pest are discussed. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.