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A comparison is made between testing techniques for examination of spider mites on their host plants. The female fecundity is related to chemical composition of different rose and strawberry cultivars using Tetranychus urticae and Panonychus ulmi. From stepwise regression analysis it is shown that a number of amino acids and minerals are correlated with mite fecundity, but the effects vary with the host plant species and cultivar. Mineral nutrition of the plant increases fecundity, while certain phenolic compounds apparently decrease it. An attempt was made to correlate female fecundity with the amounts of feeding, using plants which were radio-labelled. The pattern of food plant finding and acceptance by the females of the two spotted spider mite, Tetranychus urticae Koch was demonstrated by Dabrowski (1976). Female mites exhibited differences in gustatory response to the extracts from different plant species and the observed order of preference was the same as the mite fecundity when feeding on fresh leaves from these plants. The aim of the present study was to investigate the suitability of various methods used in the study of spider mite/host plant relationships and especially to investigate the effect of the biochemical and physiological state of plant species or cultivars upon the behaviour and biology of T. urticae and the fruit tree spider mite, Panonychus ulmi (Koch). Comparison of some techniques used in the experiments The effect of the host plant on the behaviour and reproduction of spider mites is most readily investigated using leaf discs, 25-50 mm in diameter, placed on moist cotton wool in glass or plastic dishes, but a defect of this method is that soluble compounds from the plant tissue diffuse out into the surrounding water and some biochemical degradation may occur. These changes may affect the palatability of the test plant for the mites. Because of this problem, comparisons were made between five different methods. Females of T. urticae and P. ulmi were reared on the strawberry cultivar Purpuratka × Senga Sengana (cross). Females of P. ulmi were reared on four apple cultivars, Golden Delicious, Fantazja, Bankroft and Jonathan, to establish the

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