1999 Volume 8 Issue 2 Pages 143-149
Vegetative propagation by herbaceous cuttings is commonly used in chrysanthemum production. Spider mites are also transferred with cuttings from the mother plant. We investigated the vertical distribution of mites on the cuttings of several cultivars and established a control method for mites by dipping the cuttings in acaricide solution prior to planting. Most adult female mites were found between the 4th and 6th unfolded leaves numbered from the apical leaf. Eggs and immatures were mainly found on the 4th and 5th leaves, respectively. Before planting, the cuttings were dipped for 3 min in milbemectin(10 ppm), etoxazole(50 ppm), potassium oleate(3, 000 ppm)or water. Milbemectin and etoxazole prevented mite infestation on chrysanthemums for a month after planting, whereas potassium oleate and water were unable to control the mites and the mite populations increased within 3 weeks. No noticeable developmental damage was observed in the plants after dipping, except that the stem was slightly shortened in one cultivar after dipping into potassium oleate.