Insect Pests

Chrysanthemums are propagated by cutting from stock grown by specialists. Cuttings are taken 2-3 inches long from the stock plants. They are rooted in either a peat-lite medium and then transplanted or planted directly into the pot. The cuttings are rooted under low light and intermittent mist. Usually 4-6 cuttings are planted in a 6 inch pot. Several spacing techniques can be used to grow the plants each with different temperature and light regimes. The technique used depends upon the amount of space and labor required and timing of production. Once a good root system is established and 1 to1 inches of new top growth has occurred, the plant is ready for pinching. Pinching is done to ensure the maximum numbers of flowers per plant. However, to achieve the desired plant height, it is necessary to pinch in relation to the beginning of the short day period, anywhere from 7 to 21 days from planting. Chrysanthemums are short day plants, requiring a long dark period for both flower induction and development. The exact length of the critical photoperiods depend upon the cultivar used and temperature of the greenhouse. When the flower buds show color, short day treatments can be stopped. Disbudding is used to modify the number of flower buds per shoot, delay flowering and increase flower size. Growth regulators are also used depending upon the season, the cultivar, the desired final plant height and the greenhouse setup. As with all ornamental plants, managing pests and diseases is a critical component of chrysanthemum production since any damage usually renders a plant unsaleabl