A Detailed Guide to Controlling the 3 Major Diseases of Carnations

Leaf spot, Fusarium wilt and viral diseases are the main diseases that occur on carnations. The control methods are as follows:

Leaf spot mainly infects the leaves, and the disease usually starts on the lower leaves. On severely affected plants the diseased parts are distorted, and the diseased leaves wither, droop and hang down over the stem, but do not fall off. Old leaves are affected more often and more severely, while new leaves are affected less, and the disease occurs more in open-field cultivation than in greenhouses. Control methods: start spraying regularly from the early stage of the disease; spray a fungicide immediately after disbudding and cutting flowers for protection. A 75% chlorothalonil wettable powder solution diluted 800 to 1000 times can be used for spraying. In addition, pay attention to drainage during the rainy season, and keep greenhouses ventilated and well lit.

Fusarium wilt can occur throughout the entire growth period, causing the plants to wilt and the leaves and stems to discolour, turning straw-coloured. When the diseased stem is cut crosswise, a brown ring pattern appears. It develops extremely rapidly in hot seasons and causes severe damage. Control methods: treat the soil with a 58% benomyl solution diluted 1000 times, or drench the soil before planting with a 50% captan wettable powder or a 50% carbendazim solution diluted 500 times. During the growing period, remove diseased plants promptly and destroy them; pay attention to drainage and flood prevention, and avoid damaging the roots of carnations as much as possible to reduce the routes by which the pathogen enters.

Viral diseases often cause symptoms such as weakened growth of carnations, smaller flowers, mottled petals and split buds.

Control methods: strictly implement the quarantine system to prevent the disease from spreading to disease-free areas. Carnation viral diseases are mostly transmitted by aphids, so insecticides such as omethoate, malathion or pirimicarb can be sprayed to control the spread of the disease. Diseased plants found should be removed promptly and destroyed.