How to prevent and control pests and diseases in garland chrysanthemum? Latest technical methods tutorial

Garland chrysanthemum is a semi-cold-tolerant vegetable with low light requirements, generally preferring weaker light. It originated in the Mediterranean and has a cultivation history of more than 900 years in China, and is widely distributed, but the cultivation area in all parts of the north and south is very small. During cultivation, attention should be paid to the prevention and control of pests and diseases. Let us take a look at the pest and disease control techniques for garland chrysanthemum below!

Damping-off

[Symptoms] It mostly occurs in the middle and late stages of seedling raising. It mainly harms the base of the seedling stem or the underground root. At first, oval or irregular dark brown lesions appear. In the early stage, diseased seedlings wilt during the day and recover at night. The diseased part gradually sinks and constricts, and some gradually turn dark brown. When the lesion expands and encircles the stem for one round, the plant finally dries up and dies, but does not lodge. Mildly diseased plants only show brown sunken lesions and do not die. When the seedbed humidity is high, inconspicuous light brown spiderweb-like mold can be seen on the diseased part.

[Control] In the early stage of the disease, spray 38% oxadixyl, pyrimethanil and copper bactericide 800x solution, or 41% polyoxin · pyrimethanil 600x solution, or 20% tolclofos-methyl EC 1200x solution, or 72.2% Previcur SL 800x solution, once every 7-10 days. Or dilute General + Menshen at 600x solution, and drench the seedbed at 3 liters per sq m before sowing or after sowing and before transplanting. At transplanting, after transplanting, or before the expected frequent disease period, dilute this product at 600x solution for root drenching, once every 7 days; the number of applications depends on the condition of the disease.

Leaf spot

[Symptoms] Cockscomb leaf spot infects leaves, petioles and stems. Lesions on leaves are round, then expand into irregular large lesions and produce concentric rings. The lesions change from reddish brown to dark brown, with a grayish brown center. Lesions on stems and petioles are brown and elongated. On fish-tail palm, leaf spot produces small dark brown round spots on the leaves, which later expand or merge into irregular large patches, with slightly raised edges, and small black dots scattered on both sides of the leaf. On clivia, leaf spot shows oval and elongated light reddish brown lesions on the leaves, surrounded by chlorotic halos, later expanding into irregular large patches, with black dots produced on the lesions.

[Control] In the early stage of the disease, spray 20 ml of 4% pyrimidine nucleoside antibiotic + 20 ml of 41% polyoxin pyrimethanil, mixed with 15 kg of water, once every 5-7 days, for 2-3 consecutive applications.

Sclerotinia rot

[Symptoms] It mainly harms stems and vines, leaves and fruits. When the stem base is infected, water-soaked spots first appear, then expand into light brown, causing soft rot or longitudinal splitting of the stem base, and white cottony mycelium grows on the surface of the diseased part. When leaves are infected, gray to grayish brown wet-rot large lesions appear on the leaf surface, and the boundary between the lesion edge and the healthy part is not obvious. When humidity is high, flocculent white mold appears on the lesion surface, eventually causing the leaves to rot. When fruits are infected, water-soaked spots first appear, and after expansion they become wet-rot, densely covered with white cottony mycelium, and in the late stage of the disease black rat-dropping-like sclerotia of varying numbers appear on the surface of the diseased part.

[Control] In the early and middle stages of the disease, for control use 30 ml of 20% silyl prochloraz + 25 ml of oxadixyl bactericide, mixed with 15 kg of water, once every 5-7 days, for 2-3 consecutive applications.

Cabbage webworm

[Symptoms] Early-instar larvae bore into and feed on the heart leaves of young seedlings, spin silk and form webs. In mild cases, it affects the growth of the seedlings; in severe cases, it can cause the seedlings to die, resulting in missing plants and broken rows. Older larvae not only chew the heart leaves, but can also bore into the stem pith and roots, and can transmit bacterial soft rot, causing the plants to rot and die.

[Control] At the peak hatching period of the larvae or when heart leaf damage and silk webs are first seen, apply 5% chlorfluazuron EC 4000x solution by spraying 2-3 times, and be careful to spray the pesticide onto the heart leaves.

Aphids

[Symptoms] Aphids are pests with piercing-sucking mouthparts. They often gather on leaves, tender stems, flower buds, terminal buds and other parts, piercing and sucking sap, causing leaves to shrivel, curl and become deformed. In severe cases, they cause branches and leaves to wither and even the whole plant to die.

[Control] When the number of aphids reaches 500 per 100 plants in the field and the ratio of beneficial insects to pests is greater than 1:500, use 50 ml of 25% yamanqing EC per mu, or spray 1500-2000x solution of imidacloprid series products, 60-70 g of 10% yashijing, 2500x solution of 20% imidacloprid, or 3000x solution of 25% pirimicarb for control by spraying. In wheat areas where wheat aphids have developed resistance to imidacloprid and acetamiprid, it is not suitable to use a single pesticide; it can be reasonably mixed with low-toxicity organophosphorus pesticides and sprayed.