Detailed Guide to Common Pest and Disease Control Methods for Calla Lily
I. Diseases 1. Calla lily soft rot: Soft rot and detachment occur on the plant near the soil surface, causing leaves to wilt upward and the fleshy tuber to develop a soft rot downward, with roots also rotting, and the whole plant suddenly wilting and dying. When leaf edges are affected, they become soft and wet-rotted. When flower stalks are affected, the flowers turn brown, and the stalks become soft-rotted and drop off...
I. Diseases
1. Calla lily soft rot: Soft rot and detachment occur on the plant near the soil surface, causing leaves to wilt upward and the fleshy tuber to develop a soft rot downward, with roots also rotting, and the whole plant suddenly wilting and dying. When leaf edges are affected, they become soft and wet-rotted. When flower stalks are affected, the flowers turn brown, and the stalks become soft-rotted and drop off. This is a bacterial disease.
Control methods:
(1) At harvest, remove diseased corms, treat with 40% formaldehyde 55-fold solution for 1 hour, dry, and then store.
(2) Promptly pull out and burn diseased plants when found, and disinfect the soil around the diseased plants with 40% formaldehyde 40-fold solution.
(3) Plant tubers at a depth not exceeding 5 cm, and avoid overwatering.
2. Calla lily leaf spot: Three types of fungi cause calla lily leaf spot, among which Phyllosticta is relatively common. In the early stage, the spots on the leaves are small, nearly circular, and grayish-white, gradually expanding and merging into irregular large rotten patches, sometimes also affecting flowers and flower stalks.
Control methods:
(1) Promptly remove diseased leaf remnants and avoid overwatering. Do not water directly onto the plants.
(2) When disease occurs, spray with 25% propiconazole emulsifiable concentrate 1000-1500-fold solution, or 80% Daconil 500-fold solution, once every 7-15 days, for 2-3 consecutive times.
3. Calla lily viral disease: Calla lily virus shows two types of symptoms. The mosaic symptom is that diseased plants show typical mosaic on the leaves, with leaves shrinking, twisting, and deforming. The white spot, or ringspot, symptom is the appearance of chlorotic rings or stripes near the veins, twisted leaves, white dots on the pedicels, and light-colored spots on the flower buds with deformed flowers. Mosaic disease can be transmitted by sap and by the green peach aphid.
Control methods:
(1) Select disease-free mother plants for propagation, and promptly pull out and burn diseased plants found during the growing period.
(2) Throughout the entire growing period of calla lily, use 50% malathion 1000-fold solution or 2.5% deltamethrin emulsifiable concentrate 3000-fold solution to control aphids, thrips, and other virus-transmitting vectors.
II. Pests
Two-spotted spider mite: Also known as the cotton red spider mite, its hosts include sunflower, calla lily, Chinese rose, peach, asparagus fern, wintersweet, French marigold, rose of Sharon, rose, and others. The two-spotted spider mite sucks leaf sap on the underside of leaves; in mild cases the leaves turn red, as if scorched by fire, and in severe cases the leaves drop.
Control methods:
(1) Remove diseased leaves and dispose of them in a centralized manner.
(2) Spray with 40% dicofol 1000-fold solution, or 20% fenpropathrin 2000-fold solution, or 25% profenofos 1500-fold solution.