How to Treat Downy Mildew Disease on Rohdea japonica

Rohdea japonica is distributed in China and Japan, with a flowering period from May to June and a fruiting period from September to November. It has the effects of clearing heat and detoxifying, and dispersing blood stasis and relieving pain. So how do you treat downy mildew disease on Rohdea japonica?

1. How to Treat Downy Mildew Disease on Rohdea japonica?

If white frost appears on Rohdea japonica, it should be infected with downy mildew, a disease caused by a fungus. First, trim away some of the affected areas, then spray with a liquid medicine, water less, and place it in a ventilated spot with sunlight.

2. Disease Prevention and Control of Rohdea japonica

1. Leaf spot

This disease occurs on the leaves of Rohdea japonica, and is prone to occur in weather with high humidity. The leaf spots are initially small brown spots, with a water-soaked, faded-green margin, and expand in concentric rings, round to oval, with brown edges and grayish-white centers. In the later stage, dark brown mold spots appear in the center of the lesions, becoming a dark brown mold layer under humid conditions. The method to prevent and control this disease is to promptly remove diseased and residual leaves; both in the early and late stages of onset, spray with 0.5%-1% Bordeaux mixture (or 50% carbendazim 1000 times dilution).

2. Anthracnose

This disease also occurs on the leaves of Rohdea japonica, and in severe cases can spread to the leaf stalks. The lesions initially appear as small water-soaked yellow spots, and after expanding are oval to irregular brown or yellow-brown, slightly showing concentric rings; in the later stage the lesions merge into a continuous dry and withered patch, and produce small black dots arranged in concentric rings. This disease is mainly caused by poor ventilation, and the presence of scale insect damage favors the occurrence of the disease. The method to prevent and control this disease is to strengthen care, apply additional phosphorus and potassium fertilizer; in the early stage of onset, spray with 0.3%-0.5% equal-amount Bordeaux mixture (or 60% zineb 800-900 times dilution, or 70% thiophanate 1500 times dilution).

3. Brown soft scale

This insect has complex feeding habits and can harm many plants, and Rohdea japonica is one of the affected flowers. When the brown soft scale harms plants, it generally gathers on the leaf surface or tender leaves, pierces and sucks the plant's sap, and at the same time excretes sticky fluid; its excrement easily causes a large proliferation of sooty mold fungi, making the stems and leaves turn black, affecting the plant's photosynthesis, causing weak growth and yellowed leaves, and hindering ornamental value. When the infestation is severe, the branches and stems are covered with the insects, causing the plant to turn yellow and wither, affecting growth.

Rohdea japonica is usually placed in the living room or bedroom for decorative and ornamental purposes. It also absorbs indoor toxic gases and exhaust fumes and releases oxygen, playing a purifying role, and is especially very beneficial for elderly people with relatively weak immunity.