Diseases and Pests of Yellow Bulbs and Their Control Methods

Diseases and control methods of yellow cicada

Sooty Disease

The pathogen is a fungus of the subphylum Ascomycota, including coal soot fungus, neo-coal soot fungus and many others. Its asexual stage is mostly spreading smoke mold. The pathogen overwinters in the form of epimycelium on diseased parts or diseased remains, reproduces using the honeydew secreted by scale insects as nutrients, and spreads through wind, rain, and the activities of scale insects.

In the early stage, part or most of the branches and trunks of the affected plants turn black, the diseased parts are covered with black mold, and feel sticky to the touch.

In the later stages of the disease, the black mold on the leaves may partially peel off, and the leaves become mottled with black and white. Severely infected plants have their photosynthesis blocked, grow poorly, and their leaves fall prematurely, greatly reducing their ornamental value.

Prevention and treatment methods

The plants should be placed in a ventilated environment to maintain air circulation.

Once the disease occurs, you can spray 1000-3000 times diluted 40% Suposuction EC, 1000 times diluted 40% Lorsban EC, or 2000 times diluted 25% Ultrafil (Buprofen) EC (for scale insects, spray a dilute solution in the nymph stage), or spray 2000-3000 times diluted 50% Antipyretic EC.

Pests and control methods of yellow cicada

Ceroplastes rubrum

The yellow cicada wax scale is a pest belonging to the order Homoptera, family Coccidiidae (also known as Lecanococcus). It has a very wide host range and is one of the main pests that harm the yellow cicada. The female adults and nymphs suck the sap from the branches and leaves of the yellow cicada, causing malnutrition, weak growth, and obstructed flowering and fruiting. In severe cases, the branches of the yellow cicada may wither and die.

The yellow cicada wax scale has one generation per year, and the female adults overwinter on branches as fertilized eggs. May and June of the following year is the peak egg-laying period for overwintering female insects. The eggs are laid under the body and the egg-laying period lasts for more than a month.

After a certain period of crawling, the newly hatched nymphs will fix on the host to feed. Generally, they will start to secrete wax after 6 hours and will form a star-shaped wax cover after 15 days. Once the wax layer is formed, the control effect will not be ideal.

Prevention and treatment methods

For manual control, in the early stage of the red wax scale infestation, the insects should be removed in time, or the branches and leaves with infestations should be cut off and destroyed in a centralized manner.

Horticultural control, strengthening the pruning of yellow bells, improving air circulation and light conditions will reduce the damage caused by yellow bells and red wax scale.