Lagerstroemia rust

Rust often occurs at the end and back of orchid leaves. At the early stage of the disease, many sesame-sized iron-brown protrusions will bulge on the epidermis behind the blade tip, and then the protrusions will be crushed by rust-colored or orange-yellow powder. This disease is difficult to control because:

(1) Spores of this pathogen will fly around with the wind, causing spread infection.

② The pathogen is hidden on the back of the blade tip, so it is not easy to be found in the early stage. To completely remove the infected site, it is necessary to check one by one. Careless orchid growers often overlook this point.

③ The lesion is located behind the blade tip, so it is difficult to reach by spraying.

The prevention and control methods of rust are as follows:

(1) completely cut off the sick and disabled. It should be checked pot by pot and piece by piece. All infected leaves should be cut off, and 2 cm of healthy tissue should be enlarged, and the diseased leaves should be burned centrally.

(2) pesticide prevention. Choose 500-fold solution of Pugaidan, Sheng Da 45, Yili or antivirus alum, and spray it once every half month for two consecutive times. Pay attention to spraying on all leaves, basin surfaces and surrounding environment.

③ Treatment of diseased strains. Choose one or two of Tonggao Shang, kocide, antivirus alum and chlorothalonil, dilute them to 5OO times, and spray them once a week. Copper can be used four times in a row, and can also be used for various medicines once.

So now hurry up and cut off all the sick leaves and spray them.