The occurrence of rust in pineapple and Sakya orchards, what are the symptoms and characteristics of rust? what are the prevention and control methods?

Due to the heavy moisture in orchards such as mountain areas and river valleys, it is easy to cause the spread and spread of "Annona rust". The Taitung District Agricultural improvement Farm of the Council of Agriculture (hereinafter referred to as Taitung Field) recently monitored Peinan, Luye, Donghe and other places and found that some pineapple Sakya orchards have contracted rust. Farmers are called on to step up inspection of the orchards and adopt prevention and control measures at the initial stage of the disease to reduce losses.

The initial symptoms of Fanli branch rust are similar to those of leaf mites, which leads to the wrong use of pesticides in the control of some farmers. At the initial stage, rust usually occurs only in several mature leaves at the base of the branches, and a pile of needle-shaped yellow powdery spores can be seen on the back of the leaves, then expand and cover the whole leaves in severe cases, resulting in yellowing and falling of the leaves. According to statistics, since September of last year (2017), some farmers have reported rust one after another. after December, many orchards became seriously ill, causing a large number of leaves to fall off and affecting the harvest.

At the initial stage, the rust spot is similar to that of the leaf mite, and a pile of needle-shaped yellow powdery spores can be seen on the back of the leaf.

In order to prevent the harm of rust, Taitung Field suggested that emergency control agents could be used. Include: 10% Atomine water suspension, 23% Yatoumin water suspension, 250g/L (25% WHV) Yatomin water suspension, 50% Yatomin water dispersible granule, 50% Trifluoromin water dispersible granule, 43.7% Trifluoromin water suspension, 500g/L (50% WB) Trifluoromin water suspension, 23.6% Bachlor emulsion, 25.9% Dexlide water-based emulsion and 250g/L (25% WB) Dexley water-based emulsion.

Taitung Field further pointed out that in order to avoid the emergence of drug resistance, it is suggested that farmers should take turns to use agents with different effects, such as the action mechanisms of subtopamine, paracetamol and trifluoromide, codenamed C3 and G1, and take turns using C3 and G1 agents. In addition, if it is not possible to correctly judge whether it is a rust spot, you can also contact Taitung Plant Protection Laboratory or various district pest diagnosis service stations.