Control of thick plum cone rust of spruce

Spruce thick plum cone rust occurs in Inner Mongolia, Jilin, Heilongjiang, Sichuan, Yunnan, Xizang, Shaanxi, Gansu, Qinghai, * and other places in China. The disease harms thick branch spruce, yew spruce, Lijiang spruce, oil wheat spruce, fish scale spruce, Xueling spruce, * spruce and so on.

Symptoms: the disease harms the positive scales of female cones. The susceptible scales are twisted, anti-curled and disordered. There are many purple-brown globules on the front, which are arranged in a layer, which are the sporidium of the pathogen, and sometimes the spores are also produced on the back of the scale.

The pathogen is Thekosporaareolata (Fr.) Magn., which belongs to basidiomycetes subphylum, Dipterospora, Rust order and Rust Fungi.

The regularity of the disease: the pathogen is a rust fungus with long cycle life history. Winter spores overwintered on the fallen leaves of thick plum. In the second year, when the cone scales of spruce opened and pollinated, the winter spores germinated and produced basidiospores to invade the scales. A week later, flattened, blister-like sexual spores appeared on the scales. At the end of summer, spherical, purplish-brown spores appeared on the scales. In that year, the spores did not crack, but in the next year, the spores split and spread to the thick plum leaves by the wind. The spores germinate on the thick plum leaves, invade the leaves, and then produce summer spores and summer spores, which can be re-infected many times. In autumn, teliospores and teliospores are produced on the front of the susceptible leaves. The incidence of spruce near to thick plum is high and the disease is serious.

Control: ① cut off thick plums and treat them with glyphosate, or spray herbicides such as 2meme 4murD butyl ester, which has a certain effect. ② was sprayed on spruce cones during the period of dehiscent pollination.