GB/T 15699-2013Rules for tobacco blue mold quarantine (English PDF)

3.1 Quarantine

Dissemination of a measure taken to prevent the spread of dangerous tobacco pests and diseases.

3.2 Tobacco downy mildew

Also known as blue mold, caused by tobacco downy mildew (Peronosporatabacina), tobacco leaves major damage, the system can also be infected roots, stems

Vascular bundles, is a rapid spread of devastating diseases.

NOTE. The disease occurs in Europe, America, Australia, China is no occurrence of the disease, so as Foreign quarantine. Pathogen Peronsporahyoscyami f.sptabacinaAdam, synonyms PeronsporanicotianaeSpeg, Peronosporatabacina Adam, belongs to the flagella cotina (Mastigo- mycotin), Oomycetes (Oomycetes), downy mildew mesh (Peronosporales) downy mildew Branch (Peronosporaceae), Peronospora (Peronospora).

4.1 Principle quarantine

Tobacco downy mildew obligate parasite, after being infected tobacco leaf damage, fuzzy edges appear nearly circular chlorotic spots, post-formed light brown

Color necrotic lesion may fall off. Under appropriate temperature and humidity conditions, the surface of leaf lesions grow pale blue mold shaped, namely tobacco downy mildew sporangiophore

And cysts; under certain conditions, can be formed oospores within disease tissue. Designed parasitic resistance and morphological characteristics of the pathogen is to identify tobacco downy mildew

Disease basis.

4.2 identifying characteristics of tobacco downy mildew

4.2.1 characteristics of cysts and cyst stems

Tobacco downy mildew sporangiophore colorless, pores extend from the host, the spindle relatively thick, the upper double-fork branches 3 to 10 times. Cyst

Stem length 400µm ~ 750µm, base diameter 10µm ~ 12µm; branching angle greater the more points, the end of the bifurcated branch obtuse, slightly thick tine base

Tapering to the end, the two prongs slightly different length, the longer an often curved, another branch than the straight end of long sticks 7µm ~ 14µm; cysts in the end […]