Potato early dying disease primarily affects tubers and roots, though stems can also become infected. In the initial stages, small brown spots appear on the epidermis, surrounded by a translucent halo. These spots gradually enlarge, forming "freckles" measuring 3 to 5 mm in diameter. At this point, the epidermis remains intact but powdery, marking the "closed" stage. As the disease progresses, the epidermis ruptures, and the subcutaneous tissue turns orange-red. A large amount of dark brown powder (sporangium spheres) is released, indicating the "open pod" stage for whiteflies. On the infected root, nodules the size of soybeans or clusters may develop. The pathogen, *Spongospora subterranea* (Wallr.) Lagerheim, is commonly known as the powdery mildew fungus. It belongs to the phylum Mastigomycota. The brown powder released from the "freckles" consists of dormant sporangia, which are spherical or nearly spherical, ranging from yellow to yellow-green in color. These structures measure 19–33 µm in diameter and contain internal cavities. The dormant spore capsules are generally spherical or polygonal, with a diameter of 3.5–4.5 µm. Their walls are thin and smooth, and they produce zoospores upon germination. Zoospores are nearly spherical, lack cell walls, and do not have long bi-flagella. They are motile in water and become non-motile after settling, then invade the host through root hairs or lenticels. Both zoospores and the subsequent resting bodies serve as the primary infection sources. The disease spreads through infected seed potatoes or soil containing remnants of diseased sporangia. Infected potatoes and soil are the main sources of infection for the next growing season. Long-distance spread occurs via the movement of seed potatoes, while short-distance transmission happens through infected soil, fertilizers, and irrigation water. Dormant sporangia can survive in the soil for up to 4–5 years. When conditions are favorable, zoospores germinate and transform into resting bodies that penetrate the host through root hairs, lenticels, or wounds. These bodies multiply inside the host cells, eventually developing into multinuclear protoplasts. Later, they differentiate into mononuclear dormant sporangia, forming sponge-like structures that fill the host cells. Upon decomposition of the infected tissue, these structures return to the soil, surviving the winter or summer. Optimal conditions for the pathogen include soil moisture of about 90%, temperature between 18–20°C, and a pH range of 4.7–5.4. High humidity and cooler summer temperatures increase the likelihood of infection. The severity of the disease depends mainly on the number of primary infections and the presence of initial pathogens, rather than secondary re-infections in the field. To manage the disease, strict quarantine measures must be enforced to prevent the spread of seed potatoes. Crop rotation for more than five years is recommended. Disease-free seed potatoes should be selected, and infected tubers removed during harvest, storage, and planting. If necessary, seeds can be soaked in a 2% hydrochloric acid solution or 40% formalin diluted 200 times for 5 minutes, followed by covering with plastic for 2 hours and drying. Applying phosphate and potassium fertilizers, adding lime or ash to adjust soil pH, and improving field management practices such as avoiding flood irrigation can help reduce disease spread.

Fluorine-Containing Benzoic Acid

The Fluorine-Containing Benzoic Acid series is very common form of the fluorochemical compounds, it has many product types and derivatives. Most of products are in white crystalline powder, some of products are Colorless monoclinic prismatic crystals. It was widely used as fungicide intermediates, also used in the etching process. The Fluorine-Containing Benzoic Acid series are mostly in high value-added , less polluting products. We are trying our best to make our production dock with market to give accurate and effective services for the market .

Containing Benzoic Acid,2,3-Difluorobenzoic Acid,Methoxybenzoic Acid

Taizhou Volsen Chemical Co., Ltd. , https://www.volsenchem.com