Sclerotium refers to a tightly intertwined mycelium of some fungi storing nutrients.When the fungus grows to a certain stage, the mycelium continuously differentiates and tangles with each other to form a dark and hard mycelium tissue particle.ByParenchymaA hard dormant body formed with filamentous tissue.When the conditions are appropriate, the sclerotia sprouts fruiting bodies, hyphae, conidia, etc.
Sclerotium refers to a tightly intertwined mycelium with nutrition stored by some fungi. The outer cell wall is thick and hard, which can resist adverse environment and vary in size.At the initial stage of formationTrophic tissueAt a certain stage, reproductive tissue, namely fruiting body, can be formed later.
shape
Announce
edit
The shape and size of sclerotia vary greatly. They are as small as rat dung and as big as human head. They are very hard and can withstand high temperature, low temperature and dry storage. When the conditions are suitable, they can germinate and produce fruiting bodies[1]。
classification
Announce
edit
There are three main types of sclerotia, namely fungal sclerotia, pseudosclerotia and small sclerotia.
Small sclerotia, composed of non layered hyphaeCellsIt is thick, small in size, and will appear in large numbers once formed.
features
Announce
edit
Sclerotium is formed bymyceliumTight connectionInterwoven dormant body, the inner layer is loose tissue, the outer layer is pseudo parenchyma, and the epidermiscell wallThick, dark and hard.The function of sclerotia is mainly to resist adverse environment.When the environment is suitable, sclerotia can germinate to produce new vegetative hyphae or form new propagules from above.Sclerotia is not only the vegetative storage organ of fungi, but also the dormant body that can survive adverse environmental conditions.When the conditions are appropriate, the sclerotia sprouts fruiting bodies, hyphae, conidia, etc[1]。
Harmful symptoms
Announce
edit
It mainly harms the stem and fruit of zucchini, and the diseased part is water soaked.After the disease invades the fruit, it causes the fruit to soften and grow white hyphae (mold layer), and the spot is scattered with mouse fecal black sclerotia.The stem and vine were infected. The diseased part was initially waterlogged, with brown spots. Later, white hyphae and mouse dung like black sclerotium grew, and the leaves and stems above the diseased part died.Sclerotinia sclerotiorum is serious under high humidity[2]。
Pathogenesis
Announce
edit
Sclerotinia sclerotiorum is a high humidity disease. The mycelium can grow at 0~32 ℃, and the optimal temperature for growth is 20 ℃.Therefore, low temperature, high humidity or rainy early spring or late autumn is conducive to the occurrence and prevalence of the disease. Fields planted with cucurbitaceae, solanaceae and cruciferous vegetables every year, low-lying lands with poor drainage, and nitrogen fertilizer, frost and freezing damage will cause serious disease[2]。
Prevention and control methods
Announce
edit
① Paddy dry rotation, deep ploughing and formulated fertilization can enhance the disease resistance of plants.
② Sterilization of seeds and soil.40% before plantingPentachloronitrobenzeneRake the prepared medicinal soil into the soil, apply 1 kg of medicine per mu, and mix it with 20 kg of fine soil.Soak seeds in 50 ℃ warm water for 10 minutes to kill sclerotia.
③ Ecological control.The shed is mainly heated in the morning and ventilated in the afternoon.After onset, the night temperature can be properly increased to reduce dew condensation and prevent excessive watering.
④ At the beginning of the disease, smoke or spray was used for prevention and treatment.Use 10% Sukeling smoke agent or 45% chlorothalonil smoke agent, 200g per mu each time, smoke overnight, and smoke every 8-10 days.You can also spray 50% suquelinWettable powder1500 times of liquid, or 50% of polyhydantoin 1000 times of liquid[2]。
