Cas: 26048-05-5 Beauvericin Beauveria Insecticide powder
Beauveria bassiana is a kind of entomogenous fungi of ascomycetes. The main species include Beauveria bassiana and Beauveria brucei, etc., which are often formed through asexual reproduction-conidia, and the hyphae have transverse septal branches and branches. Beauveria bassiana has a wide distribution range. Beauveria bassiana has been found in mountains from several meters above sea level to more than 2,000 meters. Beauveria bassiana can invade more than 200 insects and mites in 6 orders and 15 families, and multiply at the same time. Produce Beauverin (non-ribosomal polypeptide toxin), oosporin (benzoquinone toxin) and calcium oxalate crystals. These substances can cause insect poisoning, disrupt metabolism and cause death.The infection is mainly through contact with insect epidermis, followed by infection through the digestive tract and respiratory tract. The way of infection varies with insect species, insect state, environmental conditions, etc.
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Scanning electron microscopy or fluorescence staining showed that the highly virulent strains of Beauveria bassiana formed an invasion structure on the body wall of the cotton bollworm larvae by short-term growth, while the low virulent strains produced elongated creeping hyphae on the body wall of the larvae. These hyphae It will absorb nutrients from the pests and eventually cause the pests to die.
There are two ways to infect black-tailed leafhoppers. The first is to infect through the skin. The germinated conidia grow out germ tubes at the internode membrane where the chitin is thin on the body wall of the worm. The tip of the germ tube secretes chitinase to dissolve the chitin into a small hole,
The hair tube enters the body of the worm. At this time, the infection is about 24 hours. The germinated germ tube continuously dissolves the chitin in the body wall and elongates forward by the action of enzymes. The hyphae that are not formed until the epithelial cells of the body wall also enter the body wall and then invade the hemolymph tissue. The hyphae develop and grow along the cell membrane at first. It then passes through the cell membrane and enters the cell, so the protoplasm and nucleus are inactivated, the nutrients are depleted, and a large amount of disintegration disappears. The destruction of a large number of subcutaneous cell layers is the result of hyphae infection in the body cavity. At this time, the hyphae are surrounded by insects and blood cells in the body, the blood cells appear vacuoles, and the coloring power is reduced. At the same time, the mycelium produces many spores. After germination, the spores produce new hyphae, which proliferate repeatedly and break through the blood cell barrier to enter the body cavity. In the body cavity, it reproduces in the form of blastospores and conidia, and spreads to all the tissues of the worm body. Such as the digestive tract, Martensian tube, fat body, etc., at this time, the infection is about 48 to 72 hours. After 96 hours of infection, most of the insect tissues and organs are destroyed, and the hyphae are bundled out of the body surface to form aerial hyphae, and begin to form conidiophores and conidia. After 120 to 118 hours of infection, a large number of aerial hyphae, conidiophores and conidia grow on the surface of the worm and release. At this time, except for part of the body wall, other tissues are destroyed and nutrients are also exhausted.
Fungal spores germinate, and their germ tubes float freely in the blood cavity after entering the worm body, and gradually grow into hyphae. These hyphae continuously elongate, branch, multiply and invade organ parts by absorbing water and nutrients in the worm body. , So that the whole body is filled with mycelium. In this process, the bacterial body will produce calcium oxalate crystals, which will reduce the acidity of the hemolymph, causing the body's metabolism to be disordered.
Under suitable conditions, the mycelium in the lethal host produces conidia, the surface of the worm is broken, and the spores are released with the wind to infect other worms, forming a cyclic infection.