Chestnut seed speck disease, also known as chestnut seed kernel dry rot Bo? Chest black blotch? In China's Hebei Province, Shandong Province, the main chestnut production areas occur more common. There is no obvious abnormality in the harvesting period and good fruit, but the storage and transportation period forms small spots on the chestnut seeds, causing deterioration and rot. Therefore, it is an important disease during the storage and sale of the chestnut.
Symptoms: The chestnut kernels produce dark gray, black or dark green rot lesions and gradually turn into dry rot, with empty holes. There are gray-black hyphae in the hollows, and the seeds are easily crushed. The disease department is often infected with bacteria and becomes soft rot that produces offensive odors. The surface of the seed coat is also covered with a black-grey mycelium layer, and seed coats form granular sub-seats. When the chestnut fruit is stored, the seed coat often breaks, exposing the pathogenic sub-seats and showing a sore shape. Sometimes watching from outside the seed coat, there is no obvious change, but the kind of kernel has turned black and decayed. The disease is also harmful to the branches, dry, cause dry rot?
Some research reports classify the symptoms of chestnut seeds and blights into three types: 1 Black spots: The seed coats are generally normal in appearance, and the surface of the seed kernels has irregular dark brown to gray-black lesions on the surface of the seed. Internally, the lesion profile has grayish white to reddish black strips. 2 Brown spot: There are brown necrotic spots with different shades on the surface of the seed kernels, which are deep inside the seed kernels. The cross section of the seed kernels is white, light brown, yellowish-brown, and there are gray to grayish black bars. 3 Rotten type: The kernel becomes brown to black soft or dry rot.
The pre-storage period, that is, the harvest period to the acquisition period, is mostly brown spots, and the later stage is the processing period and the port storage period. The black spot type accounts for the majority, and the two types together account for about 90% of the diseased grains. Symptoms of rot may be later manifestations of necrotic lesions and gradually increase with storage time.
?? Pathogens? Chestnut species pathogenic bacteria are more complex, mostly Plastigomys, Phytophthora, Fusarium, Coccothrax dark conidia and other fungi infestation, in which Ascomycota spore fungus grape seat The main bacteria. The pathogen forms a sub-plant in the diseased branch of the tree. The germ development temperature is 20 to 30°C, and the optimum temperature is 28°C. According to another report from Hebei Agricultural University, there are mainly anthrax pathogens, Alternaria sp., Fusarium solani, Fusarium trifoliatum, Fusarium moniliforme, and Penicillium sp. From the results of isolation, cultivation and inoculation of pathogens, anthrax and Alternaria alternata are the main pathogens of the black-spot type symptoms of the seed. Fusarium and P. palustris are the main pathogens of brown-spot symptoms. The rot type is the later stage of the symptoms of black spots and brown spots.
发病 发病 发病 发病 发病 发病 发病 发病 发病 发病 发病 病原 病原 病原 病原 病原 病原 病原 病原 病原 病原 病原 病原 病原 病原 病原 病原 病原 病原 病原 病原 病原 病原 病原 病原 病原 病原 病原Diseases began in the near-mature stage of chestnut disease, ripening to harvest fruit disease slightly increased, at room temperature in the sand storage and transportation process, the condition quickly increased. The temperature of sand storage is about 25°C, which is conducive to the occurrence and development of disease. When the temperature is below 15°C, the disease develops slowly. When the temperature is below 5°C, the development stops. The loss of water on the surface of seed kernels is conducive to the development of diseases, but excessive water loss is the slow expansion of lesions. Saplings and strong trees are lightly affected, and old trees and weak trees suffer from severe disease; airy and clear sunspots in dense chestnut gardens are lightly diseased and poorly ventilated in dense planting gardens; tree trunks have more diseases, insect pests, and mechanical injuries than in chestnut trees; early harvesting occurs. The incidence of chestnuts in the process of storage and transportation is heavy.
Chestnut growth period, young fruit that is carrying bacteria. The chestnuts begin to show symptoms at the end of August and early September, but the incidence is low, averaging 0.5%. The disease rate is about 3% during the collection period, and it will not cause any loss. After harvesting after sand collection, pre-election, to the sale of the acquisition of the station, the disease rate significantly increased, an average of 8%. After processing, it was selected as a product chestnut, and the number of diseased grains increased again, with an average of 10%, reaching the highest peak. After that, the temperature dropped and the incidence no longer increased. From the time of harvesting to the processing period of 15 to 25 days, the high temperature is the critical period for the development of the disease.
Prevention and control methods The key to controlling the disease of chestnut seeds is to reduce operating links, improve storage and transportation methods and conditions, shorten the time of storage and transportation at room temperature, and promptly enter refrigerated or refrigerated ships to take cooling and prevent real losses. Water-centric management measures. Improving tree vigor and raising disease resistance are also important aspects of comprehensive prevention and control.
1. Strengthen cultivation and management, increase tree vigor, increase tree disease resistance, and reduce the number of trees on the tree to send bo?
2, promptly scrape the tree dry rot lesions, cut off the dead branches, reduce the source of pathogen infection.
3, when harvesting, pay attention to reduce chestnut mechanical damage. Rinse the fruit with 7.5% saline, remove the floating diseased fruit, and remove the good fruit by drying and storage.
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