Pear black spot is a worldwide disease that occurs extensively in pear growing areas and is one of the three major diseases of pears. The disease is caused by Alternaria pyogenes. The pathogenic bacteria mainly infects the leaves, shoots, and fruits of fragrant pears. When the fruit matures, it forms a nearly round or irregular black-brown lesion on the surface of the fruit, which is depressed in the middle, and produces black moldy layer on the surface of the lesion when wet, which seriously affects the yield and quality of the fruit. It is a typical latent infestation disease that can be invaded through various pathways during the flowering period and fruit development period, and is latent to the onset of storage. Korla fragrant pear is a traditional pear variety with distinctive characteristics in Xinjiang, which brings greater economic benefits to the local forestry industry. The vehicle-borne spore trap is very effective for the capture of pathogen spores, and its research has a very important role in sampling.
Pear black spot pathogens use conidia and mycelium to overwinter on diseased shoots, diseased shoots, and diseased fruit, and new conidia are produced from the diseased tissue the following spring, spreading by wind and rain. When the spores germinate, they invade through the pores and stomata of the pear bark or directly penetrate the host epidermis, causing initial infection. Then in the pear growth period, new spores can be generated multiple times to infect and form repeated infections. At present, there are no studies on conidial transmission and its incidence rules and dynamic monitoring of the disease in orchard air at home and abroad.
Vaseline-coated slides were placed in vehicle-borne spore traps in two fragrant pear orchards, and samples were taken twice a week. Slides were serially numbered and recorded, brought back to the laboratory, and counted under a biological microscope. And records. From the inflorescence extending period to the flowering stage, 8 trees were selected as the observation point around the spore trap in the test orchard. Pear blossoms were collected twice a week. Each time, 25 pear flowers were randomly collected and numbered. 15 flowers were selected for isolation and culture. They were surface-sterilized with 0.25% sodium hypochlorite for 45 seconds under aseptic conditions, washed three times with sterile water, placed on sterile PCA medium plates, incubated at 25° C. for 5-7 days, and purified to grow. Colonies, microscopic observation and identification. The DNA of the other 10 flowers was extracted with a DNA extraction kit and eluted twice with 50 μL of sterile water. The nucleic acid protein analyzer was used to determine the purity and concentration of the sample DNA, and PCR was performed to identify the sample.
The spores of P. fragariae were captured by the vehicle-borne spore catcher at different time in the export orchard and the pathogens in flowers and fruits were detected and monitored, and the growth and decay of the spores in the orchard were ascertained. The relationship between disease occurrence and severity and spores and meteorological factors in the orchard was clarified, which provided the basis for controlling orchard black pear disease in orchards.
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