Controlling Common Diseases and Pests of Paulownia Seedlings

First, Paulownia anthrax (a) symptoms. Paulownia anthracnose mainly damages paulownia leaves, petioles and young shoots. When the Paulownia seedling grows 1 to 2 pairs of true leaves, the onset of disease occurs. In the early stages of leaf damage, the lesions are punctate green, then expanded to brownish near-circular, surrounded by yellow-green, with a diameter of about 1 mm. After the rain or when wet, pink conidial piles or black dots often appear on the lesions. Late lesions often rupture, diseased leaves fall early. (B) the incidence of the law. Paulownia anthracnose is caused by the impregnation of the fungus imperfectis. Overwintering of the pathogen in the host tissue makes it the primary source of dipping in the following year. It can be repeatedly infested many times during the growing season. It usually begins in May to late June and late July. It enters the peak of onset in July and lasts until August 30th. In the growing season of Paulownia seedlings, high temperature and rain, poor drainage, poor ventilation and light transmission, and weak seedling growth are favorable for the occurrence of anthrax. (c) Control methods. When choosing nursery land, consideration should be given to choosing a place farther away from Paulownia forest; nursery land should not be used as a continuous crop; if it is necessary to replant, nursery should be thoroughly cleaned, and diseased seedlings and foliage must be burned to reduce initial dissemination; and field management of seedbeds should be strengthened. , Drainage ditch is set around the seedbed to reduce seedbed humidity, and time seedlings, weeds and topdressers are used to promote robust growth of paulownia seedlings and increase disease resistance. Bordolos can be sprayed to control anthrax in May to June, and can also be sprayed. 65% of the dexamethasone 500 times or 50% of the eubacterial 800 times were sprayed every 15 days.

Second, Paulownia black pox disease (a) symptoms and the incidence of the law. Paulownia esculenta is a fungal disease, which is caused by the infestation of rotundus paulownia, which can be seen in the middle and late April, and the onset of disease from May to June. There are black spots on the leaves and twigs, 7 to 8 per year. Severe onset of the month. After onset, the lesions on the leaves were dark brown with a diameter of 0.5-2 mm. The lesions in the middle of the lesions were perforated and often developed along the veins. The lesions on the petiole, veins, and tender shoots were sore and scab-like. The initial lesions were pale brown, producing a layer of white mold in the wet, and eventually turned into dark brown, the diseased leaf curled, and the diseased shoots withered. (b) Control methods. The paulownia varieties such as Paulownia glauca, Yuza No. 1 and Samyang Paulownia were used. Nursery should avoid continuous cropping or nursery near Paulownia forest. It is necessary to pay attention to the quarantine of the seedlings that are buried in the roots, and to cut them from the diseased seedlings. Before the sowing, the seedbed can be sprinkled with 1 to 1.5 kilograms of addicts per acre to disinfect the soil. Before seeding, 0.3% of enemy powder can be used for seed dressing. Strengthen the seedling management, the density of seedlings should be appropriate, 800-900 strains per mu. Watering and fertilizing in time to promote the neat, robust growth of paulownia seedlings and enhance disease resistance. Spray 200 times equal amount of Bordeaux mixture for 15 days every 15 days for prevention. The diseased Paulownia seedlings were alternately sprayed with 50% extinguishment 800 times or 70% thiophanate 1000 times for 10 to 15 days, and sprayed for 3 to 4 times with good control effect.

Third, Paulownia nets (a) hazard characteristics. The paulownia net worm, also known as hornback back net rake, is a hemiptera larvae. Paulownia nettles have occurred in our province for three generations a year. The first generation of adults appeared in mid-June, and the second and third generations appeared in late July and late August. Adults and nymphs are mostly concentrated on the leaf veins near the petiole at the back of the leaves, and are the most severe from July to August. On the back of the victim's leaves, dark red spots appeared on the back of the leaves, yellow spots appeared on the front, and leaves curled and browned later in the season. The dried leaves fell off and burned like a fire and died severely. Lankanmantong’s victim rate is as high as 95%. Because Paulownia nettle is not capable of flying, it mainly depends on seedlings and timber transportation. (b) Measures for prevention and control. In late May, spray 3% hypertonic phenoxyvir 4000 times, or 2.5% deltamethrin 3000 times, and spray once every 20 days. The paulownia seedlings must be subject to strict quarantine, otherwise they may not be shipped abroad. At the end of the autumn, the litters in the fields were cleared and burned. Winter deep-turning soil eliminates overwintering adults and reduces insect sources.