Loquat tree pest control:
Cancerous diseases, caused by the invasion of insect pests or wind and snow wounds, mainly harm branches, but also occur on leaves and fruits. At first, it appears as a dark brown wart-like protrusion, followed by the death of the skin tissue, revealing the xylem after shedding, and the discoloration around the lesion changes color. Scrape the affected part of the branch and its surroundings with a knife and apply it once in April or September to October with concentrated alkali water or stone sulfur compound residue. Spray 200 times Bordeaux liquid 2 to 3 times from April to May. Preventing and controlling insect pests and causing wounds. 2. Gray spot disease, the victim leaves initially appear round smooth brown small spots, after the lesions bulge gray-white, and there are black dots appear, after joining each other, the leaves fall off. When the fruit is damaged, more water-soaked purple-brown spots occur on the top side, and the flesh is softened and rotten with a foul odor, and the upper part is black and fine spots. Remove the damaged leaves and fruits and burn them in a concentrated manner. Spray Bordeaux liquid 3 to 4 times before onset. At the beginning of the disease, zinc naipu 400 to 600 times liquid is sprayed 2 to 3 times.
Bud blight, which occurs during the rainy and new shoots, makes the new shoots dry up and brown, the middle ribs of the leaves become diseased, the epidermis becomes black, and the leaves bend into deformities. Select the disease-resistant variety Da Hong Pao, cut off the dead branches and leaves, and spray Bordeaux liquid during the new shoot occurrence period. 4. Loquat yellow caterpillar larvae eat young leaves, after eating so that the leaf edge forms a yellow-white pine bubble, after eating young leaves to eat old leaves, you can eat the whole leaf pieces and die trees. Three generations occur each year, with larvae cocooning to pupate over the winter, and the overwintering cocoons are concentrated in the middle and lower parts of the trunk. The first generation occurs from may to June after the spring shoots are extracted and before the fruit is harvested. The second generation occurs after the birth of Xia Zhao. The third generation occurs from mid-August to mid-September before the buds are revealed after the autumn shoots are sprouted, and the wintering begins in early October. Bamboo brushes can be used to brush finely on the branches to eliminate overwintering cocoons. Spray 2.5% of enemies during the 2nd generation of larvae to kill 1000 times or 10% to kill 2000 times or 40.7% lesben 2000 times.
1. Loquat leaf spot disease Common leaf spot disease of loquat (see Figure 2-82) has gray spot disease, spot disease and horn spot disease. Distributed in Guangdong, Guangxi, Yunnan, Hunan, Jiangsu, Zhejiang, Fujian and other provinces (autonomous regions). When the disease is severe, it can cause early leaf defoliation, weakening plant growth and affecting the extraction of new shoots. Gray spot disease is harmful to the fruit, often causing fruit rot, affecting the yield.
Fig. 2-82 Loquat leaf spot disease
1. Loquat brown round spot disease leaf 2.Loquat horn spot disease leaf, conidia stalk and conidia 3.loquat gray spot disease leaf, diseased fruit and conidia
(1) Symptoms Spot disease and horn spot disease are only harmful to leaves, gray spot disease in addition to harming leaves, but also can infringe on fruits. These three diseases tend to be concurrent on the leaves, and their symptoms are distinguished as:
(1) Gray spot disease Leaf damage, the initial brown round spots, after the gray-white, the epidermis is dry, easy to detach from the lower tissue, most of the spots can heal into irregular large spots. The edge of the spot is obvious, a black-brown ring band, on which small black dots are scattered, that is, the conidia of the pathogen. The fruit is damaged , producing round purple-brown spots , which are later visibly sunken and covered with small black dots.
(2) Spot disease The spot is initially a small point of russet, then enlarged, nearly round, and when it occurs along the leaf margin, it is semi-circular, the central gray-yellow, the outer edge is still russet brown, or gray-brown, and most of the spots are irregular after healing. Cause the diseased leaves to die locally or in their entirety. There are small black dots, sometimes arranged in a rotunda, that is, the conidia of the pathogen.
(3) Horn spot disease The leaves are initially brown dots, which are later enlarged to be bounded by leaf veins, which are polygonal, and most of the spots often heal into irregularly shaped large spots. The spots are russet, often surrounded by a yellow halo, and the center of the later spots is slightly faded, and small black mist-like particles grow on them, which are the ovations and conidia of the pathogen and the conidia stalk and conidia.
(2) Pathogens The pathogens of the three kinds of leaf spot disease are all a kind of subphylum fungus of semi-known bacteria. Pestalotia funerea Desm.: The conidia disc matures and breaks through the epidermis and is exposed. The conidia spindle-shaped, consisting of 5 cells, 3 tan in the center, colorless cells at both ends, and 3 cilia at the apex. There is 1 foot hair at the base. Phyllosticta eriobotryae Thuem: spherical or oblate spherical, black, buried under the host epidermis, with orifices protruding from the epidermis. The conidia are oval, colorless, single- Horn spot disease [Cercospora eri-oboiryae (Enjoji) Sawada]: Mycelium assembles under the epidermis of the host, forms a ovary, and then grows a conidial stalk. The primary conidia have erect stems, single cells, light brown. When old, the apex is slightly curved, the color becomes darker, and there are 1 to 5 diaphragms. The conidia are colorless, whip-like, straight or slightly curved, with 3 to 8 septa, and contain 1 to 3 oil balls within each cell.
(3) Pathogenesis of pathogenesis with conidia and conidia and mycelium overwintering on diseased leaves or fruit residues, and from March to April of the following year, the pathogens and newly produced conidia after overwintering spread through wind and rain, causing the first infection. In the middle and lower reaches of the Yangtze River, the rapid spread of the disease is from mid-March to mid-July, and from early September to the end of October. In warmer regions, conidia of the pathogen are produced year-round, causing repeated infestations. In general, orchards with poor soil, poor drainage conditions, and poor cultivation management have a more serious incidence. The incidence of seedlings is often heavier than that of adult plants.
There are also differences in incidence between species. According to reports, the fifth child in Yuhang Tangxi, the morning of the morning, the second morning, the soft strip of white sand, the seed of Wu County, and the susceptibility of white jade. The pinnacle orbs and green seeds are more resistant to disease.
(4) Prevention and control methods (1) Selection of disease-resistant varieties. When the garden is built, deep ditches are planted and pruned, so that the canopy is ventilated and breathable, which can reduce the incidence of disease. Increase the application of fertilizer to promote the growth of the tree and improve the resistance to disease. In the rainy season, it is necessary to do a good job of drainage, reduce the groundwater level, and improve the orchard environment. (2) Remove fallen leaves in winter, cut off diseased leaves, and burn them centrally to reduce the source of overwintering bacteria. (3) Nursery or orchard, spray 1:1:160 to 200 times Bordeaux liquid after the new leaves grow, 70% methyl tolbuzin wettable powder 800 to 1000 times liquid, 50% carbendazim wettable powder 800 to 1000 times liquid, 65% daisen zinc wettable powder 500 to 600 times liquid or 50% belet wettable powder 1500 times liquid. Generally, from late April to early May, the spray begins, every 10 to 15 days, and sprays 2 to 3 times continuously.
2. Anthrax of the bacillus Anthracnose is distributed in Zhejiang, Fujian, Guangdong, Guangxi and other provinces (autonomous regions). Mainly harmful to ripe fruits, fruit in the process of storage and transportation, due to high temperature and humidity, the damage is very strong, causing great losses. The leaves are slightly more tender, and the leaf seedlings are also damaged.
(1) Symptoms When the initial occurrence occurs, light brown water-soaked round spots occur on the fruit, and then become dark brown round or oval depression, dense black dots, when the weather is wet, overflowing with reddish sticky matter to spread the whole fruit, resulting in the whole fruit rotting dark brown, and finally the diseased fruit shrinks into a zombie fruit hanging on the tree or falling on the ground, which is inedible.
(2) The pathogen (gloeosporium fructigemum berk) is a fungus belonging to the subphylum hemiknomycetes. The conidia are oblong, single, colorless, and mostly clustered cinnamon-colored.
(3) Pathogenesis Of pathogens overwinter on the diseased fruit with mycelium. The following spring, it spreads through wind and rain. It is the most severe in warm and rainy springs. When the fruit is ripe, it is seriously harmed by high temperatures and rain. Poor shade and ventilation, poor light transmission, and pest-infested orchards promote the occurrence of diseases.
(4) Prevention and control methods (1) Strengthen cultivation management, combined with winter pruning, remove diseased fruits, and bury or burn deeply. (2) Pay attention to the timely control of orchard pests. (3) Early detection of diseased fruits, immediately removed to prevent spread. (4) Combined with the prevention and control of leaf spot disease, before the fruit harvest in early May, spray 0.5% Bordeaux liquid to protect the fruit, or 50% antibacterial special wettable powder 1000 times liquid; or 65% Daisen zinc wettable powder 600 times liquid; or 70% methyl tolbuzin 700 times liquid, spray once every 10 to 15 days, spray 1 to 2 times.
3. Loquat white striped feather disease Loquat white striped feather disease is widely distributed, generally in the old loquat production areas have occurred, but also endanger apples, pears, grapes and stone fruits and other fruit trees. Mainly the root of the plant is harmed by pathogens, causing rot, yellowing of the leaves of the diseased leaves, early shedding, and then gradually dying.