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What are the control methods for azalea leaf spot?
1. Symptoms: Small reddish-brown spots first appear on diseased leaves, gradually expanding into nearly circular spots, or restricted by leaf veins into polygonal lesions, 1-5 mm in diameter, dark brown; sometimes grayish-white in the center with indistinct edges. The spots are darker on the upper surface and lighter on the lower surface of the leaf, and lesions at the leaf margin may merge with one another; when humid, grayish-black mold spots mostly form on the surface of the diseased areas. 2. Pathogen: The pathogen of azalea leaf spot is Cercospora rhododendri Ferraris, belonging to the order Hyphomycetales, class Hyphomycetes. The grayish-black mold spots on the lesions are
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Causes and Control Methods of Azalea Chlorosis
Azalea chlorosis is a non-infectious disease and also a common disease in azalea cultivation. After the plant is affected, the leaves become thinner, lose their green color, and turn pale, so this disease is also called chlorosis. The lack of green is obvious in new leaves. When the color of new shoot leaves becomes lighter and the leaf mesophyll turns yellow while the veins remain green, it is generally diagnosed as iron deficiency symptoms. This phenomenon mostly occurs in alkaline soil and in areas where slightly alkaline water is used to water flowers. After symptoms appear on the leaves, photosynthesis cannot proceed normally. In mild cases, it affects the growth and development of the plant
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Causes and Control Methods of Magnolia Chlorosis
Also known as chlorosis, it is a common disease of magnolia, and occurs more commonly in areas with alkaline soil. In the northern regions of our country, the disease is relatively severe. Symptoms: The diseased plant first shows symptoms on the young tender leaves at the top of the shoots. The mesophyll tissue of the diseased leaves turns yellow or pale yellow, while the veins remain green; as the disease progresses, the entire leaf turns yellow to yellow-white, and the leaf margins become gray-brown or brown and necrotic. The condition gradually worsens, the plant grows weak, and eventually dies. Causes: Magnolia chlorosis is a non-
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Pests Harming Orchids and Their Control Methods (Part One)
Pests that harm orchids include scale insects, aphids, spider mites, thrips, whiteflies, leaf miners, snails and slugs, nematodes, caterpillars, cockroaches, ants, and others. 1. Scale insects Scale insects are one of the most common pests harming orchids. There are many species, mainly parasitizing the stems and leaves of orchids, and they can also be seen on the petioles and the membranous sheaths at the base of pseudobulbs, appearing as a white powdery substance. They feed by sucking plant sap with their piercing-sucking mouthparts. In mild infestations, they cause the affected organs to turn yellow and age, affecting the growth of the orchid plant; in severe cases, they cover the leaf surface in patches, consuming nutrients and affecting the orchid's
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Pest and Disease Control Methods and Technical Key Points for Bonsai
Diseases on branches and trunks: These manifest as rot of the phloem and cambium of branches and trunks, stem rot and cankers on branches and trunks, surface rot of branches and trunks, decay of the inner wood, and spots on twigs. In such cases, Bordeaux mixture should usually be sprayed, followed by lime sulfur mixture, and the decayed parts should be scraped off. Foliar diseases: Foliar diseases usually show symptoms such as yellow-brown or black spots, leaf curling, wilting, and early leaf drop, and may be chlorosis, leaf spot disease, sooty mold, powdery mildew, etc. For leaf spot disease, remove the diseased leaves and spray Bordeaux mixture; for chlorosis, use 0.1-0
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Occurrence Characteristics and Control Methods of Pear Orchard Armored Scale
Pear orchard armored scale belongs to the order Homoptera, family Diaspididae, and is a pest that is relatively difficult to control on pear trees. In recent years, through observation, we have basically grasped the occurrence pattern of pear orchard armored scale in the Korla region, and through several years of control trials, we have developed a set of effective control methods. I. Damage Characteristics Pear orchard armored scale mainly damages fruit trees and forest trees. Among fruit trees, it mainly damages the branches, fruits and leaves of pear, apple, jujube, grape, apricot, plum, etc. Branches are often densely covered with many scale insects, and the damaged areas show red round spots; in severe cases, the cortex splits and even dies.
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Symptom Identification and Control Methods for Peach Leaf Curl
Peach leaf curl is a common disease in spring, mainly affecting ornamental peach, cherry, apricot, plum and others. 1. Pathogen: The disease is caused by fungi of the class Taphrinomycetes in the phylum Ascomycota. 2. Symptoms: It mainly affects leaves, and in severe cases can also affect flowers, young fruit and tender shoots. After leafing out in spring, infected plants show shrivelled, rippled leaves with the leaf tip and margins curling backwards and the leaf surface uneven. As the leaves grow, the leaf colour gradually changes from yellow-green to purplish-red, the mesophyll thickens and becomes brittle, and the unevenness increases. In late spring and early summer, the leaf surface develops
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How to control the pear yellow gall aphid? A full analysis of effective methods
The pear yellow gall aphid, also called the pear yellow powder insect, attacks only pears and fruit trees of the genus Pyrus. It is tiny: the adult is 0.7 mm long, bright yellow, and obovate, with short 3-segmented antennae, short black legs, and a long mouthpart that even extends beyond the tip of the abdomen; the egg is even smaller, only 0.3 mm long and pale yellow. Adults and nymphs of the pear yellow gall aphid feed in the calyx basin and stem cavity of the fruit. The damaged area of the fruit surface becomes sunken and then turns black and rots, forming cracked large black scars, which lowers fruit quality and causes the fruit to lose part or all of its commercial value. Manual control
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Symptom Identification and Control Methods of Ginger Eyespot Disease
[Pathogen scientific name] Drechslera spicifera (Bain) v. Arx [Host crop] Ginger. [Disease diagnosis] It damages leaves. When leaves are affected, small brown spots appear initially, and after expansion the lesions become spindle-shaped, 5-10 mm in size, grayish-white, with light brown edges and a distinct or indistinct yellow halo around them. When humidity is high, dark gray to black mold-like growth appears on both sides of the lesions. When the disease is severe, the lesions on the leaves merge into patches, causing the diseased plants to wither and die. The pathogenic fungus is Drechslera. The conidiophores of the pathogen are mostly solitary, straight and unbranched, olive-yellow, slightly lighter at the tip, with the basal cell swollen; the conidiogenous cells are mostly proliferating, with sympodial extension. The conidia are oblong-elliptical, with obtuse-rounded ends, straight, pale olive-yellow, and have 3-7 septa. The conidia are solitary or borne at the tip and sides.
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Symptom Identification and Control Methods for Ginger Leaf Blight
[Pathogen scientific name] Septoria zingiberis [Host crop] Ginger. [Disease diagnosis] It affects the leaves. When the leaves become diseased, small water-soaked spots appear at first, and after gradually expanding, the lesions become nearly fusiform, light brown, with a grayish-white center; later the lesions extend upward and downward into long streaks. Many small black dots are scattered on the lesions. In severe cases, the lesions may split longitudinally, and the leaves die. The pathogenic fungus is Septoria zingiberis. The pycnidia are superficial or borne on both sides of the leaf, spherical or subspherical, dark brown, and contain
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