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Morphological Characteristics and Control Techniques of the Rice Root Leaf Beetle
The rice root leaf beetle, also known as the rice root golden flower beetle, belongs to the order Coleoptera, family Chrysomelidae. The adult is about 6 mm long; the dorsal surface of the body and the antennae are greenish brown with a metallic sheen, and the ventral surface bears dense, thick silvery hairs. The lower half of the femur of each leg is swollen, and the femur of the hind leg has a tooth-like spine near its apex. The elytra bear several parallel longitudinal grooves made up of punctures. Eggs are laid in masses and covered with a white, transparent gelatinous substance. The eggs are long oval, slightly flattened, about 0.8 mm long, initially milky white and later turning pale yellow. The larva is about 9 mm long, spindle-shaped, white and slightly curved, with 3 pairs of thoracic legs
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How to effectively prevent and control cotton angular leaf spot
Cotton angular leaf spot is a bacterial disease. Cotton can be affected from the cotyledon stage to the mature plant stage. After infection, dark green small spots first appear on the underside of the leaves, and later the spots gradually expand, restricted by the leaf veins to form polygonal oil-soaked lesions. When the bacterial fluid is moist, it is a yellowish-brown sticky substance, and after drying it becomes a white scab-like substance. In severe cases, it can cause the leaves to dry up and fall off. If diseased leaves are held up to the light, the lesion areas look like oiled paper. The causes are, first, continuous cropping on the same land, with the disease developing from bacteria carried by diseased residues in the soil; second, poor light, high humidity and high temperature, with damaged cotton branches and leaves, which favors
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How to effectively control the Schisandra leaf-rolling worm
It occurs from July to August. The larvae are initially white, later turning green. Young larvae bite and feed on the leaf mesophyll; after the 3rd instar they roll leaves and feed, affecting fruit development. Control methods: (1) Before the larvae roll the leaves, spray with 80% trichlorfon at 1000-1500 times dilution. (2) After the leaves are rolled, spray with 40% dimethoate emulsifiable concentrate at 1000-1500 times dilution. (3) Spray with 50% phoxim at 1500 times dilution. (4) Spray with 50% phosphamidon emulsifiable concentrate at 2000 times dilution. (5) Before and after the larvae roll the leaves, they can also be caught by hand.
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Symptom Identification and Control Methods for Oleander Leaf Spot
Symptoms: The spots occur at the edges or center of the leaves, semicircular or circular in shape; when several spots merge, they form a wavy pattern. They appear on both the upper and lower surfaces, with the upper surface slightly darker than the lower, and the spots are grayish-white or grayish-brown. In the later stage, a black powdery mold layer appears on the diseased parts, generally on old leaves. Pathogen and disease status: The pathogen is a fungus of the genus Alternaria (Alternaria sp.). Spores spread by wind and rain, and excessive rain easily triggers this disease. The disease occurs more often on old leaves, lower leaves, and tiller shoots sprouting from the roots. Control methods: 1. Strengthen
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How to treat oleander leaf spot? Detailed methods for disease control in medicinal plants
Oleander, scientific name Nerium indicum Mill., is a woody plant of the family Apocynaceae. Its leaves and flowers are used as medicine; it is toxic. It has the effects of strengthening the heart and promoting diuresis, eliminating phlegm, and killing insects. It is distributed in most provinces and regions across the country. Symptoms mainly affect the leaves. At first, small purplish-red spots appear at the leaf tip or leaf margin, and after expanding they form circular, semicircular to irregular brown lesions. The lesions have concentric rings. In the later stage the center fades to white, and the red-brown margin is relatively wide. When humidity is high, a grayish-brown mold layer can grow on both sides of the lesions, namely the pathogen's conidiophores and conidia. The disease
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Privet is an evergreen broadleaf tree species with strong resistance to pollution.
Privet is an evergreen tree of the genus Ligustrum in the olive family (Oleaceae). 1. Habits: Privet is native to China and Japan. It is light-demanding but tolerant of shade, prefers a warm, humid climate, and is suited to slightly acidic to slightly alkaline or calcareous soils. It can also grow in clayey soil with a salt content of 0.2%, can withstand low temperatures of -12°C, and is not tolerant of poor, thin soils. It is deep-rooted with well-developed fibrous roots, grows quickly, has strong sprouting ability, and tolerates pruning. It is not strict about climate, but is best planted in humid, sheltered, sunny spots, and grows especially well in deep, fertile soil rich in humus.
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Red-leaf privet is a common landscaping nursery stock variety
Red-leaf privet is a horticultural cultivar of the genus Ligustrum in the family Oleaceae. It is an evergreen small tree with opposite simple leaves; the branchlets are slightly covered with fine hairs, and the leaves are ovate, ovate-round to ovate-elliptic, thin leathery, extremely similar in leaf shape to Chinese privet (Ligustrum sinense), with stronger sprouting ability, faster growth and vigorous growth. Its new shoots and young leaves are purplish red, and against the backdrop of the old leaves they appear all the more vivid and dazzling. After being pruned several times, the new branches become dense and the whole crown turns purplish red, making it even more gorgeous and striking among green plant clusters. After winter sets in, the whole plant turns purplish black again, standing out even more among all things. Red-leaf privet
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Causes of Leaf Drop in Bonsai Ficus in Northern Cultivation and Preventive Measures
Ficus (Ficus microcarpa L.) is an evergreen ornamental plant of the Moraceae family, generally grown as bonsai in the north. Its leaves are bright green, its branches and trunk are vigorous and rugged, and its forms are endlessly varied; the coiled and twisting aerial roots in particular give a sense of antiquity, desolation and richness. It is an excellent bonsai plant. However, bonsai ficus grown in the north always drops its leaves, seriously affecting its ornamental effect. The author has investigated this for many years, analyzed the causes, and summarized preventive methods. 1 Causes of leaf drop Leaf drop of bonsai ficus in the north can be divided into two
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What are the control methods for cotton red leaf disease?
Cotton red leaf disease is a physiological disorder that has a relatively large impact on cotton yield and quality. This disease usually begins to occur at the early flowering stage. If control is not timely, by the full flowering stage to the boll-setting stage the affected area expands and the condition worsens. When the disease first appears, the leaves take on a dark green color, then gradually thicken and wrinkle, becoming brittle, with yellow spots appearing between the veins while the veins remain green. As the disease worsens, the leaf edges begin to curl downward and turn from yellow to purplish red, withering and dropping off, until the cotton plant is left as bare stalks and dies. The main causes of cotton red leaf disease
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Symptoms and Control Methods of Cotton Leaf Blight
Symptoms Also known as cotton Cercospora leaf spot. It mainly damages leaves. Infection usually occurs in the late growth stage of cotton. At first, many dark red small spots appear on the leaves, then expand into nearly round lesions with purplish red, slightly raised edges and brown centers. Under moist conditions, a white mold layer forms, which is the pathogen's conidiophores and conidia. Affected leaves break very easily. Pathogen Mycosphaerella gossypina (Cooke) Earle, called cotton ball fungus, belongs to the Ascomycota fungi. The ascocarp is spherical and black, and the ascospores
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