#我来唠家常#
Zucchini is a melon vegetable, and the common diseases in the planting process are powdery mildew and gray mold. The main insect pests are aphids, thrips, whiteflies, etc. The following describes the harmful symptoms and control measures of pests and diseases.
1. Diseases
1. Symptoms of powdery mildew: zucchini powdery mildew can occur from seedling stage to harvest stage, mainly in the middle and late stages of zucchini growth, mainly harming leaves, followed by stems and petioles, and fruits are rarely damaged. At the beginning of the disease, small white near-round pink spots are produced on the leaf surface or the back of the leaf and the young stem, and the front of the leaf is numerous, and then it expands to the surrounding into a continuous white powder with unclear edges, and the whole leaf is covered with white powder, that is, the asexual fruiting body of the pathogenic bacteria, that is, the conidia. In the later stage of the disease, the white mildew turns gray due to the aging of the hyphae, and piles of yellow-brown small particles are born on the lesions, and then the small spots turn black, that is, the closed capsule shell of the pathogenic bacteria.
2. Harmful symptoms of gray mold: gray mold can damage flowers, fruits, stems and leaves, etc., and it is thought that flowers and young melons are the most common. The pathogens mostly invade from the blooming and failing flowers, causing the flowers to rot and produce a gray mold layer, and then develop from the diseased flowers to the young melons. After the young melon is infected, the tip of the initial melon fades green, and then it is soft rot in the form of water stains and produces a gray-white mold layer. Rotten flowers and fruits fall off to healthy stems, leaves, and young fruits, causing disease and rot of stems, leaves, and young fruits. The stem is infected, initially waterlogged, then rots and breaks the stem. The leaves are infected, mostly from the leaf margin, and expand in a "V" shape, and can also be diseased from the petiole, and there is a gray mold layer on the surface of the lesion when the humidity is high.
Prevention and control measures: The prevention and control methods of powdery mildew and gray mold focus on agricultural prevention supplemented by chemical control. The first is to implement crop rotation to reduce soil bacteria and reduce the number of pathogens. The second is scientific watering to reduce soil moisture. The third is to apply fertilizer rationally and reduce the amount of chemical fertilizer, especially the amount of nitrogen fertilizer.
Chemical control is to fumigate with 45% chlorothalonil fumigation agent in the early stage of the disease, pay attention to ventilation, and determine the frequency and dose of fumigation according to the condition. Second, the chemical control agents mainly include triazolone EC, in the early stage of plant disease, spray the plant with 20% EC 1500-2000 times, spray 1 time every 10-15 days, generally spray 2-3 times, you can also use 50% Suclin wettable powder 1500-2000 times, 50% Nonglilin wettable powder 1000 times, 40% polysulfur suspension 500 times, or 36% thiophanate-methyl suspension 500 times.
2. Pests
1. Symptoms of aphid damage: Adults and nymphs mostly cluster on the back of leaves, young stems and young tips to suck sap. The shoots are damaged, the leaves are retracted, the growth point is dead, and in severe cases, the whole plant can die at the seedling stage. The growing leaves are damaged, dry up and die. Aphids can also cause soot disease, affect photosynthesis, and more importantly, can spread viral diseases, plants appear mosaic, deformed, dwarfing and other symptoms, and the affected plants are prematurely senescent.
Prevention and control drugs: imidacloprid, thiamethoxam, avermectin, matrine and other drugs can be used for prevention and control.
2. Thrips hazard symptoms: leaf damage, young leaves are damaged and the leaves become thinner, gray-white or gray-brown stripes appear on both sides of the leaf midrib, the epidermis is gray-brown, deformed, curled, and the growth is weak.
The fruit is damaged, the epidermal oil cells are ruptured, and the scars expand with the expansion of the fruit, showing silvery-white or gray-white marks of different shapes.
Thrips of zucchini for control can be sprayed with imidacloprid suspension. Pyrpropyl ether, dinotefuran, thiamethran, bifenthrin
3. Symptoms of whitefly: In the early stage of whitefly damage, the leaves of the plant appear white dots, which become silvery-white along the leaf veins, and then develop to the whole leaf is silvery-white, such as galvanized film, photosynthesis is blocked, and most of the leaves of the plant except the heart leaf are covered with silvery-white membrane in severe cases, resulting in slow plant growth, thinning of leaves, leaf veins and petioles becoming white and shiny, and translucent. After being damaged, young melons and young fruits become hard, and when they are severe, they fall off and the plants shrink. Bemisi whitefly to adult, nymph sucking plant to make it grow weak, the leaves show the symptoms of silver leaves, yield and quality decline, but also secrete honeydew, causing coal stain disease, when it is serious, the leaves are black, seriously affecting the photosynthesis of the plant and the effect of flower ornamentation, and even the whole plant dies.
Prevention and control drugs: thiazinone, imidacloprid, etc.,
The above insects are all vectors for transmitting viruses, and they are also common insect infestations of zucchini. In order to control the above-mentioned pests, insect nets can be placed in the vents of the sheds or yellow boards can be hung between the rows and plants for booby-trapping. These pests usually live on weeds and can be controlled by removing them so that they lose their breeding ground. In addition, root-knot nematodes are also one of the common insect pests of zucchini, which can produce nodular-like root knots of different sizes after the onset of the disease, mainly harming lateral roots or fibrous roots, which can be controlled by flooding or chemical agents.