Diagnosis and Control Measures for Major Diseases of Flower Seedlings
In recent years, as the environment has been damaged, people have paid more and more attention to the planting of landscaping seedlings, and flower cultivation has become the primary project for most urban people to cultivate their minds and bodies. Below, the editor will tell you about the diagnosis methods and control measures for major diseases of flower seedlings. Friends who like flowers and plants can refer to it.
1 Identification and Diagnosis of Major Diseases of Flower Seedlings
Major diseases of flower seedlings are divided into non-infectious diseases and infectious diseases: non-infectious diseases are also called physiological diseases. The main cause of this kind of disease is that flowers are not suitable for the environment, which leads to physiological changes in flowers. This kind of disease will not be transmitted to other individual plants, so this kind of disease is also called non-contagious disease, for example: iron deficiency chlorosis, sunscald, etc.; infectious diseases are also called pathogenic parasitic diseases. The main cause of this kind of disease is that microorganisms such as fungi, bacteria and viruses parasitize flowers, causing flower diseases, and can infect other individuals, so they are also called contagious diseases, for example: black spot, powdery mildew and rose rust, etc.
2 Protection and Control of Major Diseases of Flower Seedlings
2.1 Control Measures for Non-infectious Diseases
Taking iron deficiency chlorosis as an example, the occurrence of iron deficiency chlorosis in flower seedlings is mainly manifested as yellowing of young buds. In severe cases, they turn from yellow to brown, and finally dry up and fall off. Generally, this situation occurs in acid-loving flowers planted in the north, such as rhododendron, gardenia, hydrangea and jasmine, etc. There are mainly the following methods for controlling iron deficiency chlorosis: First, mixed fertilizer. This method can prevent and control the iron deficiency problem of flower seedlings. The main components of the mixed fertilizer are ferrous sulfate, cake fertilizer, manure and water mixed together, with a ratio of 1:2:4:80. The specific weight needs to be determined according to the actual fertilization situation. Second, the vinegar method. Clever use of vinegar can promote the growth of flowers (acid-loving flowers) at the seedling stage and reduce diseases, mainly because vinegar contains 1% to 5% acetic acid, glucose and lactic acid and other substances beneficial to flower growth. In addition, vinegar can inhibit the biological activity of glycolate oxidase and can effectively improve the photosynthetic efficiency of flowers. The specific steps are: dilute 10 grams of vinegar in 3 kilograms of clean water, and spray the plant leaves before 10 a.m. and after 4 p.m.
2.2 Control Measures for Infectious Diseases
Taking powdery mildew as an example, the occurrence of powdery mildew in early flower seedlings is mainly manifested as yellow small spots on leaves, stems and other parts, which then expand and develop into round white lesions. Early powdery mildew is scattered, and over time it becomes a whole mildew spot, seriously affecting photosynthesis of flower seedlings. The flowers mainly harmed by its occurrence include Chinese rose, rose, chrysanthemum, cineraria and primrose, etc. The main control measures for powdery mildew are: agricultural control. Reduce the incidence of powdery mildew by selecting disease-resistant varieties; remove flowers showing pathogenic symptoms during the process of purchasing seedlings; promptly pick diseased branches and leaves during the growing period and clear fallen leaves; plant a single flower variety during planting to avoid cross-infection. Chemical control. During the overwintering process of flowers, use 3~5 degrees Be lime sulfur mixture dilution for spraying protection, and sulfur powder needs to be sprayed on the ground to ensure a clean flower environment; in the early growth stage, protective agents can be sprayed for protection, and 1:2:120 Bordeaux mixture can be used. According to the disease symptoms, choose to apply pesticide once every 5~10 days. It should be noted that flowers such as cineraria that are easily affected by pesticides cannot use pesticides; after the disease occurs, 15% triadimefon can be used as a 1000-fold diluted solution, 2% antimycin as a 300-fold diluted solution, and 10% antimycin as a diluted solution for treatment. After the disease occurs, ethirimol and kresoxim-methyl can also be used for spraying, once a week, and 2~3 times can take effect, with a ratio of 20 ml diluted in 15 kilograms of clean water. It should be noted that the prepared pesticide cannot be mixed with chemical fertilizers or pesticides; 70% sulfur diluted 300 times and 72% benothiazole and cymoxanil diluted 600 times are mixed and sprayed on seedlings in the form of spray, which can not only prevent and control powdery mildew, but also effectively prevent and control downy mildew.
The prevention and control of flower seedling diseases plays a very important role in flower growth. This article first classifies and explains the diseases that may occur in early flower seedlings, and then through the explanation of iron deficiency chlorosis and powdery mildew, etc., everyone needs to strengthen the effect of flower disease prevention and control when planting, so as to effectively prevent and treat diseases occurring in flower seedlings.
Plant production cannot avoid the invasion of diseases, and flower cultivation is no exception. If prevention and control are not timely, it will seriously affect the growth of flowers, and some will die directly. Therefore, everyone should prevent early when planting, which can reduce the incidence of diseases. The above are the diagnosis and control measures for major diseases of flower seedlings. Friends who like flowers and plants can refer to them.
Clever Prevention and Control of Diseases of Herbaceous Flower Seedlings
Damping-off and Rhizoctonia rot are the main diseases during the seedling stage of herbaceous flowers. Cockscomb, salvia, marigold, Impatiens walleriana and others are extremely susceptible. The two have different pathogens, but their control methods are similar.
Control measures: Soak seeds in 500-fold solution of 50% carbendazim wettable powder for 1 hour; spray the substrate used for seedling raising with 3000-fold solution of 95% Lvheng No. 1 for sterilization; the sowing amount should not be too large, and the bottom water at sowing should not be too much, while ensuring that no more watering is needed after sowing until the heart emerges; avoid high temperature and high humidity in the seedling raising site; when disease is found, promptly remove diseased seedlings and the seedlings around them. In the early stage of damping-off, spray 450-fold solution of 15% hymexazol aqueous solution; when Rhizoctonia rot occurs, spray 1000-fold solution of 20% tolclofos-methyl emulsifiable concentrate; when damping-off and Rhizoctonia rot occur at the same time, spray 800-fold solution of 72.2% propamocarb aqueous solution plus 800-fold solution of 50% thiram wettable powder. Spray 2~3 kilograms of pesticide solution per square meter.
Main Pests and Diseases of Flowers in Summer and Their Control Methods
According to a recent survey, there are many types of flower pests and diseases at present, and diseases are occurring relatively severely. The main pests and diseases occurring are: whitefly, American leafminer, scale insect, scarab beetle, chrysanthemum black spot, anthracnose, etc.
Whitefly
This insect occurs on many kinds of flowers, with poinsettia suffering the most. Recently, surveys in Hualong, Panyu, Zhenglong, Zengcheng, Fangcun and other places found that poinsettia, African daisy, little angel, Ludi, cineraria and other varieties have relatively large insect populations, with an average of 268.7 live insects per hundred plants, among which poinsettia and African daisy have 300—403 live insects per hundred leaves. The insect stage is mainly nymph, which is also the suitable period for control. This insect has the characteristics of rapid reproduction, overlapping generations and strong pesticide resistance, so it is necessary to apply pesticide accurately at the nymph stage to improve the control effect.
American Leafminer
This insect is a major pest of flowers such as chrysanthemum and dahlia. A recent survey showed an average leaf damage rate of 13.6%, 28 live insects per hundred leaves, and a pest index of 3.2. It is expected that this insect will occur at a moderate level.
Scale Insect
At present, the population density on areca palm, small-leaved banyan and sago palm is relatively large. The types of scale insects occurring include: armored scale, cottony cushion scale, wax scale, etc. The leaf damage rate is 7.8%, with 929.3 live insects per hundred leaves, and in some serious cases as high as 4878.
Scarab Beetle
This insect is a polyphagous pest. Adults gnaw leaves and petals, and nymphs damage roots. According to a recent survey of chrysanthemum, velvet plant, Ludi, areca palm and others, the leaf damage rate is 5%, with 2--6 live insects per hundred plants.
Chrysanthemum Black Spot
The recent weather is quite humid, which easily induces the occurrence and development of this disease. According to a recent survey of chrysanthemum varieties such as Lijin and Anning Princess, black spot occurs relatively severely, with a plant incidence rate of 27.8%, in severe cases as high as 43%, and a leaf incidence rate of 13.4%.
Anthracnose
This disease occurs on flowers such as African daisy, chrysanthemum, Hawaiian coconut, peace lily and rich coconut. The general plant incidence rate is 20.25%, the leaf incidence rate is 14.5%, and in severe cases as high as 61%.
In addition, some flowers are harmed by thrips and red spiders. African daisy has thrips per hundred plants, and small-leaved banyan has 60 live insects per hundred plants.
Control Methods
1. To control flower whitefly and scale insects, pesticide control should be carried out at the peak period of nymphs.
Whitefly: You can choose 10% imidacloprid 2000-fold or 2% diflubenzuron 2000-fold or 10% imidacloprid or dichlorvos-aphid-killing 1000-fold solution for spraying. Spray once every 7--10 days, for 2--3 consecutive sprays.
Scale insect: You can choose 40% profenofos or sujieke 1000-1500-fold or 40% omethoate and other 1000-fold solutions for spraying.
American leafminer: 1.8% abamectin or lvcaibao 1000--1500-fold or 40% chlorpyrifos 800-fold solution for spraying.
2. To control flower diseases, start applying pesticide at the seedling stage or early stage of disease. Depending on the condition, spray once every 7-15 days, for 3-5 consecutive sprays.
Chrysanthemum black spot: (1) Remove old diseased leaves and burn them centrally; (2) Chemical control; you can choose 50% carbendazim 500-fold or 80% captafol 800-fold or 25% propiconazole 1000---1500-fold solution for spraying.
Anthracnose: You can choose 50% Shibaogong 1000-fold or 40% Shibaole 1500-fold or 75% chlorothalonil + 70% thiophanate-methyl 1000-fold solution for spraying.