Through the discussion of catalpa seedlings and pest control, it aims to promote the development of catalpa tree planting.
<h1 class = "pgc-h-arrow-right" >1 catalpa tree sowing seedlings</h1>
<h1 class="pgc-h-arrow-right" >1.1 seed collection</h1>
The mother tree is selected as the mother tree, which is robust and more than 15 years old, in the local forest farm. The fruit ripens, the color finally fades to a grayish brown color, and when the upper part of the fruit is slightly cracked, it can be harvested at this time. After collection, leave to dry for about 1 week. After the seeds are threshed, they are bagged and stored, and the quality of the seeds for testing, such as clarity, 1000 grain weight, germination test, etc., as well as seed treatment before sowing, are carried out. The seed yield of catalpa trees is about 10%, and 270,000/kg catalpa seeds can be obtained, with purity of up to 80% and germination rate of 45%.
<h1 class="pgc-h-arrow-right" >1.2 Seed treatment</h1>
Potassium permanganate solution has the effect of killing seeds to prevent diseases and insect pests, and plays a role in promoting germination. Therefore, before sowing, the seeds of catalpa trees should be soaked in a permanganic acid solution with a concentration of 0.5%, or soaked in a permanganic acid solution with a concentration of 0.1% for 12 h, and the soaked seeds should be rinsed with water and soaked in water with a water temperature of 35 ° C ~ 40 ° C to fully absorb the seeds. Soak in water for 1 to 2 days, drain the water and mix it with 2 times the clean fine sand, and then store it in a room at 30 °C for 15 days before germination.
The treated seeds are mixed evenly with river sand, then sprayed with water to maintain humidity and often turned to make the accumulated seeds evenly humid inside and outside. Observation at any time, generally about 10 days of seed embryo whiteness can be sown.
<h1 class="pgc-h-arrow-right" >1.3 Preparation</h1>
Catalpa seeds should be sown in places where the terrain is relatively flat, close to the water source, conducive to drainage, the soil is deep and fertile, loose and moist, and the light is relatively sufficient. The garden should be deeply ploughed and rakeed to achieve flat compaction. The soil of the nursery should be rotated to a depth of 25 to 35 cm, the weed roots that have grown over the years should be cleaned, and the low bed of the higher terrain should be selected, and the lower ground should be used as a high bed, and the bed surface should be flat for sowing. When cultivating land, sufficient base fertilizer should be applied, and 5~6 kg/667 m2 diammonium phosphate base fertilizer should be applied in the soil for disinfection. Carbufuran with 3% granules is used to control the soil at an amount of 6 to 7 g/m2. Soils treated with sufficient base fertilizer and pest control are made into seedbeds 1 to 1.2 cm wide and 20 to 25 cm high for sowing.
<h1 class="pgc-h-arrow-right" >1.4 sowing method</h1>
Both spring and autumn can be planted, with spring planting at the end of March or mid-April and autumn in mid-November or early December. Irrigation of seedbeds 3 days before sowing ensures that seedbeds are adequately hydrated. It can be used to spread shallow ditches. Width 10 cm, row spacing 25 cm, dosage 1.5 g/m2. Mix the fine sand, decomposed horse manure and fine soil of equal proportions, stir and siev and cover the soil after sowing, and the thickness of the cover should be 0.5 to 1 cm. Timely irrigation after sowing combined with sowing conditions keeps the seedbed moist and the soil moisture sufficient while avoiding the occurrence of soil agglomeration. In the spring, a shade net can be set above the seedbed 30 cm to increase temperature and moisturize; autumn sowing is irrigated when it is frozen, which can maintain sufficient moisture in the spring of the following year.
<h1 class="pgc-h-arrow-right" >1.5 seedling management</h1>
In order to ensure the shade of catalpa seedlings, all shade nets and cover nets should not be evacuated immediately after the seedlings break the soil. Catalpa seedlings generally emerge after 12 to 18 days, when the shade net can be evacuated. Catalpa seedlings have shallow roots before two pairs of true leaves, and should be watered in time if the topsoil is dry. Flood the seedlings with small water to avoid water rushing to the seedlings, while keeping the bed surface moist.
In order to ensure that the soil has sufficient nutrients to support the seedlings after the seedlings are out, an aqueous urea solution or a quick-available nitrogen fertilizer with a concentration of 1% should be applied to the seedbed, and the fertilizer amount is 10 g/667 m2. After spraying and fertilization, the stems and leaves of the seedlings should be washed with water. In order to improve the survival rate of seedlings, seedlings should be sprayed with a concentration of 50% carbendazim wettable powder 500 times every 5 to 7 days within 15 days after the catalpa seedlings are ready. The 70% concentration of dichlorvos emulsion 800 times liquid was sprayed at a dosage of 85 g/667 m2 within two days after sowing to prevent the infestation of pests such as mites and slugs.
Carry out two seedlings when sowing the catalpa tree: the first squat seedling is carried out about 30 days after the seedlings are out, and the over-dense seedlings are removed intermittently, so that the spacing between each two seedlings is maintained at about 15 cm. The second implementation of the seedlings when the seedlings grow to about 10 cm, at this time the seedlings can be transplanted, and the success rate of transplanting seedlings can reach 90% to 95%.
<h1 class="pgc-h-arrow-right" >2 Common pests of catalpa trees</h1>
<h1 class="pgc-h-arrow-right" >2.1 catalpa borer</h1>
Catalpa wild borer, also known as catalpa borer, catalpa borer, is one of the main pests of catalpa seedlings. The larvae of the catalpa borer often reside in the trunk, treetops and other parts of the catalpa tree seedlings, which have a destructive effect on the transport tissue of the seedlings, endanger the growth of the seedlings, and even cause the wind folding of the seedlings. Studies on the catalpa borer have shown that the insect infestation of the catalpa borer occurs in two generations within 1 year. After hatching for 2 h, the catalpa borer larvae can moth into the seedling from the tip of the new shoot, petiole, etc. The larvae can be moth-eating 8 to 12 cm long before pupal, and the terminal larvae have the habit of metastasis. The damaged seedlings will appear to be highly hindered in growth, the part of the moth will usually appear nodular uplift, and the moth mouth will be filled with fecal debris, so the wound is difficult to heal, susceptible to the parasitism of fungi, blown by the wind, so that the seedlings appear trunk deformation and bending, short and multi-crowned, young trees and other phenomena can not become timber.
<h1 class="pgc-h-arrow-right" >2.2 Frost Moth</h1>
The southern frost moth is generally 2 to 3 generations per year, the north will be one generation less than the south, mature larvae will burrow into the tree in October of that year to pupate over the winter, the development period of its larvae is extremely uneven, from the end of April of the following year frost moth successively feathered into adults, this phenomenon continues until early September. The egg stage of the frost moth is about 10 days, mostly on the back of the leaves of catalpa leaves. The first generation of larvae begins to infest in early May, followed by gradual feathering, generally from the end of June to mid-July, and the second generation of larvae that lay their eggs and hatches continues into October. After hatching, the larvae initially eat the leaf epidermis, and then gradually eat the entire leaf, as the larva grows, its food intake also gradually increases, when it grows to 3 years old, it begins to enter the binge eating period, mainly at night and cloudy days for feeding, frost moth will cause great harm to the leaves of the catalpa tree.
<h1 class = "pgc-h-arrow-right" >2.3 Ginkgo giant silkworm moth</h1>
The Ginkgo silkworm moth appears in the north in an annual manner, overwintering in the form of egg masses. Hatching of wintered egg mass begins in early May. Mature larvae mature from mid-June to mid-July. From mid-August to the end of August, the ginkgo giant silkworm moth is concentrated in the behavior of feathering, mating and spawning. The larvae of the ginkgo silkworm moth feed on the leaves of catalpa trees, and may to June of each year is the prevalence of larvae, which will cause the leaves of catalpa trees to be missing, and in severe cases, the canopy leaves of seedlings will be eaten clean.
<h1 class="pgc-h-arrow-right" >2.4 White-kidneyed gray night moth</h1>
The white-kidneyed gray night moth is an omnivorous pest that feeds on the leaves of seedlings, and appears in 1 to 2 generations in the north every year, mostly in May to September, and adults pupate on trees in mid-to-late September.
<h1 class= "pgc-h-arrow-right" >3 The main disease of catalpa trees</h1>
<h1 class= "pgc-h-arrow-right" >3.1 Catalpa anthrax</h1>
Catalpa anthracnosis is common in areas with high temperatures, high humidity and poor ventilation conditions, and is more serious in years with more rainfall. The pathogens of anthrax mainly cause harm to the leaves of catalpa trees, young shoots and other parts. After the leaves of the catalpa leaves are diseased, they will wilt and fall off.
<h1 class="pgc-h-arrow-right" >3.2 Catalpa root-knot nematode disease</h1>
The damage caused by pathogenic nematodes in the soil to the roots of catalpa trees can cause root-knot nematode disease of catalpa trees, which causes more extensive harm. Root-knot nematode disease can cause damage to the roots of catalpa seedlings, young trees and large trees, of which catalpa saplings aged 1 to 2 years are the most seriously damaged, and the disease rate of catalpa trees in nurseries can reach 30% to 50%. When root-knot nematode disease infects the root system of catalpa trees, it will cause some nodules in its roots, causing the roots of catalpa trees to rot and the seedlings to grow slowly, eventually leading to death.
<h1 class= "pgc-h-arrow-right" >4 Control of catalpa tree pests and diseases</h1>
<h1 class = "pgc-h-arrow-right" >4.1 Agricultural control</h1>
In order to cultivate robust catalpa saplings, high-lying, sunny and sheltered, fertile and well-drained soils should be selected. Seedlings are bred using nutrient bowls, electric hotbeds, and homemade nutrient soil. In the process of seedling raising, pay attention to the control of temperature, humidity, ventilation and other conditions, and strengthen the treatment of high wind, overcooling, overheating and other climates. The organic fertilizer used should be fully decomposed and matured, and attention should be paid to the control of fertility and moisture to avoid the occurrence of phenomena such as long and rotten roots.
<h1 class="pgc-h-arrow-right" >4.2 Physical control</h1>
Strict quarantine. Quarantine at the place of origin before the catalpa seedlings leave the nursery, re-inspect when transferring, and use strict quarantine methods to prevent the occurrence of a variety of diseases and insect pests with the transplantation of seedlings and the phenomenon of artificial spread. At the same time, the sterile culture method can effectively cultivate healthy seedlings free of pests and diseases.
Trap adults. Lepidoptera insects have the characteristics of phototropism, and by virtue of this habit, black light lamps, electronic moth-killing lamps and other insecticidal lamps can be set up in the nursery at a density of 1 lamp/1.33 to 2hm2 to kill them during the adult and feathering stages.
<h1 class="pgc-h-arrow-right" >4.3 Biological control</h1>
A variety of parasitic bees and parasitic flies are natural enemies of moth eggs and pupae, and the parasitic rate of red-eyed bees in the adult egg laying stage and the pupal stage of larval pupal can be as high as 80%, which has a good effect on the control of pests. Moreover, a variety of birds, frogs, ants and other organisms have predators for a variety of pests, which can play a role in protecting catalpa trees, so it is necessary to strengthen the protection and utilization of natural enemies of pests.
<h1 class = "pgc-h-arrow-right" >4.4 pharmaceutical control</h1>
1) Irrigation root prevention. In the spring catalpa seedling leaf spread, the use of 10% concentration of imidacloprid suspension 1 000 times the amount of 20 kg / plant for root irrigation treatment, can effectively kill the newly hatched larvae, reduce the erosion of catalpa borer. When catalpa trees are infected with rhizode nematode disease, the root system can be irrigated with a concentration of 1.8% Avermus emulsion or 10% of thiazolium aqueous emulsion 10% to 10% of the root system to eliminate nematodes.
2) Spray prevention and control. The peak period combination agent that uses insecticidal lamps to trap and kill a variety of pests can effectively avoid the erosion of catalpa trees from pests such as moths and leaf eaters. For catalpa anthrax, before the rainy season, foliar sprays were sprayed with double-dose Bordeaux liquid (copper sulfate: quicklime: water = 1:2:200) and 75% Bacillus Clear wettable powder 500 times liquid for spray prevention.
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