Waxy corn kernels have coarse waxy endosperms, which resemble shiny vitreous kernels of hard corn and dent corn. In addition to being used as fresh food, such corn is also used for animal feed and industrial purposes. Due to the popularity of waxy corn in the market in recent years, the market value has great potential. In order to do a good job of waxy corn production, we must do a good job of pest control.
First, disease prevention
The common diseases are large spot, small spot, and rust.
1, large spot disease
Symptoms: The germs mainly damage the leaves and can also invade leaf sheaths and temporal lobes. After the plants became sick, the leaves were dry and the whole plants withered and the yields were lost. The light plants had poor growth and caused a reduction in yield. In the initial stage of disease, water-stained grayish or gray-green spots appear on the leaves, and then they spread along the leaf veins toward both ends to form prismatic or long spindle-shaped large spots. The central spot is light brown with dark brown edges. Lesion width up to 1 ~ 2cm, length 15 ~ 20cm. When the weather is wet, dark gray molds (conidia) can develop on the lesions. When the disease is severe, the lesions increase and even become large and the whole plant dies.
Incidence of the disease: The pathogens of the sclerotia were overwintering on the residue of the diseased plant in the field with mycelia and conidia, becoming the main source of infection in the following year. Under conditions of high humidity, mycelium rapidly propagates, producing a large number of conidia, which are often caused by wind, air currents, and insects.
2, small spot
Symptoms: In addition to damaging the leaves, temporal lobes, and leaf sheaths, the biggest difference between this disease and large spot disease is that it can cause diseases on the ear and stem, and can cause rot of the ear and culm breakage. The onset time is earlier than the big spot disease. At the early stage of disease, translucent brown spotted water stains appeared on the leaves, followed by an oval-shaped brown lesion with auburn brown edges. The contours were clear and there were two or three concentric rings. As the lesion progresses further, the interior fades slightly and then fades to dark brown. When the weather is wet, dark black molds are produced on the lesions, ie, conidium discs. After the leaves are damaged, the leaf green tissue is damaged, which affects the photosynthetic function and leads to a reduction in production.
Incidence of the disease: Fusarium can invade filaments, grains, cobs, etc., so that the ear turns grayish black, resulting in serious reduction in production. The pathogenic bacteria used mycelium and conidia to overwinter on the diseased plant residue, and the second year produced conidia and became the primary source of infection. Conidia spread by wind and rain splashes, forming a re-infestation in the field.
3, rust
Occurs in the middle and later stages of corn growth. The disease is mainly infected with leaves. When severe, it can be immersed in loquat leaves, ears and tassels. At the beginning of the disease, the leaves scattered on both sides or gathered together with pale yellow dots. After the protrusion, expanded to a round or oblong, yellow-brown or brown, the surrounding epidermis turned up, rust-colored powder was scattered, round black bumps appeared on the later lesions, and a dark brown powder appeared after the rupture. Wet weather is conducive to the occurrence and epidemic of diseases, and partial or excessive release of nitrogen fertilizers will aggravate the occurrence of diseases.
4. Disease prevention and treatment
Agricultural control: (1) Select disease-resistant varieties to fundamentally eliminate infection. (2) Remove debris from field disease in a timely manner, implement a reasonable rotation, and reduce the initial infection source. (3) Choose a high-lying, well-drained, fertile land as a field for cultivation. (4) Open a ditch in the field, do downfall, and control the humidity in the field to suppress the mycelial growth rate and quantity. (5) Early stage sowing, staggering the critical period of harm. (6) Proper close planting, increasing P and K fertilizers, improving the microclimate in the field, and increasing plant resistance.
Chemical control: The corn leaf spot disease can occur during the whole growth period of autumn corn, and the spread and spread is fast. Therefore, in the early stage of disease, 50% chlorothalonil 709 plus triadimefon 809 per 667m2, or 50% 100% Bacterial Chestnut 709 plus flour rust 809 foliar spray, spray 5 to 7 days later, can play a very good control effect. In the early stage of disease, rust is sprayed with 20% triadimefon EC 1500 times or 0.2% lime sulfur. When the onset is severe, spray it again 15 days apart.
Second, pest control
Corn borer, also known as corn borer, belongs to the order Lepidoptera. It is the main pest of waxy corn.
1, damage characteristics
The corn borer often chooses young, dark and moist parts for feeding hazards. When the autumn maize is in the heart-leaf stage, the larvae are harmed in the heart; after entering the heading stage, the larvae are invaded into the culm or the panicle; the larvae that occur after the silk spinning of the glutinous corn are mostly concentrated on the filaments, and later the female ear or stem is deafened. Stems; after aging, stems, stems, leaves, or leaves.
2. Morphological characteristics
1 adult: yellow-brown, body length 12~15mm, wingspan 24~35mm. Both front and rear wings have two distinct brown wavy stripes, and two lines have two dark spots. 2 eggs: flat oval, first milky white, gradient light yellow, often 30 to 40 rows of squama-like egg mass. 3 Larvae: They are divided into 5 instars and are 20 to 30 mm long at maturity. They are light brown in color and have a ventral, milky white appearance. The back lines are distinct, with darker dark brown lines on both sides.
3, occurrence characteristics
The corn borer occurs from generation to generation, and mature larvae overwinter in host stalks, cobs or root pods. In the middle and late May of the second year, wintering larvae and pupa are released, and they are gradually adultated by mid-June. Adults grow nocturnally and have phototaxis, preferring to spawn on a vigorously growing host crop. In August, during the growing period of waxy corn, drill collars harmed.
4. Control methods
Agricultural control: Before the overwintering larvae emerge, treat the stalks of wintering hosts such as corn and cotton to eliminate overwhelming insect sources.
Chemical control: In the corn leaf stage every 667m2 with pyrethroid pesticide poisonous chlorine EC 600 times irrigate 2 to 3 times. In the tasselling period of corn, when pollination of the corn is over and the larvae have not concentrated on filaments, a 50% solution of dichlorvos emulsion 800 times is sprayed on the base of the filament at the tip of the ear to kill the larvae.
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