I. Characteristics of wheat midge damage
1. Covertness
The wheat plants harmed by the midge were not significantly different in appearance from the undamaged ones, and the field plants were still standing. Wheat midge is about 11 months old in the soil (overwinter overwintering) in the year, and the remaining one month completes eclosion, spawning hatching larvae and other generations. The larvae have a hazard period of approximately 20 days and the hatched larvae are hidden in the grouting grain.
2, diapause
Conditions do not occur, even if the conditions are suitable there are still some larvae do not phlegm, so this makes the insect population density in the soil increased year by year, encountered a condition suitable for years of outbreaks.
3, short prevention period, difficult to grasp the timing of medication
From mid-April to early May, adults of wheat midge will lay eggs on the ear, and the egg period is only about 5 days. The hatched larvae can enter the glume hazard. Therefore, the best time for prevention and control is only about 7 days. Under the conditions of insufficient preparation, it is easy to miss the best opportunity for prevention and control. Even if the spraying is used, it is difficult to ensure the control effect, and it is more difficult to control.
4. Serious damage and large output loss
When the amount of mu larvae is 25,000, the yield loss is about 10%, and when the mutile larvae is between 250,000 and 1,000,000, the yield loss rate can reach about 40%, and when the mutile larvae amount is 3 million, the yield loss The rate of up to 70%, when the amount of mu larvae exceeds 5 million heads, the yield loss rate will reach more than 80%.
Second, monitoring points:
After the wheat jointing in mid- and late March, the representative representative wheat field was selected. Samples (10 cm 10 cm 20 cm) were sampled at five points on each diagonal of the field, scouring, checking, and counting. When a single sample has 2 or more insects, it must be controlled. Generally, visual inspection is used. In the adult stage, the wheat plants are gently turned to the sides by hand, visual inspection of the amount of take-off insects, and when the average catching net has 10 to 25 heads of adult, it is necessary to control the pesticide.
Third, prevention and control points:
The flood season is the weakest period, followed by the adult period. Therefore, the basic strategy of "prevention in the flood season and supplementation in the adult stage" should be followed in the prevention and control.
Control indicators:
The plots with more than 2 plots per plot were treated for flood and adult stages. In other wheat areas, adult stage control and concurrent treatment of wheat aphids.
Control methods:
The principle of prevention and treatment is based on both the term and adult stages.
1. Flood control:
Smuggle soil kills. Should be held in the 3-5 days before the heading of wheat, Ningzao Do not be late.
Use pharmaceuticals: 40% chlorpyrifos emulsifiable concentrate 500 ml (add appropriate amount of water) or 3% methylisotriphos granules 2 kg, and 20 kg of fine sand, evenly stirred, formulated as toxic soil, spread the surface uniformly in wheat ridge in the afternoon (Be careful not to sprinkle poisonous soil on the leaves). Watering the poisonous soil can increase the efficacy.
2, adult control:
It is necessary to control the spraying of wheat field crops before heading and then to treat wheat aphids.
The use of agents: 2.5% alpha-cyfluthrin EC 30 ml +10% imidacloprid wettable powder 20 g. It is generally controlled before 9 o'clock in the morning or after 5 o'clock in the evening. The spray should be thoroughly sprayed thoroughly to effectively control the number of adult populations and the number of eggs laid.
Mashworms do not need to be individually controlled. The above formulas can be added while preventing wheat scab, powdery mildew, and rust, and high-efficiency foliar fertilizers that increase the grain weight of wheat can also be added.
Precautions:
1. The time required for the prevention and control of midge pests is strict. If the key period is missed, the purpose of prevention and control will not be met. Therefore, it is hoped that the majority of wheat farmers will seize the opportunity to use pesticides in a timely manner and make a good trip to control the midge insects to ensure a high yield and harvest of wheat this year.
2. Pay attention to the safety of medication and take necessary protective measures when spraying to avoid poisoning.
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