The best time to control wheat scab is in the early stages of infection
AbstractWheat scab is most likely to occur during the heading and flowering stages, that is, between mid-April and mid-May, so control measures are generally most effective when carried out during this period. Wheat scab should be primarily prevented; if infection occurs during the flowering stage, serious consequences may only appear during the grain-filling stage, and at that point it is very difficult to stop the disease.
I. Timing of wheat scab control
Wheat scab, also known as wheat ear blight, can cause ear rot and even lead to the death of wheat plants. Wheat scab generally occurs during the heading and flowering stages, usually between April 15 and May 10; because of differences in climate from place to place, the timing varies slightly, so the heading and flowering stages of wheat should be carefully monitored for control.
Because wheat scab infects during the flowering stage, serious consequences only appear during the grain-filling stage, and the disease is difficult to control once it occurs, wheat scab is generally managed mainly through prevention. Wheat scab also prevails in rainy weather, so when controlling wheat scab it is essential to seize the key period.
II. Methods of wheat scab control
1. To control wheat scab, seeds can be dressed with yield-increasing bacteria, then dried before sowing.
2. Preventing ear rot during the flowering stage is the focus of control. Pesticide spraying should be carried out at the beginning of flowering; especially during the heading and flowering stages, when the weather forecast predicts 3 consecutive days of rain, even greater vigilance is required, and the treatment should be applied promptly 6-24 hours before rainfall. If it is not possible to apply the treatment before the rain, it can also be applied within one day after the rain stops (at the latest 36 hours) or during an interval between rains. Generally, based on climate, variety and growth-stage characteristics, a second application is made about one week later.
III. Precautions for wheat scab control
1. Choice of pesticide
(1) For scab control, choose pesticides with good permeability and persistence, and the preparation should be resistant to being washed off by rain. Generally, 50g of 10% Sike or 75g of 50% carbendazim wettable powder is used per mu, mixed with 20-30 kg of water, for spraying.
(2) Ultramicro powder or suspension concentrates give better results; when applying, aim at the wheat ears and pay attention to pressure and nozzle orifice size. Small-orifice nozzle plates should be used to ensure the mist meets requirements.
(3) Note that the water volume per mu should be greater than or equal to 15 kg, and the concentration used should be calculated correctly.
2. Watering time
Watering time should be arranged flexibly; avoid using sprinkler irrigation. Generally speaking, watering should avoid the flowering stage.
3. Mixing of pesticides
During the heading and flowering stages, this is generally also the time to control powdery mildew and other pests and diseases. At this time, some pesticides can be mixed so that one spraying prevents multiple diseases; just pay attention to the concentration used.
4. Misconceptions about disease prevention
(1) Wheat scab control cannot always rely on old experience; it must be considered comprehensively based on climate, soil and the condition of the wheat ears.
(2) Do not wait until disease is seen before applying pesticides; prevention should be the priority.
(3) Strictly control the number of applications, and the water volume should be sufficient.
(4) Pay attention to the correct mixing of different preparations so as to comprehensively prevent the occurrence of disease.