Key Technical Points for Pest Control and Fertilization of Wheat in Winter and Early Spring

When temperatures are relatively low in winter and early spring, pest control and fertilization in wheat fields should pay attention to the following two points:

Pest control: To control @#@245@#@ aphids, red spiders and other pests, spraying omethoate is more effective than dimethoate. This is because the insecticidal efficacy of dimethoate against pests decreases significantly as the temperature drops, while the efficacy of omethoate is less affected by temperature and can exert normal insecticidal action at temperatures below 15°C. Similar to omethoate is fenvalerate; the toxic efficacy of fenvalerate at 15°C is instead stronger than at 25°C.

Fertilization: For topdressing, applying ammonium bicarbonate is better than urea. After ammonium bicarbonate is applied to the soil, it can be directly absorbed and utilized by wheat, whereas urea needs to be converted into ammonium carbonate under the action of urease bacteria in the soil before it can be absorbed by the root system. The speed of urea conversion mainly depends on the soil temperature at the time; under normal conditions, all the urea applied to the soil is converted into ammonium carbonate, which takes 7-10 days when the ground temperature is 10°C. It can be seen that for topdressing wheat in winter or early spring, applying ammonium bicarbonate takes effect faster than urea. If urea is applied, the slow release of fertilizer efficacy often affects the growth of wheat seedlings.