Use Kangkuan produced by DuPont in the United States, spray 10 ml per mu. This is a globally patented product with very good systemic conductivity. The medicinal liquid will be transmitted to the entire plant. Armyworms and corn borers will die as long as they eat it. The medicinal effect can last for 30 days and is more toxic than table salt. It’s still low, so I’m not afraid of being poisoned. Domestic highly toxic pesticides mainly use contact killing and fumigation as means of killing insects. They have a short duration of 3 to 5 days before losing their efficacy. Farmers often spray them multiple times to no avail.