Dear experts , peers, 

have you met farmers did " Cocktail " mixture in fields , for pesticides and fertilizers , then spray all of them to plants at one time ? 

Do you think it is a good way or not ? 

May it cause problems ? which problems may cause ? how to solve these problems ? 

Your comments are welcome. 

it means sereral pesticides mix together , such as insecticides mix with fungicides , or PGRs ( Plant Growth Regulators )? 

or several formulations mix together , such as WP, EC, or SC, etc ? 

or several pesticides mix with fertilizers , such as N, P, K fertilizers , leaf fertilizer ?