The present work was conducted during 2017 and 2018 seasons in Diarb-Nigm district at Sharhia Governorate, Egypt to study the effect of four rates of potassium fertilization (0, 24 , 48 , 72 Kg. K2o / fed.) on maize infestation with certain piercing-sucking insects such as aphids, Rhopalosiphum maidis and R. padi, leafhoppers and planthoppers , Empoasca decipiens, E.decedens, Balclutha hortensis, Cicadulina chinai, C. bipunctella , Sogatella vibix and S. furicefera and relationship with the chemical components and epidermal cells thickness of maize plant leaves. The results showed significant differences in the population density of the aforementioned insects of the tested rates of potassium fertilization, whereas, the highest mean numbers of their insects were recorded at the rate of F1(zero Kg. K2o /fed.), while the least mean numbers of the aforementioned insects occurred at the rate of F4(72 Kg. K2o / fed.). In addition, the results of some chemical analyses revealed that a positive relationship between total protein, carbohydrates contents, k values and the epidermal cell thickness and aforementioned rates of potassium fertilization. While, a reverse relationship was recorded between pH values and potassium fertilization. Also, the fertilization influenced significantly on six amino acids; aspartic, glutamic , glycine , alanine , isoleucine and leucine, which affected the attractive of these insect species, which may explain the decreasing in numbers of the insects by increasing the rates of fertilization. According to these results, the potassium fertilization should be recommended as effective factor in the integrated pests control program.