The objectives of this project thesis are to study the pesticidal effects of plant extracts such as Cassava (Manihot esculenta Crantz) leaves and bitter almonds on harmful organisms, the lethality status of the cynanogycosides in bitter almonds by standardization and bio-formulations as well as to study the synergic effect of almond seed meal in suppressing disease as well as promoting yield. From the experiment conducted, it was concluded that: 1. the investigation of the effect of prussic acid on the control of soil pathogens was not successful but enhanced the germination rate of the seedling and weed suppression under confined conditions. 2. the investigation of pesticide activity of HCN in the cassava leaves and bitter almonds was successful. 3. Biological pesticides from Cassava leaves can be an effective strategy in controlling horticultural pests such as aphids. The overall goal of the experiment is to determine the potential of cyanide use in agriculture. Cassava leaves were used in this regard because we want to find new ways of using plant materials with cyanoglucosides for plant protection. We measured the performance of the plants using known variables. These measured variables were classified as physical and chemical characteristics of the plants. The measured physical characteristics were the growth stages of the plant (measured as a number or a code), the height of the plants (measured in centimeters), the germination rate of the plants (measured as an average of the germinated cucumber plants to the total number of plants germinated in percentage), the number of leaves (measured as an average) and the biomass (measured in grams) in this case cucumber plants.