The present study was carried out at the experimental station and the Biological Laboratory of the Economic Entomology and Agricultural Zoology Department, Faculty of Agriculture, Menoufia University. The objective is to study the effect of Potassium silicate, Salicylic acid, Biofertilizer I-PHOS, Humic acid, NPK, and Fulvic acid on the population density of root-knot nematode, M. incognita infected sweet pepper plants cv. Top star under semi-field conditions compared with Oxamyl 24% L.The obtained results recorded that the highest reduction % in M. incognita juveniles in the soil was observed at oxamyl 85.2 %, followed by Humic acid at 69.6%, Salicylic acid, at 67.6%, Potassium silicate at 67.5%, and Fulvic acid 64.3%, while the biofertilizer I-PHOS recorded 61.1 % and NPK the treatment of registered the smallest decrease as 60.7%. As for reduction percentages of M. incognita females the highest reduction percentages were observed at oxamyl treatment 83.1 %, followed by Humic acid 53.4 %, while the least decrease percentages were recorded at the biofertilizer I-PHOS 22.2 %, and NPK 27.5 %. Meanwhile the treatments of Salicylic and Fulvic acids occupied intermediate status at 45.2 and 38.6 %. Regarding the reduction of M. incognita egg masses in the roots of pepper plants, the highest reduction % was observed at oxamyl at 80.6 %, followed by Humic acid at 52.1 % and Potassium silicate at 47.4%. In comparison, the lowest decrease % was recorded at the biofertilizer I-PHOS 18.9 %, and NPK 24.9 %. Meanwhile the treatments of Salicylic and Fulvic acids occupied intermediate status at 39.5 and 33.4%. As for reduction %, the highest reduction in root gall indexwas observed at oxamyl, Potassium silicate, and Humic acid at 50 %, followed by Salicylic and Fulvic acids at 33.3 %, while the least one recorded with biofertilizer I-PHOS and NPK 16.7%. The highest increase in plant height was 53.3% at Oxamyl, followed by 34.0 at Humic acid, and 28.5 and 21.8% at Potassium silicate and Salicylic acid, respectively. Meanwhile, it was just 9.2% at NPK. Additionally, Oxamyl showed the greatest increase in shoot weight at 61.6%, followed by Humic acid at 42.6, Potassium silicate, and Salicylic acid at 38.3 and 36.3%, respectively. In comparison, it was only 16.6 % at NPK. The study recommends the possibility of using humic acid, potassium silicate, salicylic acid, and fulvic acid to reduce the number of plant-parasitic nematodes while also increasing plant resistance to pests, particularly in soil.