Vol. 11, Special Issue 4 (2022)

Cotton is one of the world's most important fibre crops. The bollworm complex and sucking pests are the most devastating of the biotic and abiotic stresses limiting cotton production. Cotton leafhoppers are devastating sucking pests, causing both quantitative and qualitative losses. The bollworm complex was stopped by the introduction of Bt cotton. But the sucking pest complex, especially leafhoppers, has flourished, gradually aggravating economic damage. The widespread use of insecticides to control sucking pests has resulted in pest resistance to insecticides of various modes of action. At this point, the host plant resistance (HPR) mechanism (natural pest management method) would be helpful for this situation's handling. In these aspects, biochemicals are an important mechanism of resistance in HPR. Tested for biochemical activity were protein, phenol, proline, free amino acid, and total soluble sugar. From January to April 2022, 41 genotypes were studied for leafhopper resistance against biochemicals. Strong resistance is linked to protein and phenol content, while susceptibility is linked to total soluble sugar content. Strong resistance is linked to protein and phenol content, while susceptibility is linked to total soluble sugar content. The highest protein content was found in TVH/JR/2021-22-3 (57.96 mg/g), and the lowest in TCH 2026 (2.07 mg/g). TCH 2021 had the most proline (145.04 µmol/g) and C14xGSHB 5-3-6-1 had the least (24.22 µmol/g). Phenol content was found to be high in JR/AKH/2021-22 9631 (94.64 µg/g) and low in C14xPP 21-3-1-3 (13.70 µg/g). JR/AKH/2021-22 9637 (32.64 mg/g) had high levels of free amino acids. C14 × C 27 5- 2-1-5 had the highest total leaf carbohydrate (7.20 mg/g).