Evaluation of resistance in cotton genotypes against leafhoppers Amrasca biguttula biguttula (Ishida), (Homoptera: Cicadellidae)

Cotton production is affected by various insect-pests attack. Among the insect pests, sucking pests impose serious crop damage. In sucking pests, the leafhopper Amrasca biguttula biguttula (Ishida), considered as a severe pest. Cultivation of susceptible hybrids and reduction in conventional insecticide applications wreak havoc of sucking pest problem. Up to 50% yield losses been reported for the pest leafhopper alone. Host plant resistance is an important component of integrated pest management strategy for leafhopper resistance. Identification of sources of resistance is way to minimize yield losses. In this study, 54 genotypes along resistant check (NDLH1938) and susceptible check (DCH32) screened for resistance in field. Based on initial resistance evaluation studies at field level, 21 genotypes were selected for further studies such as host preference studies and nymphal emergence studies in greenhouse and host plant resistance by pest infestation evaluation in field. In field screening, nine genotypes namely AKH1355, GISV 216, AKH 2012–8, GSHV 173, GISV 267, AKH 1301, GSHV 171, NDLH 2010 and AKH 2006–2 constantly showed resistance on par with resistant check (NDLH1938). Both host preference studies and nymphal emergence tests identified seven genotypes RS 2711, GISV 267, LHDP 1, AKH 1355, RS 2765, F 2164, and GISV 216, which performed on par with resistant check. Leaf anatomical parameters like distance from the lower epidermis to phloem, thickness of phloem bundle are major obstacles for stylet penetration and affect the feeding of leafhoppers. However, leaf thickness, which facilitates the insect to feed easily, succulent nature of such thick leaves preferred by the insects. Biochemical profiles revealed that higher level of chlorophyll, nitrogen, protein and amino acids favors the leafhopper infestation. In contrast, phenol compound act as feeding deterrent, as most of the resistant genotypes showed higher level of phenol.