Evaluation of cotton genotypes for host plant resistance to sucking insects and bollworms: A study on leaf morphology and insect population dynamics

Abstract

This research study investigates host plant resistance in various cotton varieties against sucking insects and bollworms, focusing on leaf morphology and insect population dynamics. The study was conducted at Central Cotton Research Institute (CCRI), Multan to explore the diverse challenges faced by cotton growers ranging from production and protection issues to marketing hurdles. The research assesses promising cotton strains included in the National Coordinated Varietal Trial 2003-2004 for their resistance or susceptibility to insect pests under unsprayed conditions. Varieties CIM-2, CIM-7, CIM-8, CIM-9, and CIM-22 were evaluated through a randomized complete block design (RCBD) with three replications. Morphological characteristics such as leaf thickness, hair length, and hair density were measured for providing valuable insights into the physiological features of each variety. Population dynamics of Jassid (Amrasca biguttula biguttula), Whitefly (Bemisia tabaci), and Thrips (Thrips tabaci) were documented for each variety revealing variations in susceptibility. Additionally, a comprehensive field survey conducted in Multan on July 27, 2004, offered a snapshot of cotton insect pests and crop development status in different areas. Farmers' practices and the prevalence of the Cotton Leaf Curl Virus were documented in pest management strategies. Varietal impact on cotton insect pests and crop parameters were analyzed and highlighted notable variations among varieties. Economic threshold levels for whiteflies, jassids, thrips, and bollworms were established. The findings emphasized the resistance conferred by specific morphological traits. For instance, CIM-2's hair density, length, and leaf thickness contributed to resistance against pests. In conclusion, this research provides a comprehensive understanding of host plant resistance in cotton varieties offering practical insights for growers and researchers to optimize crop management strategies. The findings contribute valuable information to address the complex challenges faced by cotton growers and enhance sustainable cotton production practices. © 2018 The Author(s)