Cotton Yield Response to Simulated Cotton Fleahopper and Western Tarnished Plant Bug Infestations As Influenced By Irrigation Level

Effect of manual removal of early versus late stage fruits was evaluated on two cotton cultivars as influenced by irrigation water level. Experimental design consisted of three fruit abscission treatments (removal of 100% squares prior to the initiation of flowering to mimic cotton fleahopper infestation, 20% bolls removed from the top 1/3rd of the plant canopy at crop cut-out to mimic late season Lygus infestation, and control) two water levels (high versus low) and two cultivars (PHY 350 W3FE versus ST 4946 GLB2), replicated three times and deployed in a randomized complete block design (total 36 plots). Significantly higher lint yield was recorded from ‘High’ water regime (730 lb/acre) compared to that in ‘Low’ water regime (490 lb/acre). No significant difference in lint yield was recorded between fleahopper simulated treatments and control plots regardless of the water regime. Square removal did not result in significant differences in lint yield between cotton variety PHY 350 W3FE (471 and 683 lb/A) and ST 4946 GLB2 (509 and 779 lb/A) in low and high water, respectively. Lint yield did not significantly vary between 20% late-season fruit loss via manual pruning and control plots, but the yield penalty of 20% late fruit loss was more prominent in low water treatment than in high water regime. Early-season square removal resulted in increased micronaire values at both irrigation regimes, reaching to the discount range under high water regime. The effect of late-season simulated Lygus-induced fruit removal did not significantly influence the lint micronaire. The increased irrigation water level (high water regime) increased micronaire values in both cotton cultivars, but PHY 350 W3FE had micronaire in the premium range at both irrigation levels while the micronaire values in ST 4946 GLB2 increased to move away from the premium range to the base range.