Studies were conducted in the Lower Rio Grande Valley (LRGV) of Texas to evaluate temporal effects of cotton stalk shredding on mortality of boll weevil, Anthonomus grandis Boheman. Comparison of flail- and rotary-type stalk shredders revealed no significant differences in mean percentage reduction of green cotton bolls (5060%). Undamaged bolls exposed on the bare soil surface during late-summer were subjected to intense temperatures which effected significantly higher mortality of developing weevils (90.8%) than that which occurred during the cooler period of mid-fall (15.7%). Rationale for a uniform stalk destruction deadline in the LRGV is discussed.