The cotton fleahopper, Pseudatomoscelis seriatus (Reuter), is an economic pest of Texas cotton, Gossypium hirsutum L., that feeds on and causes abortion of early-stage squares. Cotton fleahopper eggs are laid in late fall and overwinter on woolly croton, Croton capitatus Michx. Cotton fleahoppers terminate diapause in early spring in response to minimum required temperature and moisture conditions. A laboratory study quantified the effects of different amounts of moisture (soaking durations of field-collected dead woolly croton plants) on the emergence of cotton fleahopper nymphs from diapaused eggs. Five moisture treatments evaluated were: 1) 24-hour initial soaking and no further moistening of the substrate for the remainder of emergence duration (T₁); 2) 2-hour initial soaking followed by daily mist spraying of the substrate (T₂); 3) 2-hour initial soaking followed by 30-minute soaking for the next 7 days and thereafter mist spraying daily (T₃); 4) 2-hour initial soaking followed by 30-minute soaking for the next 7 days and thereafter dipping the substrate in water daily (T₄); and 5) soaking for 15 minutes every other day (T₅). Emergence of nymphs started 6 days after initial incubation in T₃, while the latest emergence was recorded from T₂. Peak nymphal emergence was recorded 12-days after incubation. Significantly more (P = 0.05) nymphs emerged from T₄ (n = 425) and T₃ (n = 404) than from T₁ (n = 173), T₂ (n = 290), or T₅ (n = 293). To maximize fleahopper emergence from overwintered eggs in a laboratory, it was recommended that egg hatching be activated by soaking host substrate (croton) for 30 minutes daily for about 7 days and keeping the substrate moist throughout the emergence period.