AbstractParathion‐methyl and monocrotophos at 1.12 kg active material/ha at intervals of 10 and 5 days, respectively, suppressed larval populations of the false codling moth,Cryptophlebia leucotretaMeyrick (Lepidoptera: Tortricidae) in cotton bolls. The use of parathion‐methyl is not recommended in Uganda because of its high oral and dermal LD50 of 12 to 16 mg/kg and 67 mg/kg, respectively, on rats. Although comparatively, monocrotophos has a high oral LD50 of 20 mg/kg, it has a reasonable dermal LD50 of 342 mg/kg and can, in practice, be handled by peasant farmers if well instruc