Acaricidal properties of some synthetic unconjugated allenic anilides

摘要

AbstractSeven unconjugated allenic anilides with the allenic moiety situated at the 3, 4 position were synthesized and evaluated for acaricidal activity againstBoophilus microplus(Canestrinii). The order of toxicity ( adult mortality) of the anilides against adultB. microplusat 0.5 μg tick−1was: N‐(3‐chloro‐4‐methyl‐phenyl)‐5‐methylhexa‐3, 4‐dienamide, (I) = N‐(4‐bromophenyl)‐5‐methylhexa‐3, 4‐dienamide(III)(100)>N‐(4‐bromophenyl)‐deca‐3, 4‐dienamide (VI)(68)>N‐(3, 4‐dichlorophenyl)‐5‐methylhexa‐3, 4‐dienamide (II) (32.3)>N‐(3, 4‐dichlorophenyl)‐5‐methylhepta‐3, 4‐dienamide (IV) (28)>N‐(3‐chloro‐4‐methylphenyl)‐5‐ethylhepta‐3, 4‐dienamide (VII) (24)>N‐(4‐bromophenyl)‐5‐methylhepta‐3, 4‐dienamide (V) (20).Comparison of the relative potencies (in parenthesis) at 1.5 μg tick−1of the anilides with three commercial acaricides: pyrenone, lindane and carbaryl, revealed the following orders of activities: in comparison with pyrenone: pyrenone = I = II (1)>VI(0.93)>II (0.67)>IV (0.55)>VII (0.46)>VI (0.37); in comparison with lindane: I = HI (6.06)>VI (5.65)>II (4.04)>IV (3.36)>VII (2.76)>V (2.39)>lindane (1.0). All anilides were more toxic than carbaryl which gave no mortality at 1.5 μg tick−1.The need for developing more effective control agents forB. microplusis highlighted by the high levels of resistance found in some Jamaican populations of the pest. Resistance of the