Description: Fenazaquin (EL-436; XDE-436) is a quinazoline-based insecticide/acaricide which exhibits contact and ovicidal activity against a broad spectrum of mites in grapes, pome fruit, citrus, peaches, cucurbits, tomatoes, cotton and ornamentals. It is a new acaricide, was determined in field trials in the UK to be as effective against Panonychus ulmi on apple at 100 and 200 p.p.m. a.i. as fenpropathrin at 50 p.p.m. a.i. It was not effective against Aculus schlechtendali. At 100 and 200 p.p.m. a.i., fenazaquin initially reduced numbers of the predatory mite,Typhlodromus pyri, but by 45 days after treatment numbers of the predator had recovered. Thus fenazaquin was shown to be a promising candidate for use in integrated pest management programmes in apple.