What's eating my granny smith apple?

Granny Smith apple is susceptible to codling moth, apple sawfly, woolly aphid, and rosy apple aphid. Its firm green skin and very late harvest leave it exposed to codling moth second-generation attack deep into autumn. Pheromone monitoring, granulovirus, and fruitlet bagging are the key controls.

Larvae tunnel to the core producing frass-clogged entry holes; Granny Smith's late ripening season means second-generation larvae can still be active at harvest. Hang pheromone traps from late May; apply codling moth granulovirus mid-June and repeat 6–8 weeks later for second generation; wrap corrugated cardboard around trunk to trap pupating larvae and destroy it.

White cottony masses on pruning wounds, branch crotches, and rootstock suckers; galling and cankers develop on infested wood. Brush colonies off with a stiff brush and insecticidal soap; prune out heavily galled wood; biological control with Aphelinus mali wasp where available.

Tight, reddened curled leaves on blossom clusters; fruitlets on affected spurs are stunted and ribbed at harvest. Treat at pink bud stage with insecticidal soap or pyrethrin before colonies are protected inside curled leaves; avoid pyrethroid sprays at blossom time.

Ribbon-like corky scar on maturing apples or internal galleries; most affected fruitlets drop in the June drop. White sticky traps hung at petal fall to catch adult flies; collect and bin all frass-filled fallen fruitlets; deep hoeing around the tree disrupts soil pupation.