Maturation and hullsplit of Nonpareil almonds and concomitant susceptibility to infestation by navel orangeworm occurred earlier in areas of the tree subject to greater radiant exposure, i.e., outside before inside, south half before north half, and earlier with increasing height. Infestation of almonds by the navel orangeworm was significantly higher with increasing height and on the outside vs. the inside of the tree canopy (P<0.05). In trees stressed by mite infestations and irregular irrigation, hullsplit developed sooner and nut maturation extended over a longer period of time.