Abstract
Infestation of harvested apple fruits by the peach fruit moth (Carposina sasakii Matsumura) was studied using a dedicated magnetic resonance imaging (MRI) apparatus equipped with a 0.2-T permanent magnet. Infested holes on the three-dimensional (3-D) images tracked ecological movements of peach fruit moth larvae within the food fruits, and thus in their natural habitat. Sensitive short solenoid coil and surface coil detectors were devised to shorten measurement times. The short solenoid coil detected infestation holes at a rate of 6.4 s per image by the single-slice 2-D measurement. The multi-slice 2-D measurement provided six slice images of a fruit within 2 min taken by the two detectors. These results indicate that the 0.2-T MRI apparatus allows one to distinguish sound fruits from infested ones, and also as a means for plant protection and the preservation of natural ecological systems in foreign trade.