Devices to detect red palm weevil infestation on palm species

the date palm (phoenix dactylifera l.) and other palm species have recently been threatened by the red palm weevil (rpw) rhynchophorus ferrugineus olivier, which is very difficult to be detected at early stage. this research tested non invasive approaches to detecting rpw including: a treeradarunit™ (tru); a densitometer, a penetrometer used for evaluation of the standing trees stability; a thermal camera and a digital camera. the technologies were applied in italy on 715 palms (173 p. dactylifera, 453 phoenix canariensis chabaud and 311 of other palm species), and on 86 adult date palms in saudi arabia. in italy, the thermal camera showed a high accuracy (96.29%) compared to close visual observation over the following nine months. the digital camera did almost as well (92.57%). tree radar unit and densitometer also showed good accuracy (83.33 and 88.89% respectively). in the kingdom of saudi arabia, the thermal camera showed a good accuracy (77.73%) when compared to invasive diagnosis (i.e. cutting down and opening up palm trunks). the digital camera showed a lower accuracy of 66.67% due to the fact that the red weevil mainly attacks the base of the stem and therefore there are no visible symptoms on the crown shape that would be picked up in image analysis. tru gave good results (74.73% compared to invasive diagnosis), with the best accuracy at ground level (80.65%). the densitometer results were similar to the tru case, with higher accuracy (82.26% compared to invasive diagnosis) and the highest at ground level (87.10%).