Fig. 1. Aeciospores (A) and pieces of lesions (B) of Cronartium pini on Petri dishes and a jar with a covid mask (C).
| Table 1. Samples of Cronartium pini and controls used in scent discrimination. Bolded target (fungal source) and nontarget (control source) samples were used in the final indoors scent discrimination tests. CF = Heteroecious life-cycle form. PP = Autoecious life-cycle form. | |
| Fungal source, type, storing | Control source, type, storing |
| C. pini (CF), aeciospores on Petri dishes, frozen | Melampsora epitea coll., leaf of Salix, frozen |
| C. pini (PP), aeciospores on Petri dishes, frozen | Melampsoridium betulinum, leaf of Betula, frozen |
| C. pini (CF), piece of fresh branch lesion, frozen | Chrysomyxa ledi, needle of Norway spruce, frozen |
| C. pini (CF), piece of old branch lesion, frozen | Coleosporium tussilaginis, leaf of Melampyrum, frozen |
| C. pini (PP), piece of fresh branch lesion, frozen | Leaf of M. pratense, frozen |
| C. pini (CF), leaf of M. sylvaticum, frozen | Leaf of M. sylvaticum, frozen |
| C. pini (CF), leaf of Paeonia lactiflora, frozen | Leaf of I. balsamina, frozen |
| C. pini (CF), leaf of Impatiens balsamina, frozen | Leaf of Euphrasia sp., frozen |
| Leaf of P. lactiflora, frozen | |
| Sawdust of Norway spruce, frozen | |
| Piece of shoot of Norway spruce, frozen | |
| Piece of resin, frost | |
| Soil, room temperature | |
| Lichen, room temperature | |
| Stone, room temperature | |
| Cone, lichen, bark, room temperature | |
| Empty jar | |
| Eppendorf vial | |
| Empty agar plate | |
| Fiber cloth | |
| Newspaper | |
| Rubber glow | |
| Respiratory mask | |
| Paper clip | |
| Foil | |
| Table 2. Dogs’ individual performance and averaged (mean) performance in the last indoor scent discrimination test. TP = True positive, TN = True negative, FN = False negative, FP = False positive. | ||||||||
| Dog code | TP | TN | FN | FP | Sensitivity TP / (TP + FN) | Specificity TN / (FP + TN) | Precision TP/ (TP + FP) | Accuracy (TP + TN) / (TP + FP + TN + FN) |
| TR_D01 | 3 | 3 | 3 | 3 | 0.50 | 0.50 | 0.50 | 0.50 |
| TR_D02 | 6 | 3 | 3 | 0 | 0.67 | 1.00 | 1.00 | 0.75 |
| TR_D03 | 4 | 2 | 1 | 5 | 0.80 | 0.29 | 0.44 | 0.50 |
| TR_D04 | 3 | 3 | 4 | 2 | 0.43 | 0.60 | 0.60 | 0.50 |
| TR_D05 | 1 | 3 | 6 | 2 | 0.14 | 0.60 | 0.33 | 0.33 |
| Total of 60 tracks | 17 | 14 | 17 | 12 | Mean 51% | Mean 60% | Mean 58% | Mean 52% |
| Table 3. Results of five dogs in the final indoor scent discrimination tests by sample type. CF = Heteroecious life-cycle form. PP = Autoecious life-cycle form. TP = True positive, FN = False negative. | |||||||||
| Dog code | CF1, aeciospores on Petri dishes* | CF2, aeciospores on Petri dishes* | PP aeciospores on Petri dishes | PP, piece of fresh branch lesion | CF, piece of fresh branch lesion | CF, piece of old branch lesion | CF, leaf of Paeonia lactiflora | CF, leaf of Impatiens balsamina | CF, leaf of Melampyrum sylvaticum |
| TR_D01 | FN | TP | FP | TP | FN | sample not tested | TP | sample not tested | FN |
| TR_D02 | TP | TP | TP | TP | TP | FN | FN | FN | TP |
| TR_D03 | TP | FP | FP | TP | TP | FP | TP | FN | FP |
| TR_D04 | FP | FN | FP | TP | TP | FN | FN | FN | TP |
| TR_D05 | FN | FP | FN | TP | FP | FN | FN | FN | FN |
| 40% | 40% | 20% | 100% | 60% | 0% | 40% | 0% | 40% | |
| *The CF sample (aeciospores on Petri dishes) appeared twice in the test tracks. The results for each occurrence have been reported separately as CF1 and CF2. | |||||||||
| Table 4. Scent detection performance in field testing at the time of aeciospore dissemination of the autoecious life-cycle form of Cronartium pini on Scots pine in Pudasjärvi. TP = True positive. FN = False negative, FP = False positive. | ||||||
| Dog code | TP | FN | FP | Sensitivity TP / (TP + FN) | Precision TP / (TP + FP) | Used time 0–30 min |
| TR_D02 | 7 | 1 | 3 | 0.88 | 0.70 | 30 |
| TR_D03 | 4 | 0 | 0 | 1.00 | 1.00 | 25 |
| TR_D04 | 8 | 0 | 0 | 1.00 | 1.00 | 20 |
| TR_D05 | 12 | 1 | 2 | 0.92 | 0.86 | 25 |
| Total | 3 | 2 | 5 | Mean 95% | Mean 89% | Mean 25 min |
| Table 5. Scent detection performance in field testing with old lesions of Cronartium pini on Scots pine in Kolari. TP = True positive, FN = False negative, FP = False positive. | ||||||
| Dog code | TP | FN | FP | Sensitivity TP / (TP + FN) | Precision TP / (TP + FP) | Used time 0–30 min |
| TR_D02 | 9 | 1 | 0 | 0.90 | 1.00 | 27 |
| TR_D03 | 2 | 1 | 0 | 0.67 | 1.00 | 17 |
| Total | 11 | 2 | 0 | Mean 78% | Mean 100% | Mean 22 min |
| Table 6. Smell detection performance in field testings of Cronartium pini on leaves of alternate hosts in plant sample plots in Kolari. TP = True positive, TN = True negative, FN = False negative, FP = False positive. | |||||||
| Dog code | TP | TN | FN | FP | Sensitivity TP / (TP + FN) | Precision TP / (TP + FP) | Used time 0–15 min |
| TR_D02 | 2 | 0 | 1 | 0 | 0.67 | 1.00 | 8.5 |
| TR_D03 | 1 | 1 | 1 | 0 | 0.50 | 1.00 | 5.6 |
| Total | 3 | 1 | 2 | 0 | Mean 58% | Mean 100% | Mean 7.1 min |