Table 2.
Turnip yellows virus (TuYV), aphid number and green peach aphid (GPA; Myzus persicae) data collected at 30 sites sown to canola (Brassica napus) in the south-west Australian grainbelt in 2017 and 2018.
| Location | Year | Zone a | TuYV Detection in Broad-Leaf Weeds b | Mean Aphids Per Trap Side Pre-Emergence to GS15 c | Trap Sides with TuYV-Carrying Aphids Pre-Emergence to GS15 (%) | Trap Sides with GPA Pre-Emergence to GS15 (%) | Crop TuYV Incidence at GS30 (%) d | Crop TuYV Incidence at GS75 (%) |
|---|---|---|---|---|---|---|---|---|
| Irish Town | 2017 | 1 | 100% VC | 5 | 32 | 32 | 60 | 100 |
| Kojaneerup | 2017 | 2 | Nil | 2 | 18 | 25 | 27 | 47 |
| Coomalbidgup | 2017 | 3 | Nil | 8 | 10 | 21 | 5 | 83 |
| Jerramungup | 2017 | 2 | Nil | 2 | 0 | 22 | 4 | 38 |
| Kendenup | 2017 | 2 | Nil | 2 | 0 | 9 | 4 | 27 |
| Wongamine | 2017 | 1 | Nil | 2 | 0 | 19 | 1 | 41 |
| Munglinup | 2017 | 3 | Nil | 4 | 0 | 25 | 1 | 27 |
| South Stirlings | 2017 | 2 | <1% WR | 2 | 4 | 0 | 1 | 25 |
| Mount Barker | 2017 | 2 | Nil | 5 | 0 | 29 | 1 | 23 |
| Esperance Downs | 2017 | 3 | Nil | 9 | 0 | 8 | 1 | 12 |
| Nunile | 2017 | 1 | <1% WR | 2 | 0 | 6 | 1 | 11 |
| Gairdner | 2017 | 2 | Nil | 3 | 0 | 0 | 0 | 75 |
| Wellstead | 2017 | 2 | Nil | 2 | 4 | 0 | 0 | 43 |
| Gibson | 2017 | 3 | Nil | 5 | 0 | 10 | 0 | 20 |
| Esperance Downs | 2018 | 3 | Nil | 7 | 32 | 39 | 88 | 100 |
| Munglinup | 2018 | 3 | Nil | 10 | 43 | 32 | 87 | 100 |
| Gibson | 2018 | 3 | <1% SC | 14 | 62 | 33 | 83 | 100 |
| Dalyup | 2018 | 3 | - | 11 | 58 | 33 | 83 | 100 |
| Coomalbidgup | 2018 | 3 | Nil | 11 | 67 | 14 | 79 | 100 |
| Grass Patch | 2018 | 3 | Nil | 6 | 54 | 29 | 62 | 100 |
| Jerramungup | 2018 | 2 | Nil | 1 | 15 | 15 | 6 | 63 |
| Gairdner | 2018 | 2 | Nil | 0 | 0 | 0 | 0 | - |
| Nunile | 2018 | 1 | Nil | 2 | 0 | 8 | 0 | 4 |
| Wongamine | 2018 | 1 | Nil | 1 | 0 | 0 | 0 | 4 |
| South Stirlings | 2018 | 2 | Nil | 1 | 0 | 0 | 0 | 3 |
| Bejoording | 2018 | 1 | Nil | 1 | 0 | 4 | 0 | 2 |
| Mount Barker | 2018 | 2 | Nil | 0 | 0 | 0 | 0 | 2 |
| Coondle | 2018 | 1 | - | 0 | 0 | 0 | 0 | 1 |
| Tenterdon | 2018 | 2 | Nil | 0 | 0 | 0 | 0 | 1 |
| Kendenup | 2018 | 2 | Nil | 0 | 0 | 0 | 0 | 0 |
a See Figure 4. b If present before sowing, leaf samples taken from afghan melon (Citrullus lanatus), blackberry nightshade (Solanum nigrum), clammy goosefoot (Dysphania pumilio), common sow thistle (Sonchus oleraceus), flaxleaf fleabane (Conyza bonariensis), marshmallow (Malva palviflora), serradella (Ornithopus sativus), soursob (Oxalis pes-caprae), subterranean clover (SC; Trifolium subterraneum), wild radish (WR; Raphanus raphanistrum) and volunteer canola (VC) tested by enzyme-linked immunosorbent assay (ELISA).—denotes site not tested, nil denotes no virus detected. c Deployed three double-sided yellow sticky traps on top of fence line and collected every two weeks and total aphid numbers counted on each trap side. Aphids caught on each trap side were counted before being pooled, homogenized, and the crude extract tested for TuYV by reverse transcription loop-mediated isothermal amplification (LAMP). Half the remaining homogenate underwent total DNA extraction and then tested for GPA by LAMP. d Tip leaf samples of 200 plants taken from each canola crop and tested individually or in groups of 2 to 10 by ELISA,—denotes site not tested. Gibbs and Gower maximum likelihood estimator used to calculate percentage (%) incidence in grouped samples. Growth stages determined using the ‘BBCH’ decimal system: GS15—five-leaf stage, GS30—beginning of stem elongation, GS75—50% podding [4].