Reflective mulch decreases the spread of two non‐persistently aphid transmitted viruses to narrow‐leafed lupin (Lupinus angustifolius)

Trials were done in 1987–1989, to investigate the effect of a reflective aluminium painted polythene mulch in protecting rows of narrow‐leafed lupin (Lupinus angustifolius) from infection with two non‐persistently aphid‐transmitted viruses, bean yellow mosaic (BYMV) and cucumber mosaic (CMV). The mulch greatly decreased the rate and extent of spread of BYMV from external sources into mulch‐protected rows in two trials, but was somewhat less effective in a third. The rate and extent of spread of CMV from an adjacent external source into reflective mulch‐protected rows was also greatly decreased in one trial in which the mulch also decreased spread within rows and was effective even when the primary infection source was only 2.5 m away. In a trial sown with CMV‐infected seed (c. 2% seed transmission), the mulch decreased CMV spread from primary foci within rows. Reflective mulch can be used to protect breeders' single row plots of lupins from infection with CMV and BYMV.