VARIATION IN TRANSMISSION OF 2 BYDV-MAV ISOLATES BY MULTIPLE CLONES OF RHOPALOSIPHUM-PADI L

Vector efficiency of up to 17 Rhopalosiphum padi L, clones originating from Europe, North America and North Africa, was evaluated by transmi tting two isolates of the serotype MAV for which this species is norma lly an inefficient vector. When test plants were inoculated by batches of 3 aphids, both isolates were rather well transmitted by one clone (Rp5), isolate MAV2 was poorly transmitted by all other clones tested and isolate MAV11 was not transmitted by eight clones and poorly trans mitted by two clones. When eight aphids were used by test plants, all clones transmitted both isolates. The epidemiological consequences of MAV transmission by some R. padi clones are discussed, as well as the interest of these clones for studying aphid-derived components of lute ovirus transmission.