Bentonite aids virus transmission.

The addition of 0.1-1% bentonite to crude sap of Erigeron glaucus containing tomato ringspot virus increased transmission of the virus to bean, but similar amounts of bentonite to the same inoculum decreased transmission to cucumber and cowpea. Addition of bentonite to crude inoculum of this virus in cucumber, bean, and cowpea reduced transmission to cucumber, bean, and cowpea. Bentonite decreased transmission to cowpea of cucumber mosaic virus from young cucumber but increased transmission from old cucumber and from sugar beet. Bentonite decreased transmission of ordinary tobacco necrosis virus from cowpea, bean, or cucumber, to cowpea, bean, or cucumber, but increased transmission of the same virus from sugar beet to cowpea, bean, or cucumber. Addition of bentonite to the inoculum was almost necessary for the transmission of a bentonite-selected mutant of tobacco necrosis from one host to another.