Show black currant nurse of rust eust acts as advance guard in spreading disease among the white pines by the united states state department of agriculture the european nur black currant Is rt public nuisance because it nets acts ns as nil advance guard in spreading sp alio t il 0 white eluo blister rust a disease of 0 r foreign forel gri origin la is destructive to al nil of our american whito or five leafed pines says ays samuel II 11 detwiler ller calef blister rust specialist of tile tha united states department of agriculture two host plants 4 tho the blister rust requires two its dla different kinds of host plants for completing its life cycle the spores that infect the pities pines are arc produced on the leaves leavea of currant or gooseberry bushes and transmitted to tile pines through the air lit in turn tile the currants all and gooseberries goose berries become infected from froin the spores speres produced on tile pines ohve nit nil species of currant and gooseberry plants take the disease dis crise to some extent the 1 block black currant to Is so susceptible that a spot on one leaf may completely spread the ill sense to the lie benth C plant os as well As noar ly hy plants tit of the saine gamo species thus the ali scattered windblown wind blown spores which may travel hundreds of nilles miles and riot not establish the rust en other species of 0 currants do infect tile tho european black and set up new centers of infection for this reason the Hur european black currant tins been called en lied the nurse plant of at blister rust and outlawed by the stated in which white pines are aio important forest crops white pines endangered the white pines in III tile united states that are endangered by blister rust have a cash timber value of approximately while this lumber value of tills this timber Is ninny many times greater tills this does tot anko into account tile the value of trees of these species used na as ornamentals ornament als anti and tho the potentially grout great value of the young pines for tile timber crops the binney value of the beyk currant plantings of the country IA fis negligible for these reasons the united states department of and the states concerned tinte have declared the european black currant curi ant n public nuisance and tire are operatively cooperatively co len ged in ili i fi calu campaign laign to systematically illy it from the country |