Show BEAN BOTH COMMON AND SEVERE injurious disease of plants in iowa on some varieties ot which it Is more destructive than others for a number of years reports have come to the botanical section of the iowa experiment station of the anu ness of bean a dis ease which Is both common and se vere in the state on some varieties of bean it Is especially severe the disease makes its appearance in small reddish brown spots which rapidly increase in size soon forming large and irregular spots the cen ter becomes dark with a brownish bor der throughout the spot occur small irregular raised portions in which may be found the reproductive bodies the fungus also occurs on the leaves and stem it Is frequently so severe on the stems that they are more or less riddled with holes it not infrequently occurs on the young seedlings in the form of brown discolored sunk en spots the spots or cankers may be so severe that many seedlings are killed the colored or nearly colorless branching separate mycelium pene the tissues of the pod and bean of the bean occurs largely perhaps by infection of seed in fruit to which dr halsted first called attention the disease spreads rapidly from pod to pod as for example in the mar ket place as has been shown by re heated inoculations in the laboratory when under the most favorable condi eions a spot may be established an otherwise healthy plant or pod in 36 hours the infect on is from with out and may be by means of wind bean affected by dripping water bearing the spores or through the agency of insects which visit the bean flowers for their honey and incidentally convey the germs with the pollen they ire distributing among the flowers prof whetzel calls attention to the mode of infection in bean plants the disease makes its first appearance on the bean seedlings as they come up it may then be detected as brown discolored sunken spots or cankers on the seed leaves or the stem the early appearance of the disease Is due to the tact that the musk melon affected by masses of threads collect at points which causes a collapse of the cells of the host plant and a breaking of the epidermis from the mass of mycelium a spore bearing layer Is pro deuced the layer contains brown hy phae known as setae which do not produce spores and ordinary erect threads of which bear the one celled spores or conidia the small contain a large number of which are held together by a mucilage ous substance the common expression Is that they ooze out forming pink masses water causes the mucilage to dissolve and the spores become separated infection fungus Is usually carried over cintel wintel in the seed and so Is already in the bean when it Is planted gain found that the disease spread from infected seed or from presence of spores placed on a seed or in the soli dr halsted in a series of tion experiments transferred the tun gus to watermelon and dr farlow reports it on watermelon and nutmeg melon it Is found in england ac cording to carrothers mr H F whetzel after long ob atlon finds that selection of clean seed Is the best means toward control of the rust |