Show MOSAIC DISEASE ATTACKS CUCUMBERS 5 0 41 3 E 1 1 unal cucumber mosaic disease produced by transferring to a healthy plant aphids from a mosaic disease plant note warty and mottled fruits prepared by the united states department of agriculture A new disease of cucumbers known as the lie mosaic disease hux appeared during tte the past few years yearn in commercial greenhouses and in fields where cucumbers are grown brown tor for pickling purposes the disease lias fins been known longest tind Is now nov most widespread and severe lit in the middle west where the industry of growing cucumbers tor for pickling Is centered particularly in the states of michigan wisconsin indiana illinois and minnesota becent investigations of the disease have resulted in the discovery of its nature that it Is s closely related to mosaic inoRi ilc diseases of other plants and the present indications tire that it con can be controlled by the introduction of sanitary measures and insect control methods further experiments with control measures are being carried out appearance of diseased plants the mosaic disease Is commonly known lit in michigan indiana anil and wisconsin us its white pickle tit in altin sota it Is commonly culled called nubbins bubbins nub bins the disease Is characterized lit in the held field by definite plant fruit and lent leaf symptoms when plants ure tire attacked while very young they are markedly inar kedly dwarfed by the action of the disease growth Is slow the runners are arc very much shortened the leave sare corre reduced in size tile the plants blos blossom sparingly and the amount of fruit Is very much reduced when older plants become diseased the principal visible effects tire are oh the subsequent growth of vines and fruit the vine tips and leaves bring being dwarfed and mottled inott led and the fruit malformed as aa described elsewhere the inver of diseased plants are dwarfed often curled and wrinkled and usually have a mosaic or marbled appearance in which arena areas of light lift hafl t aj m 40 4 0 0 tr 11 fruit from plant affected with mosa boea lo 10 disease misshapen with laege and small warts wart of dark green re bainder of pickle mottled light and dark green lark dark green alternate in sonio some cases tile the leaves brown and die back from tile tho tip tho the fruits are very conspicuously affected being dwarfed more or less mottled or blotched with areas of darker green on a background of light green greenish yellow or almost white in the roost most decided cases the green areas are raised and on appear its as definite warts or protuberances som sometimes eUmes of considerable size and tho the fruits take on oil many abnormal in some cases tho the fruits tre are inmost white benco tho the name naino white pickle this name probably Is duo due to a confusion of this diseased condition with the white or albino plants which typically bear white colored pickles and which have havo been known to occur occasionally in fields lor for malty tho the discoloration rind warty condition of tho the fruits which often appear on cucumbers not more than PI im inch or tyro ovo long render them ariit for pickling purposes so that in arfi buon lothe great reduction in yield caused by tho the disease ninny many it if not all of tile the fruits produced by diseased ones ore arc unmarketable la in 1110 house the disease in quite similar in its principal symptoms to those hose found lit in the lie held field the pal differences being that the disease appears tn be more virulent many 0 of the plants willing anti and dying nature of the disease tile the mosaic ill disease sease belongs to tha same class an the mosaic diseases ot of tobacco potato tomato poke weed and other plants which havo have been known for some time the exact cause ot of tills this class of trouble has haa not been discovered but it Is in considered to bo be what la Is known us tin the filterable virus an agent of infection which la 19 so BO finely divided that it will pass through at a porcelain celain niter filter and still retain its ith ability to reproduce the disease when otlien injected into healthy plants the sap or juice of any portion of a diseased vine if injected into it 11 healthy vine will produce the disease the period of incubation that Is tho the time which elapses front from the inoculation of the vino vine to tho the first visible toms of the disease in the lie greenhouse Is from seven to AN N 1 plant in a field badly affected by mosaic disease lead pencil shows relative size of plant note runners very much dwarfed with small wrinkled leaves also very warty fruit fourteen days while in the field it Is 19 usually fourteen to twenty five days the agencies of transmission of the disease from diseased to healthy plants are doubtless many it has been definitely proved that plant flee transferred from di diseased sensed to healthy plants will carry the disease it Is highly probable that other insects will be found to net act as carriers carrl cra it Is also practically certain that the disease la Is spread by pickers when harvesting the tha cuc cucumbers timbers control measures Me aure judging from the nature ot of the disease and front from the preliminary expert ments meats thus far carried out the remedial measures indicated by our present knowledge are 1 the eradication or control of insect pests which act as carriers of the disease and 2 application of sanitary measures to eliminate the sources of infection to be most effective those these methods must bo be carried out by all the farmers of ft a community rigid insect control men measures should be started ni an soon its as the plants are up and continued throughout the season especially previous to tho the beginning of picking ond and oil all ino sille diseased plants pulled and destroyed us aa well as plants with which they have come in contact owing to the fact that greenhouse conditions ore are much more completely under control than held field conditions it would seem nn an easier task tb control the disease there As aa previously stated for field control till all disease plants should be pulled nud and destroyed as aa soon as found and tile the insects should eradicated be to prevent their spreading tho the disease i |