112 Journal of Agricultural Research voi. xxii, No. 2 



Those borne at the upper nodes were more severely affected. The yield 

 of seed was very materially reduced (PI. 19, A, B), since a considerable 

 proportion of the pods contained no germinable seeds and the remainder 

 as a rule not more than one or two seeds (PI. 19, D) . Even the germinable 

 seeds were in general undersized. 



Observations made a month later showed that the mosaic plants were 

 remaining green longer than the normal plants, so the disease evidently 

 delayed maturity. 



FIELD INOCULATIONS 



In another field of soybeans in which no mosaic was present inocula- 

 tions were made August 2 7 by rubbing the young intemodes with cotton 

 soaked in the juice from crushed mosaic soybean leaves and then wound- 

 ing these intemodes with a needle. One hundred and fourteen plants were 

 thus inoculated, but no mosaic developed. Fifty- two plants were simi- 

 larly inoculated, except that the juice of leaves from mosaic garden beans 

 was used as inoculum, and none developed the disease. Forty-six garden 

 bean plants were also inoculated in a similar manner with the virus from 

 soybean mosaic, and none developed mosaic. 



SEED TRANSMISSION 



To determine whether or not the disease was seed-borne, a quantity 

 of seed was saved from mosaic and healthy plants early in October for 

 subsequent tests in the greenhouse. On October 25, 150 seeds from 

 mosaic plants were planted in 25 pots of sterilized soil, 6 in each pot. 

 By December 15, 124 plants had come up, and 18 showed unmistakable 

 mosaic symptoms. None of the 148 controls grown from seed from 

 normal plants showed mosaic. 



In a second trial about 180 seeds from mosaic plants were planted 

 December 9 in 59 pots of sterilized soil. February 3, 192 1, 11 out of the 

 106 plants which were up showed mosaic. None of the 38 controls 

 grown from seed from normal plants showed the disease. As a result 

 of these two tests it is evident that about 13 per cent of the seedlings 

 from seed produced on mosaic plants developed the disease. 



The mosaic seedlings were spindling (PI. 18, F, G), and the j&rst pair of 

 true leaves were characterized by downward, longitudinal curling or 

 rolling, a crinkling, and a faint etiolation or mottling. These leaves 

 turned yellow prematurely. The leaves subsequently formed were 

 greatly stunted and showed the mottling and crinkling more conspicu- 

 ously than the first leaves. 



GREENHOUSE INOCULATIONS 



From these mosaic seedlings the disease was transmitted to healthy 

 soybean seedlings. Several methods of inoculation proved successful. 

 A number of inoculations made early in January yielded only negative 

 results, but later better success was obtained. 



