4 MISC. PUBLICATION -4 4 0, U. S. DEPARTMENT OF AGRICULTURE 



The causal organisms live in the soil and are present on the as- 

 paragus shoots when they are cut and packed for shipment. At 

 least two species of Fusarium have been isolated from decaying 

 shoots and from wilted, stunted, and yellowish plants in the field. 

 Whether these or other species cause the moldy tips and decay dur- 

 ing transit is not yet known. 



Test shipments under different methods of precooling and refrig- 

 eration and laboratory temperature studies have shown that the 

 decay-producing organisms are held in check satisfactorily at a 

 temperature of 40° F. Affected stock develops decay rapidly, how- 

 ever, soon after it becomes warm. 



(See 11.) 



GRAY MOLD ROT 



(Botrytis spp.) 



Although the organisms that cause gray mold rot are ever present 

 in most vegetable-growing regions, they seldom cause serious injury 

 to asparagus. Under conditions favorable to them, however, they 

 have been known to cause a tip wilt and decay in the field and 

 during transit. The water-soaked lesions usually show a small 

 amount of white surface mold in the early stages; later, the grayish- 

 brown mycelium and granular spore masses serve to identify the 

 disease. 



For a more complete discussion of gray mold rot, see Carrot (p. 41) 

 and Peas (p. 34). 



PHYTOPHTHORA ROT 

 (Phytophthora *pp. ) 



A serious decay induced by a species of Phytophthora occurred in 

 shipments of California asparagus during the seasons of 1938 and 

 1940. 3 This disease had not previously been found affecting aspara- 

 gus on the market. 



The decay is characterized by large semiwatery, light -brown le- 

 sions generally occurring on the side of the shoots about 1 or 2 

 inches above the base (pi. 1. A). At times the decay completely en- 

 circles the shoot, but most often one side only is affected and the 

 broken-down tissues collapse, causing an infolding and shriveling that 

 result in the production of a flattened or creased side to the shoot. 

 Under moist conditions a grayish-white, wet, appressed mold is 

 evident on the surface of the larger lesions, but under dry condi- 

 tions there may be no surface mold apparent. The decaying shoots 

 have no odor unless bacteria are also present. 



As this soil fungus usually causes no serious damage except un- 

 der excessively wet conditions, it is not probable that the disease 

 will commonly occur on asparagus. The California asparagus fields 

 were flooded in the springs of 1938 and 1940 when this disease caused 

 so much decay in the field and during transit and marketing. 



(See 5.) 



■'■ Wi.wt. Jambs s., and Bbatlbt, C. O. diseases of fruits and vegetables on the nkw 



Yokk MARKET DURING JANUARY FEBRUARY, MARCH, AND Aran, 193S. U. S. Bur. Plant Indus., 

 Plant Dis. Rptr. 22: 190-193. 1938. [Mimeographed.] 



