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A recent epiphytotic disease on citrus in Florida nurseries was caused by strains of Xanthomonas campestris with different host specificity and lower pathogenic capacities than those of previously described strains of X. campestris pv. citri. The new strains were classified as X. campestris pv. citri because they were isolated from rutaceous hosts and despite the fact that they caused a different disease than strains previously described in that pathovar. Restriction fragment length polymorphism analyses revealed that the Florida strains comprised a heterogeneous (E) group, interrelated with X. campestris pv. alfalfae, X . campestris pv. cyamopsidis, and X. campestris pv. dieffenbachiae. In contrast, the previously described strains of X. campestris pv. citri formed two highly distinct, homogeneous (A and B/C/D) groups. Furthermore, the strains of X. campestris pv. campestris, X . campestris pv. glycines, X . campestris pv. malvacearum, X . campestris pv. phaseoli, X . campestris pv. pisi, and X. campestris pv. vignicola tested were also distinctive and appeared to be only distantly related to one another and to all X. campestris pv. citri strains. We concluded (i) that some pathovars are sufficiently distinct from the type strain of the species X. campestris to be considered as separate species, (ii) that X. campestris pv. citri group A and X. campestris pv. phaseoli (not including X . campestris pv. phaseoli var. fuscans) represent distinctly separate subbranches of the genus and should be respectively reinstated to species as X. citri (ex Hasse) nom. rev. 3213 and X. phaseoli (ex Smith) nom. rev. 627, and (iii) that the X. campestris pv. citri B/C/D strains and the heterogeneous E strains should be respectively renamed X. campestris pv. aurantifolii pv. nov. and X. campestris pv. citrumelo pv. nov.

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S EVERE EPIDEMICS of white mold of snap bean {Phaseolus vulgaris L.), caused by Whetzelinia (=Sclerotinia) sclerotiorum (Lib) Korf and Dumont, have occurred repeatedly in central and western New York State in recent years. The disease has caused significant economic losses, especially during prolonged periods of wet weather 1-12. White mold epidemics in New York are initiated by ascospores produced mainly outside bean fields by sclerotia of the fungus'. Ascospores do not directly infect bean tissues in the prebloom stage, since blossoms are needed as an energy source for germination and infection '• 5 ' 10-12. A prolonged period of wet soil is required for the production of ascospores, and 48-72 hours of continuous moisture is required for initiation of infection 1 ' 9 ' 10. The fungus completely colonizes mature and senescent blossoms in 2-3 days 3. These infected blossoms then serve as an efficient source of inoculum when in contact with leaf, stem, and pod tissues. Chemical control of this disease with benomyl has been successful 2 ' 1M2 , but its relatively high cost, the rigidity of the spray program, and the threat of the development of a benomyl-resistant strain of the pathogen have stimulated the search for sources of resistance in P. vulgaris and other Phaseolus species. A large number of cultivars, breeding lines, and plant introductions were evaluated using an inoculation technique and conditions that simulated natural infection (Abawi et al. 4 ; Abawi et al., unpublished data). All the accessions of P. vulgaris were susceptible, although a few plants of some lines appeared to be tolerant. However, a high degree of resistance was found in selections of P. coccineus, including a white-flowered line, B-3749, a selection of P.I. 175829. This line and other accessions of P. coccineus had been found resistant to white mold by Adams et al. 6 using a different inoculation procedure. Recently, Coyne et al. 8 reported that Black Turtle Soup was the most resistant dry bean germplasm to the white mold fungus under natural inoculation conditions in western Nebraska. This paper reports the inheritance of resistance in line B-3749 to W. sclerotiorum and the progress made in transferring the resistance to two commercial snap bean cultivars. Materials and Methods The genetic material used in this investigation was derived from crosses and backcrosses of B-3749 with Bush Blue Lake 274. Seeds of B-3749 were obtained

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