Perennial-delphinium ringspot

Abstract does not appear. First page follows.

Introduction

Among the virus diseases encountered in the course of the investigation of celery calico on perennial delphiniums ⁽⁵⁾4 was one which caused ringspot of perennial delphinium; this was found on unknown varieties or hybrids at Berkeley, Hillsborough, and Montara, California, the symptoms being identical in the three places. The symptoms of celery calico on delphinium are confined to the basal or intermediate leaves, whereas ringspots occur on all of the leaves.

Work was undertaken on the host range, properties of the virus, and determination of the vectors. The symptoms of the disease were compared with those of ringspot previously reported on delphiniums.

Valleau ⁽⁷⁾ found a virosis of delphinium in Kentucky closely resembling ringspot of tobacco. He later ⁽⁸⁾ reported a delphinium virus causing a “coarse etch” when transferred to tobacco and suggested seed transmission. In another paper ⁽⁹⁾, he described the symptoms in more detail and gave delphinium, tobacco, tomato, and cucumber as host plants of the virus. The symptoms on delphinium consist of chlorotic ring patterns on individual lobes of the affected leaf, sometimes extending into every lobe. He also stated that this disease occurred naturally in tobacco both in Kentucky and in Minnesota and that “this virus corresponds most closely to the typical cucumber viruses.”

Johnson ⁽³⁾ found patterns on delphinium similar to the large, yellowish, concentric patterns on dark tobacco caused by a tobacco-ringspot virus identical with that described by Fromme, Wingard, and Priode ⁽²⁾.

Burnett ⁽¹⁾ described a virus disease causing dark-brown to black lesions on delphinium leaves. Tobacco plants inoculated from these showed an irregular mottle with ring-and-line patterns. Delphinium plants inoculated from these tobacco plants developed dark-brown ring and- line patterns during the first season.