Some host plants of curly top

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Introduction

Sugar-beet curly top, transmitted by the beet leafhopper, Eutettix tenellus (Baker), affects many species of plants among both cultivated plants and weeds. In years when a disastrous outbreak of curly top occurs among sugar beets in the western part of the United States, other cultivated plants are seriously damaged by the disease.

Forty thousand acres of beets were planted in the San Joaquin Valley during the season of 1918-19. Thirty thousand acres affected with curly top were plowed under or were not worth harvesting, and the beet leafhoppers were thus forced to seek other food plants.

During 1919, cantaloupes were a failure in the San Joaquin Valley. There was no evidence of a root rot, although root knots caused by the garden nematode, Heterodera radicola, were found on some of the plants examined. The trouble was attributed to a cold spring followed by warm weather, to the use of cold irrigation water, and later to a shortage of water. During the, past two years cantaloupes were found to be naturally infected with curly top in the Salinas Valley and the symptoms resembled those observed in the San Joaquin Valley during 1919.

Spinach was found to be naturally infected with curly top in the San J oaquin Valley in 1919, and in many other localities in later years.