Weed host range and overwintering of curly-top virus

Abstract does not appear. First page follows.

Introduction

It is important to know what plants growing in the cultivated areas and on the uncultivated plains and foothills are reservoirs of the curlytop virus. After sugar beets and other economic host plants of the beet leafhopper, Eutettix tenellus (Baker), are harvested, the adults of the overwintering generation feed on weeds and perennials during their flights from the cultivated areas to the uncultivated plains and foothills. After the pasture vegetation becomes green, the adults of the overwintering generation leave the perennials and feed on the pasture vegetation. After the pasture vegetation becomes dry on the plains and foothills, the adults of the spring generation fly into the cultivated areas and are often abundant on favorable weeds. Some of these food plants of the beet leafhoppers serve as host plants of the curly-top virus.

A number of papers have appeared on the experimental infection of weeds with curly top, but the contributions on naturally infected weeds are limited. A review of the literature on this subject follows:

Boncquet and Stahl⁽¹⁾ experimentally infected dwarf mallow (Malva rotundifolia L.) with curly top and demonstrated that this weed growing in the vicinity of beets in the Salinas Valley was naturally infected with the disease.

Severin⁽⁵⁾, ⁽⁷⁾ and Severin and Henderson⁽¹¹⁾ reported that 26 species of weeds and shrubs in 10 genera belonging to 6 families were experimentally infected with curly top, and 25 species of wild plants in 11 genera of 8 families were demonstrated to be naturally infected with curly top.

Carsner⁽²⁾ found 11 species of wild plants and 3 species of economic plants belonging to 11 families susceptible to curly top and recovered the virus from 12 species. He reported 24 species of uncultivated and economic plants as nonsuseeptible to curly top. In a later paper⁽³⁾ he reported that the virus of curly top became attenuated when passed through certain weeds such as Chenopodium murale L., Rumex crispus L., and Suaedea moquini Greene.