Plant symptoms induced by feeding of some leafhopper species

Abstract does not appear. First page follows.

Introduction

In a recent paper, (Severin, Horn, and Frazier (1945))3 described certain symptoms of curly top or aster yellows induced by the saliva of Xerophloea vanduzeei Lawson. On sugar beets it produced cleared veinlets, considered a reliable symptom of curly top. On asters it caused cleared venation with yellow veinbanding, stunting of the plants, development of axillary shoots from the bud in the axil of the leaves, and virescence of the flowers, all symptoms of aster yellows. The most striking effect produced by the feeding of the leafhoppers is breaking in color of the petals of asters.

In an investigation of a large number of leafhopper vectors of the California aster-yellows virus, 10 species induced symptoms on healthy China aster (Callistephus chinensis) and Golden Self-Blanching celery (Apiumgraveolens var. dulce) apparently by the saliva or by the feeding. A brief description of the symptoms produced by these leafhopper species follows.

Texananus Latipex Delong

In working on the life history of Texananus latipex it has been observed that some single noninfective nymphs induce cleared veins and veinlets with yellow veinbanding (plate 1, A) on the youngest leaf of healthy celery plants. In a later stage numerous small, green islands develop, surrounded by yellow areas (plate 1, B). Chlorotic areas appear on the intermediate leaves with scattered green islands. In the advanced stages, chlorosis gradually spreads on the inner and intermediate leaves until all of these leaves are yellow.

Texananus Lathropi Osborn and Lathrop

The symptoms produced by the feeding of some single noninfective nymphs of Texananus lathropi are similar to those described for T. latipex.

Texananus Pergradus DeLong

With this species the symptoms on the youngest leaf of healthy celery caused by the feeding of the leafhoppers are cleared veins and veinlets with white veinbanding (plate 1, C), followed by mottling.

Texananus Spatulatus van Duzee

The symptoms on the leaves of healthy celery induced by the feeding of nymphs and adults vary according to the populations of the leafhoppers. The first symptom is a clearing of the veins and veinlets (plate 2, A) on the youngest leaf of healthy celery, accompanied later with yellow veinbanding (plate 2, B).