Notes on the Green Leafhopper, <i>Empoasca lybica</i>, Berg. (Hom. Jassid.) in Palestine

In the coastal area of Palestine, Empoasca lybica has eight annual generations. The average number of offspring per female is 16, 81 being the maximum. The adults live in summer up to seven weeks whilst those of the autumn-generation overwinter and live up to five months. The pre-oviposition period, the development of the egg and larva and the total development last from 2 to 23, 5 to 49, 8 to 50 and 15 to 72 days, respectively, according to the season of the year. The threshold of development is between 10 and 12°C. in the various stages of development. The duration of development depends mainly on the temperature. Air humidity has no influence on the duration of development so long as the leaves are sufficiently succulent. Activity of the adults ceases below 14°C. and a temperature above 46°C. results in immediate death. During khamsin-days no oviposition takes place, and many larvae die, especially those of the first stage. The most important local hosts are Solanaceous plants. The characteristic damage is the appearance of yellowish stains on the leaves and leaf-curling; the plants are delayed in development, and shed their flowers and small fruits. Young plants wither when heavily attacked. Damage is most severe in young plants in mid-summer. So far no satisfactory control measures have been found in Palestine.