S. Mahunka szerk.: Folia Entomologica Hungarica 46/2. (Budapest, 1985)

Morphological features Streptanus aemulans (Kirsch.) The newly emerged first instar of nymphs is brown in color and toward the end of the instar it becomes brownish white. The legs and upper surfaces of the head, thorax, and abdomen are marked with small black and dark brown spots. In the second instar the body of the insects appears light bowinsh green in color with light brown legs, wing pads are barely disecernible as small projections of the mesothorax. The dark spots are present on the body and legs in the third instar, the mesothoracic wing pads are readily discernible and appear as light green to yellow green areas at the sides of the thorax. Body color is light green with light brown margins on the thorax and head. Dark spot are present on body and legs. In the fourth instar the mesothoracic wing pads are well developed and extended somewhat over the metathoracic region. The wing pads appear as light greenish yellow areas at the sides of the thorax, the hind wing pads just begin to develop and appear as slight posterior projections of the metathorax. The general coloration of the fourth instar is similar to that of the previous instar but with the dark spots more pronounced on the thorax and head. In the fifth instar the mesothoracic pads reach the posterior margin of the third abdominal segment. The mesothoracic pads are visible as cream-colored areas at the sides of the thorax. The body is gray, legs and anterior margin of the crown light brown, the spots are barely discernible on most of the abdomen but are prominent on the posterior margins of the thoracic segments, head, and last abdominal segment. - Size 5 and ç 3.6 to 4.1 mm. Streptanus marginatus (Kirsch.) The nymphs of S. marginatus are similar in features without any conspicuous pattern, it is uniformity likeness to the nymphs of S. aemulans in different instars, pattern of abdomen arranged, into 4 longitudinal lines. Life-cycle and longevity A male and female were kept in each enclosing one of healthy and diseased of the following different host plant (apple, apricot, strawberry, clover and celery) seedling. The eggs usually were oviposited in the veins and petioles, and were burried in the tissue. The eggs could be most easily found by first locating the oviposition slits. Gravid females were transferred daily to successive plants for one week. The plants in which eggs were deposited were kept in isolators and examined daily for hatching of nymphs. The periods of egg stage are shown in Table 1. For females the egg duration varied from 14,13,13,11,9 days for S. aemulans to 12,12,12,10,9 days for S. marginatus

, in healthy apple, apricot, strawberry, clover and celery plants. While it ranged from 12,11,10,9,8 days for S. aemulans to 10,11,10,9,7 days for S. marginatus in infected ones respectively. Newly emerged nymphs were caged single on different healthy and diseased host plants (apple, apricot, strawberry, clover and celery) and maintained in a rearing room at a temperature of 69-72° F, 60 % - 65 % R.H. and a 16 hours a day the insects were checked daily to determine when ecdysis occurred. The females reared on healthy leaves required 28, 27,25,24,23 days in case of S. aemu lans and 26,27,26,24,21 days in case of S. marginatus for the above selected host plants respectively, and they took 25, 25, 23, 21,18 days in case of S. aemulans and 24, 23, 22, 29 and 18 day in case of S. marginatus on infected ones respectively. In the male insects, development is accelerated and the mean duration of the egg and nymphal stages was slightly shorter than those recorded in the case of female insects. Approximately one week-old adults were caged on the above-mentioned host seedling (apple, apricot, strawberry, clover and celery) and transferred daily to new plants until all individuals died (25 female and 25 male were used in the experiment). The results indicated that the longevity of S. aemulans and S. marginatus adults on infected seedling was longer than those recorded on healthy ones (Table 2). It is also concluded that longevity of female was longer than in case of male insect. These results agreed with the findings of HEGAB (1983) who studied the biology and longevity of the spittlebug Philaenius spumarius on infected and healthy host plants. To study the fecundity of female insects young female leafhoppers were cages singly on celery plants and one male insect was added to each for two weeks. The female insects were then transferred to new seedlings at an interval of