Ground-active arthropod response to distance from the Mediterranean seashore in coastal sand areas of western Israel

Information on the effects of distance from the seashore on soil biotic communities is limited and restricted to soil arthropods and microarthropods. The aim of this study, conducted in a sand-dune area, was to distinguish the changes of a ground-active arthropod community along a 4-km-transect from the seashore going inland. Pitfall traps were set up in open spaces at four locations (L1, through L2, L3, and L4 going inland) through the year. The abiotic gradient from the seashore going inland was found to be mostly dependent on seasonality. Group richness was found to be remarkably greater at the L2, L3, and L4 locations compared with the L1 location in winter, and at the L2 and L3 locations compared with the L1 location in spring. The Fisher α index was 0.32?±?0.21, 3.51?±?0.87, 5.04?±?0.70, and 4.86?±?0.54 in winter and 3.29?±?0.55, 13.79?±?1.49, 10.12?±?1.24, and 5.06?±?0.62 in spring at the L1, L2, L3, and L4 locations, respectively. Regarding abundance and group richness, the trophic relationships between predators, phytophages, omnivores, and saprophages were remarkably affected by both location and seasonality. The dominant groups and dominant index distribution of ground-active arthropod communities were found to follow a similar pattern. Soil organic carbon content was found to be the key factor driving the ground-active arthropod community structure along a coastal gradient going inland in winter and spring. We conclude that the distribution, trophic composition, and diversity index are affected by both location and seasonality, while total abundance is consistently affected by location across all three seasons.     

Mass rearing of the florida wax scale,Ceroplastes floridensis,for production of natural enemies

A method was developed for mass rearing the Florida wax scale (FWS),Ceroplasta floridensis Comstock — an important pest of citrus and other fruit trees in the Mediterranean basin — for production of natural enemies. The effect of host plant species, intensity of illumination and scale insect density on survival and size of the FWS was studied.Myrtus communis was found to be the most efficient host plant, and the required intensity of illumination was 200 µmol m^-2s^-1(with a photoperiod of 12L: 12D). Under these conditions, a density of 500 scale insects per plant could be achieved without reducing the size of the FWS below that required for the development of natural enemies.     

Diapause induction in field populations of the codling moth,Cydia Pomonella,in Northern Israel

Diapause induction in field populations of the codling moth,Cydia pomonella L., was studied for three consecutive seasons (1984–86) in two commercial apple orchards in Upper Galilee. One orchard was located in the Hula Valley and the other in the high mountain region. The onset of diapause sometimes occurred during increasing day-length, before the summer solstice. This phenomenon represents a small proportion of the population which is probably genetically univoltine. The critical photoperiod which induces 50% diapause (= CPhP₅₀) varied up to 5 days within the valley region, up to 6 days within the mountain region, and up to 7 days between the two regions. The trend of this variation was consistent: the CPhP₅₀ of the valley poulation preceded that of the mountain on both ‘Jonathan’ and ‘Granny Smith’ apple varieties and, within each location, the CPhP₅₀ on the early-ripening ‘Jonathan’ preceded that of the late-ripening ‘Granny Smith’. The higher prediapause temperatures of the Hula Valley caused earlier diapause induction as compared with the lower temperatures of the mountain region. Immature fruits delayed diapause induction in comparison with mature ones.