Effect of vegetation type and cultivation method on occurrence, diversity and dominance of spiders and other arthropods in chia and quinoa.
The experiment was carried out on chia and quinoa plants at Fayoum governorate during 2019/2020 season, to study the effect of conventional and organic cultivation on diversity and abundance of spiders and other arthropods. Spiders and other arthropods in the soil were collected using pitfall traps, while arthropods on plant leaves were surveyed using the direct count. Number of spiders collected from organic cultivation were (486 - 251 indv.) higher than those collected from conventional cultivation (423 - 213 indv.) for chia and quinoa respectively. The most abundant family was Lycosidae. Pardosa spp. was the most abundant species in two cultivations. The results revealed that chia cultivation included the highest number of dominant species in both cultivations. The total number of arthropods collected by pitfall traps was recorded (5985 - 2812 indv.) in conventional cultivation and (6703 - 2951 indv.) in organic cultivation of chia and quinoa respectively. Arthropods on leaves were recorded (643 - 488 indiv. in chia) and (256 - 238 indv. in quinoa) for conventional and organic cultivation, respectively. The mite Tetranychus urticae Koch and Phytoseiulus persimilis Athias-Henriot were recorded on chia plants only, while Liriomyza spp. and Tuta absoluta (Meyrick) were recorded on quinoa plants only. Tetranychus urtica and Bemisia tabaci (Gennadius) were recorded as the highest dominant and abundant in chia, however, Aphis spp. and Thrips tabaci Lindeman were recorded in quinoa in both cultivations. A significant difference was found between chia and quinoa plants for the occurrence of arthropods, while an insignificant difference was found between conventional and organic cultivation.