Soil mites associated with onion Giza 6 and Giza 20, fodder beet and
broad bean belonging to the five major groups: Astigmata, Cryptostigmata,
Heterostigmata, Prostigmata and Mesostigmata (Krczal, 1959, Abd- EL.
Shahëed, et al., 1972 and Gilyarov, 1975). Population dynamics of soil Acari
inhabiting onion Giza 6 and Giza 20 fields reached the maximum in February
and March with average of 80 and 49 individuals /1000 cc. soil, respectively.
While under fodder beet and broad bean occurred in February with average of 56
and 101 individuals /1000 cc. soil, respectively. The highest population density
of Acari was recorded in broad bean (309 individuals), while the lowest
population was found under onion Giza 6 (116 individuals). Under onion Giza 6,
seven astigmatide mite species were recorded with population density 43 md.
/1000 cc. soil, while under Giza 20, five species were found with abundance of
78 md, /1000 cc. Soil. However, in fodder beet and broad bean fields six species
were observed with population dynamics of 39 and 47 ind./1000 cc. soil
respectively. Tyrophagus putrescentiae (Schrank) occurred in great number
dominated other species under the aforementioned crops. No relationship was
observed between number of species and their density, as in fodder beet field, 6
species with density 32 ind./1000 cc. soil were recorded, while under broad bean
plantation four species with density of 71 md. /1000 cc. soil were obtained.