New approaches in biological control of phytophagous mites

. There are many reasons for using pheromones. One is that they are elegant (Arn, 1990). Pheromones are indeed elegant and safe tool for mite control. Entomophagous fungi may also be the biological control of two-spotted spider mites. Two species, Entomophthora thaxteriana and E adjarica can cause a heavy epizootic in populations of T urticae and may be useful in greenhouses when humidity can be maintained near saturation for a period of time. Success of fungal preparations is based on their dependency on humidity for conidial germination and problems of survival of conidia in the field. The SR (sex ratio ) of these species (the tertiary SR) was affected by densityindependent factors such as temperature, humidity and wind velocity. It was not changed by mite numbers, a density dependent factor, or by the vegetation, a density-independent cause, seasonal trends in the SRs of the various low or high temperatures and humidities influence the mate finding, copulation and sperm vitality of various ABAs, according to their provenances and affecting the SR. The influence of such climatic factors on the SR of phytoseiids in the field was noted by (Dyer and Swift, 1979). Genetic improvement of a natural enemy is the directed alteration of its genome in order to increase the enemy's efficiency as a biocontrol agent, correcting or improving a trait that is limiting efficacy. Major aspects which are significant in IPM of mite pests through predatory mites are: _Discourage indiscriminate use of broad spectrum pesticides. _Use only selected and bioeffective pesticides. _Laboratory mass culture and inoculative release in field of the beneficial mites from time to time. _Maintain an alternate food source during critical time when the pest species are scare. More recently, success has been achieved in developing pesticide resistant strain of phytoseiid predators for use in intensive managed agroecosystems. This may stabilize the mite fauna in certain ecosystem.