The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is one of the most devastating pests. It has become a serious threat to tomato production. Five greenhouse trials were conducted on tomato crop during the season 2013 – 2014 for exploring control strategies by using the egg-parasitoid, Trichogramma achaeae Nagaraja and Nagarkatti (at a rate of 50 adults ̸ m2) compared with a microbial control ( using Bacillus thuringiensis at a rate of 2gm ̸ L). The effectivites of the insect predator, Macrolophus caliginosus Wagner (at a rate of 1 ̸ 2 adults ̸ m2) was also tested in a commercial tomato farm at El-Kanater district, Giza Governorte, Egypt, beside a combination of these three bioagents (T. achaeae, M. caliginosus and B. thuringiensis) at a rate of 25 adults ̸ m2, 1 ̸ 4 adults ̸ m2 and1gm ̸ L. The present study compared the efficiency of these methods for biological control of the tomato leaf miner, T. absoluta.The obtained results showed that all treatments were highly significant efficient in reducing T. absoluta mines during the present study, especially the three associated treatments.
Key words: Biological control; Tomato leaf miner " Tuta absoluta"; Trichogramma achaeae ; Bacillus thuringiensis; Macrolophus caliginosus; greenhouse; Egypt.

Biological control is the use of living organisms to suppress pest populations, making them less damaging than they would otherwise be.

Natural enemies play an important role in limiting the densities of potential pests. This has been demonstrated repeatedly when pesticides have devastated the natural enemies of potential pests. Insects which were previously of little economic importance often become damaging pests when released from the control of their natural enemies.
Biological control of Tetranychus urticae Koch by phytoseiid mites is now widely used by the greenhouse industry in Europe, some parts of Asia and Africa, Australia and North America. The most commonly used species are: Phytoseiulus persimilis Athias–Henriot ,P.macropilis (Banks) ,Neoseiulus californicus (McG.) , N. fallacies (McG.) , N. longispinosus (Evans) and Galendromus occidentalis Nesbitt . They are often released repeatedly in biological control, but also inoculatively in which predators and spider mites were introduced together early in the season.

There are three primary methods of using biological control in the field: 1) conservation of existing natural enemies, 2) introducing new natural enemies and establishing a permanent population (called "classical biological control"), and 3) mass rearing and periodic release, either on a seasonal basis or inundatively.
The impact of pesticides on natural enemies can be reduced by careful timing and placement of applications to minimize contact between the beneficial organism and the pesticide. Less persistent pesticides reduce contact, especially if used with knowledge of the biology of the natural enemy to avoid susceptible life stages.
The successful trials which carried out in Egypt by Heikal & Ibrahim, 2001 & 2002 for mass rearing the predatory mite, P. macropilis encouraged to increase its application as a bio-control agent on strawberry plantations. Heikal et al. 2007 carried out an attempt to expand the application of producing and releasing the predatory mite, P. macropilis on a large scale in a commercial strawberry farm.

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.

Under a screen greenhouse conditions the predatory mite, Neoseiulus ( Amblyseius ) californicus (McGregor ) was released with two levels of adults at the rate of three females and one male or with six females and one male of the predator individuals/pot on bean plants inoculated 7 days prior with different densities of Tetranychus urticae Koch .The obtained results indicated that populations of T. urticae were comparatively high after 7 and 14 days (from the predator release) when the predatory mite, N. californicus was released with a low level than those obtained with the high level of predator release .On the other hand, higher reductions of T. urticae were obtained after 7 and 14 days when the predator was released with a high rate .That indicated the importance of the initial ratio between numbers of prey and predator for regulation of prey density. High numbers of the predator individuals were subsequently recorded with this high release rate. Also, the prey predator ratios were very low as a result of high reduction of the T. urticae populations.

An area of about one feddan (about 4200 m2) at El-Mahala El-Kobra district (El-Gharbia Governorate). was chosen to study the effective of the two predatory mites, Phytoseiulus macropilis (Banks) and Neoseiulus ( Amblyseius ) californicus (McGregor ) on the two-spotted spider mite, Tetranychus urticae Koch infested watermelon. The predator individuals were released in each predator's area, once or twice (at two weeks intervals), at the rate of 3, 6 and 9 individuals/2plants.The obtained results indicated that single release of P. macropilis gave high reductions for the red spider mite, T. urticae population comparing with those of N. californicus during the different post-counts.
Double release of the predatory mite, P. macropilis was the best for reducing the red spider mite population , this may be due to the behavior of the predatory, mite P. macropilis which is known to be specific predator of spider mite and the nature of N. californicus which is known to be a generalist predator, which does not exhibit an equally strong numerical and functional response towards spider mites as prey specialist.
One release of the predatory mite, N. californicus with the medium rate (6 predators/2 plants) or low rate {3 predators /2 plants) , as well as releasing the predator two releases with the low rate resulted in low mite population reduction.

The two predatory mites , Neoseiulus ( Amblyseius ) californycus (McGregor ) and Phytoseiulus macropilis ( Banks ) were mass reared in the laboratory on mulberry leaf arenas infested with the two-spotted spider mite as animal diet and pollen as plant diet. Both predators were successfully maintained and mass reared on the two-spotted spider mites . The rate of increase of N.californicus on the two-spotted spider mite were 8.1 ,12.0 and 23.5 fold after 6 ,12 and 15 days, respectively . While that of P. macropilis they were 17.9 ,33.6 and 53.1 fold . Pollen of apricot , palm , peach and apple were unsuitable for rearing the predatory mite , P. macropilis , but proved to be suitable for the predatory mite , N. californycus . However , the rate of the predator increase were comparatively low when compared with rearing on the two-spotted spider mite ,Tetranychus urticae Koch . They were 1.2 , 3.6 , 1.5 and 1.8 fold after 15 days when reared on pollen of apricot , palm , peach and apple , respectively .

A laboratory study was conducted to evaluate the feeding efficiency of different stages of the predatory mite, Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) on those of each of the two-spotted spider mite,Tetranychus urticae Koch and the European red mite, Panonychus ulmi (Koch) (Acari:Tetranychidae). The predator larva proved to be a feeding stage .Average consumption of eggs, larvae, protonymphs, deutonymphs and adult males and females of T. urticae by the predator larva were : 1.1±0.75, 1.2±0.74, 0.8±0.66, 0.5±0.58, 0.6±0.63 and 0.1±0.36 individuals , respectively. These values gradually increased in the subsequent predator stages to reach in the case of the predator adult female with average of 15.4±1.25, 16.9±1.15, 12.6±1.48, 7.2±1.07, 9.2±1.25 and 5.3±0.99 individuals from the previous prey stages, respectively. Comparatively low numbers of different stages of P. ulmi were eaten by the predator individuals. Average consumption of eggs, larvae, protonymphs, deutonymphs and adult males and females of P.ulmi by the predator larva were: 0.8±0.75, 0.9±0.66, 0.6±0.64, 0.3±0.48, 0.5±0.51 and 0.08±0.27 from the previously mentioned prey stages, respectively. Also, these values gradually increased in the progressive predator stages to reach for the predator adult female 11.8±1.38, 13.0±1.62, 9.7±1.73, 5.6±1.07, 7.1±1.52 and 4.09±1.38 from P. ulmi different progressive stages, respectively. Thus, N.californicus adult female when fed on T. urticae or P. ulmi ate more than any other predator stages.
Also, prey eggs and larvae were eaten most frequently. The foregoing results showed that N. californicus can play an important role as a bio- control agent of the two tetranychid mites T. urticae and P. ulmi.

A commercial strawberry farm at Abo-Sower district (Ismailia Governorate,Egypt) was chosen for large scale producing and releasing the predatory mites Phytoseiulus macropilis (Banks) for controlling the two-spotted spider mite, Tetranychus urticae Koch on commercial strawberries in the same farm. Two screen-houses (6.5m width x 40m length x 2m height) were established for producing the predators in early and late production periods (November –December, 2004 and January-February, 2005) where about 3.4 and 3 million moving stages of predators were collected in the two previous producing periods, respectively. Augmentative releases of the predator were applied on a commercial strawberry field of about 40 feddans in the same farm to control the two-spotted spider mites T. urticae. The predator was released in the early or late season with a rate of 3-5 predators/bit (about 60000-100000predators/feddan). In the early predator release the T. urticae densities remained near or within the economic threshold levels, while in the late predator release the spider mite infestations were relatively higher than those in the early predator release. In the two predator release times several hot spot areas were detected where additional predator releases were applied to reduce the pest populations. The highest predator populations occurred on both time releases on late and early March with relatively high densities in the late predator release.

Studies were conducted during two successive seasons in cantaloupe field, at Ismailia Governorate, to control the two-spotted spider mite, T. urticae by releasing the predatory mite, P. macropilis using gelatin capsules or bean leaflets harbouring the predator individuals. The pest populations were generally low or moderate at the time of the predator releases then decreased and continued in low densities till last inspection. Obtained results indicated the possibility to control the two-spotted spider mite, T. urticae in cantaloupe field in early spring season by releasing the predatory mite, P. macropilis at the rate of about 5 individuals/bit using gelatin capsules or bean leaflets harbouring the predator individuals. One predator release also seemed to be effective for phytophagous mite control.

A preliminary study was conducted during two successive seasons on rose bushes at Orman garden (Giza Governorate) to control the two-spotted spider mite, Tetranychus urticae KOCH by releasing the predatory mite,Phytoseiulus macropilis (Banks), at the rate of 20or 40 individuals/bush using gelatin capsules or bean leaflets harbouring the predator individuals. In 2003 season the predator was lately released on April the 2nd .Few predators were recoded on the release bushes during the different post- counts probably due to the prevailing unfavourable environmental conditions where several hot spells coincided the time of predator release which might negatively affected the predator activity.In2004 season, the predator was eariy released on February the 10th . Satisfied results were obtained. Releasing the predator using gelatin capsules or bean leaflets at the rate of 20 or 40 individuals/bush greatly reduced the T. urticae population after 4 weeks from the predator release. Mean reduction of the pest population over the experimental period was 76% (20 predators /bush) and 82% (40 predators /bush) when using gelatin capsules and 85 and 87% when using bean leaves, respectively.

A preliminary study was carried out to control the two-spotted spider mite, Tetranychus urticae Koch on cucumber in a net greenhouse and in an open field by releasing the predatory mite, Phytoseiulus macropilis (Banks).The T. urticae reduction in the greenhouse reached about 90% after 24 and 28 days from the predator release at the rate of 4 and 2 individuals /pot ,respectively . Maximum reduction of the pest in the open field was 85 90 % after 4 weeks from the predator release at the rate of 5 and 10 individuals /pot ,respectively . The previous study indicated the possibility to control the two-spotted spider mite ,T. urticae on cucumber by using the predatory mite, P. macropilis as a biocontrol agent.