*2.4.4 Management*

## *2.4.4.1 Biological control*

The use of predatory mites as biological control agent of citrus thrips is well documented. The most important predacious mites recommended against citrus thrips are phytoseiid mites: *Euseius tularensis* Congdon and *E. hibisci* (Chant) (Acari: Phytoseiidae) and anystid mite: *Anystis agilis* Banks (Acari: Anystidae). These species can be conserved and released in mature citrus orchards and scarring of citrus fruits can be minimized [204–209]. Some other predacious mite species such as *Iphesius* (= *Amblyseius*) *degenerans* Berlese, *Neoseiulus barkeri* (Hughes) (Hughes) (= *Amblyseius mckenziei*), and *N. cucumeris* (Acari: Phytoseiidae) can be used as potential biological control agents against immature thrips in citrus nursery [210]. Another predatory mite *Gaeolaelaps aculeifer* (Acari: Laelapidae) has been shown to successfully reduce the infestation of thrips in commercial citrus orchards of Valencia, eastern Spain after the augmentative release [211].

#### **Figure 3.**

*Citrus fruit (Kinnow mandarin) infested by thrips showing scarring mark as one of the diagnostic damage patterns. Photograph by Bodil N. Cass, Department of Entomology and Nematology, University of California, Davis, USA.*

#### *Ecology, Biology, Damage, and Management of Sucking and Chewing Insect Pests of Citrus DOI: http://dx.doi.org/10.5772/intechopen.109846*

The use of natural insect predators is advocated for the control of thrips in citrus orchards in different regions of the world. Among the generalist predators of thrips, *Orius insidiosus* (Say) (Hemiptera: Anthocoridae) commonly known as minute pirate bug is an aggressive and voracious predator of thrips adults and nymphs in citrus [173, 179, 212, 213]. Some other generalist thrips predators known are chrysopids, coccinellids, and mirids [214]. Two predatory thrips species *Karnyothrips flavipes* (Jones) and *Leptothrips* spp. have been identified and are known to attack thrips in citrus in Florida, USA [215].

#### *2.4.4.2 Chemical control*

Complete thrips control in citrus orchards cannot be obtained merely by biological control agents; therefore, application of different insecticides for the suppression of thrips population below economic damaging levels is unavoidable. The insecticides from organophosphorus (OP), pyrethroids, and new chemical groups are recommended for thrips control. Spray with systemic insecticides at pre-flowering or post-flowering stage is recommended. Dimethoate, a systemic and broad-spectrum OP insecticide, is highly recommended and widely used insecticide against thrips in citrus orchards. It is applied before petal fall when less than 10% buds have opened. Its application on nursery plants is not recommended; however, mature fruits can be sprayed only twice with this insecticide. Among the pyrethroid group insecticides, one application of cyfluthrin or fenpropathrin (broad spectrum) in a year is recommended in the citrus orchards to trees ≤3 years of age. Application of two different pyrethroid insecticides in sequence must be avoided in order to minimize the resistance development. OP and pyrethroid insecticides should be used in rotation as a part of insecticide resistance management tactic. In California, chemical control is initiated when 75 percent petal-fall is complete. In order to minimize the impact of insecticides on natural enemies, and to reduce the resistance development against OP and pyrethroid insecticides, some botanical or microbial nature insecticides such as sabadilla, abamectin, and spinosad should be used for spray. Among the new chemistry insecticides, imidacloprid, acetamiprid, and thiamethoxam from neonicotinoid group and chlorfenapyr from pyrroles group are also recommended against citrus thrips [177, 216–219].
