**7.5 Chemical control**

Chemical control of the invasive TLM is difficult; however, its arrival to new invaded areas has been linked to an excessive application of broad-spectrum insecticides [1, 6, 55], in attempts to curb the outbreaks of the pest and to reduce yield losses in tomato crop. Currently, insecticides application seems to be the most commonly used strategy against *T. absoluta* worldwide in open fields of tomato [1, 56–58]. The cryptic behavior and the endophagous habit of larvae make it extremely difficult to control TLM with insecticides [1, 19]. The possible reasons for difficulty of controlling TLM with insecticides, according to Biondi et al. [1] and Guedes et al. [58] include the following:


**87**

Tuta absoluta *(Meyrick) (Lepidoptera: Gelechiidae): An Invasive Insect Pest Threatening…*

Insecticides from different chemical classes were used against TLM in South America, Europe, and other parts of the world. These chemical classes include, but not limited to, organophosphate, pyrethroids, pyrrole, spinosyns, diamides, benzoylureas, and avermactins [54, 56, 59]. Spinosad, azadirachtin, and *Bacillus thuringiensis* toxins (Bt) have been to control TLM in organic tomato production

The excessive application of insecticides to prevent and control the outbreaks of *T. absoluta*, particularly in open fields lead to an increased selection pressure which, eventually reduce the effectiveness of such insecticides [58, 60]. For example, when the moth was introduced in Brazil, the farmers initially used insecticides at frequencies of 10–12 applications per cropping season, which was later increased to 30 applications [60]. In Turkey, the annual cost of chemical insecticides used against *T. absoluta* in 2014 was about 160 million Euros [27]. The frequent use of insecticides speeded the appearance of resistance in tomato leaf miner populations, which can migrate outside their geographical range into new invaded areas [1, 6, 56–59]. Guedes et al. [58] reported that enhanced levels of detoxification enzymes and altered target sites are the main resistance mechanisms commonly found in *T. absoluta*. In addition to the development of resistance in TLM populations, due to excessive use of insecticides, compromising of biological control, in tomato agroecosystems, is also not avoidable. In this respect, Soares et al. [43] studied the lethal and sublethal effects of five insecticides (spinetoram, chlorantraniliprole + abamectin, triflumuron, tebufenozide, and abamectin) on adults and the third instar nymph of the predator *Macrolophus basicornis*. They concluded that abamectin caused high mortality in both adult and nymphs. All tested insecticides caused

To overcome the problems of insecticide resistance and other harmful effects on tomato ecosystem, due to the excessive use of insecticides, insecticide resistance management (IRM) strategies are needed to sustain production of tomato crop [1, 58]. Such strategies include adoption of alternative control options such as cultural control, semiochemically based control, biological control, and host plant resistance. All these alternative strategies and tactics would reduce the reliance on insecticides and accordingly the selection pressure on TLM populations [1, 58].

Recently, tomato leaf miner has emerged as a highly invasive key pest threatening the global production of tomato. The global commercialization and trade of fresh tomato fruit and transplanting material have accelerated the spread of the pest. The impact of *T. absoluta* on global tomato production industries and on the livelihood of small tomato farming communities in Africa and Asia might be more severe in the coming years, unless great efforts are made to contain its spread. Chemical control of *T. absoluta* with insecticides seems to be ineffective and not sustainable; therefore, alternative management options such as biological control and semiochemically based control should be encouraged. The socioeconomic impact of

this moth on subsistent agriculture need to be addressed in future studies.

*DOI: http://dx.doi.org/10.5772/intechopen.93390*

systems [1, 56].

negative effect on the predator.

**8. Conclusions**

Tuta absoluta *(Meyrick) (Lepidoptera: Gelechiidae): An Invasive Insect Pest Threatening… DOI: http://dx.doi.org/10.5772/intechopen.93390*

Insecticides from different chemical classes were used against TLM in South America, Europe, and other parts of the world. These chemical classes include, but not limited to, organophosphate, pyrethroids, pyrrole, spinosyns, diamides, benzoylureas, and avermactins [54, 56, 59]. Spinosad, azadirachtin, and *Bacillus thuringiensis* toxins (Bt) have been to control TLM in organic tomato production systems [1, 56].

The excessive application of insecticides to prevent and control the outbreaks of *T. absoluta*, particularly in open fields lead to an increased selection pressure which, eventually reduce the effectiveness of such insecticides [58, 60]. For example, when the moth was introduced in Brazil, the farmers initially used insecticides at frequencies of 10–12 applications per cropping season, which was later increased to 30 applications [60]. In Turkey, the annual cost of chemical insecticides used against *T. absoluta* in 2014 was about 160 million Euros [27]. The frequent use of insecticides speeded the appearance of resistance in tomato leaf miner populations, which can migrate outside their geographical range into new invaded areas [1, 6, 56–59].

Guedes et al. [58] reported that enhanced levels of detoxification enzymes and altered target sites are the main resistance mechanisms commonly found in *T. absoluta*. In addition to the development of resistance in TLM populations, due to excessive use of insecticides, compromising of biological control, in tomato agroecosystems, is also not avoidable. In this respect, Soares et al. [43] studied the lethal and sublethal effects of five insecticides (spinetoram, chlorantraniliprole + abamectin, triflumuron, tebufenozide, and abamectin) on adults and the third instar nymph of the predator *Macrolophus basicornis*. They concluded that abamectin caused high mortality in both adult and nymphs. All tested insecticides caused negative effect on the predator.

To overcome the problems of insecticide resistance and other harmful effects on tomato ecosystem, due to the excessive use of insecticides, insecticide resistance management (IRM) strategies are needed to sustain production of tomato crop [1, 58]. Such strategies include adoption of alternative control options such as cultural control, semiochemically based control, biological control, and host plant resistance. All these alternative strategies and tactics would reduce the reliance on insecticides and accordingly the selection pressure on TLM populations [1, 58].
