**Resistance and Its Management to Microbial and Insect Growth Regulator Larvicides in Mosquitoes**

Tianyun Su

[104] Fonseca I, Quiñones M. Resistencia a insecticidas en mosquitos (Diptera: Culicidae): mecanismos, detección y vigilancia en salud pública. Revista Colombiana de Ento‐

[105] Sosa MA. Consideraciones generales sobre resistencia de los insectos a los plaguici‐ das con especial referencia a los "piretroides." Publicación Miscelánea. N°5. INTA

[106] Mani GS. Evolution of resistance in the presence of two insecticides. Genetics. 1985;

[107] Lagunes TA. Impact of the use of mixtures and sequences of insecticides in the evo‐ lution of resistance in *Culex quinquefasciatus* Say (Diptera: Culicidae) [thesis]. River‐

[108] Keiding J. Resistance in the housefly in Denmark and elsewhere. In: DL Watson, edi‐ tor. Pesticide management and insecticide resistance. New York: Academic Press;

mologia. 2005; 31: 107–115.

Reconquista. 1992; p. 5–10.

side California: University of California. 1980.

109: 761–783.

134 Insecticides Resistance

1977. p. 261–302.

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/61658

#### **Abstract**

Mosquito larvicides derived from microbial organisms and insect growth regulators have been increasingly used to control mosquito larvae worldwide. Their relative target specif‐ icity, nontarget safety, and environmentally friendly profile have been well documented. The current chapter was intended to review and analyze the relevant information regard‐ ing resistance development and resistance management tactics. *Bacillus thuringiensis isra‐ elensis* de Bajac (*B.t.i.*) is a quick-acting and highly target-specific biopesticide against mosquitoes, blackflies, and other nematoceran species. Resistance development toward intact complementary toxin complex of *B.t.i.* was rare; however, low to high levels of re‐ sistance to individual toxins have occurred in laboratory mosquito populations. The tox‐ ins from bacterium *Bacillus sphaericus* Neide (recently renamed *Lysinibacillus sphaericus* Meyer and Neide) is another highly active larvicide against mosquitoes, toward which low to high levels of resistance have occurred in both laboratory and field mosquito pop‐ ulations. The Cyt1A toxin from *B.t.i.* and Mtx toxin from certain strains of B. *sphaericus* are the key components in resistance management to *B.t.i.* and *B. sphaericus*. The resist‐ ance management strategies have been well developed and implemented. Spinosad de‐ rived from *Saccharopolyspora spinosa* Mertz and Yao has been recently used for mosquito control; high levels of resistance and cross-resistance have occurred in laboratory mosqui‐ to populations and no management tactics have ever been developed. Methoprene has been used to control mosquitoes for decades, and low to high levels of resistance have been occasionally reported in both laboratory and field mosquito populations. Studies on mechanism and management of methoprene resistance are quite meager. Very little at‐ tention has been paid to the resistance management in mosquitoes to other insect growth regulators such as pyriproxyfen and diflubenzuron. The prevention of resistance and re‐ storation of susceptibility in mosquitoes to these biorational larvicides are crucial to the success of sustainable integrated mosquito management.

**Keywords:** Microbial larvicides, Insect growth regulators, Mosquito control, Resistance, Resistance management

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

## **1. Introduction**

Mosquitoes and mosquito-borne diseases remain one of the leading public health concerns and socioeconomic burdens of mankind globally, particularly in tropical and subtropical regions. Nowadays, human and animal population movement, freight exchange, fast demo‐ graphic growth, economic development, and subsequent environmental impact further elevate the scope and magnitude of the problem. Mosquito control is often the only or most effective way of the integrated management to combat mosquito-borne illnesses. Considering the strict governmental regulations, high environmental vulnerability, and increasing demand of mosquito control upon emergence, and spreading of mosquito-borne diseases, ecologically friendly management approaches based on microbial and insect growth regulator larvicides have been the great promise for their high activity and efficacy, target specificity, and envi‐ ronmental and nontarget safety profile. However, the development of resistance in the mosquito populations to these biorational larvicides has been reported since the past decades. In order to maintain the sustainability of mosquito control, susceptibility monitoring and resistance management tactics toward these available control tools must be developed and implemented.
