ABSTRACT
Many insect and mite species possess an astounding potential to cause damage in fi eld crops and storage. For developing appropriate management strategies, it is important to have a correct identifi cation of the pest species. Correct taxonomic identifi cation is also important for import and export of plant material and food grains to implement appropriate quarantine procedures. Quarantine measures are critical to prevent or delay the introduction of exotic pests into newer areas. Identifi cation of insect pests of quarantine importance has primarily relied on morphological characters of adult life stages. However, intercepted specimens often are not in the adult stage and may be damaged, which seriously handicaps correct identifi cation. The molecular tools now enable precise and rapid identifi cation of insect pests irrespective of the developmental stage and condition of the samples. The modern tools of biotechnology can be used for detection and identifi cation of insect pests, insect biotypes, and understand genetic diversity, population structure, tritrophic interactions, and insect plant relationships (Caterino, Cho, and Sperling, 2000; Heckel, 2003). Molecular markers can also be used to gain a basic understanding of insect metabolism, development, interaction with the environment, and for developing sound strategies for pest management. Molecular techniques have also been found to be useful for studying insect phylogeny and predatorprey relationships (Hillis, Martiz, and Noble, 1996; Crampton, Beard, and Louis, 1997; Osborne, Loxadale, and Woiwod, 2002; Hoy, 2003). Molecular tools also enable genetic characterization of specifi c attributes of an organism, and if combined with a high-throughput technology such as microarrays, they are ideally suited for rapid molecular screening. Molecular diagnostics will play a vital role in detection and identifi cation of insect pests. Common molecular techniques that can be used for detection of insect pests include:
Hydrocarbons for species recognition;• Secondary metabolites;•
Isozyme and protein profi les;• Immunodiagnostic methods; and• DNA-based methods.•
Polymerase Chain Reaction
Current molecular systematics depends on polymerase chain reaction (PCR) amplifi cation of a few “universal” genes to provide phylogenetic data. However, the need for sequencing is increasing quite fast (Murphy et al., 2001; Wheeler et al., 2001; Philippe et al., 2004; Teeling et al., 2005), and expanding PCR approaches to a wider selection of genes becomes diffi cult because of the need to develop new degenerate primers for the amplifi cation of singlecopy loci.
