Molecular Identification of Three Stored Product Insect Species on Dried Fruits and Their Control with the Use of Some Aqueous Plant Extracts

Mortality of three insects; red flour beetle (Tribolium castaneum Herbst), khapra beetle (Trogoderma granarium Everts) and sawtoothed grain beetle (Oryzaephilus surinamensis (L.)) were evaluated via some aqueous plant extracts. The identification of three examined insects was carried out via designing specific primers for each aforementioned species with the use of PCR technique. The toxicity of aqueous plant extracts; eucalyptus (Eucalyptus camaldulensis Dehnh), mint (Mentha canadensis L.) and myrtle (Myrtus communis L.) at three dosages (12500, 25000 and 50000) ppm for 1, 2, 3 and 7 days were tested for their insecticidal activity against examined adults on dried fruits. Percentage mortality of insect was increased with an increase of doses and exposure times, whereas, not influenced significantly by the fruit types. T. castaneum was the most susceptible species, followed by T. granarium and O. surinamensis. Likewise, LC50 values were (3887.25, 10816.34 & 22763.48) on red flour, khapra & sawtoothed grain beetles respectively via using eucalyptus aqueous extract after 7 days on black raisin. While, higher doses required in order to kill fifty percentage of the population via myrtle aqueous extract and thus the LC50 values increased to (14726.86, 18421.43 & 39016.78) on the three aforementioned species respectively.

COI barcode based species-specific primers for identification of five species of stored-product pests from genus Cryptolestes (Coleoptera: Laemophloeidae)

Flat grain beetles of the genus Cryptolestes (Coleoptera: Laemophloeidae) are one of the economically most important stored-product pests which feed on many kinds of agricultural products, especially grains. Nine of more than 40 described Cryptolestes species are recognized as stored-product pests and two of the pest species have a cosmopolitan distribution. Given the rapid growth in global trade of food products, ecological barriers to the spread of pests are easily overcome. Therefore, development of reliable systems for routine quarantine inspection and early infestation detection is vital. In the present study, we established a new rapid and accurate cytochrome c oxidase subunit I-based system for molecular identification of five common stored-product Cryptolestes species, namely, Cryptolestes capensis, Cryptolestes ferrugineus, Cryptolestes pusilloides, Cryptolestes pusillus and Cryptolestes turcicus. Five species-specific primer pairs for traditional uniplex polymerase chain reaction assay are described and their specificity and sensitivity for the identification process is evaluated using larval samples of 12 different populations from three continents (Asia, Europe and North America).