Mayetiola

Abstract: We identified, synthesized, and field-tested the sex pheromone of female red cedar cone midge Mayetiola thujae (Hedlin) (Diptera: Cecidomyiidae), a pest insect in red cedar Thuja plicata seed orchards Coupled gas chromatographic (GC)-electroantennographic detection analyses of pheromone extract revealed three components (A, B, C) that elicited responses from antennae of males, all of which occurred below the detection threshold of the mass spectrometer and thus had to be identified without spectroscopic data Taking into account (1) their retention indices (RI) on three GC columns (DB-5, DB-23, and DB-210), (2) intercolumn RI differentials, and (3) the molecular structures of known cecidomyiid pheromones, we synthesized seven candidate pheromone components: 2,10-, 2,11-, 2,12-, 2,13-, 2,14-, 2,15- and 2,16-diacetoxyheptadecanes Of these, 2,12-, 2,13-, and 2,14-diacetoxyheptadecane had RIs on all columns consistent with those of A, B, and C and elicited strong antennal responses when tested at picogram levels In field experiments with the twelve stereoselectively synthesized stereoisomers, only the SS-stereoisomers of 2,12-, 2,13-, and 2,14-diacetoxyheptadecane attracted male M thujae The three-component SS-stereoisomer blend was more attractive than the 12-component blend of all stereoisomers, suggesting that one or several nonnatural stereoisomers are inhibitory One-, two-, and three-component lures of the SS-stereoisomers were equally effective in attracting male M thujae, indicating redundancy in the pheromone Identification of the M thujae sex pheromone will allow development of pheromone-based monitoring, and possibly control, of M thujae populations in T plicata seed orchards

Abstract: Hessian fly, Mayetiola destructor (Say), is one of the most destructive pest of wheat (Triticum species) worldwide. In Morocco, damage caused by Hessian fly can result in total crop loss if high infestations occur during early stages of crop development. Genes that confer resistance to Hessian fly provide the most efficient and economical means of crop protection against this damaging insect. To date, 27 resistance genes (HJ-H27) have been reported in wheat; among these, 11 are very effective in Morocco. In this study, we have utilized amplified fragment length polymorphism (AFLP) analysis in conjunction with near-isogenic lines (NILs) and bulked segregant analysis (BSA) to identify molecular markers linked to Hessian fly resistance genes in bread wheat. Two pairs of NILs were used as source of DNA, one differing for H5 resistance gene and the other for H22 resistance gene. Using 42 primers combinations, 4200 selectively DNA fragments were analyzed throughout the wheat genome, with an average of 100 bands per combination and per pair of NILs. This technique appeared to be promising, since 28 polymorphic bands were detected, among which 13 associated to H5 locus and 15 to H22 locus.