Identification of sex pheromone components of the Hessian fly, <i>Mayetiola destructor</i>.

Abstract:
Coupled gas chromatographic (GC)–electroantennographic

detection (EAD) analyses of ovipositor

extract of calling Hessian fly, Mayetiola destructor, females

revealed that seven compounds elicited responses from

male antennae. Four of the compounds—(2S)-tridec-2-yl

acetate, (2S,10Z)-10-tridecen-2-yl acetate, (2S,10E)-10-

tridecen-2-yl acetate, and (2S,10E)-10-tridecen-2-ol—were

identified previously in female extracts. Two new EADactive

compounds, (2S,8Z,10E)-8,10-tridecadien-2-yl acetate

and (2S,8E,10E)-8,10-tridecadien-2-yl acetate, were identified

by GC–mass spectroscopy (MS) and the use of synthetic

reference samples. In a Y-tube bioassay, a five-component

blend (1 ng (2S)-tridec-2-yl acetate, 10 ng (2S,10E)-10-

tridecen-2-yl acetate, 1 ng (2S,10E)-10-tridecen-2-ol, 1 ng

(2S,8Z,10E)-8,10-tridecadien-2-yl acetate, and 1 ng

(2S,8E,10E)-8,10-tridecadien-2-yl acetate) was as attractive

to male Hessian flies as a similar amount of female extract

(with respect to the main compound, (2S,10E)-10-tridecen-

2-yl acetate). The five-component blend was more attractive

to male flies than a three-component blend lacking the two

dienes. Furthermore, the five-component blend was more

attractive than a blend with the same compounds but that

contained one tenth the concentration of (2S,8E,10E)-8,

10-tridecadien-2-yl acetate (more accurately mimicking the

ratios found in female extract). This suggests that the ratios

emitted by females might deviate from those in gland

extracts. In a field-trapping experiment, the five-component

blend applied to polyethylene cap dispensers in a 100:10 μg

ratio between the main component and each of the other

blend components attracted a significant number of male

Hessian flies. Also, a small-plot field test demonstrated the

attractiveness of the five-component blend to male Hessian

flies and suggests that this pheromone blend may be useful

for monitoring and predicting Hessian fly outbreaks in

agricultural systems.