The Great Lakes Entomologist (2003) 36, p. 54 (Lundgren et al.)

J.G. Lundgren, K.L. Steffey and R.N. Wiedenmann (2003)
The distribution and prevalence of the alfalfa blotch leafminer (Diptera: Agromyzidae) in Illinois
The Great Lakes Entomologist 36 (1-2), 54-54
Abstract: Surveys were made in 2001 and 2002 to determine the distribution and prevalence of the alfalfa blotch leafminer, Agromyza frontella (Diptera: Agromyzidae), and its primary parasitoids, Dacnusa dryas and Chrysocharis liriomyzae (Hymenoptera: Braconidae and Eulophidae, respectively), in Illinois. We collected 239 samples from alfalfa fields in the alfalfa-producing regions of Illinois. Samples from each site consisted of 20 cut stems and 10 sets of 10 sweeps in 2001, and 40 stems and 10 sets of 20 sweeps in 2002. Each trifoliate was examined for mining and pinholing injury, and the number of aduls A. frontella, D. dryas, and C. liriomyzae per 10 sweeps was calculated for each site. We found that 16.3% of the sites were infested with A. frontella, and all infested fields were north of 39.95° N latitude. Although up to 95% of stems were injured at some sites, mean injury per stem never exceeded 12% of trifoliates. Maximum adult abundance was 8.1 adults per 10 sweeps. We did not detect D. dryas or C. liriomyzae in any of the sweep samples. Because of consistently low populations and the relatively slow rate of A. frontella 's spread in Illinois, we conclude that A. frontella is not a serious threat to alfalfa production in this state at this time.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)

Research topic(s) for pests/diseases/weeds:
surveys/sampling/distribution
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
surveys/distribution/isolation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Agromyza frontella	Alfalfa/lucerne (Medicago sativa)	U.S.A. (mid N)
Dacnusa dryas (parasitoid)	Agromyza frontella
Chrysocharis liriomyzae (parasitoid)	Agromyza frontella