Journal of Economic Entomology (2011) 104, 1568-1574

S.C. Hong, A. MacGuidwin and C. Gratton (2011)
Soybean aphid and soybean cyst nematode interactions in the field and effects on soybean yield
Journal of Economic Entomology 104 (5), 1568-1574
Abstract: How above- and belowground plant pests interact with each other and how these interactions affect productivity is a relatively understudied aspect of crop production. Soybean cyst nematode, Heterodera glycines Ichinohe, a root parasite of soybean, Glycine max (L.) Merr., is the most threatening pathogen in soybean production and soybean aphid, Aphis glycines Matsumura, an aboveground phloem-feeding insect that appeared in North America in 2000, is the key aboveground herbivore of soybean in the midwestern United States. Now, both soybean aphid and soybean cyst nematode co-occur in soybean-growing areas in the Upper Midwest. The objectives of this study were to examine aphid colonization patterns and population growth on soybean across a natural gradient of nematode density (range, ≈900 and 27,000 eggs per 100 cm³ soil), and to investigate the effect of this pest complex on soybean productivity. Alate (winged) soybean aphid colonization of soybean was negatively correlated to soybean cyst nematode egg density (r = -0.363, P = 0.0095) at the end of July, at the onset of peak alate colonization. However, both a manipulative cage study and openly colonized plants showed that soybean cyst nematode density below ground was unrelated to variation in aphid population growth (r ≈ -0.01). Based on regression analyses, soybean aphids and cyst nematodes had independent effects on soybean yield through effects on different yield components. High soybean cyst nematode density was associated with a decline in soybean yield (kg ha^-1), whereas increasing soybean aphid density (both alate and apterous) significantly decreased seed weight (g 100 seeds^-1).
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Claudio Gratton

Research topic(s) for pests/diseases/weeds:
damage/losses/economics
environment - cropping system/rotation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Heterodera glycines	Soybean (Glycine max)	U.S.A. (mid N)
	Aphis glycines	Soybean (Glycine max)	U.S.A. (mid N)