As with the seed- and pod-feeding guild, many of the same orders of insects (Coleoptera, Lepidoptera, Diptera) that feed on foliage also feed on stems. Within Asia, members of the leaf-miner fly family (Agromyzids, specifically the genus Melanagromyza) are thought to have a co-evolved relationship with soybean (Chiang and Norris, 1983). These stem-boring flies can interfere with growth (Talekar, 1989), but this damage does not often result in yield loss (Van den Berg et al., 1998b). In general, the damage observed by growers to stem-feeding maybe at harvest when the weakened stems are prone to falling, often referred to as lodging, making harvesting difficult. Outside the native range of soybean, novel associations have formed between stem-boring insects and soybean. Such insects include Elasmopal-pus lignosellus (the lesser cornstalk borer) and Dectes texanus. The latter has expanded its host range from sunflower (Helianthus annuus) to include soybean (Michaud and Grant, 2005). There are few known soybean obligate root feeders. Several generalist root herbivores, including various species of grubs (Scarabaeidae species), wireworms (Elateridae species) and the seed-corn maggot (Delia platura), have been reported to cause stand loss (Turnip-seed and Kogan, 1976; Hammond, 1995), especially when soybean is planted in high-residue situations (mature hay stands, some no-till fields and following cover crops). The larval stages of C. trifurcata (bean leaf beetle) have been recorded feeding on the roots of soybean (Pedigo, 1994), although the impact of this feeding is not considered to be great.
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