Legume host range and soybean host plant resistance for soybean tentiform leafminer, <i>Macrosaccus morrisella</i> (Lepidoptera: Gracillariidae)

The soybean tentiform leafminer, Macrosaccus morrisella (Lepidoptera: Gracillariidae), was known to feed on only two legumes native to North America, and it has recently expanded its host range to soybean, Glycine max (Fabales: Fabaceae). However, the threat to other legume crops and potential for host plant resistance for M. morrisella management in G. max is unknown. Thus, M. morrisella host range among different species of legume crops and genotypes of G. max were evaluated through complementary choice and no-choice experiments. Macrosaccus morrisella oviposited on its native host American hogpeanut (Amphicarpaea bracteata (Fabales: Fabaceae)) and G. max (both grain and vegetable types), but not on Phaseolus vulgaris, Vigna unguiculata, Cicer arietinum, Vicia faba, Pisum sativum, and Lens culinaris (Fabales: Fabaceae). Low oviposition was observed on Vigna radiata and Phaseolus lunatus (Fabales: Fabaceae) in a choice test, but no larvae survived on either legume. When G. max genotypes were compared, lower but detectable oviposition (50 to 100 eggs per plant) was observed on PI229358 and PI227687 in choice and no-choice tests, and lower survival rates (20 to 40%) on PI229358 and M15-105140 in a no-choice test. These results indicate that M. morrisella host range appears to be restricted to the previously known native hosts and G. max, but continued monitoring for adaptation to other legumes and further studies testing multiple populations of M. morrisella are necessary. Furthermore, sources of G. max with lower susceptibility against M. morrisella were identified and could be utilized in G. max breeding programs for the development of host plant resistance for M. morrisella management.