Tuesday, August 7, 2018
ESA Exhibit Hall, New Orleans Ernest N. Morial Convention Center
Nana Britwum, School of Integrative Plant Science, Cornell University, Ithaca, NY and William Wetzel, Department of Entomology, Michigan State University, East Lansing, MI
Background/Question/Methods Insect herbivory is detrimental to the production of agricultural crops. A key component of sustainable pest management programs is plant breeding and the use of crop varieties that are resistant to attacks by herbivorous insects. Typically, research on crop resistance to insects focuses on average resistance levels in monocultures, but it overlooks the effects of plant trait diversity on insects. We investigated the consequences of intraspecific trait diversity in immature and mature tomatoes (Solanum lycopersicum) for the preference of an important agricultural pest, the cabbage looper, Trichoplusia ni. We hypothesized that exposing larvae to a diet with intraspecific plant diversity would decrease insect growth and survival. We used Solanum pennellii x S. lycopersicum (cv .M82) introgression lines (ILs) to test larval preference. In the trials, we grew caterpillars on constant diets of one or two genotypes or forced caterpillars to switch between genotypes, and we recorded larval growth, survival, and development.
Results/Conclusions
Preliminary studies on immature leaves IL 8-1-1 and IL 2-2 resulted in adequate performance on each line in monoculture, but the caterpillars had low performance when they were switched from one line to the other. In respect to IL 2-2 and IL 8-1-1 the forced switch from IL2-2 to IL 8-1-1 was significantly different from the unforced choice treatment (t =-4.542, p= 0.0005 ). The forced switch from IL2-2 to IL 8-1-1 also differed from IL 8-1-1 (t=-3.452, p= 0.0112). The forced switch from IL 8-1-1 to IL2-2 was significantly different from the unforced choice treatment (t =-2.973, p= 0.0381). Because the switching treatment mimics what happens when larvae move to a neighboring host plant in a field with intraspecific crop diversity, this result suggests that intraspecific crop diversity could be useful for reducing pest damage. Focusing plant breeding efforts on diversity relevant to insect pests through incorporating intraspecific diversity holds potential for increasing the sustainability of agroecosystems.
