Western corn rootworm (Coleoptera: Chrysomelidae) larval survival and damage potential to corn subjected to nitrogen and plant density treatments
1988
Spike, B.P. | Tollefson, J.J.
A 2-yr field study was used to examine the main effects and interactions of western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, infestations, nitrogen (N), and corn plant population levels on larval survival and damage, and root growth response. Nitrogen application and higher plant density treatments increased adult emergence, although there were significant N by plant density interactions both years. In 1985, root damage ratings increased with moderate N application but decreased with high N levels. Plant density treatments had no effect on damage ratings. Nitrogen application in 1985 decreased lodging by 44% in plants injured by WCR. Increased N and low to moderate plant population levels resulted in larger root systems and greater regrowth and brace root development. A significant N by plant density interaction indicated that a high plant population level negated the positive response of brace root development to increased N application. WCR infestation promoted root regrowth and brace root development. Decreased adult emergence, root damage ratings, lodging, and increased root regeneration were observed in 1984, a year characterized by excessive June rainfall and saturated soil conditions. These results suggest that N, plant population, and soil moisture levels are contributing factors in WCR larval survival and recovery of the corn plant root system.
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