Environmental Entomology (2016) 45, 747-761

J.C. Martinez and M.A. Caprio (2016)
IPM use with the deployment of a non-high dose Bt pyramid and mitigation of resistance for western corn rootworm (Diabrotica virgifera virgifera)
Environmental Entomology 45 (3), 747-761
Abstract: Recent detection of western corn rootworm resistance to Bt (Bacillus thuringiensis) corn prompted recommendations for the use of integrated pest management (IPM) with planting refuges to prolong the durability of Bt technologies. We conducted a simulation experiment exploring the effectiveness of various IPM tools at extending durability of pyramided Bt traits. Results indicate that some IPM practices have greater merits than others. Crop rotation was the most effective strategy, followed by increasing the non-Bt refuge size from 5 to 20%. Soil-applied insecticide use for Bt corn did not increase the durability compared with planting Bt with refuges alone, and both projected lower durabilities. When IPM participation with randomly selected management tools was increased at the time of Bt commercialization, durability of pyramided traits increased as well. When non-corn rootworm expressing corn was incorporated as an IPM option, the durability further increased.
For corn rootworm, a local resistance phenomenon appeared immediately surrounding the resistant field (hotspot) and spread throughout the local neighborhood in six generations in absence of mitigation. Hotspot mitigation with random selection of strategies was ineffective at slowing resistance, unless crop rotation occurred immediately; regional mitigation was superior to random mitigation in the hotspot and reduced observed resistance allele frequencies in the neighborhood. As resistance alleles of mobile pests can escape hotspots, the scope of mitigation should extend beyond resistant sites. In the case of widespread resistance, regional mitigation was less effective at prolonging the life of the pyramid than IPM with Bt deployment at the time of commercialization.
(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): Michael A. Caprio

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
application technology
resistance/tolerance/defence of host

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Diabrotica virgifera	Maize/corn (Zea mays)
Bacillus thuringiensis (entomopathogen)	Diabrotica virgifera