Trap-Corn to Control Corn Rootworms12

Influence of Corn Phenology on Adult Western Corn Rootworm (Coleoptera: Chrysomelidae) Distribution

“…When scouting Þelds, it is important to be aware of possible shortor long-term shifts in beetle densities within Þelds or at the interface of Þelds if contrasting phenologies occur side by side. If the corn growth stage in an individual Þeld is different than surrounding cornÞelds, the Þeld may act as a donor or receiver Þeld for beetles (Meinke 1995), which may inßuence oviposition (Hill and Mayo 1974). Results from this study suggest that when crop phenology contrasts are present, scouting should occur at frequent intervals to reduce the possibility of missing a dramatic shift in beetle distribution.…”

“…A conceptual model that combines both random and nonrandom movement may best explain the population distribution trends that have been quantiÞed in this study. The following hypothesis may explain how beetles were redistributed when contrasts between pollinating and nonpollinating corn were present and a trap crop effect (Hill and Mayo 1974) resulted. Random trivial movement occurs in relatively homogeneous habitat until beetles detect semiochemical plumes emitted from pollinating corn within or among Þelds.…”

“…Western corn rootworm beetles are very mobile insects with both trivial movement (Naranjo 1991(Naranjo , 1994 and migration (Coats et al 1986, Grant and Seevers 1989, Naranjo 1990) events impacting spatial dynamics over time. When movement occurs among cornÞelds (Hill and Mayo 1980), the majority of the dispersal activity appears to be by females (Hill and Mayo 1974, Godfrey and Turpin 1983, Naranjo 1991.…”

“…Volatiles in maize silks act as adult attractants (Prystupa et al 1988), and some silk compounds are electroantennogram-active (Abou-Fakhr et al 1996, Hibbard et al 1997. Hill and Mayo (1974) examined the idea of using a late-planted trap crop for corn rootworm management. They observed that the trap crop attracted western corn rootworm beetles from the surrounding early-planted corn, and increased oviposition in the trap area, therefore reducing the larval injury potential in corn planted near the trap area the following year.…”

Influence of calcareous soil on Cry3Bb1 expression and efficacy in the field

“…Because the WCR is highly attracted to maize or weed pollen and younger plant tissues (Darnell et al 2000;Campbell and Meinke 2006), the phenological contrast between maize and weeds in calcareous soils and surrounding maize can act as a sink for immigrating beetles causing densities to rise in calcareous soil patches later in the season (Wangila 2016). Trap crop situations can lead to greater oviposition and higher larval densities the following season (Hill and Mayo 1974). Therefore, larval densities and associated injury potential in some patches of calcareous soil may be greater than densities found in the remainder of the field.…”