Habitat manipulation in potato affects Colorado potato beetle dispersal

The Colorado potato beetle [Leptinotarsa decemlineata (Say); Coleoptera: Chrysomelidae] is a significant pest of potatoes in North America and Eurasia and can cause severe defoliation and yield loss (Ferro 1985; Weber and Ferro 1994b). Managing the Colorado potato beetle with intensive pesticide applications has led to resistant populations (Forgash 1985; Ioannidis et al. 1991; Stewart et al. 1997) which make alternative methods of control imperative. Habitat manipulation of agricultural fields is a potentially viable ecologically based approach for Colorado potato beetle management that could provide a non-chemical preventative strategy for population regulation of this pest (Weber and Ferro 1994a; Schmera et al. 2007). In a previous study, increasing host plant density and diversity reduced all stages of the Colorado potato beetles in potato fields (Horton and Capinera 1987); the authors suggested that increased time and energy costs of movement in a high plant diversity potato plot could be responsible. Physical plant characteristics were important in reducing walking speeds of the Colorado potato beetle in turf or tall wheat-crops compared with bare ground (Ng and Lashomb 1983; Lashomb and Ng 1984; Schmera et al. 2007). Reduced colonization rates by Colorado potato beetles were found in the presence of non-host plants (Bach 1982; Zehnder and HoughGoldstein 1990) and tenure time was reduced in non-host habitats (Weber and Ferro 1994a). Colorado potato beetle populations are negatively affected in the presence of mulch in potato and