Effect of Insecticide Seed Treatments on Sugarbeet Storability

Abstract

Sucrose loss in sugarbeet storage is a concern for all roots, but particularly those stored under ambient conditions. In order to control or suppress insect pests in sugarbeet production and consequently improve root storability, two neonicotinoid seed treatments, Poncho Beta (60 g a.i. [active ingredient] clothianidin + 8 g a.i. beta-cyfluthrin/100,000 seeds) and Cruiser Tef (60 g a.i. thiamethoxam + 8 g a.i. tefluthrin/100,000 seeds), were used to produce roots from four commercial sugarbeet cultivars grown in Declo, ID. At harvest, eight-beet samples from each cultivar x treatment combination were collected and placed inside an outdoor pile. Samples were removed on approximately 30-day intervals beginning on December 6 and 8 in 2008 and 2009, respectively. Discolored and frozen root area, weight and percent sucrose reduction, and sucrose recovery were evaluated. Across six-sampling dates, Poncho Beta was always ranked first for recoverable sucrose and performed well for the other variables assessed. Over the three sampling-dates when Poncho Beta was significantly better (P < 0.10) than the non-treated check, recoverable sucrose was increased by an average of 17% with only insect pest pressure and no disease pressure. Cruiser Tef tended to rank intermediate between Poncho Beta and the non-treated check for recoverable sucrose and other variables. The insecticide seed treatments not only have the potential to limit yield losses and increase profits in the field, but also to improve sucrose recovery in storage.