Length of efficacy for control of curly top in sugar beet with seed foliar insecticides

Strausbaugh, C.A. and Wenninger, E.J. and Eujayl, Imad A. (2016) Length of efficacy for control of curly top in sugar beet with seed foliar insecticides. Plant Disease. 100(7):1364-1370. 8 June 2016.

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Abstract

Curly top in sugar beet caused by Beet curly top virus (BCTV) is an important yield limiting disease that can be reduced via neonicotinoid and pyrethroid insecticides. However the length of efficacy of these insecticides is poorly understood, so a series of field experiments was conducted with the seed treatment Poncho Beta (60 g a.i. clothianidin + 8 g a.i. beta-cyfluthrin/100,000 seed) and foliar treatment Asana (55.48 g a.i. esfenvalerate/ha). A series of four experiments were conducted in 2014 and repeated in 2015 with four treatments (untreated check, Poncho Beta, Asana, and Poncho Beta + Asana) which were arranged in a randomized complete block design with 8 replications. To evaluate efficacy, viruliferous (contain BCTV strains) beet leafhoppers were released at different times for each experiment – either 8, 9, 10, or 11weeks after planting (1 to 4 weeks after Asana application). Over both years, in 30 of 32 comparisons for treatments with Poncho Beta and 14 of 16 comparisons for Asana, visual curly top ratings were decreased an average of 41% and 24%, respectively compared to the untreated check. Over both years, in 8 of 8 comparisons for treatments with Poncho Beta and 6 of 8 comparisons for Asana, root yields were increased an average of 39% and 32%, respectively compared to the untreated check. When considering estimated recoverable sucrose (ERS) over both years, the Poncho Beta treatments increased yield by 75% compared to the untreated check over the first two weeks. By week 10 only the Poncho Beta + Asana treatment consistently led to increases in ERS, while the influence of increasing host resistance may have made other treatments more difficult to separate. When considering all variables among all weeks and years, there was a tendency for the insecticides in the Poncho Beta + Asana treatment to complement each other to improve efficacy.

Item Type:	Article
NWISRL Publication Number:	1579
Subjects:	Irrigated crops > Sugarbeet > Curly top Irrigated crops > Sugarbeet > Seed treatment Irrigated crops > Sugarbeet Irrigated crops > Sugarbeet > Seed treatment > Insecticide
Depositing User:	Dan Stieneke
Date Deposited:	09 Jun 2016 21:43
Last Modified:	09 Jun 2016 21:43
Item ID:	1622
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/1622