Sugarbeet Root Maggot Control, 1996

Abstract

Abstract Experimental plots were established approximately 10 miles east of Hazelton, ID. The soil type was Portneuf silt loam and the plots were sprinkler irrigated. Eleven treatments and an untreated check were replicated 4 times in a RCB design. Individual plots were six rows (22 inch row spacing) by 30 ft. Alleys were cut between plots prior to harvest to give 25 ft of row per plot. On 29 Apr all plots were planted at which time, band applications of Temik and Counter were made. Temik, Counter 15G and Counter CR were applied as a 4inch band over the row and chain incorporated. On 31 May, post-emergence applications of Furadan and Lorsban were made. Furadan and Lorsban were applied as a 3 inch-4 inch banded S (early fly emergence) using a CO2-pressurized backpack sprayer (20 gpa at 30 psi). On 7 Jun, post-emergence applications of Temik. Thimet, Counter 15G and Counter CR were made (peak fly emergence) in a band as previously described. On 25 Jul, after most larval feeding had ended. 5 adjacent beets were dug from the middle of rows 2 and 5 to give 10 beets per plot for rating root maggot damage. The beets were washed and rated for damage using the following scales; 5-Point scale: 0 = no scars; 1 = 1-4 small scars of pinhead size; 2 = 5-10 small scars to 3 large scars; 3 = more than 3 large scars; 4 = one-half to three-quarters of root area blackened by scars; 5 = more than three-quarters of root area damaged, dying beet: 7-Point Scale: 0 = no damage; 1 = 1-4 small scars of pinhead size; 2 = 5-10 small scars, or up to 3 larger scars; 3 = more than 3 large scars; 4 = 4 large scars to one-quarter root surface covered with scars; 5 = one-quarter to one-half root surface covered with scars; 6 = one-half to three-quarter root area blackened by scars; 7 = more than three-quarter root surface blackened, dying beet. On 14 Sep, sugar beets in rows 3 and 4 (middle two rows) in all treatment plots were machine lifted, hand topped and untared weights were taken for yield estimates. All data were analyzed using ANOVA and Newman-Keuls.