Evaluating application timing and tank mix combinations on leaf rust development in Louisiana, 2008

摘要

Soft red winter wheat was planted (100 lb seed/A) on 8 Nov 07 in a Gigger silt loam soil at the Macon Ridge Research Station near Winnsboro, LA. Standard chemical and cultural practices for wheat production were followed according to recommendations of the Louisiana Cooperative Extension Service. Treatments were replicated three times in a randomized complete block, and separated by 10 ft alleys. Plot size was 9 rows on 7 in. spacings by 15 ft. Rainfall totals for Feb, Mar, Apr, and May were 6.64,2.56, 3.70, and 2.40 in., respectively. Fungicide treatments were applied at flag leaf emergence (F8) on 28 Mar or 50% heading (F10.3) on 9 Apr using a CO2-charged spray boom configured with 8002 or ULD120-02 flat fan nozzles spaced on 19 in. centers delivering 17.4 gal/A at 36 psi. The area colonized by Puccinia triticina was assessed and estimated as percent on the flag and flag minus one leaves on 18 Apr and 1 May. Plots were harvested using asmall-plot combine on 27 May. Data were subjected to analysis of variance and treatment means were compared using Fisher’s protected least significant difference test.