Wheat (Triticum aestivium �Knudson�)� ����������������������������������������������� ��������������� ��������������� S. Halley

�� Fusarium head blight; Fusarium graminearum�������������������������������������������������� ��������������� Langdon Research Extension Center

� �Tan spot; Pyrenophora tritici-repentis��������������� ������������������������������� ��������������� ��������������� North Dakota State University

� �Septoria blotch; Septoria tritici����������������������������������������������������������� ��������������� ��������������� Langdon, North Dakota, 58249

� �

Adjuvants to Enhance the Efficacy of Folicur Fungicide for Control of Fusarium Head Blight (FHB), 2003.

 

����� Adjuvants often are recommended added to fungicides for improved consistency under different environmental conditions. The study objective was to determine if efficacy of fungicide, Folicur (tebuconazole), can be enhanced by addition of different adjuvants (Preference, Activate Plus, Rivet, and Placement and experimental adjuvants AG 01023, AG 02059, AG 02013, AG01005, and AG 02013 + Preference). �Knudson� HRSW was planted for evaluation of adjuvants for enhancement of efficacy of Folicur on 16 May with an Almaco double disk drill, disks spaced 6-inches apart. Border plots were planted between treatment plots to reduce potential spray drift between plots. The field, soil type Barnes-Svea complex, was located at the Langdon Research Extension Center. The selected trial area was previously fallowed. The area was planted to plots 7 rows wide 16 ft. long arranged in a RCB design with six replicates. Recommended production practices for Northeast North Dakota, NDSU Extension, were followed. An herbicide tank mix of 2/3 pt/acre Puma and 4/5 pt/acre Bronate Advanced in 14 gpa solution at 40 psi was applied on 11 June to control weeds. A wheat Fusarium spawn was hand broadcast on individual plots at 100 grams per plot to increase chance of infection to FHB on 20 June. A second Fusarium spawn application, corn-barley, was made on 26 June. Folicur with �Placement�, and both �AG 02013� alone, and in combination with �Preference� were premixed and added to warm water for mixing. No compatibility problems were apparent. Fungicides and adjuvants were applied on 14 July to HRSW at Feekes growth stage 10.51 immediately after mixing. In addition to required treatments an additional treatment of Bayer experimental fungicide JAU 6476 was added as a control. A CO₂ backpack sprayer applying 18.4 gpa solution at 40 psi with XR8001 nozzles on a double swivel adapter angled 30� downward and oriented to spray forward and backward was used for fungicide and adjuvant applications at 11:40 a.m. Average air temperature was 76� F and relative humidity was 63%. Wind direction was ESE at 13.8 mph with gusts to 18.9 mph, recorded at the NDAWN weather station 0.5 mile NE of the trial site, but were reduced considerably by the multi-row shelterbelt East of the trial site. Spray applications were made in an East-West direction. Movement of spray drift to border plots was minimal. Visual assessment of FHB and leaf disease was made on 4 August. The trial was combined with a Hege plot combine on 22 August and the grain sample cleaned and processed for yield, and test weight measurement. Data was analyzed with the general linear model (GLM) in SAS. Least significant differences (LSD) were used to compare means at the 5% probability level.

 

����� All the adjuvants mixed well with the fungicide. No visible phytotoxicity was evident throughout the summer. FHB incidence and field severity (spikelet count per individual head multiplied times FHB infected spikes per head) was reduced to negligible levels (estimated <0.5%) with all fungicide treatments so only the untreated plots were rated. The mean incidence and field severity on the untreated were 58.3% and 6.7%, respectively. However, when the untreated plots were analyzed for DON (deoxynivalenol), low levels were present so three replicates were ground and submitted to NDSU for DON determination. The growing season was one of the most productive in recent years due to little visible disease development. No differences in yield, test weight, and leaf disease were measured. All fungicide applications reduced DON levels from the untreated. No differences in DON levels were measured by any adjuvants added to Folicur. The JAU 6476 fungicide had lower DON levels than Folicur with no adjuvant and Folicur with AG 01023 adjuvant. Financial support for this research was received from Agriliance LLC.

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Fungicide	Adjuvant	Adjuvant	Yield	Test	Leaf	DONz
		Rate		Weight	Disease
			bu/acre	lb/bu.	%	ppm
Untreated			71.2	56.7	6.0	6.1
Folicur	None		73.7	57.3	5.2	2.7
Folicur	Preference	0.25% v/v	73.5	57.2	7.2	2.0
Folicur	Activate Plus	0.25% v/v	74.2	56.9	4.3	2.1
Folicur	Rivet	0.5% v/v	73.4	57.3	4.6	1.8
Folicur	AG 01023	0.5% v/v	72.8	57.2	4.3	2.6
Folicur	AG 02059	0.25% v/v	75.6	57.7	3.3	1.7
Folicur	Placement	2 oz/a	74.1	57.1	3.3	2.1
Folicur	AG 02013	2 oz/a	76.7	57.4	4.9	1.6
Folicur	AG 02013 + Preference	2 oz/a + 0.25% v/v	74.4	57.0	6.8	1.6
Folicur	AG 01005	1% v/v	75.5	56.8	4.2	1.6
Folicur	Induce	0.125% v/v	76.1	57.3	4.5	1.6
JAU6476	None		74.8	57.5	3.6	1.1
LSD y			NS	NS	NS	1.2
% C.V.			5	1	49	32

^z Determinations from three replicates

^y Significant 0.05 probability level for mean comparisons, respectively.