Integrated control of target spot and yield of cotton in the Brazilian <i>cerrado</i> biome

SOUZA, HUGO M. DE; THEODORO, GUSTAVO F.; DIAS, ALFREDO R.; SOUZA, CHRISTIAN R.W.; MAGALHÃES, FERNANDO F.

doi:10.1590/0001-3765202020181205

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AGRARIAN SCIENCES • An. Acad. Bras. Ciênc. 92 (suppl 1) • 2020 • https://doi.org/10.1590/0001-3765202020181205 linkcopy

Integrated control of target spot and yield of cotton in the Brazilian cerrado biome

Authorship SCIMAGO INSTITUTIONS RANKINGS

Abstract

Target spot is a disease that has caused serious damage to cotton crops. This study was carried out to examine if different cotton genotypes, plant heights and fungicide treatments can be used as tools of an integrated control methods of target spot. The experiment was carried out in the 2014/15 crop season, in cerrado biome of Chapadão do Sul - MS, Brazil. It was used a randomized block design in a 2 × 3 × 3 factorial arrangement with four replicates. The factors were two plant heights (1 and 1.5 m), three cultivars (FMT 701, FM 975, and FM 944), and three fungicide treatments (control, FT1, and FT2). Fungicide treatments consisted of sequential applications of different fungicides of the triazole, strobilurin, and carboxamide groups. Cultivar FM 944 showed lower susceptibility to target spot. The shorter plants exhibited lower disease severity. The fungicides pyraclostrobin + fluxapyroxad and trifloxystrobin + prothioconazole reduced the severity of target spot. Cultivar FM 975 had the highest yield. A higher yield was obtained in the upper stratum than in the lower stratum of the plant.

Key words
Corynespora cassiicola; Sustainability; Control; Management

Treatments	Active ingredients	Phenological stage (+days) at spray	Dose of CP* L ha^-1	Dose of ai** Kg L^-1
Control	-	-	-	-
FT1	¹Pyraclostrobin + Fluxapyroxad	B1	0,3	0,333+0,167
	²Trifloxystrobin + Prothioconazole	B1+ 15	0,4	0,150+0,175
	¹Pyraclostrobin + Fluxapyroxad	B1+30	0,3	0,333+0,167
	¹Pyraclostrobin + Fluxapyroxad	B1+45	0,3	0,333+0,167
	¹Pyraclostrobin + Fluxapyroxad	B1+60	0,3	0,333+0,167
	²Trifloxystrobin + Prothioconazole	B1+75	0,4	0,150+0,175
FT2	Azoxistrobin+ Difenoconazole	B1	0,3	0,200+0,125
	Difenoconazole	B1+ 15	0,3	0,250
	Azoxistrobin+ Difenoconazole	B1+30	0,3	0,200+0,125
	Azoxistrobin+ Difenoconazole	B1+45	0,3	0,200+0,125
	Azoxistrobin+ Difenoconazole	B1+60	0,3	0,200+0,125
	Difenoconazole	B1+75	0,3	0,250

Variation factor	F values
Variation factor	AUTSPC
Height (H)	63,0729 *
Cultivar (C)	95,8543 *
Fungicide treatment (FT)	20,4846 *
H x C	5,2904 *
H x FT	1,9662 ns
FT x C	3,1004 *
H x C x FT	0,3467 ns
CV (%)	17,18

Fungicide treatments*	AUTSPC
Fungicide treatments*	FMT 701	FM 975	FM 944
Control	173,92 aA	119,60 aB	82,27 aC
FT1	131,33 bA	99,88 bB	75,57 aC
FT2	195,15 aA	139,15 aB	88,78 aC
Height (m)
1,0	141,73 bA	93,68 bB	73,89 aC
1,5	191,87 aA	145,40 aB	90,53 aC
CV %	----------------------------17,18---------------------------

Variation factor	F values for yield
Variation factor	Upper portion	Lower portion	Total yield
Height (H)	9,8297 *	0,7422 ns	3,7615 ns
Cultivar (C)	8,0612 *	8,9931 *	10,5746 *
Fungicide treatment (FT)	2,4732 ns	0,6381 ns	0,6318 ns
H x C	1,1215 ns	4,2390 *	1,3931 ns
H x FT	4,2373 *	0,2194 ns	3,5976 *
FT x C	2,0666 ns	5,4522 *	1,2636 ns
H x C x FT	0,5229ns	0,7867 ns	0,9222 ns
CV (%)	11,67	11,57	8,28

Height (m)	Upper portion yield (kg ha^-1)
Height (m)	Control	FT1	FT2
1,0	2767,2 aB	3238,0 aA	3077,2 aA
1,5	2844,7 aA	2802,4 bA	2684,6 bA
CV (%)	------------------------------------11,68---------------------------------
Height (m)	Total yield (kg ha^-1)
	Control	FT1	FT2
1,0	5047,7 aB	5483,8 aA	5332,2 aA
1,5	5232,6 aA	5055,1 bA	4986,6 aA
CV (%)	------------------------------------8,51-----------------------------------

Cultivars	Yield (kg ha^-1)
Cultivars	Upper portion	Total yield
FMT 701	2884,9 b	4988,4 b
FM 975	3106,7 a	5516,2 a
FM 944	2715,9 b	5064,3 b
CV (%)	11,68	8,51

Cultivars	Plant stratum
Cultivars	Upper	Lower
FMT 701	2884,9 bA	2103,5 bB
FM 975	3106,7 aA	2409,5 aB
FM 944	2715,9 bA	2348,8 aB
CV (%)	-----------------------------14,66--------------------------

Fungicide treatment*	Yield (Kg ha^-1)
	Cultivars
	FMT 701	FM 975	FM 944
Control	2097,0 aB	2709,0 aA	2196,4 bB
FT1	2175,2 aA	2225,9 bA	2317,2 bA
FT2	2038,0 aB	2264,2 bB	2532,9 aA
Height (m)
1,0	2185,0 aA	2268,7 bA	2327,4 aA
1,5	2021,9 aB	2550,2 aA	2370,4 aA
CV %	-----------------------------11,57--------------------------------

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[tfnI] ¹Addition of mineral oil Assist® (500 ml.ha^-1); ²Addition of mineral oil Áureo® (0,25% of spray volume); *Commercial product; **Active ingredient.