Cotton seed treatment

Using quality seeds and treating them with fungicides is an essential measure to guarantee good results in cotton cultivation. Easy to implement, this tool is relatively cheap when evaluating the benefits it provides to cotton farmers, such as preventing infestation or reinfestation of areas with diseases that limit the crop.

Brazilian cotton farming currently presents a new production model, in which high technologies, investment in fiber quality and sowing in large areas are used. This production model has been used in the various cotton-producing regions of the country. However, despite this technological revolution, cotton farming is experiencing serious phytosanitary problems of economic relevance, especially when it comes to the quality of cotton seeds. Therefore, it is important that cotton growers know the origin of the material to be used on the property and also seek to acquire batches of seeds from reputable producers/companies, as their sanitary quality is fundamental in the establishment of the crop. The use of healthy seeds and/or seeds treated with fungicides becomes necessary and indispensable for the adequate control of numerous diseases, the causal agents of which are transmitted by seeds. The use of seeds treated with fungicides is considered the most economical and safe way to control pathogens that are transmitted by seeds, providing less use of pesticides in the crop. Fungi are the main phytopathogenic agents that can be associated with cotton seeds, which, if not controlled, can cause a reduction in crop yield and economic losses to the producer, whether in the initial phase and/or during the crop cycle in the field.

The main etiological agents of the aerial part that may be associated with cotton seeds are Alternaria spp., Ascochyta gossypii, Colletotrichum gossypii, Colletrotrichum gossypii South var. cephalosporioides Costa, Corynespora cassiicola, Lasiodiplodia theobromae, Myrothecium roridum, Sclerotinia sclerotiorum, Sclerotium rolfsii and the bacteria Xanthomonas axonopodis p.v. malvacearum. The etiological agents present in the soil that affect the roots and vascular system of the plant and are transmitted by seeds are Fusarium oxysporum f.sp. vasinfectum, Fusarium sp. Macrophomina phaseolina, Rhizoctonia solani, Verticillium white-black e Verticillium dahliae. There are also organisms that cause seed deterioration in storage that are transmitted to cotton seeds, for example, Aspergillus flavus, Aspergillus glaucus, Aspergillus candidus, Aspergillus ochraceus and also several species of Penicillium. These fungi can be transported in a mixture with the seeds, as part of the impure fraction of the lot, especially the sclerotia of Sclerotinia sclerotiorum, or also be present inside the seeds, such as species belonging to the genera Fusarium e Colletotrichum.

The importance and objectives of controlling pathogens in cotton seeds with the use of fungicides registered with the Ministry of Agriculture, Livestock and Supply (Table 1) before implementing the crop or sowing in the field are to eradicate or reduce, to the lowest levels possible, the fungi present in the seeds; provide protection to seeds and seedlings against soil fungi; prevent the transmission and dissemination of inoculum through seeds and promote uniformity in the germination and emergence of cotton seedlings. These fungicides, however, must be toxic to pathogens and cannot be toxic to seeds.

Seed treatment is one of the main measures for integrated disease control. Recent studies, conducted in different regions of the country, have demonstrated that the fungicides currently available for treating cotton seeds (belonging to the protective and systemic groups) have controlled to varying degrees the complex of fungi associated with the seeds of this crop. The most used are those with active ingredients based on capitan, thiram, carboxin, carbendazim, fludioxonil, metalaxyl, triadimenol, pencycuron, methyl thiophanate, azoxystrobin, flutriafol, difeconazole, quintazene and procymidone. The combination of two or three systemic fungicides with protectants, in which each product is effective against a specific fungus, has provided a greater spectrum of action in controlling these fungi in seeds and soil, compared to the isolated use of a specific fungicide. An effective strategy for controlling a greater number of pathogens present in seeds and/or in the soil has been the combination of fungicides with different spectrums of action, in addition to largely avoiding the emergence of resistant populations among pathogens and ensuring an ideal stand. of plants in different situations. Therefore, seed treatment with fungicides has been, to date, the main measure adopted and the most economical option to minimize the negative effects of seed-borne pathogens. This is an easy-to-implement measure, relatively cheap when evaluating the cost/benefit ratio and which meets the need to rationalize the use of chemical products in agriculture. Therefore, due to its low cost and the benefits it provides, its use is essential. It is considered appropriate to highlight that, especially when it comes to cotton, treating seeds with fungicides is necessary and even indispensable, avoiding infestation or reinfestation of areas with diseases.

Pathogen		Active Ingredient (chemical group)	Dose of commercial product (p.c)
Aspergillus spp.		Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate)	400-500g/100kg seeds
		Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate)	400-500ml/100kg seeds
		Captan (dicarboximide)	350ml/100kg seeds
Colletotrichum gossypii		Captan (dicarboximide)	350ml/100kg seeds
		Carbendazim (benzimidazole) + Thiram (dimethyldithiocarbamate)	600ml/100kg seeds
		Carbendazim (benzimidazole)	80ml/100kg seeds
		Captan (dicarboximide)	240-300g/100kg seeds
		Carbendazim (benzimidazole)	80ml/100kg seeds
Colletotrichum gossypii var. cephalosporioides		Carbendazim (benzimidazole)	80ml/100kg seeds
		Captan (dicarboximide)	350ml/100kg seeds
		Captan (dicarboximide)	160g/100kg seeds
		Captan (dicarboximide)	80ml/100kg seeds
		Carbendazim (benzimidazole)	100ml/100kg seeds
		Thiophanate-methyl (benzimidazole)	300ml/100kg seeds
		Carbendazim (benzimidazole)	80ml/100kg seeds
		Carbendazim (benzimidazole)	100ml/100kg seeds
		Azoxystrobin (strobilurin) + fludioxonil (phenylpyrrole) + metalaxyl – M (acylalaninate)	300ml/100kg seeds
		Carbendazim (benzimidazole)	80ml/100kg seeds
		Carbendazim (benzimidazole)	80ml/100kg seeds
		Carbendazim (benzimidazole)	80ml/100kg seeds
		Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate)	400-500g/100kg seeds
		Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate)	400-500ml/100kg seeds
Fusarium oxysporum f.sp. vasinfectum		Carbendazim (benzimidazole)	100ml/100kg seeds
		Carbendazim (benzimidazole)	100ml/100kg seeds
		Azoxystrobin (strobilurin) + fludioxonil (phenylpyrrole) + metalaxyl – M (acylalaninate)	100-300ml/100kg seeds
		Flutriafol (triazole)	150ml/100kg seeds
		Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate)	400-500ml/100kg seeds
		Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate)	500g/100kg seeds
Lasiodiplodia theobromae		Carbendazim (benzimidazole)	80ml/100kg seeds
		Carbendazim (benzimidazole)	80ml/100kg seeds
		Carbendazim (benzimidazole)	80ml/100kg seeds
		Carbendazim (benzimidazole)	80ml/100kg seeds
		Carbendazim (benzimidazole)	80ml/100kg seeds
		Carbendazim (benzimidazole)	80ml/100kg seeds
		Carbendazim (benzimidazole)	80ml/100kg seeds
		Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate	400-500ml/100kg seeds
		Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate	400-500g/100kg seeds
Penicillium spp.		Captan (dicarboximide)	350ml/100kg seeds
		Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate)	400-500g/100kg seeds
		Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate)	400-500ml/100kg seeds
Rhizoctonia solani		Triadimenol (triazole)	200ml/100kg seeds
		Captan (dicarboximide)	350ml/100kg seeds
		Captan (dicarboximide)	220g /100kg seeds
		Carbendazim (benzimidazole) + Thiram (dimethyldithiocarbamate)	600ml/100kg seeds
		Azoxystrobin (strobilurin) + fludioxonil (phenylpyrrole) + metalaxyl – M (acylalaninate)	200-300ml/100kg seeds
		Fludioxonil (phenylpyrrole)	200ml/100kg seeds
		Pencicuron (phenylurea)	300ml/100kg seeds
		Captan (dicarboximide)	240-300g/100kg seeds
		Thiram (dimethyldithiocarbamate)	560ml/100kg seeds
		Thiram (dimethyldithiocarbamate)	560ml/100kg seeds
		Difeconazole (triazole)	33,4ml/100kg seeds
		Procymidone (dicarboximide)	150-300g/100kg seeds
		Quintozene (chloroaromatic)	300-600g/100kg seeds
		Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate)	500g/100kg seeds
		Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate)	400-500ml/100kg seeds

Pathogen

 

Active Ingredient (chemical group)

Dose of commercial product (p.c)

Aspergillus spp.

 

 Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate) 

400-500g/100kg seeds

 

 

Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate) 

400-500ml/100kg seeds

 

 

Captan (dicarboximide)

350ml/100kg seeds

 

 

 

 

Colletotrichum gossypii

 

Captan (dicarboximide)

350ml/100kg seeds

 

 

Carbendazim (benzimidazole) + Thiram (dimethyldithiocarbamate) 

600ml/100kg seeds

 

 

Carbendazim (benzimidazole)

80ml/100kg seeds

 

 

Captan (dicarboximide)

240-300g/100kg seeds

 

 

Carbendazim (benzimidazole)

80ml/100kg seeds

 

 

 

 

Colletotrichum gossypii var. cephalosporioides

 

Carbendazim (benzimidazole)

80ml/100kg seeds

 

 

Captan (dicarboximide)

350ml/100kg seeds

 

 

Captan (dicarboximide)

160g/100kg seeds

 

 

Captan (dicarboximide)

80ml/100kg seeds

 

 

Carbendazim (benzimidazole)

100ml/100kg seeds

 

 

Thiophanate-methyl (benzimidazole)

300ml/100kg seeds

 

 

Carbendazim (benzimidazole)

80ml/100kg seeds

 

 

Carbendazim (benzimidazole)

100ml/100kg seeds

 

 

Azoxystrobin (strobilurin) + fludioxonil (phenylpyrrole) + metalaxyl – M (acylalaninate)       

300ml/100kg seeds

 

 

Carbendazim (benzimidazole)

80ml/100kg seeds

 

 

Carbendazim (benzimidazole)

80ml/100kg seeds

 

 

Carbendazim (benzimidazole)

80ml/100kg seeds

 

 

Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate) 

400-500g/100kg seeds

 

 

 Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate) 

400-500ml/100kg seeds

 

 

 

 

Fusarium oxysporum f.sp. vasinfectum

 

Carbendazim (benzimidazole)

100ml/100kg seeds

 

 

Carbendazim (benzimidazole)

100ml/100kg seeds

 

 

Azoxystrobin (strobilurin) + fludioxonil (phenylpyrrole) + metalaxyl – M (acylalaninate)       

100-300ml/100kg seeds

 

 

Flutriafol (triazole)

150ml/100kg seeds

 

 

 Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate) 

400-500ml/100kg seeds

 

 

 Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate) 

500g/100kg seeds

 

 

 

 

Lasiodiplodia theobromae

 

Carbendazim (benzimidazole)

80ml/100kg seeds

 

 

Carbendazim (benzimidazole)

80ml/100kg seeds

 

 

Carbendazim (benzimidazole)

80ml/100kg seeds

 

 

Carbendazim (benzimidazole)

80ml/100kg seeds

 

 

Carbendazim (benzimidazole)

80ml/100kg seeds

 

 

Carbendazim (benzimidazole)

80ml/100kg seeds

 

 

Carbendazim (benzimidazole)

80ml/100kg seeds

 

 

 Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate

400-500ml/100kg seeds

 

 

 Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate

400-500g/100kg seeds

 

 

 

 

 

 

 

 

Penicillium spp.

 

Captan (dicarboximide)

350ml/100kg seeds

 

 

 Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate) 

400-500g/100kg seeds

 

 

 Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate) 

400-500ml/100kg seeds

 

 

 

 

Rhizoctonia solani

 

Triadimenol (triazole)

200ml/100kg seeds

 

 

Captan (dicarboximide)

350ml/100kg seeds

 

 

Captan (dicarboximide)

220g /100kg seeds

 

 

Carbendazim (benzimidazole) + Thiram (dimethyldithiocarbamate) 

600ml/100kg seeds

 

 

Azoxystrobin (strobilurin) + fludioxonil (phenylpyrrole) + metalaxyl – M (acylalaninate)       

200-300ml/100kg seeds

 

 

Fludioxonil (phenylpyrrole)

200ml/100kg seeds

 

 

Pencicuron (phenylurea)

300ml/100kg seeds

 

 

Captan (dicarboximide)

240-300g/100kg seeds

 

 

Thiram (dimethyldithiocarbamate) 

560ml/100kg seeds

 

 

Thiram (dimethyldithiocarbamate) 

560ml/100kg seeds

 

 

Difeconazole (triazole)

33,4ml/100kg seeds

 

 

Procymidone (dicarboximide)

150-300g/100kg seeds

 

 

Quintozene (chloroaromatic)

300-600g/100kg seeds

 

 

Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate) 

500g/100kg seeds

 

 

Carboxine (carboxanilide) + thiram (dimethyldithiocarbamate) 

400-500ml/100kg seeds

Luiz Gonzaga Chitarra, Embrapa Algodão; Gilma Silva Chitarra, Federal Institute of Education, Science and Technology of Mato Grosso (IFMT) – Sinop Campus

Article published in issue 196 of Cultivar Grandes Culturas.