{"id":27643,"date":"2026-09-02T19:29:47","date_gmt":"2026-09-02T23:29:47","guid":{"rendered":"https:\/\/mmcereais.com.br\/2026\/soja\/soja-veja-como-reconhecer-os-primeiros-focos-de-antracnose\/"},"modified":"2026-09-02T19:29:47","modified_gmt":"2026-09-02T23:29:47","slug":"soja-veja-como-reconhecer-os-primeiros-focos-de-antracnose","status":"publish","type":"post","link":"https:\/\/mmcereais.com.br\/en\/2026\/soja\/soja-veja-como-reconhecer-os-primeiros-focos-de-antracnose\/","title":{"rendered":"Soybeans: learn how to recognize the first signs of anthracnose."},"content":{"rendered":"

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Anthracnose in soy<\/a> It can cause anything from poor plant stand to significant productivity losses. Between September and April, the sowing and crop development period in the main producing regions, identifying the first symptoms is crucial to prevent the disease from spreading and to guide phytosanitary management.\n<\/p>\n

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Caused primarily by Colletotrichum truncatum, often still cited in older materials as Colletotrichum dematium, the disease can affect soybeans from initial establishment to grain formation. In regions such as Mato Grosso, Rio Grande do Sul, Paran\u00e1, Goi\u00e1s, Mato Grosso do Sul, and Bahia, conditions of high humidity and frequent rainfall can favor its development.<\/p>\n

Anthracnose is a fungal disease that can affect different plant structures. The pathogen survives in infected seeds and crop residues from previous harvests, while conditions of high humidity, frequent rainfall, and mild to warm temperatures favor infection.<\/p>\n

The intensive use of no-till farming, with a large volume of straw on the surface, can provide shelter for the fungus. Other factors contributing to the increased importance of the disease include a wide planting window, insufficient or poorly planned crop rotation, and the presence of more susceptible cultivars, especially when plants are subjected to stresses such as excessive rain or lack of sunlight.<\/p>\n

Since the initial symptoms can be subtle and similar to those of other diseases or physiological problems, identification often only occurs in more advanced stages. At this point, flower abortion, pod drop, and grain filling failures may appear.<\/p>\n

The fungus can reach crops mainly through contaminated seeds and infected crop residues. In seeds, the pathogen can impair germination or cause lesions in seedlings, leading to damping-off or the development of weakened plants.\n<\/p>\n

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In the straw of soybeans, corn, or other host crops, the fungus can remain during the off-season and release spores when environmental conditions are favorable.<\/p>\n

The cycle begins with the pathogen surviving in seeds, crop residues, and, in some cases, volunteer soybean plants or host weeds. Then, the spores can be disseminated primarily through rain splash, irrigation, or contact between plants.<\/p>\n

Infection is favored by prolonged leaf wetness and mild to warm temperatures. After penetrating the tissues, the fungus forms new structures that produce spores and fuel the infection cycle during rainy periods.<\/p>\n

During the germination and establishment phase, one of the first signs may be the occurrence of stand failures unrelated to mechanical problems during sowing. Small, dark, sunken lesions may also appear near the collar or the first internodes.<\/p>\n

Damping-off is another warning sign. Seedlings may wilt, lodge, and die shortly after emergence, showing darkening of the basal tissue.<\/p>\n

At this stage, anthracnose can be confused with other soil fungi. Observing well-defined lesions, initially water-soaked in appearance and later darkening, around the root collar can help raise suspicion.<\/p>\n

During vegetative growth and the beginning of the reproductive period, attention should be focused primarily on stems, petioles, and branches.<\/p>\n

Elongated, dark lesions may appear on the stems and petioles, forming streaks or brownish to blackish spots. In some cases, these lesions have a burnt appearance and follow the axis of the tissue.<\/p>\n

Another sign is what's called tip burn, characterized by the death of the branch tips and the main stem. The tips become dry and dark, while the lower part of the plant may still remain green.<\/p>\n

Petiole wrinkling or curling may also occur, accompanied by dark spots and premature leaf drop.<\/p>\n

Under conditions of high humidity, small dark spots can be observed clustered within the lesions. These fungal fruiting structures can release a mass of salmon-colored to orange spores when the environment is very humid.<\/p>\n

On the leaves, the symptoms are less specific. The disease can cause irregular brown to dark spots, sometimes with less defined edges than those observed in target spot.<\/p>\n

Burning of the edges of leaves near heavily attacked stems and irregular defoliation may also occur on branches or sections of the plant where petioles are damaged.<\/p>\n

Therefore, inspections to identify anthracnose should prioritize stems, petioles, branches, and pods, and not just the spots present on the leaves.<\/p>\n

From flowering and during grain filling, the disease can become more destructive. Flower abortion, for example, may appear with greater intensity without other apparent causes, such as water deficit or phytotoxicity.<\/p>\n

Sunken, black or dark brown lesions may appear on the pods, sometimes in the shape of rings or bands. As the problem progresses, the pods may become dry and wrinkled.<\/p>\n

Damage to these tissues can also result in malformed or empty pods. The grains may exhibit dark surface spots, low quality, and reduced vigor, in addition to acting as a source of inoculum for the next crop.<\/p>\n

In severe attacks, areas of the crop may exhibit smaller, wrinkled pods with few or malformed grains, often associated with defoliation and branch burn.<\/p>\n

Differentiation from other diseases is important because different problems can occur simultaneously during periods of high phytosanitary pressure.<\/p>\n

In target spot disease, caused by Corynespora cassiicola, well-defined, rounded leaf spots with concentric rings predominate. The disease mainly affects the leaves, while lesions on stems and pods are less characteristic.<\/p>\n

In anthracnose, on the other hand, the damage can be more intense in stems, petioles, branches, flowers, and pods, with the occurrence of tip burn and defoliation associated with lesions in these tissues.<\/p>\n

Asian soybean rust, caused by Phakopsora pachyrhizi, presents as small leaf spots, mainly on the underside of the leaves, where pustules that release light to brownish spores can be observed.<\/p>\n

In severe cases, Asian soybean rust can cause widespread defoliation. Anthracnose, on the other hand, tends to be more intense on stems and pods and does not form pustules on the underside of the leaves.<\/p>\n

Collar and root rots caused by soil fungi can also lead to damping-off and stand failures similar to those observed in the early stages of anthracnose.<\/p>\n

In these cases, darkening of the root system and collar is common, as well as a possible odor of decay and softer tissues. In anthracnose, the lesions may be more superficial and well-defined, while the root system remains relatively preserved when the infection is concentrated in stems and petioles.<\/p>\n

Some signs from the crop itself help indicate the beginning of an outbreak. Among them are stand failures in areas where sowing was technically correct, with no evidence of mechanical problems.<\/p>\n

Also deserving attention are areas where plants exhibit burnt and darkened tips, contrasting with the rest of the crop, as well as irregular defoliation associated with lesions on petioles and stems.<\/p>\n

The increase in flower abortion and premature pod drop, especially after periods of frequent rain, should also be noted.<\/p>\n

Another sign is the presence of darkened and sunken pods. In humid conditions, dark spots accompanied by masses of orange spores may be observed.<\/p>\n

Areas with a history of anthracnose, planting over soybean straw, and poorly planned crop rotation require extra attention during inspections.<\/p>\n

Monitoring should begin soon after emergence, observing for stand failures, weak seedlings, and symptoms at the crown and first internodes.<\/p>\n

During vegetative growth, periods of rain require inspection of stems, petioles, and shoot tips. From the beginning of flowering to grain filling, monitoring should be intensified, mainly to identify flower abortion, pod blemishes, and associated defoliation.<\/p>\n

The inspection can be carried out in a zigzag or "W" pattern, evaluating plants at different points in the area. The procedure should be repeated after periods of humid and rainy weather, since the fungus depends on leaf wetness to spread and infect.\n<\/p>\n

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Early identification of symptoms allows for integrated management planning, combining cultural measures, appropriate seed selection and, when indicated, chemical practices as directed by an agricultural engineer.<\/p>\n

Among the benefits is a reduced risk of control failures, since preventive interventions or those carried out in the early stages can be more efficient.<\/p>\n

Early diagnosis also allows for planning the use of registered fungicides, respecting the application stages and intervals established in the product label.<\/p>\n

Furthermore, it allows for adjustments to practices such as crop rotation, crop residue management, and cultivar selection for future harvests, reducing the possibility of significant losses caused by flower abortion, pod drop, and the formation of shriveled grains.<\/p>\n

Confirmation of the diagnosis and definition of chemical control measures must be carried out by an agricultural engineer, considering field inspection, the history of the area, and official recommendations and product labels or leaflets.<\/p>\n

When chemical control is indicated, only products registered for soybean cultivation and for the disease should be used. It is also necessary to respect the dosage, spray volume, application time, and safety interval.<\/p>\n

The use of Personal Protective Equipment (PPE) is mandatory in all stages of handling and applying pesticides. Applications should also be avoided in conditions of strong wind, high temperature, or risk of drift to neighboring crops and sensitive areas.<\/p>\n

Empty containers must undergo triple rinsing and be properly disposed of at authorized collection points.<\/p>\n<\/p><\/div>\n

THE MM Cereais<\/strong> works with the best grains on the market and also keeps you up to date with the latest news and analyses on agribusiness.
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A antracnose na soja pode provocar desde falhas de estande at\u00e9 perdas significativas de produtividade.…<\/p>","protected":false},"author":1,"featured_media":27386,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[259],"tags":[244,248,255,249,254,250,246,247,256,245,253,252,251],"class_list":["post-27643","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-soja","tag-agrolink","tag-agrotoxicos","tag-artigos-tecnicos","tag-classificados","tag-colunistas","tag-compra","tag-cotacoes","tag-defensivos","tag-eventos","tag-noticias","tag-precos-agricolas","tag-previsao-do-tempo","tag-venda"],"_links":{"self":[{"href":"https:\/\/mmcereais.com.br\/en\/wp-json\/wp\/v2\/posts\/27643","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mmcereais.com.br\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mmcereais.com.br\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mmcereais.com.br\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mmcereais.com.br\/en\/wp-json\/wp\/v2\/comments?post=27643"}],"version-history":[{"count":0,"href":"https:\/\/mmcereais.com.br\/en\/wp-json\/wp\/v2\/posts\/27643\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/mmcereais.com.br\/en\/wp-json\/wp\/v2\/media\/27386"}],"wp:attachment":[{"href":"https:\/\/mmcereais.com.br\/en\/wp-json\/wp\/v2\/media?parent=27643"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mmcereais.com.br\/en\/wp-json\/wp\/v2\/categories?post=27643"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mmcereais.com.br\/en\/wp-json\/wp\/v2\/tags?post=27643"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}