Nematodes in coffee

Despite the benefits of intercropping tree species with coffee, attention must be paid to the reaction to the crop's main nematodes

10.03.2020 | 20:59 (UTC -3)

Economic benefits, reduced need for labor to control weeds and reduced incidence of Cercospora, Phoma and leafminer are among the advantages of intercropping tree species with coffee trees. However, it is necessary to pay attention to the reaction of these plants to the main crop nematodes to avoid damage to the main crop.

Currently, 17 species of Meloidogyne infecting coffee plants, being Meloidogyne incognita, M. exigua e M. paranaensis the most harmful, due to the wide dissemination, the high capacity to destroy the root system, the persistence in the soil and the susceptibility of most cultivars to these nematodes, which makes it difficult to establish new areas cultivated with coffee and to maintain areas already infested. In Paraná, two species, M. unexplained e M. paranaensis, constitute the worst problems in coffee farming. For the state of Minas Gerais, another important coffee hub, the main species is M. exigua.

The parasitism of these nematodes on weeds that occur in the coffee plantation, as well as on crops used in intercropping with coffee, is an aggravating factor within the crop, since such plants can considerably increase nematode populations in the soil and damage to the crop. main. Therefore, prior knowledge about the reaction of plants that will be grown in the coffee area is extremely important to guarantee the success of the crop and avoid further damage to the coffee plantation.

In several coffee producing regions, especially on small and medium-sized properties, it is quite common to plant annual crops between the rows of the coffee plantation, for a more rational use of the soil during the crop formation phase. This allows subsistence and even the generation of additional income for the producer, with a consequent reduction in the costs of establishing the coffee plantation. However, once the crop is formed, intercropping coffee with annual crops is impractical, at least in the spacing currently recommended. Crops such as beans, pumpkin, corn, azuki beans, vegetables, green manures, etc. are frequently observed between the rows of coffee crops and, many are known to be hosts of the nematodes that affect the crop, which can cause an increase in the population of these pathogens and, consequently, , increasing damage to the main crop.

The protection of coffee plantations against frost, especially in the Southeast and South regions of the country, through the so-called “pigeon pea tunnel”, can also have negative consequences in relation to nematodes. In this method of protection, pigeon pea is used interspersed with newly planted coffee trees, forming a tunnel over the plants, which changes the microclimate and establishes an environment conducive to the survival of the coffee tree, even under frost. However, the pigeonpea genotype to be used in areas infested by nematodes must be observed, since several genotypes have already been reported as hosts of these parasites, including those of M. unexplained, important for Brazilian coffee farming.

In addition to this practice, intercropping of coffee with fruit trees, forestry species with high economic value for their wood, and with rubber trees has been practiced since the 80s. The association of coffee trees with other trees is called “agroforestry system (SAF)” and “coffee plantation afforestation”. Coffee crops grown in SAF suffer moderate shading, which improves the sustainability of the environment and increases the stability of coffee production, by mitigating stressful conditions, which can deplete crops in full sun, and by microclimatic conditions that are more appropriate for production. Shading the coffee plantation is, therefore, not the only objective expected when cultivating tree species associated with coffee. The diversification of production is also highlighted in this system.

In addition to the extra income from the cultivation of trees associated with coffee, other benefits may arise, such as reducing the need for labor to control weeds, improving or maintaining soil fertility, reducing wind speed , maintaining relative air humidity and buffering soil water supply, in addition to reducing the incidence of cercospora, Phoma and leafminer.

Despite the benefits presented, the cultivation of coffee trees in association with trees, or in SAF, is still controversial, since diversification makes it difficult to mechanize coffee farming, especially in large areas. However, for small producers, the consortium presents an economic strategy associated with greater production per area, greater return on labor and greater security in periods of low coffee prices. Furthermore, felling trees to harvest wood can cause physical damage to the crop. Despite the damage, crop repair costs are low and can be easily offset by the additional profit from selling the wood obtained.

In addition to the negative points presented, the choice of the tree species to be cultivated in association with coffee must also be careful and take into account several factors, including diseases, which can occur concomitantly in both crops. Among the diseases, nematodes stand out, which are one of the main problems of coffee crops. For example, the tree Inga spp., used for shading coffee plantations, may be an alternative host for coffee plant parasitic nematodes.

Although SAFs allow the maintenance of high levels of organic matter in the soil, which could help stabilize the nematode populations present in the area in order to keep them below the critical level for coffee cultivation, the wrong choice of the species to being used for shading could result in the opposite effect, with a considerable increase in the population levels of these pathogens.

Tephrosia sp. is a plant belonging to the legume family, originating in West Africa, where it is cultivated as a green fertilizer in rubber plantations and palm oil plantations and as a shading tree in various crops, in addition to being used as a windbreak and for ornamental purposes. In Brazil, Tephrosia sp. It is mistakenly known as “sacha”, and is commonly used between rows of coffee crops, due to the large amount of dry matter produced and nitrogen fixation.

However, Tephrosia sp. it can host pests and diseases common to the main crop, increasing damage to the crop. Among the diseases, phytonematodes stand out. Recently, M. javanica was detected parasitizing roots of T. vogelii in Paraná, on coffee plantations. Furthermore, T. vogelii was described as a new host of M. unexplained in Maranhão. Other species of Tephrosia have already been identified as hosts of Meloidogyne in Brazil. T. candida was found parasitized by M. javanica in Ceará and, later, parasitism of M. unexplained in the same species in Pará; was also reported T. cinerea as a hostess M.hapla In Ceara.

In relation to nematode species important for coffee farming, the reaction of Tephrosia sp. The M. unexplained, M. exigua e M. paranaensis under greenhouse conditions, in Iapar, in Londrina, Paraná. Seedlings of Tephrosia sp. 30 days after sowing, they were inoculated separately with each nematode species and, after 60 days, evaluated. The results showed that all species of root-knot nematodes evaluated were efficient in parasitizing Tephrosia sp., with high multiplication of nematodes. These results show that the use of Tephrosia sp. between coffee trees as green manure, in infested areas, can be disastrous for the crop, since the plant can considerably increase the population levels of nematodes in the soil, causing damage to the main crop.

In addition to this species, other trees used in intercropping with coffee have been investigated for their reaction to nematodes. In a nematological survey carried out in coffee areas intercropped with trees Croton floribundus (“capixingui”), Heliocarpus popayanensis ("raft"), Flocculent Mimosa (“bracatinga de Campo Mourão”) and mimosa scabrella (“bracatinga”) in Londrina, PR, the presence of abundant root galls was observed in the aforementioned species, although without evident symptoms in the aerial part. Root samples were collected and taken to the Iapar Nematology Laboratory. The results obtained in the laboratory showed that, for H. popayanensis, Croton floribundus, Mimosa floculosa e M. scabrella, the species identified was M. unexplained, one of the main nematodes in coffee crops.

Other trees that are known to be able to multiply some species of nematodes include, Corymbia citriodora (without. Eucalyptus citriodora) (susceptible to M. unexplained); teak (Tectona grandis) (susceptible to M. javanica); black ear, timburi or timboúva (Enterolobium contotisiliqum) (susceptible to M. unexplained e Pratylenchus brachyurus); purple IPE (Tabebuia avallanedae) (susceptible to M. unexplained); copaiba (Copaifera langsdorffii) (susceptible to M. unexplained); Brazilwood (Caesalpinia echinata) (susceptible to M. javanica e M. arenaria); among others.

Therefore, knowledge about the reaction of tree species to be cultivated in consortium with coffee trees to the main nematodes of the crop is of utmost importance, since such plants can considerably increase the population of these organisms in the soil, causing greater damage to the main crop.

Figure 1 - Symptoms caused by nematodes in coffee roots. A) Meloidogyne paranaensis. B) Meloidogyne exigua. Photos: Santino Aleandro da Silva
Figure 1 - Symptoms caused by nematodes in coffee roots. A) Meloidogyne paranaensis. B) Meloidogyne exigua. Photos: Santino Aleandro da Silva
Figure 2 - Intercropping of coffee plants with beans in a commercial crop in the municipality of São Jorge do Patrocínio, PR. Photo: Andressa C. Z. Machado
Figure 2 - Intercropping of coffee plants with beans in a commercial crop in the municipality of São Jorge do Patrocínio, PR. Photo: Andressa C. Z. Machado
Figure 3 - Intercropping of coffee plants with Tephrosia sp. in commercial farming in the municipality of Grandes Rios, PR. Photo: Andressa C. Z. Machado
Figure 3 - Intercropping of coffee plants with Tephrosia sp. in commercial farming in the municipality of Grandes Rios, PR. Photo: Andressa C. Z. Machado
Figure 4 - Symptoms caused by Meloidogyne sp. in roots of Tephrosia sp. Photo: Santino Aleandro da Silva
Figure 4 - Symptoms caused by Meloidogyne sp. in roots of Tephrosia sp. Photo: Santino Aleandro da Silva
Figure 5 - Coffee crop intercropped with tree species in Iapar, municipality of Londrina, PR. Photo: Santino Aleandro da Silva
Figure 5 - Coffee crop intercropped with tree species in Iapar, municipality of Londrina, PR. Photo: Santino Aleandro da Silva
Figure 6 - Coffee crop intercropped with tree species in Iapar, municipality of Londrina, PR. Photo: Santino Aleandro da Silva
Figure 6 - Coffee crop intercropped with tree species in Iapar, municipality of Londrina, PR. Photo: Santino Aleandro da Silva


Andressa CZ Machado, Iapar; Daniela S. Matunaga, Unifil; Santino Aleandro da Silva, Iapar


Article published in issue 197 of Cultivar Grandes Culturas. 

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