Introduction

The coffee or coffee tree, Coffea spp., is a plant belonging to the Rubiaceae Family and is native to Ethiopia. It was first cultivated in the province of Kaffa in Ethiopia in the middle of the 12^th century, from where it spread through trade to the Middle East and from the 15th century it was introduced to Europe, where its consumption became widespread for the next 200 years (^{Perez and Díaz, 2000}).

At present, more than one hundred species of Coffea are known, of which Coffea arabica L. and Coffea canephora L., are the two most important cultivated species, the first with a contribution of 58% of world production and the second with 42% (^{ICO, 2017}). For 2014, the main green coffee producers in the world were Brazil with 2 804 070 t, Vietnam with 1 406 469 t, Colombia with 728 400 t, Indonesia with 643 900 t and Ethiopia with 419 980 t (^{FAO, 2017}).

In Mexico, Coffea arabica L. occupies more than 97% of the coffee growing area and the robusta coffee tree Coffea canephora L. (Var. Robusta) is located to a lesser extent in the rest of the area, the latter aimed almost exclusively at the instant coffee sector. Currently there are about 120 varieties of Arabica coffee; highlighting the varieties Creole (Typica), Bourbon, Catimores, Caturra (red and yellow), Colombia, Costa Rica, Garnica, Maragogipe, Mundo novo, Oro azteca, Pacamara and Pluma hidalgo (^{AMECAFÉ, 2016}).

In 2015, in 16 states of the Mexican Republic 1 026 251 98 t of coffee were produced, in an area of 734 291 03 ha, distributed in the mountain areas that cross the country, with a production value of $5 340 761 16. In this sense, the main producers with 64.2% of national production are the states of Chiapas and Veracruz with 383 059 62 (37.3%) and 276 054 71 (26.9%) tons respectively (^{SAGARPA-SIAP, 2017}).

The presence of pests is of great importance in the cultivation of coffee, mainly due to their high incidence or the level of damage they cause. Phytoparasitic nematodes constitute one of the main limiting pathogens that affect coffee cultivation, particularly the Coffea arabica species that is susceptible to nematodes; capable of causing reductions in yield ranging between 15-60% (^{Campos and Villain, 2005}; ^{ANACAFÉ, 2017}).

Numerous species of nematodes have been reported in association with this crop; however, the species of the genera Pratylenchus Filipjev (Tylenchida: Pratylenchidae) and Meloidogyne Goeldi (Tylenchida: Heteroderidae) are the most widely distributed and the most economically important, with the greatest losses in cultivation; the former with yield losses of 29-78% and the latter, yield losses of between 10-15% or up to 100% under certain conditions (^{Inomoto et al., 1998}; ^{Oliveira et al., 1999}; ^{Campos and Villain, 2005}; ^{Carneiro and Cofcewicz, 2008}; ^{Villain, 2008}; ^{Souza and Bressan-Smith, 2008}).

The phytosanitary problem with nematodes is increasing, and the control alternatives are few, mainly systematic applications of chemical compounds are used, due to their effective effect on the different species of phytoparasitic nematodes (^{Perry, 1998}; ^{Baños et al., 2010}). However, their use has been restricted by the harmful effects on the environment and they can become very toxic to the health of producers and consumers (^{Fe, 2002}; ^{Baños et al., 2010}).

On the other hand, the cost, residuality and phytotoxicity of nematicides for cultivation limit their application, so it is essential to look for alternatives to combat phytopathogenic nematodes, which considerably affect production (^{Hernández et al., 2015}).

Currently agriculture demands the reduction of chemical products and an increase in products that are friendly to the environment and human health; for this reason, biorational control; based on biological extracts and biological control organisms, it is presented as a very promising alternative, which allows the development of a more profitable agriculture that does not pollute the environment; This is why it is proposed to evaluate the biological effectiveness of Nemaxxion XT Plus, based on plant extracts and organic components for the control of the nematodes Meloidogyne incognita and Pratylenchus sp., associated with the cultivation of coffee in Motozintla, Chiapas.

Materials and methods

Results and discussion

Table 2 shows the population at the beginning of the investigation and the final population found 120 days after the application of the treatments for the control of Meloidogyne spp. and Pratylenchus sp., obtained from the soil of the coffee plantation.

A significant reduction in the nematode population is observed as a result of the application of control treatments; while the control treatment presented an increase in the population in Pratylenchus; however, in M. incognita, the control presented a reduction of 12.84%, with respect to the initial population.

Table 3 shows the reduction of the population of M. incognita and Pratylenchus sp., in which it is observed that the treatments based on plant extracts and organic components, present a significant control (p< 0.05) over the different nematodes of the crop of coffee.

Between the test treatments (1-4) for the control of M. incognita., no significant differences were found, with a control of 97.31 to 99.08% of the populations, while the control presented a significantly lower reduction, with a survival of 87.16% (gl= 8, 24; F= 334.12; p< 0.0001; R²= 0.99, CV= 4.07) (Table 3).

The plant extracts of Nemaxxion XT Plus did not allow the population density of M. incognita to increase, reducing in a range of 0.009 to 0.026 times the initial population, mainly in treatment 3 (Nemaxxion XT Plus 6 L ha^-1), the which resulted with greater efficiency with 98.93% (Table 4).

The application of treatments for the lesion nematode Pratylenchus sp., presented a significant control effectiveness (p< 0.05) that fluctuated from 87.47 to 92.87% (Table 3), treatments that reduced the population density in a range of 0.067-0.125 times the initial population, highlighting with greater efficiency (94.82%) treatment 3 (Nemaxxion XT Plus 6 L ha^-1) (Table 4).

The control treatment without nematode control did not present a reduction in the population (Table 3) (gl= 8, 24; F= 416.54; p< 0.0001; R²= 0.99; C.V.= 4.35), with a population increase of 1.294 times (Table 4), increasing 13 more nematodes to the starting population (Table 2).

Based on the results, the use of the Nemaxxion XT Plus product based on plant extracts and organic components showed high efficiency for the control of M. incognita and Pratylenchus sp., reducing the density of the populations in the coffee tree crop; whose effect is similar to the organophosphate product Nemacur^® 400 CE, which suggests that the product of biological origin can be used as a control alternative for these nematodes.

Various authors have pointed out the importance and effectiveness of using ecological alternatives for the management of nematodes, mainly plant extracts, which allows the development of a more profitable and non-polluting agriculture (^{Parada and Guzmán, 1997}; ^{Dama, 2002}; ^{Jothi et al., 2004}; ^{Vinueza et al., 2006}; ^{Zakaria et al., 2013}; ^{Garrido et al., 2014}).

Conclusions

Nemaxxion XT Plus is effective for the control of the root-knot nematode Meloidogyne incognita and the lesion nematode Pratylenchus sp., in coffee cultivation, in addition to its organic and environmentally friendly characteristics it can be used in any agricultural production system, presenting itself as an alternative for a more sustainable agriculture.