How to disinfect agricultural machinery and implements

Disinfecting agricultural machinery and implements when moving from one area to another can prevent the transport of pests, some of which are important, such as nematodes.

Nematodes constitute a serious problem for the cultivation of various crops in practically all regions of the world. Losses can vary from 20 to 100% of production, depending on population density, cultivar susceptibility, nematode species, soil type and environmental conditions (temperature and relative humidity). In Brazil, the most significant damage results from attacks by root-knot nematodes, mainly Meloidogyne incognita and Meloidogyne javanica, which are the most widely distributed species (Embrapa, 2010).

In countries with a tropical and subtropical climate, nematodes find conditions such as humidity and ideal temperatures for reproduction and feeding. Such factors are aggravating the control of these pathogens, which, after having established themselves in an area, are very difficult to eradicate. In Brazil, the species that cause the greatest damage to large crops such as soybeans, cotton, sugar cane and corn are Meloidogyne javanica, Meloidogyne incognita, Heterodera glycines, Pratylenchus brachyurus and Rotylenchulus reniformis (Torres et al).

It is very common for agricultural areas to be abandoned due to nematode infestation, forcing farmers to open new areas, but this generates very high costs. Nematode control occurs mainly following phytopathological principles: such as exclusion, eradication, regulation and immunization.

Exclusion is used to prevent the infestation of unharmed areas by species or new breeds, on the property or in a larger geographic region, that is, to prevent introduction and spread. Nematode eradication requires crop rotation with non-host and/or antagonist summer and winter species, aiming to reduce the population density of the pest. Regulation is the modification of the environment and nutrition of plants, while immunization is the use of cultivars resistant to certain species or races.

There are several ways of spreading nematodes, however, irrigation with contaminated water stands out, especially when the water source is close to the place where the roots are washed; the use of dirty seeds with small clods of contaminated earth adhered to them and the movement of animals and humans in cultivation areas (Embrapa, 2010).

However, it is necessary to highlight that the spread through contaminated agricultural machinery and implements has attracted a lot of attention. It is very common for machines and implements to travel between healthy areas and areas infested by nematodes during the same working day. Machines and implements can lead to the introduction of root pathogens, which become attached to soil particles present in rotary hoes, harrows, plows, subsoilers and the tires of agricultural tractors, and propagations of not only nematodes, but fungi and bacteria.

The spread of diseases by machines and implements takes on even greater proportions when it comes to cooperatives, where machines are shared among a greater number of agricultural producers and consequently a greater number of areas. It is recommended to adopt cultural practices that prevent the spread, such as cleaning agricultural machinery and implements before carrying out work in areas not yet infested (Embrapa, 2007).

To eliminate the risk of contamination by nematodes, agricultural machinery and implements must be cleaned with strong jets of water. The most suitable equipment for this cleaning are high-pressure washers, before operating with this equipment in another area. All equipment must be washed, but greater attention must be paid to the wheels and active parts of agricultural equipment that come into contact with the soil, ensuring that clods of soil are completely removed. The wastewater from this washing must be disposed of safely, otherwise it will also be a vehicle for nematode infestation, as well as care must be taken to clean the tractor cabin and the boots of the tractor operators. 

The dispersion of the Soybean Cyst Nematode (Heterodera glycines) in Brazil is happening very quickly. In 91/92, the infested area was estimated at 10.000 ha. Currently, this area fluctuates around 1 and a half million hectares. However, there are many properties located in municipalities considered infested, where the Soybean Cyst Nematode (NCS) is not yet present. However, there are many properties located in municipalities considered infested, where the NCS is not yet present. Therefore, prevention should still be the main strategy. The transit of machinery, equipment and vehicles has been the main agent of dispersion of NCS in the country (Embrapa, 1997).

Chemical control through the use of nematicides is uneconomical and ineffective. In excess, these products are toxic to humans and the environment, in addition to high application costs (Embrapa, 2005). Control of areas infested by nematodes can be carried out through cultural control, such as crop rotation, antagonistic plants and fallow or fallow. However, these control alternatives are very costly to the producer and the result is not always positive. To adopt fallow as a cultural control in an area infested by nematodes, all vegetation must be excluded from the soil, including invasive plants, for at least two years, always stirring the soil through plowing and harrowing.

It is interesting that producers are aware of the importance of cleaning, disinfecting and disinfesting machines and implements, especially when this equipment is transported to other states. Inspection of sanitary barriers in relation to the sanitization of these machines should be carried out.

Agricultural machines and implements during the working day cause friction on the tops of plants, thus spreading fungi and bacteria, in addition to causing injury to branches and leaves, creating an entry point for these pathogens. Therefore, cleaning agricultural machinery and implements before starting a new area is extremely important. 

Aline Castro Praciano, Daniel Albeiro, Erialdo de Oliveira Feitosa, Deivielison Ximenes Siqueira Macedo, Viviane Castro dos Santos, Rafaela Paula Melo, Federal University of Ceará 

Article published in issue 148 of Cultivar Máquinas.