Received October 28, 2014; Accepted October 30, 2014; Published October 30, 2014
Citation: Neiva Knaak (2015) Xanthomonas sp : Phytosanitary Threat to Brazil. J Rice Res 3:e109. doi: 10.4172/2375-4338.1000e109
Copyright: © 2015 Knaak N, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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The ever-growing flow of tourists and world trade increases the risk of entry of new pests in Brazil due to the free movement of goods. As a result of this expansion, situations that compromise the security of agriculture, such as the transmission of diseases to areas where the pathogen did not occur before, by cuttings, seeds or any contaminated material can occur. These quarantine pests mean risk because they can survive in latent form in seeds and seedlings, and have the ability to be disseminated over long distances and introduced into areas previously free of the disease, disrupting international trade.
The Ministry of Agriculture, Livestock and Supply (MAPA) periodically revises and publishes the list of Quarantine Pests, which is critical for regulating the commercial, national and international exchange of goods and produce byproducts transparently base. The present quarantine pests affecting interstate transit of plants and their products, controlled by the phytosanitary certification of origin and transit of plants permission. The list of quarantine pests absent supports international agricultural surveillance inspection of goods arriving at the ports of Brazil border, ports and airports . With this measure, the country marks the international market that their products are better protected against entry of pests, there is a concern with the environment and its sustainable use and mostly, they do not want to trade in agricultural products with the presence of pests, avoiding hence, and so-called "sanitary barriers". The countries conducting ongoing studies on socio-economic impact caused by the entry of pests into their territories have alarming figures that justify taking measures to eradicate and control these unwanted organisms . The intensification of crops, planting susceptible varieties associated with the favorable climatic conditions has favored the emergence pathogens of plant health problems that can affect the production and productivity of vegetables . The planting of seedlings without certification also contributes to the introduction of disease-producing regions .
Phytopathogenic bactéria of the genus Xanthomonas cause severe diseases on many crop plants, including economically important plants such as rice, wheat, banana, beans, tomato, Citrus spp., and cotton. Common disease found in nature include vascular wilt, cankers, leaf spots, fruit spots, leaf blight, and leaf straeck . Bacterium invades the xylem tissue, either through wounds or water pores, leading to systemic infection. According to the official newspaper of December 19, 2013, in the group of prokaryotes, bacteria Xanthomonas citri susp. citri (=X.axonopodis pv. citri ), citrus; X. campestris pv. viticola, vine; are on the list of quarentine pests present in Brazil. Species already X. campestris pv. cassavae , cassava; X.axonopodis pv. citri (Biotypes B and E), citrus; X. oryzae pv. oryzae , rice; X. oryzae pv. orizicola , rice; quarantine pests are absent.
The bacterium X. oryzae pv. oryzae , has been detected in Venezuela and Colombia, which makes the high possibility of entry into Brazil. Known as bacterial wilt and blight of rice, is the pathogen responsible for significant damage to rice in Asia can cause losses of up to 75% of production and affect grain quality . It is the most damaging disease of rice in South and Southeast Asia and Japan. In Japan, up to 400,000 ha per year may be affected, with losses of 20-30% and even 50%. In Africa, the losses of 2.7 to 4.1% in grain yield are found. In the Philippines, current losses are of the order of 22.5% on wet rice to 7.2% in dry seasons crops susceptible and 9.5 to 1.8%, respectively, in resistant crops . The leaves, seeds and virtually all other parts of the plant can be attacked by X. oryzae pv. oryzae , and the means of dispersal of this pathogen are: rice seeds (can survive 10 months at room temperature), machinery, rice straw infected, survival in soil (even for a few months), broadcast on irrigation water, flood (there is some limited survival days), leaves, seedlings (micro propagated plants), rods (above ground), wind and rain. The dispersion medium can be assets and liabilities .
The potential risk to Brazil can be regarded as a mean, since high temperatures and humidity can favor the proliferation of the disease; however, resistant varieties and seed treatments can decrease the pathogen not significant disease conditions.