Nematodes in potato and carrot crops cause millions of dollars in crop losses

By Leonardo Aquino, PhD in Phytotechnics from the Federal University of Viçosa (UFV) and is a professor in the areas of Plant Production, Soil Fertility and Plant Nutrition also at UFV

03.04.2018 | 20:59 (UTC -3)

Technology, climate and availability of natural resources are key factors in ensuring a good harvest. But, in addition, the farmer needs to be aware of diseases, weeds and pests. Nematodes have been one of the main causes of concern and headache for carrot and potato producers.

Widely disseminated in the main growing regions of these two crops - Southeast, Central-West and Chapada Diamantina (BA) - nematodes are organisms that attack plant roots and affect their absorption of water and nutrients. In Brazil, two are the main species found in these crops: root-knot nematodes and root lesion nematodes.

When we talk about crop losses, carrot losses are, on average, 20% - but some crops can be completely destroyed by nematodes - and 33% for potatoes. Monetarily speaking, losses can exceed R$ 10.000,00 per hectare, practically making the cultivation of both crops in these areas economically unfeasible.

Some factors are decisive for the proliferation and high incidence of nematodes in potato and carrot production areas, such as intensive soil use, lack of crop rotation and the use of varieties without resistance to nematodes. The main potato varieties grown commercially in Brazil, for example, are highly sensitive to nematodes, which harms good yield, production quality and consequently the profitability of the crop. When affected by the disease, the potato's growth is limited and becomes unattractive for sale on the market due to the formation of galls that damage the visual appearance of the tubers. In carrots, the main symptom is the deformation of the roots with forks or the formation of galls, which also strongly depreciate the commercial value of the product.

To manage nematodes, it is recommended that the farmer manages the agricultural system well, with crop rotation, choosing a planting area with no history of nematodes and resistant or tolerant plant varieties when available. Due to the difficulty in adopting the above practices for good nematode control, the producer can use chemical and/or biological nematicides.

*Leonardo Aquino is 

*Leonardo Aquino is 

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