Considering that the root-knot nematode Meloidogyne exigua has caused great yield losses to coffee production in Brazil, this study aimed to determine whether the penetration and the reproduction events of this nematode on the roots of plants from two coffee cultivars with different levels of basal resistance to this nematode could be affected by silicon (Si). Coffee plants from the cultivars Catuaí and IAPAR 59, which are susceptible and resistant, respectively, to M. exigua, were grown in pots containing Si-deficient soil that was amended with either calcium silicate (+Si) or calcium carbonate (–Si). The Si concentration on the root tissue significantly increased by 159 and 97% for the +Si plants from the cultivars Catuaí and IAPAR 59, respectively, compared to the –Si plants of these cultivars. The population of M. exigua, the number of galls and the number of eggs were significantly reduced on the roots of the +Si plants of the cultivars Catuaí and IAPAR 59 compared to the –Si plants of these cultivars. It was concluded that the development and reproduction events of M. exigua were negatively impacted on the roots of coffee plants supplied with Si.

The combined application of organic fertilizer with mineral fertilizer increases the yield of sugarcane. It promotes greater residual beneficial effect in relation to the use of each fertilizer in isolation. The organo-mineral fertilizer presents gradual solubilization during the period of development of the crop. Thus, when compared to soluble mineral sources, its agronomic efficiency may be higher. Various types of organic material can be used, such as pig manure, poultry litter, filter cake and sewage sludge, among others. Organic matter is responsible for maintaining and increasing soil porosity to improve water retention and to ensure soil microbial balance. The efficiency in nourishing the sugarcane crops or availing the available nutrients is maximized. The use of biostimulants in world agriculture has achieved significant growth rates in the last decades. Hormone compounds ensure the sustainability of crops. It can be an alternative to improve plant nutrition, support of abiotic and biotic stresses. They act in the activation and potentiation of the metabolism of the cells, give more vigor to the immune system and help to enable the physiological processes in the different stages of development. The emergence and use of new technologies is the way to achieve greater productivity, sustainability and profitability.

Em Meloidogyne exigua, um dos principais patógenos do cafeeiro no Brasil, já foram observadas variabilidade bioquímica, molecular, morfológica e fisiológica. No entanto, a expressão desta variabilidade quanto à virulência a genótipos de cafeeiro não é bem conhecida. O objetivo deste trabalho foi estudar o efeito de populações de M. exigua, as quais exibiam diferentes fenótipos de esterase e preferências por hospedeiros, em 25 genótipos de cafeeiro, com o propósito de se conhecer melhor a interação de biótipos desse nematóide com o gênero Coffea. Seis mudas de cafeeiro por tratamento foram inoculadas no estádio de 3 a 4 pares de folhas definitivas com 5.000 ovos de cada população de M. exigua por planta. O número de galhas e ovos por sistema radicular e a biomassa da matéria fresca das raízes foram avaliados aos 110 dias após a inoculação. Em função da reação frente às populações de M. exigua, os genótipos de Coffea spp. foram classificados em 14 suscetíveis, 5 imunes e 6 segregantes. Estes últimos segregaram de maneira diferenciada conforme a população do patógeno, evidenciando a existência de variabilidade intraespecífica em relação à virulência ao cafeeiro. Assim, o uso de diferentes populações desse patógeno, que englobem essa variabilidade é fundamental no desenvolvimento de cultivares resistentes.

Problems with root-knot nematodes, caused by genus Meloidogyne, can be controlled through the introduction of resistance genes in commercial varieties of tomatoes. However, plants of the hybrid ‘Heinz 9992’ for industrial processing, carrying the Mi gene, were reported with their roots severely infected in experimental cultivation in Goiás State of Brazil with symptoms typical of galls caused by Meloidogyne spp. After dissecting the galls present in the root samples, the females of the nematodes were removed and afterwards, performed the analysis of the perineal pattern and the biochemical characterization by electrophoresis of isoenzymes, besides the pathogenicity test. The pathogen analyzed was identified as Meloidogyne incognita. The pathogenicity test confirmed the supplanting resistance of the tomato hybrid with the Mi gene by this virulent population of M. incognita.