br

Diseases and pests are among the main limiting factors for the vine (Vitis spp.). Among these, damage caused by phytonematodes can occur from the implantation of seedlings in the orchard to adult plants, consequently influencing the quality of the fruits, production and costs incurred. Annual losses of 12,5% ​​caused by nematodes in grapevines are estimated, however, direct losses can reach 20%, characterizing these pathogens as one of the limiting factors of productivity. The root-knot nematode (Meloidogyne spp.), the lesion nematode (Pratylenchus spp.), the dagger nematode (Xipinema spp.) and the citrus nematode (Tylenchulus semipenetrans), considered the most harmful to the vine worldwide.

The gender Meloidogyne is considered the main group of phytopathogenic nematodes of economic importance to grapevines. Worldwide, the most frequent and damage-related species are: Meloidogyne javanica, M. unexplained, M. arenaria and occasionally M.hapla. In Brazil, the occurrence of these four species is recorded, in addition to M. morocciensis. However, M. javanica e M. unexplained are the most frequent in culture. Plants seriously affected by root-knot nematodes present symptoms in the aerial part, such as reduced vigor, reduced-sized leaves and different shades, and, on the roots, with small thickenings called galls. In cases of severe infections, these root galls coalesce, forming more elongated thickenings (Figure 1), and plant productivity may decrease with each cycle. In Brazil, there are few reports of damage caused by root-knot nematodes in the crop, probably due to the use of rootstocks resistant to several species of the pathogen, such as, for example, Palsen and SO4 (Table 1). However, depending on the material used and the nematode species(s), damage may occur, according to a recent report of the presence of M. unexplained in a vine orchard in the state of Pernambuco. In this location, the affected plants showed symptoms of reduced vigor, yellowed leaves and sparse foliage, in addition to roots with many galls in the midst of jack bean cultivation (Canavalia ensiformis), also attacked by the nematode (Figure 1).

Approximately 20 years ago, the presence of M. ethiopica associated with kiwi plants in Serra Gaúcha; This species is responsible for serious damage to vines and kiwi in Chile, where it has been associated with low productivity in affected orchards and plant death. Despite M. ethiopica has been detected and related to the decline of kiwi plants in southern Brazil, it has not yet been recorded in vines in the country.

In practical terms, it is not always easy to visually diagnose root-knot nematodes, as, very often, the symptoms can be confused with the presence of galls caused by phylloxera (Daktulospharia vitifoliae), an aphid widely disseminated in Serra Gaúcha and which attacks the leaves and roots of the vine, causing thickening of the roots, a symptom very similar to that caused by Meloidogyne sp. (Figure 2).

The citrus nematode (T. semipenetrans) has already been reported on vines in the states of São Paulo, Minas Gerais and Rio Grande do Sul. In the São Paulo region of Jundiaí, damage caused by this species has already been reported on vines of the Niágara Rosa cultivar, grafted onto the Traviú rootstock, which presented symptoms of stunting and death of shoots, reducing flowering and, consequently, production. Damage resulting from lesion nematode attack (Pratylenchus spp.) are more severe than those caused by root-knot nematodes; and once the orchard declines, the vine no longer responds to cultural practices. Although it has already been reported in vine orchards in Minas Gerais and Rio Grande do Sul, in Brazil, there are no records of symptoms or economic impact of this nematode on the crop.

Various species of Xipinema are associated with vine cultivation. Despite causing direct damage to the attacked plants, occasionally, the greatest damage is due to the fact that some species of this genus are vectors of important viruses, such as X.index, which can transmit the vine decay virus (Grapevine fanleaf virus, GFLV), one of the main crop viruses in Europe and the USA. In Brazil, GFLV is among the four most common viruses in grapevines, however, its incidence is low. It is speculated that the low frequency of this disease is mainly due to the use of virus-free seedlings and the absence of the nematode in the country.

In a recent study on nematofauna associated with grapevine decline, an association of the ringed nematode was observed (Mesocriconema sp.) to 100% of the samples from orchards in Bento Gonçalves and Farroupilha, in Rio Grande do Sul, with the presence of plant death. Although no correlation between symptoms and population levels of this nematode was found, future studies deserve to be carried out to establish its pathogenicity in culture.

The main measures for managing nematodes in grapevines are the use of resistant rootstocks (Table 1) and planting pathogen-free seedlings in places where these pests do not occur, or are present in low populations. If the presence of phytoparasitic species harmful to vines is detected in the area, annual species that are not hosts to the nematode can be planted, in rotation, for a period of at least two years before establishing the orchard; or the introduction of other resistant fruit plants into the infested area. However, it is necessary to know which nematode species(s) are occurring in the area, since the resistance or susceptibility of crops varies depending on the plant species and/or cultivars used. In this sense, it is recommended to consult a technician specialized in the area.

In the case of disinfestation of nurseries, nematicides can be used pre-planting. However, these products do not eradicate the pathogen from the area, and subsequent reinfestations may occur. Furthermore, there is no commercial product registered with the Ministry of Agriculture, Livestock and Supply (Mapa) for the vine, which makes its application unfeasible. in the affected area. Considering the occurrence of M. ethiopica, in addition to other important phytosanitary problems for grapevines in Brazil, management practices involving mainly the acquisition of healthy material and/or resistant to other species can contribute effectively, avoiding or reducing the impact of these pests on grape production.

Table 1 - Reaction of grapevine cultivars and rootstocks (Vitis sp.) most used in Brazil Meloidogyne spp., Xiphinema index, Tylenchulus semipenetrans, Pratylenchus spp. and phylloxera (Daktulospharia vitifoliae)

Rootstocks/ Cultivars	Meloidogyne spp.				Xipinema index	Tylenchulus semipenetrans	Pratylenchus spp.	Daktulospharia vitifoliae
	M. javanica	M. arenaria	M. unexplained	Meloidogyne ethiopica
SO4	Resistant1	Resistant1	Resistant1	Resistant8	Susceptible1	Resistant1	Resistant1	Resistant6
420A	Resistant2	Resistant2/ Susceptible5	Resistant2/ Susceptible 5	Susceptible8				Resistant6
Palsen 1103	Resistant3	Resistant3	Susceptible5		Susceptible3		Resistant3	Resistant6
RR 101-14	Resistant4	Resistant4	Resistant4					Resistant6
Rupestris du Lot	Susceptible1	Susceptible1,5	Susceptible1,5			Susceptible1	Resistant1	Resistant6
IAC 766		Resistant5	Susceptible5					Resistant6
IAC 313		Resistant5	Resistant5	Resistant8
IAC 572		Resistant5	Resistant5
106-8 Traviú		Susceptible5	Susceptible5
Pink Niagara		Susceptible5	Susceptible5	Highly Susceptible7				Highly susceptible6

Rootstocks/

Cultivars

Meloidogyne spp.

Xipinema

index

Tylenchulus semipenetrans

Pratylenchus

spp.

Daktulospharia vitifoliae

M. javanica

M. arenaria

M. unexplained

Meloidogyne ethiopica

SO4

Resistant¹

Resistant¹

Resistant¹

Resistant⁸

Susceptible¹

Resistant¹

Resistant¹

Resistant⁶

420A

Resistant²

Resistant²/

Susceptible⁵

Resistant²/

Susceptible ⁵

Susceptible⁸

Resistant⁶

Palsen 1103

Resistant³

Resistant³

Susceptible⁵

Susceptible³

Resistant³

Resistant⁶

RR 101-14

Resistant⁴

Resistant⁴

Resistant⁴

Resistant⁶

Rupestris du Lot

Susceptible¹

Susceptible^1,5

Susceptible^1,5

Susceptible¹

Resistant¹

Resistant⁶

IAC 766

Resistant⁵

Susceptible⁵

Resistant⁶

IAC 313

Resistant⁵

Resistant⁵

Resistant⁸

IAC 572

Resistant⁵

Resistant⁵

106-8 Traviú

Susceptible⁵

Susceptible⁵

Pink Niagara

Susceptible⁵

Susceptible⁵

Highly

Susceptible⁷

Highly susceptible⁶

Source: Adapted from Campos et al (2002)

1 - Pinochet et al (1992); 2 - Nogueira (1984); 3 - Goumas & Tzortzakakis (1988); 4 - Uriz (1986); 5 - Somavilla et al (2012); 6 - Button et al (2003); 7 - Ram et al (2003); 8 - Somavilla (personal communication)

Photo: C.B. Gomes

Figure 1 - Festival grapevine plants, grafted onto 'IAC 766-Campinas', showing smaller foliage (a) and root galls caused by M. unexplained (B); and jack bean plants infected by the nematode in the same orchard (c)

Photos: M. Botton and J. Grannett

Figure 2 - Grapevine roots and leaves parasitized by phylloxera (D. vitifoliae)