scholarly journals Reaction of weeds, found in vegetable production areas, to root-knot nematodes Meloidogyne incognita and M. enterolobii

2019 ◽  
Vol 37 (4) ◽  
pp. 445-450
Author(s):  
Jadir B Pinheiro ◽  
Giovani Olegario da Silva ◽  
Danielle Biscaia ◽  
Amanda G Macedo ◽  
Núbia Maria Correia

ABSTRACT Root-knot nematodes cause great damage to vegetable crops in Brazil, besides having a large range of host plants, such as weeds. Weeds can maintain the inoculums or even favor the multiplication of these nematodes. In this study we evaluated the reaction of selected weed species, present in a vegetable production area, to root-knot nematodes Meloidogyne incognita and M. enterolobii. The trials were conducted in a greenhouse at Embrapa Hortaliças, Brasília-DF, in a completely randomized design with six replicates. Fifteen weed species were evaluated for M. incognita race 1, and 16 weed species were evaluated for M. enterolobii. Two tomato cultivars were evaluated as resistance and susceptibility standards. Gall index (IG), egg mass index (IMO), number of eggs per gram of roots (eggs/g roots) and reproduction factor (FR) were evaluated. M. enterolobii survives and multiplies more easily in weeds collected in vegetable production areas than M. incognita race 1 and, the great majority of weed species evaluated in this study are hosts of both nematode species. Only the species Urena lobata, Sonchus oleraceus, Euphorbia heterophylla, Melampodium perfoliatum and Tagetes sp. were immune to M. incognita race 1. All evaluated species are either hosts or favor the multiplication of M. enterolobii. The species which are the most susceptible to M. incognita race 1, and therefore require greater control of crops infected by this nematode are Ipomoea nil, I. triloba and Eleusine indica, and for M. enterolobii are I. nil, Solanum americanum, Hyptis suaveolens, Portulaca oleracea, I. triloba and Euphorbia heterophylla.

2021 ◽  
Vol 9 (11) ◽  
pp. 2268
Author(s):  
Xiaoyu Mei ◽  
Xin Wang ◽  
Guohong Li

Plant parasitic nematodes, especially parasitic root-knot nematodes, are one of the most destructive plant pathogens worldwide. The control of plant root-knot nematodes is extremely challenging. Duddingtonia flagrans is a type of nematode-trapping fungi (NTF), which produces three-dimensional adhesive networks to trap nematodes. In this study, the pathogenicity and volatile organic compounds (VOCs) of the NTF D. flagrans against the plant root-knot nematode, Meloidogyne incognita, were investigated. The predatory process of D. flagrans trapping M. incognita was observed using scanning electron microscopy. Gas chromatography-mass spectrometry analysis of the VOCs from D. flagrans led to the identification of 52 metabolites, of which 11 main compounds were tested individually for their activity against M. incognita. Three compounds, cyclohexanamine, cyclohexanone, and cyclohexanol, were toxic to M. incognita. Furthermore, these three VOCs inhibited egg hatching of M. incognita. Cyclohexanamine showed the highest nematicidal activity, which can cause 97.93% mortality of M. incognita at 8.71 µM within 12 h. The number of hatched juveniles per egg mass after 3 days was just 8.44 when treated with 26.14 µM cyclohexanamine. This study is the first to demonstrate the nematicidal activity of VOCs produced by D. flagrans against M. incognita, which indicates that D. flagrans has the potential to biocontrol plant root-knot nematodes.


2020 ◽  
Vol 38 (2) ◽  
pp. 126-133
Author(s):  
Paula Andrea O Carmona ◽  
Jadir B Pinheiro ◽  
Geovani Bernardo Amaro ◽  
Giovani Olegario da Silva ◽  
José Ricardo Peixoto ◽  
...  

ABSTRACT One of the main obstacles for food production in many developing countries, as in Brazil, is the damage caused by root-knot nematodes, mainly those belonging to the genus Meloidogyne. This study aimed to assess the resistance levels of 44 sweet potato genotypes to M. javanica, M. incognita race 1 and M. enterolobii. These researches were carried out in 2014, under greenhouse conditions in Brasília-DF, Brazil. A completely randomized design with six replicates of one plant/plot/treatment was used. We determined the gall index (GI) and egg mass index (EMI) in the root system of each plant, the number of eggs and juveniles per gram of root with galls and the nematode reproduction factor. M. javanica was less aggressive and reproduced in only 9.09% of the evaluated genotypes; M. incognita race 1 was intermediate (47.73%); whereas M. enterolobii was more aggressive, with a population increase in 79.55% of the genotypes. The genotypes CNPH 1200, CNPH 1219, CNPH 1292, CNPH 1392, CNPH 60 and ‘Coquinho’ were the most resistant to the three species and can be used in breeding programs for multiple resistance to root-knot nematodes.


1998 ◽  
Vol 8 (3) ◽  
pp. 423-427 ◽  
Author(s):  
Daniel J. Cantliffe ◽  
Stephen R. Kostewicz

For many years, the former Vegetable Crops Department, now the Horticultural Sciences Department, at the University of Florida offered a vegetable crop industries course. This one-credit course is offered each year as a 3- to 5-day field trip into vegetable production areas of Florida in the spring semester during spring break. The intent of the course is to give undergraduate students an extensive on-site evaluation of the application of scientific principles learned in lectures related to Florida's commercial vegetable industry. A new, innovative approach to structuring this course was initiated recently wherein only alumni of the department interacted with the students on all phases of commercial vegetable agriculture in Florida. These alumni had obtained degrees at the BS, MS, or PhD level and represented many professional backgrounds related to producing, handling, and marketing vegetables. Students were exposed to real-life situations and were encouraged to discuss and seek employment opportunities during the farm visitations. Student expenses were offset by donations from the Florida vegetable industry.


Plant Disease ◽  
2007 ◽  
Vol 91 (11) ◽  
pp. 1514-1514 ◽  
Author(s):  
I. Pajovic ◽  
S. Širca ◽  
B. Geric Stare ◽  
G. Urek

Root-knot nematodes (Meloidogyne spp.) are common pathogens that parasitize vegetables and other crops and cause significant yield reductions worldwide. In the early spring of 2006, severe plant stunting, chlorosis, and extensive root galling were observed on cucumber plants grown in a greenhouse on Zeta plain, Zetska ravnica, Montenegro. In the summer and autumn of 2006, infected roots of different crops were collected from greenhouses and vegetable production fields of Zeta plain, which represents the largest area of Montenegro's vegetable production. Several vegetable crops were found to be infected with root-knot nematodes, including tomato (Lycopersicon esculentum Mill.), squash (Cucurbita pepo L.), cucumber (Cucumis sativus L.), pepper (Capsicum annuum L.), and lettuce (Lactuca sativa L.). Symptoms on these crops included root-galling, leaf chlorosis, and stunting. Heavily infected tomato plants growing in two greenhouses also displayed early flower and fruit drop. Nematode species were determined based on characterization of (i) female perineal patterns, (ii) male and second-stage juvenile morphology (2,3), and (iii) esterase and malate dehydrogenase phenotypes (PhastSystem; Amersham Biosciences, Piscataway, NJ) from young egg-laying females (1). The most prevalent species was M. incognita, which was isolated from the roots of tomatoes, peppers, cucumbers, and lettuce from nine locations. Meloidogyne arenaria was detected at three locations from the roots of tomatoes grown in a greenhouse and the weeds Convolvulus arvensis L. and Solanum nigrum L., which were growing in open fields in separate locations. M. javanica was found on tomato and squash in the same field where M. arenaria was also found on S. nigrum. M. javanica was isolated from tomato and squash. In this study, we found high incidence of Meloidogyne spp. in intensive vegetable production areas of Montenegro. The implementation of an effective integrated pest management program is essential for future use of infested areas. To our knowledge, this is the first report of M. arenaria, M. incognita, and M. javanica from Montenegro. References: (1) P. R. Esbenshade and A. C. Triantaphyllou. J. Nematol. 17:6, 1985. (2) S. B. Jepson. Identification of Root-Knot Nematodes. CAB International, Wallingford, UK, 1987. (3) G. Karssen. The Plant-Parasitic Nematode Genus Meloidogyne Göldi, 1892 (Tylenchida) in Europe. Koninklijke Brill NV, Leiden, the Netherlands, 2002.


2020 ◽  
Vol 38 (3) ◽  
pp. 239-245
Author(s):  
Jadir B Pinheiro ◽  
Giovani Olegário da Silva ◽  
Danielle Biscaia ◽  
Amanda G Macedo ◽  
Fábio A Suinaga

ABSTRACT Genetic resistance is the most suitable mechanism to control root-knot nematodes in lettuce. However, information about the resistance levels of currently used lettuce cultivars is scarce in the literature. Thus, the objective of this research was to characterize lettuce cultivars for resistance to root-knot nematodes Meloidogyne incognita (Mi) and M. javanica (Mj), aiming the identification of resistance sources for breeding, and to transfer information to the productive sector. We evaluated 97 lettuce genotypes in tree trials. In the first one (preliminary assessment), 92 lettuce genotypes were inoculated simultaneously with M. incognita race 1 and M. javanica species, 17 days after sowing. The gall index (GI) was evaluated 41 days after inoculation. In the second trial nine genotypes, selected from the first trial, were evaluated; and in the third trial, two new cultivars from Embrapa were evaluated. In the last two trials, the nematode species were inoculated separately, and the egg mass index (EMI), number of eggs per gram of roots (NEGR) and reproduction factor (RF) were also evaluated. In both trials, the lettuce cultivars Salinas 88 and Grand Rapids were used as resistant controls, as well as cultivar Irene as the susceptible control. The data were submitted to analysis of variance and treatments means grouping by Scott-Knott´s test. The crisp leaf cultivars presented a higher degree of resistance to the root-knot nematodes compared to the smooth leaf type cultivars. Cultivars Vera and Amanda present resistance to M. incognita, and Vanda to M. javanica. ‘Salinas 88’ present resistance mainly to M. javanica; while cultivar Mônica and the Embrapa cultivars BRS Leila and BRS Mediterrânea are resistant to both nematode species.


2002 ◽  
Vol 20 (2) ◽  
pp. 101-103
Author(s):  
Jerry T. Walker

Abstract Eight herb species were inoculated with two common species of root-knot nematode and grown for 2 months in a greenhouse. Root systems were examined for galls and egg mass production. All herb species were susceptible but developed fewer galls and had lower gall indices than Rutgers tomato. Burnet, chives, valerian and winter savory had few galls or low gall indices. Eggs were produced on all. Chamomile had a high gall index. Chicory, parsley, and sorrel had intermediate indices. Herbs were equally susceptible to the southern (Meloidogyne incognita) and peanut root-knot nematodes (M. arenaria), particularly at the highest inoculum densities. Mean dry weights of inoculated herbs were not always significantly less than the non-inoculated plants, suggesting that some herbs may be tolerant to root-knot nematodes.


HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 832C-832
Author(s):  
Richard Smith* ◽  
Krishna Subbarao ◽  
Steve Koike ◽  
Steve Fennimore ◽  
Adelia Barber

Growers in the Salinas Valley are not able to rotate away from lettuce to other crops such as broccoli, as often as would be desirable due to economic pressures such as high land rents and lower economic returns for rotational crops. This aggravates problems with key soilborne diseases such as Sclerotinia minor, Lettuce Drop. Mustard cover crops (Brassica juncea and Sinapis alba) are short-season alternative rotational crops that are being examined in the Salinas Valley for the potential that they have to reduce soilborne disease and weeds. Mustard cover crops have been have been shown to suppress various soilborne diseases and there are also indications that they can provide limited control of some weed species. However, no studies have shown the impact of mustard cover crops under field conditions on S. minor. In 2003 we conducted preliminary studies on the incidence of S. minor and weeds following mustard cover crops in comparison with a bare control or an area cover cropped to Merced Rye (Secale cereale). There was a slight, but significant reduction of S. minor infection in one of three trials following mustard cover crops. Mustard cover crops also reduced emergence of Shepherd's Purse (Capsella bursa-pastoris) and Common Purslane (Portulaca oleracea) these studies. Mustard cover crops have distinct nitrogen cycling characteristics. They were shown to reach a peak of release of nitrogen in 30 to 50 days following incorporation into the soil. The levels of nitrogen that are released by mustard cover crops were substantial and could be useful in nitrogen fertilizer programs for subsequent vegetable crops.


HortScience ◽  
2015 ◽  
Vol 50 (1) ◽  
pp. 9-12 ◽  
Author(s):  
Judy A. Thies ◽  
Sharon Buckner ◽  
Matthew Horry ◽  
Richard Hassell ◽  
Amnon Levi

Southern root-knot nematodes (Meloidogyne incognita) are an important re-emerging pest of watermelon in the United States and worldwide. The re-emergence of root-knot nematodes (RKNs) in watermelon and other cucurbits is largely the result of the intensive cultivation of vegetable crops on limited agricultural lands coupled with the loss of methyl bromide for pre-plant soil fumigation, which has been the primary method for control of RKNs and many soilborne diseases of cucurbits and other vegetable crops for several decades. One alternative for managing RKN in watermelon is the use of resistant rootstocks for grafted watermelon. We have developed several RKN-resistant Citrullus lanatus var. citroides lines (designated RKVL for Root-Knot Vegetable Laboratory), which have shown promise as rootstocks for grafted watermelon. In 2011 and 2012, we demonstrated that F1 hybrids derived from our selected RKVL lines exhibited resistance to RKN that was equal to or greater than that of the parental RKVL lines when grown in fields highly infested with M. incognita. In 2011, although significant differences were not observed among rootstocks, the F1 hybrids produced slightly higher yields compared with the selected parental lines. Among the selected parental lines, RKVL 318 produced high yields in both years. In 2011, three of four RKVL parental lines and all four of their F1 hybrids produced greater (P < 0.05) fruit yields than self-grafted ‘Tri-X 313’, ‘Emphasis’ bottle gourd, and ‘Strong Tosa’ squash hybrid. In 2012, three RKVL F1 hybrid lines produced higher yields than the selected parents. Overall, these F1 hybrids were vigorous and should provide useful genetic material for selection and development of robust RKN-resistant C. lanatus var. citroides rootstock lines.


HortScience ◽  
2010 ◽  
Vol 45 (2) ◽  
pp. 320-322 ◽  
Author(s):  
Sindynara Ferreira ◽  
Luiz Antonio A. Gomes ◽  
Wilson Roberto Maluf ◽  
Vicente Paulo Campos ◽  
José Luiz S. de Carvalho Filho ◽  
...  

This study assessed the reaction of dry bean and snap bean cultivars to infection by Meloidogyne incognita (races 1, 3) and by Meloidogyne javanica, two species of root-knot nematodes. Three independent experiments were done, one for each species or race of Meloidogyne, using randomized complete block designs with four replications (plots) and four plants per plot. A plot with the susceptible tomato cultivar Santa Clara was used in each block to determine the efficiency of the inoculum and to calculate the reproduction rate for each of the genotypes assessed. The bean cultivars Aporé and Talismã were highly resistant to Meloidogyne javanica, slightly resistant to Meloidogyne incognita race 1, and moderately resistant and slightly resistant, respectively, to Meloidogyne incognita race 3. The snap bean cultivars Macarrão Atibaia and Macarrão Preferido were slightly resistant to Meloidogyne javanica and moderately resistant and susceptible, respectively, to Meloidogyne incognita race 1. The reactions of the latter cultivars against Meloidogyne incognita race 3 were very resistant and slightly resistant, respectively. The results of these experiments showed that the dry bean cultivars Aporé and Ouro Negro and the snap bean cultivar Macarrão Atibaia have potential to be used in breeding programs for a broader spectrum of root-knot nematode resistances.


Sign in / Sign up

Export Citation Format

Share Document