THE INTERACTION OF PLANT, PATHOGEN, AND SCAPTOCORIS TALPA CHAMP

1961 ◽  
Vol 39 (3) ◽  
pp. 695-703 ◽  
Author(s):  
M. I. Timonin

The effects of the odoriferous volatile matter produced by Scaptocoris talpa Champ on the activity of Fusarium oxysporum f. cubense (E.F.S.) Sny. and Hans., F. oxysporum f. lycopersici (Sacc.) Sny. and Hans., and Meloidogyne incognita in soil, and its phytotoxicity to tomato seedlings, were investigated.The results obtained indicated that 50–75 insects per pot protected tomato seedlings (Bonny Best) and banana plants (Gros Michel) from attack by their respective fungus pathogens and one insect per 2 grams of soil protected tomato seedlings from attack by root-knot nematode.The apparatus especially constructed to study the phytotoxicity of odoriferous volatile matter to tomato seedlings and its effect on microbial population of the soil was described. By means of this apparatus it was found that 6 days of a weak flow of a mixture of air and volatile matter produced by 350–400 insects was not phytotoxic to six tomato seedlings. Furthermore, it was also found that volatile matter produced by 800 insects, under the same conditions, was not toxic to one tomato seedling. Under similar conditions the non-phytotoxic concentration of volatile matter produced by 350–400 insects reduced the density of F. oxysporum f. cubense population in soil samples containing 25 and 15% (w/w) of moisture by 61.20 and 45.78% respectively.It was also demonstrated that one insect per 2 grams of soil infested with the root-knot nematode during 16 hours' incubation produced a nematocidal concentration of volatile matter.The possibility of selective toxicity of volatile odoriferous matter to various bacteria is also discussed.

Plant Disease ◽  
2017 ◽  
Vol 101 (6) ◽  
pp. 948-956 ◽  
Author(s):  
Alois A. Bell ◽  
Robert C. Kemerait ◽  
Carlos S. Ortiz ◽  
Sandria Prom ◽  
Jose Quintana ◽  
...  

Locally severe outbreaks of Fusarium wilt of cotton (Gossypium spp.) in South Georgia raised concerns about the genotypes of the causal pathogen, Fusarium oxysporum f. sp. vasinfectum. Vegetative complementation tests and DNA sequence analysis were used to determine genetic diversity among 492 F. oxysporum f. sp. vasinfectum isolates obtained from 107 wilted plants collected from seven fields in five counties. Eight vegetative complementation groups (VCG) were found, with VCG 01117B and VCG 01121 occurring in 66% of the infected plants. The newly recognized VCG 01121 was the major VCG in Berrien County, the center of the outbreaks. All eight VCG resulted in significant increases in the percentages of wilted leaves (27 to 53%) and significant reductions in leaf weight (40 to 67%) and shoot weight (33 to 60%) after being stem punctured into Gossypium hirsutum ‘Rowden’. They caused little or no significant reductions in shoot weight and height or increases in foliar symptoms and vascular browning in a soil-infestation assay. Soil infestation with Meloidogyne incognita race 3 (root-knot nematode) alone also failed to cause significant disease. When coinoculated with M. incognita race 3, all VCG caused moderate to severe wilt. Therefore, the VCG identified in this study belong to the vascular-competent pathotype, and should pose similar threats to cotton cultivars in the presence of the root-knot nematode. Use of nematode-resistant cultivars, therefore, is probably the best approach to control the disease in Georgia.


2012 ◽  
Vol 36 (4) ◽  
pp. 685-695 ◽  
Author(s):  
MI Faruk ◽  
ML Rahman ◽  
MMM Mustafa ◽  
IR J Coosemans

Dimethyl disulfide (DMDS), the natural biopesticide extracted from Allium spp., was evaluated against root-knot nematode (Meloidogyne incognita) of tomato (Lycopersicon esculentum L.) in greenhouse pot culture. All concentrations of DMDS viz. 30 ml, 60 ml, and 80 ml and Aldicarb @ 2g per square meter of soil were effective against root-knot disease under both wet and dry conditions of soil. Nematode incidence was reduced drastically by higher dose of DMDS and Aldicarb @ 2g but did not accelerate vegetative growth of tomato plant especially when tomato seedlings were transplanted immediately after soil treatment. Low concentration of DMDS (30 ml per square meter of soil) was found appropriate for controlling root-knot nematode of tomato, accelerating saprophytic nematode population in soil and also enhancing vegetative growth of tomato plant under dry condition of soil.   DOI: http://dx.doi.org/10.3329/bjar.v36i4.11759   Bangladesh J. Agril. Res. 36(4): 685-695, December 2011  


2012 ◽  
Vol 48 (No. 4) ◽  
pp. 170-178 ◽  
Author(s):  
M.S. Khalil ◽  
M.E.I. Badawy

The nematicidal activity of four molecular weights (2.27 &times; 10<sup>5</sup>, 3.60 &times; 10<sup>5</sup>, 5.97 &times; 10<sup>5</sup>, and 9.47 &times; 10<sup>5</sup> g/mol) of a biopolymer chitosan was assayed against the root-knot nematode, Meloidogyne incognita, in vitro and in pot experiments. In laboratory assays, the nematode mortality was significantly influenced by exposure times and chitosan molecular weight. Low molecular weight chitosan (2.27 &times; 10<sup>5</sup> g/mol) was the most effective in killing the nematode with EC<sub>50</sub> of 283.47 and 124.90 mg/l after 24 and 48 h of treatment, respectively. In a greenhouse bioassay, all the compounds mixed in soil at one- and five-fold concentrations of the LC<sub>50</sub> value significantly reduced population, egg mass, and root galling of tomato seedlings compared with the untreated control. In general, the nematicidal activity of these compounds was increased dramatically with a decrease in the molecular weight. The results suggest that the chitosan at low molecular weight may serve as a natural nematicide


Plant Disease ◽  
2018 ◽  
Vol 102 (9) ◽  
pp. 1820-1827 ◽  
Author(s):  
Anthony P. Keinath ◽  
Paula A. Agudelo

Interspecific hybrid squash (Cucurbita maxima × C. moschata ‘Strong Tosa’) and bottle gourd (Lagenaria siceraria ‘Macis’) rootstocks are resistant to Fusarium oxysporum f. sp. niveum but susceptible to Meloidogyne incognita (Southern root-knot nematode). Coinfection of Early Prolific Straightneck summer squash (C. pepo) with root-knot nematode and F. oxysporum f. sp. niveum has been reported to increase susceptibility to Fusarium wilt. The objectives of this study were to determine whether such an interaction occurred between M. incognita and F. oxysporum f. sp. niveum races 1 and 2 on Strong Tosa, Macis, and watermelon cultivars Fascination (resistant to race 1) and Tri-X 313 (susceptible to both races). Hosts were inoculated in a greenhouse with one of four pathogen treatments: F. oxysporum f. sp. niveum, M. incognita, both pathogens, or neither pathogen. Galling was present on ≥10% of the root systems of 90% of the plants inoculated with M. incognita. Bottle gourd had less galling than interspecific hybrid squash. Plants not inoculated with F. oxysporum f. sp. niveum did not wilt. Four weeks after inoculation, incidence and severity of Fusarium wilt and recovery of F. oxysporum did not differ for any hosts inoculated with F. oxysporum f. sp. niveum alone and F. oxysporum f. sp. niveum plus M. incognita (host–treatment interactions not significant). In general, Early Prolific Straightneck grouped with the F. oxysporum f. sp. niveum-resistant rootstocks when inoculated with F. oxysporum f. sp. niveum race 2 and with the susceptible watermelon when inoculated with race 1, regardless of inoculation with M. incognita. Recovery of F. oxysporum from stems of inoculated watermelon was greater than recovery from the other three hosts, regardless of nematode inoculation. In conclusion, our experiments do not support the hypothesis that resistance to F. oxysporum f. sp. niveum in cucurbit rootstocks or resistant watermelon cultivars would be compromised when M. incognita infects the roots.


Nematology ◽  
2007 ◽  
Vol 9 (6) ◽  
pp. 771-776 ◽  
Author(s):  
Richard Sikora ◽  
Abd El-Fattah Dababat

AbstractThe non-pathogenic endophytic Fusarium oxysporum strain 162 (FO162) has been selected for its capacity to reduce root-knot nematode galling on tomato. The objectives of this study were to investigate the influence of this fungus on invasion of tomato roots by Meloidogyne incognita. The number of M. incognita that invaded roots of plants treated with FO162 was significantly lower (reductions of 36.0-55.9%) than in the non-treated controls in linked twin-pot chambers. The results demonstrated that colonisation of the roots by FO162 affects the number of M. incognita that penetrate the roots. The results of a choice test in the absence of a plant indicated that the tomato root exudates collected from plants colonised by FO162 are either less attractive or they exude substances that have repellent activity toward M. incognita juveniles.


1970 ◽  
Vol 36 (3) ◽  
pp. 477-486 ◽  
Author(s):  
MI Faruk ◽  
MI Rahman ◽  
MR Ali ◽  
MM Rahman ◽  
MMH Mustafa

A field experiment was conducted in two consecutive years to find out the efficacy of poultry refuse (PR), mustard oilcake (MOC), and Furadan 5G for the management of root-knot disease (Meloidogyne incognita) of tomato. Soil was treated with PR @ 3 and 5 t/ha, MOC @ 0.3 and 0.6 t/ha 3 weeks before transplanting and Furadan 5G @ 40 kg/ha on the day of transplanting of tomato seedlings. PR @ 3 t/ha and MOC @0.3 t/ha were applied alone and also mixed with Furadan 5G @ 20 kg/ha. The soils of the experimental plots were inoculated with chopped severely galled (M incognita) roots of tomato at the time of treatment application. In both the years, considerable reduction in rootknot disease and increase in plant growth and fruit yield were achieved with different treatments with two organic materials applied alone or mixed with Furadan 5G. The most effective treatment was PR @ 3 t/ha + Furadan 5G @ 20 kg/ha followed by PR alone @ 5 t/ha. Efficacy of PR @ 3 t/ha and MOC @ 0.6 1/ha were also appreciable. In first year and second year, gall index values were 6.50 and 6.27 under control, respectively. The severity was reduced to 2.27-4.00 in first year and 1.73-4.07 in second year due to application of the four treatments. On the other hand, fruit yield under control was 50.9 t/ha at first year and 47.6 t/ha in second year. The highly effective four treatments increased fruit yield to 71.1-82.5 t/ha in first year and 60.8-82.0 t/ha in second year. The fruit yield of tomato was directly and linearly correlated with gall indices in tomato gall. Based on findings of the study PR @ 3 t/ha + Furadan @20 kg/ha and PR alone @ 5 t/ha were noted as effective treatment to manage root-knot disease of tomato. Keywords: Poultry refuse; mustard oilcake; Furadan; Meloidogjyne incognita; tomato. DOI: http://dx.doi.org/10.3329/bjar.v36i3.9275 BJAR 2011; 36(3): 477-486


Plant Disease ◽  
2019 ◽  
Vol 103 (6) ◽  
pp. 1383-1390 ◽  
Author(s):  
Anthony P. Keinath ◽  
W. Patrick Wechter ◽  
William B. Rutter ◽  
Paula A. Agudelo

Interspecific hybrid squash (Cucurbita maxima × Cucurbita moschata) rootstocks used to graft watermelon (Citrullus lanatus var. lanatus) are resistant to Fusarium oxysporum f. sp. niveum, the fungus that causes Fusarium wilt of watermelon, but they are susceptible to Meloidogyne incognita, the southern root knot nematode. A new citron (Citrullus amarus) rootstock cultivar Carolina Strongback is resistant to F. oxysporum f. sp. niveum and M. incognita. The objective of this study was to determine if an interaction between M. incognita and F. oxysporum f. sp. niveum race 2 occurred on grafted or nongrafted triploid watermelon susceptible to F. oxysporum f. sp. niveum race 2. In 2016 and 2018, plants of nongrafted cultivar Fascination and Fascination grafted onto Carolina Strongback and interspecific hybrid squash cultivar Carnivor were inoculated or not inoculated with M. incognita before transplanting into field plots infested or not infested with F. oxysporum f. sp. niveum race 2. Incidence of Fusarium wilt and area under the disease progress curve did not differ when hosts were inoculated with F. oxysporum f. sp. niveum alone or F. oxysporum f. sp. niveum and M. incognita together. Fusarium wilt was greater on nongrafted watermelon (78% mean incidence) than on both grafted rootstocks and lower on Carnivor (1% incidence) than on Carolina Strongback (12% incidence; P ≤ 0.01). Plants not inoculated with F. oxysporum f. sp. niveum did not wilt. At the end of the season, Carnivor had a greater percentage of the root system galled than the other two hosts, whereas galling did not differ on Fascination and Carolina Strongback. F. oxysporum f. sp. niveum reduced marketable weight of nongrafted Fascination with and without coinoculation with M. incognita. M. incognita reduced marketable weight of Fascination grafted onto Carnivor compared with noninoculated, nongrafted Fascination. In conclusion, cucurbit rootstocks that are susceptible and resistant to M. incognita retain resistance to F. oxysporum f. sp. niveum when they are coinfected with M. incognita.


Sign in / Sign up

Export Citation Format

Share Document