scholarly journals Outbreak of Leaf Miner and Root Knot Nematode-wilt Disease Complex on Cucumber- A New Threat under Protected Cultivation in District Gurugram Haryana

2021 ◽  
Author(s):  
Neetu Singh ◽  
Manoj Kumar Jat ◽  
Bharat Singh
Keyword(s):  
Fusarium Oxysporum ◽  
Meloidogyne Javanica ◽  
Leaf Miner ◽  
Dilution Method ◽  
Cucumber Plant ◽  
Morphological Identification ◽  
Root Knot Nematode ◽  
Isolation And Identification ◽  
Fungal Isolation ◽  
Protected Cultivation

Background: Crops are constantly exposed to various organisms feeding on above and belowground parts under both natural and protected conditions. As compare to open field, the warm and humid conditions besides abundant food under protected conditions provide a stable environment for pest and disease development either alone or together. However, the natural enemies i.e. predators, parasites and parasitoids that keep pests and pathogens under control naturally are not present under protected environment. For these possible reasons, pest and pathogens often develop in polyhouses more rapidly and with greater severity than open fields.Methods: A polyhouses study was carried out during last two months June and July in Patudi block of district Gurugram, Haryana where growers are facing failure of cucumber crop due to outbreak of insect pests- disease complexes on common host cucumber. On closer observation, symptoms of leaf miner as mining lines on leaves and galls or knots on roots the symptoms of root knot nematode were encountered. Further detailed lab based investigation were carried out on affected cucumber plant and root samples with the objective for isolation and identification of both pests and pathogens. For leaf miner morphological identification, the pattern of the feeding tunnel and the layer of the leaf being mined by leaf miner is one of the diagnostic key are useful to determine the species and instar of the leaf miner. However, Sieving and decantation method for nematode isolation and soil dilution method for fungal isolation were carried out and followed by morphological identification. Result: Two types of herbivore i.e. leaf miner Liriomyza trifolii (Burgess) on aerial parts while root knot nematode, Meloidogyne javanica and wilt causing fungus Fusarium oxysporum f. sp. cucumerinum were identified on the basis of their specific morphological characters. Galled roots of cucumber were affected by combined attack of vascular bundle feeders, root knot nematode, Meloidogyne javanica and wilt causing fungus Fusarium oxysporum f. sp. cucumerinum identified in both soil and root samples. This kind of field report on cucumber crop under protected cultivation has not been reported so far in which three types of pest and pathogens are feeding on the same host. Poly houses or ‘hot spots’ are selected for detailed investigation especially for growers’ friendly management in addition to interaction studies of upper and lower ground herbivores on cucumber crops. 

scholarly journals Isolation and Identification of Fungi Associated with Solanum lycopersicum L. (Tomato) Leaves in Alapoti, Ogun State Nigeria

2021 ◽  
pp. 1-11
Author(s):  
Tolulope S. Ewekeye ◽  
Adegboyega C. Odebode
Keyword(s):  
Fusarium Oxysporum ◽  
Solanum Lycopersicum ◽  
Control Measures ◽  
Limiting Factors ◽  
Infected Leaf ◽  
Pathogenicity Test ◽  
Isolation And Identification ◽  
Fungal Isolation ◽  
Solanum Lycopersicum L ◽  
Ogun State

Solanum lycopersicum (tomato) is an essential vegetable crop consumed worldwide. Major limiting factors in its production include fungal foliar diseases. Therefore, this work was aimed at investigating the fungi associated with diseased tomato leaves. Infected leaf samples (3 per plant, 30 plants per farm) of Kerewa variety were randomly collected at the expression of disease symptoms from 3 farms in Alapoti, Ogun State. Samples were cultured on Potato Dextrose Agar for fungal isolation. All isolates were identified using morphological and microscopic features. Pathogenicity test was conducted based on Koch’s postulates. Identified symptoms on the leaf samples were chlorosis, leaf spot and wilt. Fungi isolated from diseased tomato leaves were Aspergillus aculeatus, A. niger, A. tamarii, A. ustus, A. versicolor, Epicoccum nigrum, Fusarium oxysporum, Phialophora melinii, Phomopsis sp. and Trichodema asperellum. Fusarium oxysporum and Phomopsis sp. were found to be the causal organisms of the leaf infections. Due to the effect of the leaf diseases of the overall productivity of tomato, it is important to put in place adequate control measures to mitigate the effect of the diseases.

scholarly journals Mineral composition of beetroot treated with potential elicitors and inoculated with Meloidogyne javanica

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Paula Juliana Grotto Débia ◽  
Beatriz Cervejeira Bolanho ◽  
Claudia Regina Dias-Arieira
Keyword(s):  
Population Density ◽  
Mineral Composition ◽  
Integrated Management ◽  
Meloidogyne Javanica ◽  
Nematode Population ◽  
Root Knot Nematode ◽  
Cu Content ◽  
Manganese Zinc ◽  
Nematode Population Density ◽  
Elicitor Treatments

Abstract Background The root-knot nematode Meloidogyne javanica can infect beetroots, causing extensive damage to this food crop. As chemical and genetic control tactics have shown limited efficacy, new strategies are needed to improve the integrated management of this parasite. This study assessed the influence of potential defence elicitors and M. javanica infection on the mineral composition of beetroot. Plants were treated with acibenzolar-S-methyl (ASM), citrus biomass, or a mannanoligosaccharide-based product (MOS) and inoculated with 1000 eggs and second-stage juveniles of M. javanica. At 60 days after inoculation, beetroot plants were harvested and evaluated for nematode population density, vegetative growth, and mineral content. Results All potential elicitors reduced nematode population density in beetroots (p ≤ 0.10) and improved the vegetative parameters of inoculated plants (p ≤ 0.05), except shoot fresh weight. Some minerals were found to be negatively affected by treatments, particularly calcium, whose levels were consistently lower in treated plants. On the other hand, M. javanica inoculation increased magnesium, iron, manganese, zinc, and copper contents in beetroots. However, the latter mineral (Cu content) of inoculated plants was positively influenced by MOS and ASM. Conclusion Potential elicitor treatments did not improve the mineral composition of beetroot, but were effective in reducing nematode population density. Plants inoculated with M. javanica had higher mineral levels. However, gall formation decreases the commercial value of the crop and might render it unsuitable for commercialisation. M. javanica-infected beetroots may be used for nutrient extraction or sold to food processing industries.

scholarly journals Genetic Diversity, Virulence, and Meloidogyne incognita Interactions of Fusarium oxysporum Isolates Causing Cotton Wilt in Georgia

Plant Disease ◽  
2017 ◽  
Vol 101 (6) ◽  
pp. 948-956 ◽  
Author(s):  
Alois A. Bell ◽  
Robert C. Kemerait ◽  
Carlos S. Ortiz ◽  
Sandria Prom ◽  
Jose Quintana ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Fusarium Oxysporum ◽  
Meloidogyne Incognita ◽  
Root Knot Nematode ◽  
Soil Infestation ◽  
Causal Pathogen ◽  
Complementation Groups ◽  
Shoot Weight ◽  
Cotton Wilt ◽  
Significant Disease

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.

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