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Burrowing nematode (Radopholus similis) abundance, distribution and agronomic impact on bananas in Kirinyaga County, Kenya
7-14.Views:97Burrowing nematodes (Radopholus spp.) are the most significant parasites of bananas (Musa spp.) world over. They feed on the root tissue of bananas resulting to toppling disease at the fruit bearing stage. This study assessed the impact of farmers selected agronomic practices that influenced distribution of burrowing nematodes. We also assessed the abundance of Radopholus spp. across four AEZs namely; UM 2, UM 3, LM 3 and LM 4 of Kirinyaga County, Kenya. Purposive sampling was done on April, 2024 targeting farmers that grew ‘dwarf Cavendish’ variety of bananas, those that grew an average of 25 banana stems and those whose farms that were 1km apart. A structured questionnaire was issued to ninety farmers to collect demographic information and to determine their awareness of burrowing nematodes and toppling disease. Soil and banana root samples were also collected to determine abundance and distribution of burrowing nematodes. Data from the questionnaire and samples was subjected to R -statistical software and analysed at p≤ 0.02. The study revealed that majority of banana farmers practised mixed cropping and were not aware of toppling disease associated with Radopholus spp. It also revealed that majority of banana farmers were male and of ˃ 50 years of age. The findings also showed Radopholus spp was rarely distributed in lower AEZs of LM 3 and LM 4 compared to Pratylenchus spp. which was pre- dominantly distributed in upper AEZs of UM 2 and UM 3 in both soil and root samples.
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Grapevine - and apple - replant disease in Hungary
29-33.Views:210Field experiment was conducted to study the replant problems of grapevine and apple. Plantings were in three different fields: on virgin soil, on apple replant soil and on vine replant soil. Each field was planted with 60 pieces of grafted vine (variety Bianca on rootstock Berl. X Rip. T.K. 5BB) and 60 pieces of grafted apple (variety Gloster on rootstock MM. 106). Fungicide (BUVICID K with 50% captan agent, 0.5 g/1 1 soil) and nematocide (VYDATE 10 G with 10% oxamil agent, 0.03 g/1 1 soil) treatments were used in the soil in order to identify the causal factor of the problem.
Biological soil test was conducted to test 17 soil samples of 11 wine districts and vine growing fields in plastic pots, under shading net. No root pieces were left in the soil. Two bud-cuttings of the Berl. X Rip. T 5C rootstock varieties were used as test plants. In each case, samples were taken from the vineyard and from the virgin soil. One fourth of the soil from the vineyard was left untreated and the other three part was treated with nematocide, fungicide or heat.
The results of the field experiment suggest that there was no problem growing grapevine after apple and apple after grapevine, but both species had been inhibited growing after itself. The fungicide and nematocide treatments did not succeed in determining the casual factor of the problem. Heat treatment of replant soil (in pot test) was useful in AS and VNS soils.
Results of biological soil test suggest, that grapevine replant problem do not occur in every vineyard. In fifty percent of soils, no significant differences between the treatments for shoot length, weight of cane, length, diameter and wood:ratio of the fourth internode were observed. In one case, difference was not found in any of the measured characters. However, fruiting bodies of Roesleria pallida (Pers.) Sacc. and the mycelium of Rosellinia necatrix Prill. were observed in this sample. In other samples, there was no significant difference between the treatments, but nematode and fungus infection appeared to be involved in increased shoot growth in nematocide and fungicide treated plants (mycelium of Rosellinia necatrix was detected). In other samples, the fungus infection caused significant difference between the virgin, untreated and fungicide treated soils and infection of Rosellinia necatrix was observed.
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Virus and virus-like diseases of grapevine in Hungary
25-36.Views:463Viruses and viroids are submicroscopic infectious particles which can cause disease symptoms on grapevine. These parasites are depending completely on the energy metabolism of the plant cell. To enter the host cell plant viruses depend on injuries or on transmission via invertebrates (insects, nematodes, etc.). Viruses are classified by many characters including particle morphology, host range and information content of the genome. At present about 70 viruses including 7 viroids infecting grapevine are known. In single or mixed infections they are potentially detrimental to the quality and quantity of grape production in any growing area of the world. Some viruses can cause severe economic damage in vineyards. In Hungary many important viruses and viroids have been detected in grape. This review summarises characteristics of viruses and the results of detection and characterization of virus and virus like diseases of grapevine in Hungary. The identification of the causal agent, its transmission, geographical distribution and the development of the diagnostic methods are also discussed.
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Grapevine and apple replant disease in Hungary
57-61.Views:260Field experiment was conducted to study the replant problems of grapevine and apple. Plantings were in three different fields: on virgin soil, on apple replant soil and on vine replant soil. Each field was planted with 60 pieces of grafted vine (variety Bianca on rootstock Berl. X Rip. T.K. 5BB) and 60 pieces of grafted apple (variety Gloster on rootstock MM. 106). Fungicide (BUVICID K with 50 % captan agent, 0.5 g/1 1 soil) and nematocide (VYDATE 10 G with 10 % oxamil agent, 0.03 g/1 I soil) treatments were used in the soil in order to identify the causal factor of the problem.
Biological soil test was conducted to test 17 soil samples of II wine districts and vine growing fields in plastic pots, under shading net. No root pieces were left in the soil. Two bud-cuttings of the Bed. X Rip. T 5C rootstock varieties were used as test plants. In each case, samples were taken from the vineyard and from the virgin soil. One fourth of the soil from the vineyard was left untreated and the other three part was treated with nematocide, fungicide or heat.
The results of the field experiment suggest that there was no problem growing grapevine after apple and apple after grapevine, but both species had been inhibited growing after itself. The fungicide and nematocide treatments did not succeed in determining the casual factor of the problem. Heat treatment of replant soil (in pot test) was useful in AS and VNS soils.
Results of biological soil test suggest, that grapevine replant problem do not occur in every vineyard. In fifty percent of soils, no significant differences between the treatments for shoot length, weight of cane, length, diameter and wood:ratio of the fourth internode were observed. In one case, difference was not found in any of the measured characters. However, fruiting bodies of Roesleria pallida (Pers.)Sacc. and the mycelium of Rosellinia necatrix Prill. were observed in this sample. In other samples, there was no significant difference between the treatments, but nematode and fungus infection appeared to be involved in increased shoot growth in nematocide and fungicide treated plants (mycelium of Rosellinia necatrix was detected). In other samples, the fungus infection caused significant difference between the virgin, untreated and fungicide treated soils and infection of Rosellinia necatrix was observed.
