Soil chemical treatments for the control of Fusarium wilt of carnation in Spain

VII International Symposium on Chemical and Non-Chemical Soil and Substrate DisinfestationTo study the effectiveness of soil chemical disinfestation treatments in the control of Fusarium wilt of carnation (FWC), two experiments were carried out during 2006-08 and 2008-09, respectively, in a naturally infested greenhouse planted with susceptible carnation ‘Master’. Na-azide (65 ml m-2), 1,3-dichloropropene (1,3-D)+chloropicrin (CP) (40+10 ml m-2), and dimethyl disulphide DMDS+CP (30+10 ml m-2) were applied in early August 2006 (Experiment 1). In early July 2008 (Experiment 2) the two former treatments and DMDS, combined or not with soil solarisation (SS), respectively at the rates of 53 and 80 ml m-2, were tested. An untreated control was included in both experiments. In Exp. 1, viability of F. oxysporum f. sp. dianthi (Fod) was nil at 30 cm depth in plots treated with DMDS+CP and low residual viability was observed at 15 cm depth, while it was much reduced with 1,3-D+CP at both depths. In Exp. 2, both fumigants eradicated Fod at 15 cm depth, except DMDS applied without SS. In Exp. 1, FW incidence of dead plants reached 100% in the control plots after 13 months from planting whereas in the other treatments it was under 18%. At the end of this experiment, 7 months later, FWC incidence ranged 14-44% for 1,3-D+CP and Na-azide, respectively. Nine months were required in Exp. 2 for control plots to reach 90% FWC incidence, whereas it was 44% in Na-azide-treated plots and the rest of treatments were under 9%. This suggests a consistency in the efficacy of 1,3-D+CP and DMDS. Total yields (number of stems m-2) in experiment 1 were increased to 412% that of the control in 1,3-D+CP treated plots, 248% for Na-azide and 371% in the case of DMDS+CP treatment; yields in experiment 2 were 292% and 236% for the first two, and 283% for DMDS (53 ml m-2) + SS whereas, in DMDS (80 ml m-2), 333% that of the control was reached. DMDS and 1,3-D+CP treated plots showed a significantly lower percentage of the lower commercial quality stems than the control, thus improving qualitative yield.Peer Reviewe

Effects of soil amendment with poultry manure on carnation Fusarium wilt in greenhouses in southwest Spain

In a search for alternatives to methyl bromide for controlling carnation vascular wilt caused by Fusarium oxysporum f. sp. dianthi (Fod), poultry manure plus soil solarization was studied in soil under greenhouse conditions in four 2-year experiments. These were conducted in naturally infested soil to compare the effects of this treatment with soil solarization alone and methyl bromide. Soil treatments were performed during June 2000 for Experiment 1, from July to mid-August 2002 for Experiment 2, from late July to late August 2006 for Experiment 3 and from late May to late June 2008 for Experiment 4. Additionally, a treatment with commercial poultry manure pellet plus soil solarization was included in the two latter experiments. Poultry manure caused reductions of Fod viability in soil samples at depths of 15 and 30. cm, ranging respectively from 93 to 100% and 89 to 100% for Experiments 1, 2 and 3. Carnations planted in plots treated either with poultry manure, methyl bromide or soil solarization had lower final disease incidences, smaller areas under their disease progress curves and higher yields in comparison with untreated plots in Experiments 2, 3 and 4. In Experiment 1, soil solarization was performed under suboptimal conditions, and it provided disease levels and yields similar to those of the untreated control plots. Nevertheless, under the same conditions, previous amendment of Fod-infested soil with poultry manure increased disease control over soil solarization alone, improved carnation yield and quality and also increased plant vigor, thus providing a satisfactory alternative to methyl bromide. The application of organic amendment to the same plot before every crop cycle is recommended to ensure continuous disease control, but the rates of application could be reduced to half for the third and fourth crop cycles, thereby reducing undesirable environmental effects. © 2011 Elsevier Ltd.The authors thank the financial support of the Spanish Ministries of Agriculture and Environment to R&D Projects SC97-130-C7-6, OT03-006-C7-5 and AT06-006-C7-3, and to the Junta de Andalucía for financing the Research Project AGR2313.Peer reviewe

Control de fusariosis del clavel en invernadero mediante aportaciones de gallinaza en suelo

Comunicación presentada en las V Jornadas Ibéricas de Horticultura Ornamental, celebradas en Faro (Portugal) del 13 al 15 de octubre de 2011.Peer Reviewe

Use of poultry manure combined with Soil Solarization as a control method for meloidogyne incognita in carnation

The effectiveness of a combination of soil solarization and poultry manure (raw or pelletized) amendments for the control of root-knot nematode (Meloidogyne incognita) was tested in carnation (Dianthus caryophyllus) crops grown in in-ground beds under plastic-covered greenhouse conditions in southern Spain. Our trials demonstrated that soil solarization alone did not provide sufficient control of root-knot nematode, because the carnation growing season in this region only partly coincides with the most effective period for solarization, resulting in an insufficient duration of treatment during a key period for effectiveness. Chemical fumigation with 1,3-dichloropropene + chloropicrin prior to planting was effective in reducing nematode population densities in soil. Its effects spanned 9 months after planting, resulting in acceptable crop yields. In comparison, the combination of soil solarization and raw or pelletized poultry manure was slightly less effective than chemical fumigation for control of this pathogen but crop yields after 9 months were similar. However, the higher root gall indices observed after 9 months, in comparison with chemically fumigated plots, indicated the need for a reapplication of the organic manure treatment at the start of each successive growing season. © 2012 The American Phytopathological Society.This work was financially supported by INIA (Instituto Nacional de Investi- gación y Tecnología Agraria y Alimentaria) through projects AT06-006-C7-3, CC09-074 and FEDER funding from the European Union.Peer Reviewe

Soil solarization and sustainable agriculture

Pesticide treatments provide an effective control of soilborne pests in vegetable and fruit crops, but their toxicity to animals and people and residual toxicity in plants and soil, and high cost make their use hazardous and economically expensive. Moreover, actual environmental legislation is imposing severe restrictions on the use or the total withdrawal of most soil-applied pesticides. Therefore, an increasing emphasis has been placed on the use of nonchemical or pesticide-reduced control methods. Soil solarization is a nonpesticidal technique which kills a wide range of soil pathogens, nematodes, and weed seeds and seedlings through the high soil temperatures raised by placing plastic sheets on moist soil during periods of high ambient temperature. Direct thermal inactivation of target organisms was found to be the most important mechanism of solarization biocidal effect, contributed also by a heat-induced release of toxic volatile compounds and a shift of soil microflora to microorganisms antagonist of plant pathogens. Soil temperature and moisture are critical variables in solarization thermal effect, though the role of plastic film is also fundamental for the solarizing process, as it should increase soil temperature by allowing the passage of solar radiation while reducing energetic radiative and convective losses. Best solarizing properties were shown by low-density or vynilacetate- coextruded polyethylene formulations, but a wide range of plastic materials were documented as also suitable to soil solarization. Solar heating was normally reported to improve soil structure and increase soil content of soluble nutrients, particularly dissolved organic matter, inorganic nitrogen forms, and available cations, and shift composition and richness of soil microbial communities, with a marked increase of plant growth beneficial, plant pathogen antagonistic or root quick recolonizer microorganisms. As a consequence of these effects, soil solarization was largely documented to increase plant growth and crop yield and quality along more than two crop cycles. Most important fungal plant pathogenic species were found strongly suppressed by the solarizing treatment, as several studies documented an almost complete eradication of economically relevant pathogens, such as Fusarium spp., Phytophthora spp., Pythium spp., Sclerotium spp., Verticillium spp., and their related diseases in many vegetable and fruit crops and in different experimental conditions. Beneficial effects on fungal pathogens were stated to commonly last for about two growing seasons and also longer. Soil solarization demonstrated to be effective for the control of bacterial diseases caused by Agrobacterium spp., Clavibacter michiganensis and Erwinia amylovora, but failed to reduce incidence of tomato diseases caused by Pseudomonas solanacearum. Solarization was generally found less effective on phytoparasitic nematodes than on other organisms, due to their quicker soil recolonization compared to fungal pathogens and weeds, but field and greenhouse studies documented consistant reductions of root-knot severity and population densities of root-knot nematodes, Meloidogyne spp., as well as a satisfactory control of cyst-nematode species, such as Globodera rostochiensis and Heterodera carotae, and bulb nematode Ditylenchus dipsaci. Weeds were variously affected by solar heating, as annual species were generally found almost completely suppressed and perennial species more difficult to control, due to the occurrence deep propagules not exposed to lethal temperature. Residual effect of solarization on weeds was found much more pronounced than on nematodes and most fungal pathogens. Soil solarization may be perfect fit for all situations in which use of pesticides is restricted or completely banned, such as in organic production, or in farms located next to urban areas, or specialty crops with few labeled pesticides. Advantages of solarization also include economic convenience, as demonstrated by many comparative benefit/cost analyses, ease of use by growers, adaptability to many cropping systems, and a full integration with other control tools, which makes this technique perfectly compatible with principles of integrated pest management required by sustainable agriculture