Dazomet Research Articles

Comparative Efficacy of Different Approaches to Manage Meloidogyne Incognita onGreen Beans

Comparative Efficacy of Different Approaches to Manage Meloidogyne Incognita on Green Beans A greenhouse study was conducted to compare the relative efficacy of different approaches to manageMeloidogyne incognita on green beans. These approaches included: chemical (fumigant, nonfumigant, seed dressing, and seed dip), biological (the egg-parasitic fungus, Paecilomyces lilacinus, and the mycorrhyzal fungus Glomus sp.), physical (soil solarization), and cultural practices (chicken litter, and urea). In total, nine different control materials and methods of applications were compared. Two important parameters were considered: plant response (plant growth and root galling), and nematode reproduction (production of eggs and the reproduction factor Rf). Results showed that the organic fertilizer, chicken litter, has severely affected the growth or survival of the seedlings. Therefore, this treatment was removed from the evaluation test. All other treatments were found to be effective against the nematode, but with different levels of efficacy. The eight treatments decreased (38.9-99.8%) root galling, increased plant growth and suppressed nematode reproduction. Based on three important criteria, namely: gall index (GI), egg mass index (EMI), and reproduction factor (RF), the tested materials and methods were categorized into three groups according to their relative control efficacy under our test conditions. These three groups were: 1) the relatively high effective group (GI=1.0-1.4, Rf=0.07-0.01) included: the fumigant dazomet, the non-fumigant fenamiphos, soil solarization, and seed-dip with fenamiphos; 2) the relatively moderate effective group (GI=3.4-4.0, Rf=0.24-0.60) included: seed dressing with fenamiphos, and urea; and 3) the relatively less effective group (GI=5.0, Rf=32.2-37.2) included: Paecilomyces lilacinus and Glomus sp....

The Effects of Fungicide, Soil Fumigant, Bio-Organic Fertilizer and Their Combined Application on Chrysanthemum Fusarium Wilt Controlling, Soil Enzyme Activities and Microbial Properties.

Sustained monoculture often leads to a decline in soil quality, in particular to the build-up of pathogen populations, a problem that is conventionally addressed by the use of either fungicide and/or soil fumigation. This practice is no longer considered to be either environmentally sustainable or safe. While the application of organic fertilizer is seen as a means of combating declining soil fertility, it has also been suggested as providing some control over certain soil-borne plant pathogens. Here, a greenhouse comparison was made of the Fusarium wilt control efficacy of various treatments given to a soil in which chrysanthemum had been produced continuously for many years. The treatments comprised the fungicide carbendazim (MBC), the soil fumigant dazomet (DAZ), the incorporation of a Paenibacillus polymyxa SQR21 (P. polymyxa SQR21, fungal antagonist) enhanced bio-organic fertilizer (BOF), and applications of BOF combined with either MBC or DAZ. Data suggest that all the treatments evaluated show good control over Fusarium wilt. The MBC and DAZ treatments were effective in suppressing the disease, but led to significant decrease in urease activity and no enhancement of catalase activity in the rhizosphere soils. BOF including treatments showed significant enhancement in soil enzyme activities and microbial communities compared to the MBC and DAZ, evidenced by differences in bacterial/fungi (B/F) ratios, Shannon–Wiener indexes and urease, catalase and sucrase activities in the rhizosphere soil of chrysanthemum. Of all the treatments evaluated, DAZ/BOF application not only greatly suppressed Fusarium wilt and enhanced soil enzyme activities and microbial communities but also promoted the quality of chrysanthemum obviously. Our findings suggest that combined BOF with DAZ could more effectively control Fusarium wilt disease of chrysanthemum.

Dissipation kinetics of pre-plant pesticides in greenhouse-devoted soils

This work was conducted to study the distribution of methyl isothiocyanate (MITC) in greenhouse soils treated with the fumigant dazomet (DZ) from the formulated product “Basamid Granular®”, but also of 1,3-dichloropropene (1,3-D) and chloropicrin (CP) from the fumigant “Agrocelhone NE®”. In order to achieve this aim, several methods for the determination of fumigants residues in soils, but also pepper fruits were optimized and characterized. With independence of the soil depth, no residues of MITC, 1,3-D and CP above the detection limits were observed in soils covered with a polyethylene (PE) film (0.04mm thick) after 27, 13 and 8days of treatment, respectively. Liberation and dissipation curves of MITC in soil in presence of a PE film (0.04mm) used to limit volatilization losses were also obtained. According to the results, the rate of decomposition of DZ into MITC have a half-life of 3.7days in the surface horizon (5–10cm) of the soil while in the subsurface horizon (15–20cm), MITC formation rate is slightly slow (half-life of 3.2days). With respect to the dissipation process, half-lives lower than 1day were obtained for both depths (0.8 and 0.9 for the surface and the subsurface horizon, respectively). In the case of 1,3-D and CP in soil, the dissipation half-life of 1,3-D on soils was a bit higher than for CP (2days vs. 1). In addition, the presence of residues of the fumigants on green pepper fruits grown on the treated soils was not detected as expected.

Evaluation of chemical alternatives to methyl bromide in tomato crops in China

Tomato is a high-value cash crop in China that requires vigorous transplants free of pathogens. However, local tomato growers commonly face heavy root-knot nematode and weed infestations, especially while phasing out methyl bromide (MB). The soil fumigants chloropicrin (CP), 1,3-dichloropropene (1,3-D) and dazomet (DZ) were evaluated at several rates alone and in combination as alternatives to MB soil fumigation in tomato production. Field trials revealed that used alone, CP, 1,3-D and DZ were not comparable to MB in the reduction of Meloidogyne incognita, weeds or increase of tomato marketable yield. Only the combination of reduced rates of 1,3-D and CP which had excellent nematicide efficacy and good to moderate weed control, matched the efficacy of MB. The present data indicate that the combination of 1,3-D plus CP is an efficient MB alternative for managing nematodes and weeds in tomato crops and can be used in integrated pest management programs. To get a better weeds control efficacy, it is recommended to add herbicides to the two fumigants combination.

Interaction between nitrification, denitrification and nitrous oxide production in fumigated soils

Soil fumigation can increase mineral nitrogen due to the mineralization of soil microbial biomass killed during the fumigation, and as a result nitrous oxide (N2O) emission would increase. In addition, a fumigant's impact on soil nitrification and denitrification would also alter the dynamics of N2O production in fumigated soils. Laboratory incubation studies were conducted to quantify the dynamic changes in N2O production following various fumigant treatments, and to determine the interaction between nitrification, denitrification and N2O production in fumigated soils. Results showed a substantial increase in NH4+–N and dissolved amino acids (DAA) during 7 days fumigation at 1WAF (week after fumigation). The application of fumigants caused significant inhibition of nitrification. However the results relating to potential denitrification were quite different. The rates of potential denitrification in chloropicrin (Pic) and dazomet (DZ) treatments at 1WAF were 3.5 and 5.6 times higher than the untreated control. Potential denitrification was greatly stimulated after Pic and DZ fumigation. The N2O production rates in Pic and DZ fumigated soil were significantly higher than the untreated control at 1WAF in the tested soil type. The cumulative N2O emissions in Pic and DZ fumigated soil were also significantly higher than the untreated control, but there were no significant differences among 1,3-dichloropropene (1,3-D), dimethyl disulfide (DMDS) and untreated control. A positive relationship between N2O production and potential denitrification (PDN) was observed (r = 0.951, P < 0.01). Pic and DZ are both nitrogenous compounds. The breakdown products of Pic and DZ would be available for microbial-aided denitrification reactions as nitrogen sources leading to N2O production, indicating that Pic and DZ degradation stimulated denitrification activity responsible for soil N2O production.

Evaluation of the combination of 1,3‐dichloropropene and dazomet as an efficient alternative to methyl bromide for cucumber production in China

The combination of 1,3-dichloropropene (1,3-D) and dazomet (DZ) offers a potential alternative to methyl bromide (MB) for soil disinfection. MB is scheduled to be withdrawn from routine use by 2015 in developing countries. Combination treatments of 1,3-D + DZ were evaluated in a laboratory study and in two commercial cucumber fields. Laboratory studies found that nearly all of the tested combinations of 1,3-D and DZ displayed positive synergistic activity on root-knot nematodes (Meloidogyne spp.), two major soilborne fungi (Fusarium spp. and Phytophthora spp.) and the seeds of two major weed species (Digitaria sanguinalis and Abutilon theophrasti). Field trials revealed that the combination of 1,3-D and DZ (at 10 + 25 g m(-2) ) successfully suppressed Meloidogyne spp. root galling, sharply reduced Fusarium spp. and Phytophthora spp. and maintained high cucumber yields. The combination treatment of 1,3-D + DZ was more effective than 1,3-D or DZ alone and provided results similar to methyl bromide with respect to pest control, plant mortality, plant height, yield and income. All of the treatments were significantly better than the non-treated control. The results indicate that the tested combination of 1,3-D and DZ offers an efficient alternative to methyl bromide for cucumber production.

Effects of olive processing waste, chicken manure and Dazomet on weeds with or without soil solarisation

Three non-chemical weed control alternatives (chicken manure (10 t ha-1), olive processing waste (OPW) (30 t ha-1), and solarisation (6-7 weeks at > 40.9 - 47.1oC at a 15 cm soil) were applied to greenhouse grown tomatoes alone and in combination and were compared with a soil fumigant (dazomet) for the ability to control weeds. Both dazomet (485 kg a.i. ha-1) and solarisation provided excellent control of common purslane, slender amaranth and bristly foxtail. Excellent weed control was also achieved with a half dose of dazomet (242.5 kg a.i. ha-1) plus 21 days of solarisation. OPW provided moderate control of these weeds, but chicken manure did not. OPW and chicken manure applied with solarisation provided 100% control of common purslane, slender amaranth and bristly foxtail, but did not significantly improve control compared to solarisation alone. OPW plus a short-duration of solarisation may provide weed control that is comparable to dazomet in greenhouse grown tomatoes. Key words: Chicken manure, olive processing waste, solarisation, dazomet, weed control, tomatoes.

ALTERNATIVES TO METHYL BROMIDE FOR STRAWBERRY NURSERY PRODUCTION IN SPAIN

The Spanish Methyl Bromide (MB) Alternatives Project (INIA) has carried out experiments over nine-years in Castilla-Leon, Spain, for strawberry nurseries. During the years 1998-2006, more than 25 soil fumigant treatments (i.e., 1,3-dichloropropene+chloropicrin (1,3D:CP), dazomet (DAZ), metam sodium (MS), metam potassium (MK), dimethyl disulphide (DMDS), ethanedinitrile (EDN), propylene oxide (PO), sodium tetrathiocarbamate (ENZ), sodium azide (SEP), methyl iodide (MI), furfural (FUR), etc.) were applied during March/April in two locations. Planting of mother-plants, cv. 'Camarosa', was carried out in May and runner plants were harvested during October. CP alone, 1,3D:CP and DAZ compared well with MB for control of soilborne fungi. All the fumigants reduced the soil fungal population, but only MB:CP and DAZ caused a clear change in their fungal composition. Results suggest that while some chemical alternatives had similar behaviour to MB:CP in regard to weed control, all alternative compounds evaluated to date are inferior to MB due to inconsistent nursery yields.

CHEMICAL ALTERNATIVES TO METHYL BROMIDE FOR STRAWBERRY IN THE AREA OF HUELVA (SPAIN): 2002-2007 RESULTS

The Spanish Methyl Bromide (MB) Alternatives Project (INIA) has carried out experiments over ten-years in Huelva for strawberry production. More than 20 soil fumigant treatments have been evaluated on cv. 'Camarosa'. The last series has been carried out in two locations of Eastern coastal Huelva (Moguer and Palos de la Fra.) from 2002-2003 until now. Treatments: MB + chloropicrin, 1,3-dichloropropene + chloropicrin (1,3D:CP), chloropicrin (CP) alone, metam sodium (MS), dimethyl disulphide (DMDS), ethanedinitrile (EDN), propylene oxide (PO), sodium tetrathiocarbamate (ENZ), methyl iodide + chloropicrin (MI), essential oils (EO), were shank-applied, or drip-irrigated such as sodium azide (SEP), furfural (FUR) under mulched (VIF film) pre-formed beds, or incorporated into the soil: dazomet (DAZ) and calcium cyanamide (CC). Treatments were applied in September and cultivation cycle was between October and the end of May every year. Black root rot complex and nematodes Meloidogyne hapla and Pratylenchus penetrans appear as the main phytosanitary problems related to soil. Our results supported feasible alternatives to MB with 1,3D:CP, CP alone or DMDS plus CP (DMDS:CP). In coastal Huelva, significant amounts of alternative fumigants have been applied to the strawberry crop since 2005, mainly 1,3D:CP, CP alone, DAZ:1,3D and MS. This activity has allowed 100% MB replacement rates in 2007. However some concerns remain due to the implementing of the Directive 91/414/EEC.

Combined application of dazomet and Trichoderma asperellum as an efficient alternative to methyl bromide in controlling the soil-borne disease complex of bell pepper

Bell pepper ( Capsicum annuum) is an important greenhouse crop in central Europe. However, due to its monoculture cultivation soil-borne pathogens, especially Verticillium dahliae, are a significant yield-limiting factor. Apart from treatment with methyl bromide (MB) phytopathogens can be controlled by several alternative soil treatments. However, a universal control agent such as methyl bromide does not exist and there is crop specificity with respect to efficient treatments. Thus, the efficacy of chemical (dazomet), biological ( Trichoderma asperellum) and combination of both treatments in the control of soil-borne pathogens of bell pepper in comparison with MB was examined. In 3 consecutive years six demonstration trials were conducted on commercial farms in Poland. In five of the six trials, the application of MB resulted in the best control of Verticillium wilt. However, there were no differences between the AUDPC values of MB and dazomet (DZ) alone or DZ combined with T. asperellum B35. Among tested alternatives, the most consistent effect on the yield, as well as on control of the root rot disease complex and Verticillium wilt, was observed for treatment with DZ in combination with Trichoderma asperellum. The average increase in yield induced by this treatment (40.1%) was similar to that of MB (41.4%). There was a correlation ( r = 0.790) between Verticillium wilt disease severity and root rot symptom scores at the end of the vegetation season. Verticillium wilt reduced fruit yield to a larger extent than the root rot associated with a complex of pathogenic soil-borne fungi ( Colletotrichum coccodes, Fusarium spp.). Dazomet, combined with T. asperellum, provided the highest net marginal return and a higher return on investment than MB. The efficacy of T. asperellum applied alone was too variable (coefficient of variation 76%) to be accepted by the pepper growers.

Accelerated degradation of metam-sodium and dazomet in soil: characterization and consequences for pathogen control

Metam-sodium (MS) and dazomet (DAZ) are soil fumigants that generate methyl-isothiocyanate (MITC) in soil. The latter effectively controls soilborne plant pathogens. Recently, we have found that repeated applications of MS yield less effective pathogen control . Soil samples collected from 12 field sites in Israel without (nonhistory) or with (history) previous applications of MS or DAZ were tested for MITC generation and dissipation. Accelerated MITC degradation in history soils, as reflected by a sharp reduction in the concentration×time ( C×T) values and half-lives of MITC, was evident in most of the tested history soils. Exposure to MS and DAZ in those soils resulted in a significant reduction in Verticillium dahliae, Sclerotium rolfsii and Fusarium oxysporum f. sp. radicis-lycopersici mortality compared to exposure in nonhistory soils. The chemical and biological assays were well correlated. This is the first report of accelerated degradation of MITC resulting from repeated applications of DAZ. MITC was rapidly degraded in soils which had been previously treated with either MS or DAZ, indicating induced cross-accelerated degradation with both fumigants. In two field soils, accelerated degradation of MITC capacity was still evident for 18 to 30 months after treatment. This study suggests that accelerated degradation of MITC is a likely cause of the poor pathogen control observed in commercial potato and peanut fields upon repeated application of the fumigants MS and DAZ, and emphasizes the need for rational use of pesticides to maintain their efficacy.