Effect of time between soil infestation with Pochonia chlamidosporia and planting on the efficacy of the fungus in managing Meloidogyne javanica

The fungus Pochonia chlamydosporia acts on populations of the root-knot nematode by parasitizing their eggs before they hatch, preventing the release of juveniles. In this study, the effect of the time at which the fungus is applied to soil infested with the nematode, before transplanting tomato and lettuce seedlings, was evaluated. The reduction of symptoms and the nematode population in the host plant was also evaluated, as well as the fluctuation of the fungus population during the studied period. The seedlings were transplanted at 0, 5, 10, 15 or 20 days after incorporation of the inocula of the fungus and the nematode into the soil. The population of P. chlamydosporia, without the presence of plants, increased and reached its maximum 10 days after its incorporation into the soil. At the end of the experiments, the number of colony forming units (CFU) of the fungus in the soil remained high enough to act on the next cycle of crops. For both cultures, the greatest effect on reducing the number of galls and eggs of Meloidogyne javanica was obtained by increasing the contact time of the fungus with the nematode in the soil before transplanting seedlings. In the second run, for both cultures, there was an increase in shoot weight with increasing of incubation time before the transplantation of seedlings.     

Soil suppressiveness to Meloidogyne javanica as induced by organic amendments and solarization in greenhouse crops

We assessed soil suppressiveness against root-knot caused by Meloidogyne javanica, following the incorporation of crop residues (organic amendments [OA]) and soil solarization, under agricultural conditions. Two field experiments were established in tomato greenhouses and a third in a nethouse for growing Antirrhinums, all infested with M. javanica. Dried residues of wild rocket (WR) were incorporated into the soil and then it was solarized to moderate temperatures to partially effect the pathogen population. Root galling on the roots of the successive tomato crop was significantly reduced to different levels by WR, solarization or their combination, in two experiments. Solarization, alone or combined with WR amendment, significantly reduced root knot incidence in the roots of snapdragon, but suppression of root galling in the roots of snapdragon in the following crop was not evident. We further assessed the potential of various herb residues, incorporated in small plots, and solarization to induce soil suppressiveness against root-knot caused by M. javanica. Amending soil with residues of WR, tarragon, peppermint or sage induced soil suppressiveness to root knot even when M. javanica was introduced into the soil after the termination of the treatment, and reduced the galling index in subsequently grown tomato plants, compared with non-amended soil. Our findings further validate the potential role of OA and solarization in inducing soil suppressiveness, which contributes to sustainable management of soilborne pathogens.     

Growth promotion and induction of resistance in tomato plant against Xanthomonas euvesicatoria and Alternaria solani by Trichoderma spp.

In tomato crop, the induction of resistance emerges as an important alternative for achieving the reduction of chemicals in disease control. This study aimed to evaluate the ability of 28 Trichoderma isolates to promote the growth of tomato seedlings and to induce systemic resistance (ISR) against Xanthomonas euvesicatoria and Alternaria solani, the causal agents of bacterial spot and early blight, respectively. Twelve isolates promoted the increase of plant dry matter mass (DMM) above 100%, showing the great potential of these strains. All isolates were able to colonize the root system of tomato plants. The plant growth-promoting isolates were further evaluated for potential elicitation of ISR. Treatment of the soil with all Trichoderma isolates provided protection in tomato plants from 24.13 to 95.94% against X. euvesicatoria and 30.69 to 95.23% against A. solani. The most efficient isolates in reducing the severity of bacterial spot and early blight were the isolates IB 28/07, IB 30/07, IB 37/01 and IB 28/07, IB 30/07 and IB 42/03, respectively. The effect of different time intervals between Trichoderma application and inoculation with pathogens in inducing systemic resistance in tomato plants was evaluated for the isolate IB 28/07. IB 28/07 conferred protection against both diseases at all time intervals, confirming the ability of the isolate to reduce the severity of these diseases up to 21 days after treatment of tomato plants. In vitro assays revealed that all isolates of Trichoderma were able to degrade cellulose. Only the isolate IB 34/08 showed antagonistic activity against X. euvesicatoria and none caused reduction in the in vitro mycelial growth of A. solani. Trichoderma isolates were identified at species level by DNA sequencing.     

Interface of the environment and occurrence of Botrytis cinerea in pre-symptomatic tomato crops

Botrytis cinerea (Grey mould) is a necrotrophic fungus infecting over 230 plant species worldwide. It can cause major pre- and post-harvest diseases of many agronomic and horticultural crops. Botrytis cinerea causes annual economic losses of 10–100 billion US dollars worldwide and instability in the food supply (Jin and Wu, 2015). Grey mould losses, either at the farm gate or later in the food chain, could be reduced with improved knowledge of inoculum availability during production. In this paper, we report on the ability to monitor Botrytis spore concentration in glasshouse tomato production ahead of symptom development on plants. Using a light weight and portable air sampler (microtitre immunospore trap) it was possible to quantify inoculum availability within hours. Also, this study investigated the spatial aspect of the pathogen with an increase of B. cinerea concentration in bio-aerosols collected in the lower part of the glasshouse (0.5 m) and adjacent to the trained stems of the tomato plants. No obvious relationship was observed between B. cinerea concentration and the internal glasshouse environmental parameters of temperature and relative humidity. However the occurrence of higher outside wind speeds did increase the prevalence of B. cinerea conidia in the cropping environment of a vented glasshouse. Knowledge of inoculum availability at time periods when the environmental risk of pathogen infection is high should improve the targeted use and effectiveness of control inputs.     

Nemato-toxic potential of Betel (Piper betle L.) (Piperaceae) leaf

In vitro and in-planta trials were conducted to determine the nemato-toxic potential of aqueous leaf extracts of Betel (Piper betle L.) against the root-knot nematode species, Meloidogyne incognita, at five concentrations, standard extract (S) [1:2 (w/v] and its four dilutions, 20%, 40%, 60%. 80% of S. In the in vitro trials, second-stage juveniles (J₂s) and eggs of M. incognita were directly exposed to the extract while in the in-planta trials, the effect of the extract was evaluated as a root dip treatment using tomato plants. The findings indicated that the extract was lethal to J₂s but also inhibited egg hatch. The seedling dip treatments reduced root infestations in terms of gall formation, egg production and J₂ population densities in soil while simultaneously enhancing the growth of tomato plants. All these effects varied in a dose-dependent manner. Based on the LC₅₀ value, the eggs were found to be less sensitive to the extract than J₂s. One hundred percent of mortality of J₂s was recorded at four concentration levels, 40%, 60% and 80% of S and S, while 100% egg inhibition was only recorded at S. The highest reductions in gall formation (i.e., number of galls/root system), egg production and J₂ population were all recorded at S as 83%, 87% and 84% compared to the untreated water control. The maximum growth enhancement, which was 235% of the control, was detected in the root length of treated tomato plants. It appears the aqueous leaf extract of P. betle shows promise as a sustainable eco-friendly nematicide for the management of M. incognita.     

Aphid vectors of Papaya ringspot virus and their weed hosts in orchards in the major papaya producing and exporting region of Brazil

Papaya ringspot, one of the most important diseases of papaya, is caused by Papaya ringspot virus type P (PRSV-P), which is transmitted by various aphid species. Objectives of this research were to identify the aphid species and their weed hosts of papaya orchards in the major papaya producing and exporting region of Brazil in northern Espírito Santo State. Aphids were collected from weed hosts, and with Möericke-type traps in papaya orchards of twenty farms in Linhares, Sooretama and Aracruz municipalities of Espírito Santo, Brazil. A total of forty aphid species were collected, of which 22 are new records in the State. Thirty-eight aphid species were identified from traps, including Aphis craccivora Koch, A. gossypii Glover, A. spiraecola Patch, Myzus persicae (Sulzer), and Toxoptera citricidus (Kirkaldy), known vectors of PRSV-P. Cryptomyzus Oestlund (Aphididae) is recorded for the first time in Brazil. Thirteen aphid species associated with 22 weed species of 14 families were collected. Aphis gossypii, which has been reported to be one of the most efficient vectors of PRSV-P, infested the greatest number of weed hosts. Chamaesyce hyssopifolia (L.) Small, Euphorbia hirta L. (Euphorbiaceae), Commelina benghalensis L. (Commelinaceae), Lepidium virginicum L. (Brassicaceae) and Sida sp. (Malvaceae) were the most frequently infested weeds. Commelina benghalensis was infested by the greatest number of aphid species during this study. Integrated management of weed hosts of aphids to reduce aphid populations in papaya orchards may be useful for control of PRSV-P. Based on accurate knowledge of the aphid and weed species present in papaya orchards obtained in this study, integrated pest management efforts may be more efficiently directed toward eliminating the most frequently infested weed species that serve as hosts for aphid vectors of PRSV-P.     

Evaluation of bacterial biological control agents for control of root-knot nematode disease on tomato

Among 19 bacterial strains isolated in Yunnan from rhizosphere soils and plant tissues, Bacillus methylotrophicus strain R2-2 and Lysobacter antibioticus strain 13-6 exhibited the highest antagonistic activity against the tomato root-knot nematode Meloidogyne incognita in plate and greenhouse pot experiments. The two strains, when applied as soil drenches or seed treatments in greenhouse experiments, reduced root-knot severity and incidence on tomato compared to no-bacteria controls. In tomato field trials conducted in separate years, soil drench treatment with either strain reduced root-knot disease levels and increased yields compared to the control. Levels of disease control and yield enhancement provided by the strains were higher than those using the chemicals abamectin and carbofuran. This is the first report of B. methylotrophicus being used as a biocontrol agent against a plant parasitic nematode and the first demonstration that B. methylotrophicus and L. antibioticus can suppress disease caused by root-knot nematodes in the field.     

Races of Colletotrichum graminicola pathogenic to maize in Brazil

Anthracnose caused by the fungus Colletotrichum graminicola (Ces.) Wilson is the most important disease of maize in Brazil, especially in no-tillage without crop rotation. In this system, maize debris from earlier plantings increases the fungal inoculum potential over time. The use of genetic resistance is the most appropriate and advantageous strategy for anthracnose control. However, the effectiveness and durability of this practice depends on knowledge concerning the genetic variability of C. graminicola. In this study, fifteen maize genotypes were tested against 190 single spore of C. graminicola collected from infected leaves of maize plants cultivated in seven different Brazilian ecogeographic areas. Five races of C. graminicola were identified, and eleven maize genotypes were susceptible to all isolates. Results indicated that both the number of pathogen isolates and the number of genotypes to be tested are pivotal for an accurate identification of C. graminicola races. This is the first study showing the occurrence of C. graminicola races in Brazil.     

Virulence response to the Mi.1 gene of Meloidogyne populations from tomato in greenhouses

In a comparison of reproductive traits of 29 field populations of Meloidogyne spp. on resistant and susceptible tomatoes, 48% of the populations were virulent against the Mi.1 gene. Virulent populations produced more (P < 0.05) egg masses/plant, eggs/plant, eggs/g root, and showed higher infection frequencies and multiplication rates than the avirulent populations. The fecundity of females did not differ between the resistant and susceptible genotype, and did not change with the virulence status of the populations. On the resistant genotype, the populations collected from the susceptible tomato showed lower (P < 0.05) reproductive traits than those collected from rootstocks followed by those from resistant tomato. Meloidogyne javanica produced more (P < 0.05) egg masses/plant and eggs/g root than Meloidogyne incognita on the resistant genotype. A time course experiment was conducted to determine if root penetration by M. javanica populations with different Mi.1 virulence status is conditioned by the expression of resistance on tomato. Significant differences between populations were observed as early as of 2 days post-inoculation on the susceptible genotype. On the resistant genotype, low juvenile numbers from populations with acquired virulence penetrated the roots up to 4 dpi, but their numbers significantly increased 7 dpi. Juveniles of the natural virulent population followed similar penetration pattern on the resistant and susceptible genotypes. Peroxidases are involved in the oxidative burst typically associated with the hypersensitive response in incompatible host–pathogen interactions. Isoelectrofocusing isozyme analysis revealed an increase in the peroxidase activity on the resistant genotype after inoculation with the avirulent population and to a lesser degree with the populations with acquired virulence in comparison with the natural virulent population.     

Use of tomato crop residues into soil for control of bacterial wilt caused by Ralstonia solanacearum

Tomato debris can be used as the soil amendment to reduce agricultural residue accumulation problems and increase soil fertility. However, pathogens present in the debris may form a risk for subsequent crops. In this study, tomato growth substrate was amended with tomato debris artificially inoculated with Ralstonia solanacearum and the effect of heat treatments on the survival of the pathogen was measured. Experiments were carried out in the laboratory and in greenhouses, using peat moss and sand mix in pots as substrates. Pots were enclosed in plastic bags or left open. Then 0, 5, 10 and 15 g of tomato debris were applied to 500 g growing medium, with four replicates per treatment. Treatments at 45 °C lowered tomato wilt indices in tomato cv. Money-Maker and that the pathogen was not eradicated after pot treatments at 25 °C. R. solanacearum remained pathogenic on the assayed growing media after a six-week treatment at 25 °C, but was eradicated after treatments at 45 °C. The lower infectivity of infected debris tomato plants when buried with high doses of organic matter and at temperatures above 45 °C suggests that adverse effects on the soil inoculum would be exerted through increased soil temperatures. This study demonstrates that tomato crop residues, usually considered waste material, could be used as soil amendments to reduce their effect as a source of contamination as they offer additional advantages.     

Biological control of the false root-knot nematode Nacobbus aberrans by Pseudomonas protegens under controlled conditions

The use of antagonistic biological agents, such as fungi and bacteria, offers an economical and safe strategy to manage plant–parasitic nematodes in infested fields. The false root-knot nematode, Nacobbus aberrans, is a damaging parasite of many agronomic and horticultural crops in South and North America. The management of this nematode is challenging and often not profitable for farmers. In greenhouse tests, conducted in Argentina, applications of the strain Pseudomonas protegens CHA0 and its isogenic derivative ARQ1 (used as control) at a rate of 10⁸ cfu ml⁻¹ suppressed infection and reproduction of N. aberrans on tomato roots. However, neither of the strains promoted plant root or shoot growth of the treated plants. Root colonization by the bacteria was assessed by specific PCR–RFLP protocols and fluorescence microscopy. The results obtained in this preliminary study were encouraging and showed the potential of P. protegens CHA0 to be used for the management of the false root-knot nematode on tomato.     

Management of Meloidogyne incognita in yam-based cropping systems with cover crops

The effect of intercropping cover crops was with yam was assessed for nematode management both in pot and field conditions in Nigeria. The cover crops were sown with yams in pots containing sterile soil and inoculated with 5000 eggs of Meloidogyne incognita. In the field, each cover crop was separately intercropped with yams inoculated with 10,000 nematodes. From both pot and field experiments, no nematode damage was observed on yam tubers that were intercropped with Aeschynomene histrix, Crotolaria juncea, and Tagetes erecta. Damage in intercropped tubers was reduced by 72.7% with Mucuna pruriens, Centrosema pubescens, and Pueraria phaseoloides and by 58.3% with Stylosanthes guianensis compared to yams planted without cover crops; they also had lower (p ≤ 0.05) nematode populations. Cajanus cajan, Lablab purpureus and Vigna unguiculata however, supported high nematode populations and led to nematode damage in intercropped yams. Tubers from M. incognita-inoculated plants were more damaged and lost 42% more weight (p ≤ 0.05) following three months of storage than tubers from uninoculated plants. Intercropping yams with selected cover crops can be useful in managing M. incognita without reducing yam yields.     

Actinomycetes mediated biochemical responses in tomato (Solanum lycopersicum) enhances bioprotection against Rhizoctonia solani

Six actinomycetes isolates, namely Streptomyces toxytricini vh6, Streptomyces flavotricini vh8, S. toxytricini vh22, Streptomyces avidinii vh32, Streptomyces tricolor vh85 and vh41, an isolate of an unknown species of Actinomycetales, were tested for their efficacy in protecting tomato (Solanum lycopersicum) against Rhizoctonia solani under green house conditions. Actinomycetes treated plants showed better growth in terms of high chlorophyll content, higher phenylalanine ammonia lyase (PAL) activity and high total phenolic content. Qualitative and quantitative estimation of phenolic compounds from tomato leaves showed significant accumulation of six phenolic acids, gallic (29.02 μg g⁻¹ fresh leaf wt), ferulic (11.44 μg g⁻¹ fresh wt), cinnamic (56.84 μg g⁻¹ fresh wt), gentisic (24.19 μg g⁻¹ fresh wt), chlorogenic acid (1.72 μg g⁻¹ fresh wt) and salicylic (0.39 μg g⁻¹ fresh wt) acid, in actinomycetes treated plants. Biochemical profiling, when correlated with plant mortality in actinomycetes treated and untreated plants, indicated that isolates vh6 and vh8 offered 44.55% and 40.14% disease reductions, respectively compared to the control. These results established that these organisms have the potential to act as biocontrol agents.     

Effect of inoculum density and quantitative PCR-based detection of Rhizoctonia solani AG-2-1 and Fusarium avenaceum on canola

Canola seedling blight, caused by Rhizoctonia solani, and Fusarium spp., can result in large yield losses to canola (Brassica napus) at high inoculum pressure. The effect of inoculum density was studied by mixing different amounts of R. solani AG-2-1 and Fusarium avenaceum into a sterilized natural soil and soil-less mix (2:1, v:v) separately, and recording seedling emergence, damping-off and seedling height within ten days after seeding; root rot severity at 12 days after seeding and seed yield at harvest on canola cultivars ‘45H29’ and ‘73-77RR’. Root rot severity increased and emergence, plant height and seed yield decreased with increased inoculum density of both R. solani and F. avenaceum. For quantification of R. solani AG-2-1, a primer and TaqMan probe set (Rs21F/Rs21R/Rs21P) was designed based on the nuclear ribosomal internal transcribed spacer (ITS) region of R. solani AG-2-1. From a conventional PCR amplification, an 88-bp product was amplified from all isolates classified as AG-2-1 with the primers Rs21F and Rs21R. No product was amplified with DNA from isolates belonging to other anastomosis groups of R. solani, other pathogens or the host plant. By using quantitative PCR, DNA amounts as low as 100 fg of R. solani AG-2-1 were detected. The quantity of DNA from soil samples with different inoculum densities estimated using qPCR was highly correlated to the number of colony-forming units (cfu) obtained from the same soil samples for both R. solani AG-2-1 and F. avenaceum.     

Biological control of southern stem rot caused by Sclerotium rolfsii using Trichoderma harzianum and arbuscular mycorrhizal fungi on Jerusalem artichoke (Helianthus tuberosus L.)

Efficacy of Trichoderma harzianum and the arbuscular mycorrhizal fungus (AMF) Glomus clarum for suppression of southern stem rot caused by Sclerotium rolfsii in Jerusalem artichoke was investigated in Thailand under greenhouse conditions. Experimental factors included two Jerusalem artichoke genotypes (HEL 246 and JA 37), two levels of T. harzianum and G. clarum (inoculated and blank). The biological control agents were added to the potting medium immediately before seedlings of Jerusalem artichoke were transplanted into it; 20 days later, seedlings were inoculated with S. rolfsii by placing infested sorghum seeds at the base of the stem. The combination of cv. HEL 246 with addition of both G. clarum and T. harzianum had the lowest disease incidence (30%) and required the longest time to permanent wilt (11 days after inoculation). Inoculation of cv. JA 37 and HEL 246 with G. clarum alone gave better control of the disease than did inoculation with T. harzianum alone. The results are the first published report of biological control of S. rolfsii on Jerusalem artichoke.     

Host range study of Argentine Nacobbus aberrans sensu Sher populations and comments on the differential host test

The existence of races within the species Nacobbus aberrans sensu Sher has been confirmed; however, there is no consensus on a consistent system for race determination. Four plant species previously used as differential hosts in some N. aberrans race tests (tomato, pepper, sugarbeet and potato) were tested for susceptibility to seven nematode populations from Argentina. Plants were inoculated with second-stage juveniles and kept under glasshouse conditions at 21 °C for 90 days. The parameters evaluated (root gall index, egg mass index, and reproduction factor) in different nematode populations and plants showed significant differences. The reproductive fitness of the nematode populations differed among the plants that showed some degree of susceptibility. The results showed that N. aberrans comprises populations differing in host preference. Based on the nematode populations’ behaviour on these hosts, two groups were distinguished: i) populations that multiplied on all hosts, ii) populations that did not multiply on potato. The present work contributes to the analysis of criteria for developing a differential host test.     

Verticillium albo-atrum carried by certified seed potatoes into Washington and control by chemicals

Fifty-one percent of 110 lots of certified seed potatoes from 10 states and Canada sampled in 1968 and 30% of 134 lots from nine states and Canada sampled in 1969 were infected withVerticillium albo-atrum. Fortyone percent of the 1968 lots and 13% of the 1969 lots carried soil infested with the fungus on tuber surfaces. The dark mycelial type ofV. albo-atrum was found infecting tubers more often than the microsclerotial type, however, high propapgule populations of the microsclerotial type were present on tuber surfaces in the soil of infested lots. Over 24% of the isolates ofV. albo-atrum infecting and infesting tubers from lots of seed potatoes were pathogenic to eggplant var. Black Beauty. Captan^®, household bleach (5.25% sodium hypochlorite), Polyram^®, Orthocide^®, and Semesan Bel^®, were effective in preventing germination of the fungus in small amounts of soil such as might be carried by infested tubers. Liquid treatments were more effective than dusts.     

Susceptibility levels of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) to minor classes of insecticides in Brazil

The tomato leafminer, Tuta absoluta (Meyrick), is one of the most important pests of tomato worldwide. The use of chemicals is still the major tactic of control against this pest in Brazil, where spray overuse leads to resistance, frequently associated with control failures in the field. In this study, a survey of the susceptibility to indoxacarb, metaflumizone, chlorfenapyr, cartap, and abamectin aimed to determine the resistance status of T. absoluta populations. Also, the major enzyme systems associated with metabolic resistance were assessed to infer variability. The LC₅₀ values varied among the populations for abamectin (0.54–3.38 mg a.i./L), cartap (93.1–589.8 mg a.i./L), chlorfenapyr (0.62–2.83 mg a.i./L), indoxacarb (0.86–2.89 mg a.i./L), and metaflumizone (0.35–7.44 mg a.i./L). Resistance ratios varied among populations being 6.2-, 6.4-, 4.6-, 3.3-, and 21.2-times for abamectin, cartap, chlorfenapyr, indoxacarb, and metaflumizone, respectively. Only the cartap confidence limits of the LC₈₀ bracketed the recommended label concentration for three populations (Anápolis, Guaraciaba do Norte, and Tianguá), suggesting control failures. No cross-resistance was observed between indoxacarb and metaflumizone, and natural variation may explain the variability of response to this latter insecticide. The activity of enzymes frequently associated with metabolism of insecticides significantly differed among populations, and glutathione S-transferases and cytochrome P450-dependent monooxygenases were variable among the populations of T. absoluta, while alpha and beta-esterases were very homogeneous. T. absoluta resistance to abamectin and cartap has not been critical in Brazil despite their long use and together with chlorfenapyr appear to be an interesting option of rotation with indoxacarb, for which there is no cross-resistance to metaflumizone.     

Allelopathic effects of Ambrosia artemisiifolia L. in the invasive process

Ambrosia artemisiifolia (common ragweed), an annual native to North America, is now present in many European countries where it causes summer hay fever and interferes with several important crops. We investigated if common ragweed invasiveness could be explained by its leaf tissue and root exudate allelopathic potential on indicator crops (alfalfa, barley, maize, lettuce, tomato, and wheat), weeds (Echinochloa crus-galli, Solanum nigrum, Portulaca oleracea, and Digitaria sanguinalis), and common ragweed itself in laboratory and greenhouse conditions. Different residue substrates were prepared for soil incorporation and trials were conducted under both laboratory (1, 2, and 3 g residues/Parker dish) and greenhouse conditions (1.28 g residues/pot). The effect of the preparations on the germination and growth of the indicator crops and weeds were evaluated relative to soil previously used to grow A. artemisiifolia. Results showed tomato was the most sensitive indicator crop species as growth was reduced by more than 50% in both laboratory and greenhouse experiments. Lettuce root and shoot growth were also inhibited, but only when common ragweed residues, and not root exudates, were added to the substrate. Among the weeds, E. crus-galli was not affected by common ragweed while D. sanguinalis suffered a large germination reduction (90%) after incorporation of 3 g of residues. If common ragweed occurred as weed in a field, the cultivation of a less sensitive crop such as winter wheat should be considered before the cultivation of a more susceptible crop.     

Effects of 1,3-dichloropropene on nematode,weed seed viability and soil-borne pathogen

1,3-dichloropropene (1,3-D, C₃H₄Cl₂) is one of the potential candidates as soil disinfectant since the restriction of methyl bromide (MeBr) in soil fumigation due to its ecological risk. Its nematode, soil-borne pathogen and weed control efficacies were evaluated in a laboratory dose-response study and in two commercial tomato fields. Laboratory studies found that the seeds of Digitaria chinensis Hornem. were the most sensitive to soil fumigation with 1,3-D, followed by Eleusina indica (Linn.) Gaertn., Echinochloa crusgalli (L.) Beauv. and Amaranthus retroflexus L. with the LC₉₀ values between 14.23 and 73.59 mg kg⁻¹ soil. Among the pathogens, Phytophthora capsici Leonian was the most sensitive and Fusarium oxysporum f. sp. fragariae was the least sensitive to 1,3-D fumigation with the LC₅₀ values were 0.24 and 1.55 g m⁻². Rhizoctonia solani Kühn., Phytophthora nicotianae var. nicotianae and Botrytis cinerea Persoon exhibited intermediate susceptibility. Field trials revealed that 1,3-D applied to the field at 180, 120 and 80 L ha⁻¹ could suppress Meloidogyne incognita root galling while maintaining high tomato marketable yields, better than Dazomet at the concentration of 400 kg ha⁻¹. Our results indicated that 1,3-D was an excellent nematicide and could provide good to moderate weed and pathogen control. Based on our results, 1,3-D, in combination with other alternatives to MeBr is recommended to reach an integrated pest management.