Incidence of root rot of muskmelon in different soil

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Eur J Plant Pathol https://doi.org/10.1007/s10658-018-1488-6

Incidence of root rot of muskmelon in different soil management practices Paula G. M. L. Nascimento & Márcia M. Q. Ambrósio & Francisco C. L. Freitas & Beatriz L. S. Cruz & Andrea M. M. Dantas & Rui S. Júnior & Washington L. da Silva

Accepted: 20 April 2018 # Koninklijke Nederlandse Planteziektenkundige Vereniging 2018

Abstract The objective of this study was to estimate the effects of tillage systems and cover crops on the incidence of root rot in melon and to identify the fungal pathogens associated with the disease. Two consecutive trials were carried out in a randomized complete block design with four replications in each trial. The treatments were arranged in split-plots. Two tillage systems (no-tillage (NT) and conventional tillage (CT)) were assigned in the main plots and in the subplot the six types of ground cover crops were tested (sunn hemp, pearl millet, sunn hemp + pearl millet, corn + brachiaria, spontaneous vegetation, spontaneous vegetation + polyethylene film) or bare soil. At the end of the trials all melon plants were collected and assessed for disease incidence, isolations from symptomatic plants were made for fungal identification. Root rot incidence was lower in the NT treatments with sunn hemp, pearl millet, P. G. M. L. Nascimento : M. M. Q. Ambrósio (*) : F. C. L. Freitas : B. L. S. Cruz : A. M. M. Dantas : R. S. Júnior Departamento de Ciências Agronômicas e Florestais, Universidade Federal Rural do Semi-Árido – UFERSA, Campus de Mossoró, Mossoró, RN 59.625-900, Brazil e-mail: [email protected] F. C. L. Freitas Departamento de Fitotecnia, Universidade Federal de Viçosa, Campus de Viçosa, Viçosa, MG 36.570-900, Brazil W. L. da Silva School of Integrative Plant Science, Plant Pathology & Plant-Microbe Biology Section, Cornell University, Ithaca, NY 14853-5904, USA

and spontaneous vegetation. The main fungi isolated from symptomatic roots were Fusarium solani, M ac rop h om i n a p h as eo l i na , M o n os po r as cu s cannonballus and Rhizoctonia solani, but F. solani was the most frequently isolated fungus in both tillage systems. The results suggest that the NT system has the potential to control incidence of root rot of muskmelon, but is necessary to realize crop rotation between the planting cycles. Keywords Cucumis melo . Fusarium solani . Macrophomina phaseolina . Monosporascus cannonballus . Rhizoctonia solani . No-tillage

Introduction Melon (Cucumis melo L.) is an important fruit crop worldwide. Brazil is the ninth largest melon producer in the world with crops mainly concentrated in the Northeast region (Fao 2016). Of the melons produced in Brazil, 47.36% come from a single state, Rio Grande do Norte, which accounts for 254.530 tons of fruit per year (IBGE 2015). The crop is well adapted to the region’s soil and climate conditions, with high temperatures and low precipitation for most of the year. This is due to the good soil and climatic conditions of the region for melon production, combined with the use of high technology by production companies. Monoculture is common in this region, with up to three melon cropping cycles in a year in the same plots, favoring the build-up of soil-borne pathogens.

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Consequently, high disease incidence, decrease in yield and fruit quality are observed yearly. Fungal pathogens cause large losses in melon productivity, mainly as a consequence of damage to the plant root system and the loss of smaller feeder roots, which can lead to plant decay and death. Furthermore, these fungi are difficult to manage because they survive in the soil or crop residue for long periods with resistant structures such as chlamydospores (Fusarium) and sclerotia (Macrophomina, Rhizoctonia and Sclerotium), hindering melon production. The use of resistant melon cultivars is conceptually the best disease control strategy. However, the success of breeding programs for soil-borne pathogen resistance is influenced by many factors, such as the nature of the pathogen, diversity of virulence in the population, availability, diversity, and type of genetic resistance, and the effectiveness of methods and tools used for assessing plant resistance (Oumouloud et al. 2013). Furthermore, the pathogen could create, by mutation, new races that may make the varieties susceptible to diseases. Presently there are no melon cultivars resistant to root rots available to melon producers in Brazil. In intensive horticulture, soil-borne plant pathogens were efficiently controlled by methyl bromide applications to the soil (Noling and Becker 1994). However, the Montreal Protocol established that by 2015, the use of methyl bromide, in agriculture was to be phased out in developing countries (Duniway 2002). With the ban of methyl bromide problems with root pathogens increased, demanding the adoption of integrated disease management strategies to reduce the inoculum density in the soil (Lopes et al. 2005). The methods to manage root diseases are chemical and nonchemical, environmentally friendly, such as the use of resistant varieties (Dias et al. 2004; Salari et al. 2012; Ambrósio et al. 2015), adjustment in irrigation schemes (Cohen et al. 2000), soil solarization (Stapleton 2000), chemical control with fungicides and other fumigants, alone or combined with soil solarization (Gamliel et al. 1996; Guimarães et al. 2008; Cohen et al. 2012), grafting melon plants onto resistant rootstocks (Cohen et al. 2002; Cohen et al. 2012), bio-pesticides (Narayan et al. 2015), and incorporation of plant residues (Dantas et al. 2013). Green manures in turn, may favor soilmicrobiome equilibrium, and improve diseases management, but this strategy has not yet tested in the control of melon root rots. Plant residues, when incorporated in the soil, can improve soil biomass, soil microbial biomass,

and soil fertility, and releases antagonistic substances against soil-borne pathogens (Stone et al. 2004). However, these benefits depend on cover crop species and incorporation methods. In Brazil, plants belonging to the Fabaceae and Poaceae species (e.g., Crotalaria juncea, Pennisetum glaucum and Urachloa brizantha) are preferred cover crops used for green manure and are well adapted to different edaphoclimatic conditions, and can result in improvements to the physical, chemical, and biological soil properties (Carvalho et al. 2013). Green manures can be managed by burying crop residues in the soil or with the adoption of the no-tillage (NT) farming system, where the straw layer remains on the soil surface. The NT System is effective in controlling cucurbit diseases and could be used to tackle soil-borne pathogens. NT cover crops have been widely adopted in Maryland, USA, because of the noticeable benefits in reducing soil erosion and nutrient runoff and improving soil health in pumpkin fields (Everts 2002). The combined use of NT with moderately resistant cultivars reduces the need for fungicides. This will reduce production costs, including labor, can minimize fungicide residues, and may assist in delay of resistance development of pathogens to fungicides (Everts 2002). The application of raw and composted paper mill residuals also has been shown to have potential to control several soil-borne pathogens in cucumber (Stone et al. 2003). Composted amendments may reduce diseases by inducing plant defenses (Stone et al. 2003). Root pathogens can be managed in green manure farming by biofumigation, when toxic substances are released during plant residue decomposition, which kills pathogens or inhibits pathogen growth. There is also an increase in the number of microbial antagonists in the soil that can compete with pathogens for nutrients, resulting in decrease in pathogen mycelial growth and reproduction (Rossi 2002). Mulching can also create physical barriers in the soil to block the light, which is an essential factor for the development of pathogen structures and the germination of resting spores and/or resistant structures such as sclerotia (Lobo Junior et al. 2009). However, little is known about cover crops that can interfere with the incidence of melon root diseases and their causal agents in a tropical environment. Therefore, the aims of this study were to: (i) evaluate the effects of two tillage systems, no-tillage (NT) and conventional tillage (CT), and different cover crops on the incidence

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of root rot of melon; and (ii) identify the fungal pathogens associated with the disease.

Material and methods Two experiments were conducted on the Agrícola Famosa farm, located at the border of Tibau and Icapuí cities, in the Brazilian states of Rio Grande do Norte and Ceará, respectively. The trials were carried out in the 2011–2013 melon growing seasons. The region’s climate, according to the Köppen classification, is BSh type, dry and hot, with an annual average rainfall of 700 mm and temperature and air relative humidity of 26.7 °C and 68.9%, respectively. The rainy season is from February to June, with low chances of rain occurrence between August and December (Alvares et al. 2014). The treatment and plot arrangement in the second trial matched those of the first one. The experimental area was kept under fallow for three years and had a previous history of melon diseases caused by root pathogens. Before the cover crops were established, all spontaneous vegetation (weeds) was removed, except in the experimental subplot treatments, in which the spontaneous vegetation was kept. The 0– 20 cm topsoil from the experimental area presented the following chemical characteristics: pH(H2O) = 7.49; P(mg dm−3) = 60.00; sum of bases (SB) (cmolc dm−3) = 3.07; K+(mg dm−3) = 28.83; Mg+2(cmolc dm−3) = 0.64; Al+3(cmolc dm−3) = 0.0; cation exchange capacity (CEC) (cmolc dm−3) = 4.29; O.M = 0.65 (dag Kg−1) and base saturation (V) = 71.63 (%). The physical composition of the soil was 0.8881 (Kg/Kg) of sand, 0.053 (Kg/Kg) of silt, and 0.0661 (Kg/Kg) of clay. Each trial was conducted in the subdivided plot scheme, distributed in a completely randomized block design with four replications (Fig. 1). In the plots were evaluated two systems of preparation of the soil: conventional tillage (CT) (cover crops incorporated in the soil by tillage) and no-tillage (NT) (cover crops burned by herbicides and plant residues left on the soil surface) and in the subplots, six cover crops [sunn hemp (Crotalaria juncea L.), pearl millet (Pennisetum glaucum (L.) R. Brown), sunn hemp + pearl millet, corn (Zea mays L.) + brachiaria (Urachloa brizantha), spontaneous vegetation, spontaneous vegetation + polyethylene film], and bare soil. All CT treatments had a polyethylene film cover because it is a standard practice carried out by growers

for weed management. Each experimental unit had three 6.0 m length rows, 2.0 m between rows, and a 0.3 m space between plants within rows. Cover crops were sown in all of the main plots, during the rainy season on 04/18/2011 and 05/15/2012 (for corn + brachiaria) and 05/15/2011 and 08/09/2012 (for the remaining treatments), for the first and second trials, respectively. The different planting dates for the cover crop species were necessary to match their different development with the timing of straw distribution or residue burial in the soil. For both trials, in the treatment corn + brachiaria, corn was planted in double rows with brachiaria between the rows in an intercropping system. Both crops were sown simultaneously with planter/fertilizer equipment. The mineral fertilization at planting was done with NPK 6–24-12 (350 Kg ha−1) and top dressing fertilization with urea (200 Kg ha−1) was performed via fertigation, according to the soil chemical analysis. After corn harvest, brachiaria was left to grow freely until September 2011 and October 2012. The green manure/cover crop plants were herbicide-killed at flowering stage with a mixture of glyphosate and 2,4D, at 1.8 and 0.67 L ha−1 of active ingredients, respectively, 20 days before transplanting the melon seedlings. The dry matter of the aerial part of the green manure/ cover crop plants was sampled, twice in each treatment, with a 0.50 m × 0.50 m frame in the subplots. Subsequently, samples were dried at 65 °C until a constant mass was obtained for weighing and determination of the dry matter (t ha−1). One week before transplanting, crop/green manure plant residues were incorporated into the soil in the CT treatment. In the CT subplots, the soil was prepared by tilling once with a plow and twice with a disc harrow. In the no-tillage treatment, the soil was not prepared, and the plant residues were maintained on the soil surface. The melon seedlings of the Goldex hybrid were transplanted and immediately covered with agrotextil (TNT), polypropylene tunnels, for 25 days for protection mainly from white flies (Bemisia argentifolii) and leaf mines (Liriomyza spp.). The irrigation system consisted of 0.4-spaced drippers of 1.7 L h−1. The daily irrigation schedule was estimated by the Penman-Monteith equation (Allen et al. 1998) and the coefficient of culture (Kc) recommended by the Food and Agriculture Organization of the United Nations (FAO 2015). All plants were assessed 60 days after transplanting for disease incidence (%) and fungal pathogens identification, in each trial. Six fragments of 4 mm2 from roots

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Fig. 1 Design of the experimental plot in subdivided plot scheme, distributed in a completely randomized block design

and lower stems, near the soil line, were collected from all symptomatic plants (Fig. 2) and surface disinfected (Bueno et al. 2004). The plant fragments were then placed on the surface of potato-dextrose-agar (PDA) + tetracycline 0.05 g/l and incubated for seven days at 28 ± 2 °C under continuous light. Three distinct isolates of Fusarium and Rhizoctonia were identified as F. solani and the Rhizoctonia isolates as R. solani AG 7. F. solani was morphologically identified on PDA, using the Fusarium Laboratory Manual (Leslie and Summerell 2006). After the monosporic cultivation of the isolates, DNA extraction was performed followed by PCR reactions. The amplified fragments were purified and sequenced for the study of molecular phylogeny, where two genic regions were analyzed, Gene elongation factor- 1α (TEF-1α) (O’Donnell et al. 1998) and, second largest subunit of RNA polymerase (RPB2) (O’Donnell et al. 2008). For the amplification of the TEF-1α were used primers Ef-1 (forward, 5-ATGGGTAAGGAGGACAAGAC-3) and Ef-2 (reverse 5-GGAAGTACCAGTGATCATGTT-3)

(O’Donnell et al. 1998). In the amplification of the RPB2 fragment were used primers 5F2 (forward, 5GGGGWGAYCAGAAGAAGGC-3) and 7cR (reverse 5- CCCATRGCTTGYTTRCCCAT-3) (O’Donnell et al. 2008). R. solani was morphologically identified on selective medium (Ko and Hora 1971). After purification of the isolates in PDA medium, DNA extraction was performed and three genic regions analyzed, ITS, TEF1α and RPB2. The nucleotide sequences were submitted to alignment through the software Basic Local Alignment Search Tool – BLAST (Altschul et al. 1997). The soil’s maximum temperature was recorded with type T (copper-constantan) thermocouples at 0.05 m deep. The sensors were wrapped with Styrofoam noodles to avoid oxidation. Data were collected every 10 min and stored in Campbell CR 1000 dataloggers. The correlations of dry matter amount and incidence root rot were generated using Microsoft excel 2013 (Ribeiro Júnior 2004). Results were subjected to variance analysis at 5% probability and the averages were

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Fig. 2 Examples of symptomatic plants. a = Muskmelon with yellowing and wilting symptoms; b, c and d = Root rot of muskmelon

compared at 5% using the Tukey test with Assistat statistical software, version 7.6 beta (Silva 2008).

Results The greatest variation of the maximum temperature of cultivated soil with melon was observed among treatments in the no-tillage system. The cover crops pearl millet and spontaneous vegetation had the lowest temperature throughout the planting cycle (Fig. 3). In the conventional tillage system, 10 to 18 days after transplanting (DAT) the seedlings, the spontaneous vegetation + polyethylene film showed the highest temperatures. However, in the period of 30 to 46 DAT, this was not observed, perhaps because of the shade created by the melon plants, which eliminated the cover crop effect. The corn + brachiaria cover crop treatment produced the greatest dry matter amount in both trials. Sunn hemp,

spontaneous vegetation and spontaneous vegetation + polyethylene film treatments (all from the first trial); and pearl millet and sunn hemp + pearl millet (second trial) (Fig. 4) revealed dry matter amounts below the ideal threshold for a good cover crop (6 to 12 t ha-1) according to Teodoro et al. (2011). In the present study, in both trials, there was no significant correlation between amount of dry cover crop matter and incidence of root rot [first trial (P > 0.05) and second trial (P > 0.05)] (Table 1). The results revealed interactions between the tillage systems and cover crops for all variables, which justified the partitioning of factors. In the NT system, melons in bare soil were more affected by the disease in comparison with sunn hemp, pearl millet, corn + brachiaria, and spontaneous vegetation (P < 0.05). Melons cultivated in soil with sunn hemp and spontaneous vegetation + polyethylene film treatments also demonstrated a lower incidence of root

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Fig. 3 Maximum soil daily temperature during the first trial as a function of the tillage systems and cover crops. a = Soil temperatures in conventional tillage during the period of 10 to 18 days after planting; b = Soil temperatures in conventional tillage during the

Fig. 4 Dry matter (t/ha) of cover crops used during the first and second trials with melon (Cucumis melo)

period of 30 to 46 days after planting; c = Soil temperatures in notillage system during the period of 10 to 18 days after planting; d = Soil temperatures in no-tillage system during the period of 30 to 46 days after planting

Eur J Plant Pathol Table 1 Pearson correlation coefficient between the amount of soil cover (t/ha) and incidence of root rot of melon (Cucumis melo L.) in two tillage systems (conventional tillage and no-till), in the first and second trial Dry cover crop matter

Correlation coefficient

First Trial

Second Trial

CT

NT

CT

NT

−0.60ns

−0.46ns

−0.43ns

−0.50ns

CT conventional tillage, NT no-till. ns Not significant by T test at 5% probability

rot in the NT than in the CT system in both trials (P < 0.05) (Table 2). In the second trial, the spontaneous vegetation treatment had a lower incidence of root rot (P < 0.05) (Table 2). However, the association of spontaneous vegetation and polyethylene film, in the CT system, resulted in a higher root rot incidence, regardless of the trial (P < 0.05). There was no statistical difference between the trials on the average incidence of root rot (P > 0.05). The fungi isolated from symptomatic melon plants, in both trials, were F. solani, M. phaseolina, Monosporascus cannonballus, and R. solani, with F. solani found as the most frequent, regardless of trial or tillage system (Fig. 5, Tables 3 and 4). Overall, there was no significant difference between cover crops on the frequency of fungi isolated from symptomatic plants

in the first trial (Table 3). However, melon cropping in the NT system preceded by sunn hemp and spontaneous vegetation + polyethylene film had lower frequencies of F. solani and M. phaseolina in comparison with these same treatments in the CT system. Furthermore, there was a lower incidence of R. solani in the bare soil treatment in the NT compared to the CT. In the second trial, melon cultivated in bare soil had a higher incidence of F. solani than those cultivated in sunn hemp, sunn hemp + pearl millet and spontaneous vegetation soil treatments. There was a lower occurrence of M. cannonballus and R. solani in the NT compared to the CT system when pearl millet and spontaneous vegetation crops were used as cover crops (Table 3 and 4).

Discussion In the NT system, the use of cover crops pearl millet and spontaneous vegetation resulted in lower temperatures during the entire melon cycle than the bare soil treatment. Similar results were observed by Torres et al. (2005), who found that pearl millet, in the NT system, promoted low temperatures and thermal amplitude in the soil when in rotation with corn and soybean. This finding may be explained by the high quantity of dry matter produced by those cover crops (Jimenez et al. 2008). Dry matter has a low decomposition rate and,

Table 2 Incidence of root rot (%) of melon (Cucumis melo L.) in two tillage systems and different cover crops Materials

First Trial CT

Second Trial NT

Average

CT

NT

Average

S. hemp

32.7 abA

11.3 bB

22.0

39.3 abA

21.0 bcB

30.1

P. millet

19.3 bA

9.3 bA

14.3

45.3 abA

22.0 bcB

33.6

S. hemp + P. millet

22.3 abA

29.0 abA

25.6

36.5 abA

34.0 abA

35.3

C. + bra.

21.0 abA

13.3 bA

17.1

31.3 bA

34.5 abA

32.9

Spon.veg.

22.6 abA

9.3 bA

16.0

32.3 bA

11.8 cB

22.0

B. soil

31.6 abA

39.6 aA

35.6

50.8 abA

46.0 aA

48.4

Spon.veg. + poly. Film

51.3 aA

15.7 abB

33.5

56.3 aA

29.3 abB

42.8

Average

28.7

18.3

41.6

28.4

Average per trial

23.5 A

35.0 A

CV %

19.1

12.0

Within each management system and between systems, means followed by the same lowercase letters (columns) or uppercase letters (lines), do not differ significantly to the level of 5% probability. Tukey test (Alpha = 0.05). CT conventional tillage; NT no-till; S. hemp Sunn hemp; P. millet Pearl millet; C bra corn + brachiaria; Spon. Veg Spontaneous vegetation; B. soil Bare soil; Spon. veg. + poly. Film = Spontaneous vegetation + polyethylene Film.; CV coefficient of variation

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Fig. 5 Occurrence of fungi (%) isolated from melon (Cucumis melo L.) showing root rot in both trials. a = First trial; b = Second trial; c = Conventional tillage; d = No-tillage; 1 = Sunn hemp; 2 =

Pearl millet; 3 = Sunn hemp + Pearl millet; 4 = Corn + brachiaria; 5 = Spontaneous vegetation; 6 = Bare soil; 7 = Spontaneous vegetation + polyethylene Film

therefore, keeps the soil covered for a longer period of time. The temperature of these treatments had the effect of reducing root rot incidence in muskmelon in comparison to the bare soil treatment. In the first trial, in the NT

system, the cover crops pearl millet and spontaneous vegetation reduced disease incidence by 76.5%. In the second trial, these treatments reduced by 52.2% (pearl millet) and 74.4% (spontaneous vegetation) the

Eur J Plant Pathol Table 3 Occurrence of fungi (%) isolated from melon (Cucumis melo L.) showing root rot in the first trial Materials

F. solani

M. phaseolina

M. cannonballus

R. solani

CT

NT

CT

NT

CT

NT

CT

NT

S. hemp

4.48 aA

2.58 aB

3.27 aA

1.22 aB

1.15 aA

0.00 aA

2.49 aA

1.72 aA

P. millet

4.03 aA

3.52 aA

1.87 aA

0.00 aA

1.32 aA

0.00 aA

2.46 aA

1.96 aA

S. hemp + P. millet

4.20 aA

3.80 aA

1.75 aA

1.80 aA

0.00 aA

1.40 aA

1.93 aA

1.60 aA

C. + bra.

3.64 aA

3.32 aA

0.85 aA

0.50 aA

0.00 aA

0.00 aA

1.89 aA

2.59 aA

Spon.veg.

4.60 aA

2.88 aA

2.14 aA

1.30 aA

0.00 aA

0.83 aA

3.76 aA

2.08 aA

B. soil

5.30 aA

4.03 aA

2.93 aA

1.98 aA

1.32 aA

2.31 aA

4.34 aA

2.35 aB

Spon.veg. + poly. Film

5.14 aA

3.23 aB

3.65 aA

0.56 aB

1.35 aA

0.00 aA

2.03 aA

1.67 aA

Average

4.48

3.33

2.35

1.05

0.73

0.64

2.70

1.99

CV (%)

29.9

62.9

131.8

48.7

Within each management system and between systems, means followed by the same lowercase letters (columns) or uppercase letters (lines), do not differ significantly to the level of 5% probability. Tukey test (Alpha = 0.05). The data were transformed by using the formula √(X) + 0.5. CT = Conventional tillage; NT = No-till; S. hemp = Sunn hemp; P. millet = Pearl millet; C + bra = Corn + brachiaria; Spon. veg. = Spontaneous vegetation; B. soil = Bare soil; Spon. veg. + poly. Film = Spontaneous vegetation + polyethylene Film; CV = Coefficient of variation. F. solani = Fusarium solani; M. phaseolina = Macrophomina phaseolina; M. cannonballus = Monosporacus cannonballus; R. solani = Rhizoctonia solani

incidence of root rot in comparison to bare soil. Many plants, such as pearl millet have been cultivated with the purpose of covering or being incorporated into soil. The addition of pearl millet straw to soil can reduce the disease and favour the fluorescent Pseudomonas population growth (Pereira Neto and Blum 2010), bacteria that are present in agricultural soils and have traits that

make them well suited as biocontrol agents of soil-borne pathogens (Weller 2007). Even though corn + brachiaria were the cover crops that had the highest quantity of dry matter in this study, they did not result in the lowest temperatures. This can be attributed to the high C/N ratio found in grasses in relation to Fabaceae such as sunn hemp as reported by

Table 4 Occurrence of fungi (%) isolated from melon (Cucumis melo L.) showing root rot in the second trial Materials

F. solani CT

M. phaseolina

M. cannonballus

R. solani

NT

CT

NT

CT

NT

CT

NT 3.45aA

S. hemp

5.87 aA

4.47 bA

2.16 aA

0.61 aA

3.49 aA

2.22 aA

3.15aA

P. millet

6.28 aA

5.05 abA

1.88 aA

1.49 aA

3.95 aA

1.58 aB

3.91aA

3.15aA

S. hemp + P. millet

5.77 aA

4.58 bA

0.91 aA

1.86 aA

3.07 aA

1.31 aA

3.77aA

3.44aA

C. + bra.

5.28 aA

4.88 abA

1.14 aA

0.43 aA

2.93 aA

1.84 aA

3.23aA

3.45aA

Spon.veg.

6.03 aA

2.92 bB

0.61 aA

0.71 aA

3.14 aA

0.93 aA

4.13aA

1.96aB

B. soil

6.61 aA

7.37 aA

1.18 aB

3.16 aA

3.18 aA

2.22 aA

3.91aA

3.74aA

Spon.veg. + poly. Film

7.06 aA

5.26 abB

1.58 aA

0.56 aA

4.29 aA

2.05 aA

4.65aA

3.64aA

Average

6.12

4.93

1.35

1.26

3.43

1.73

3.82

3.26

CV (%)

19.8

74.2

52.1

28.9

Within each management system and between systems, means followed by the same lowercase letters (columns), or uppercase (lines), do not differ significantly to the level of 5% probability. Tukey test (Alpha = 0.05). The data were transformed by using the formula √(X) + 0.5. CT conventional tillage, NT no-till, S. hemp sunn hemp, P. millet pearl millet, C + bra corn + brachiaria, Spon. Veg spontaneous vegetation, B. soil bare soil, Spon. veg. + poly. Film spontaneous vegetation + polyethylene Film, CV coefficient of variation. F. solani = Fusarium solani, M. phaseolina Macrophomina phaseolina, M. cannonballus monosporacus cannonballus, R. solani rhizoctonia solani

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Teixeira et al. (2009) in addition to the action of microorganisms that may have contributed to the raising of soil temperatures. Organic matter has been recommended to manage plant diseases caused by soil-borne pathogens. Bonanomi et al. (2007) reviewed reports on the application of organic matter amendments, focusing on the suppressive capacity of different organic materials and the response of different soil-borne pathogens, verified that the effect of crop residues was suppressive in 45% of the cases, but enhanced disease in 28%. However, there are few studies that have demonstrated a reduction in soil-borne disease incidence as the result of the amount of dry matter applied to the soil surface. In both trials in the present study, there was no correlation between the amount of dry matter and root rot. In contrast, other studies have reported a positive correlation between the disease suppression and the amount of dry matter. For example, two months after amendment application, Darby et al. (2006) reported that higher rates of fresh and composted dairy manure were suppressive to damping-off of cucumber (30%), bean root rot (29%) and corn root rot (67%), and the lowest rates of amendment application were not suppressive. Although both studies deal with the use of organic materials in the control of soil-borne disease, the materials and the pathogens involved were distinct, which may justify that there was no correlation between the amount of dry matter and root rot in the current work. When green manure was applied at 6, 12, and 24 Mg ha−1 to field plots infested with Verticillium dahliae, previous research reported that none of the covers reduced disease severity at the lowest application rate, while all cover crops suppressed wilt at the highest rate (Ochiai et al. 2007). Linhares et al. (2016) reported that there was no correlation between survival of M. phaseolina and amount of dry matter. Nevertheless, in the same study, the material that presented the highest dry matter (Pennisetum glaucum) was one of the materials that presented the lowest survival rate. The effect of dry matter on the incidence of root rot should be more related to the type of coverage. Green manures increase soil microbial biomass and activity, and cause distinct changes in soil microbial populations that may be partially responsible for suppression of diseases. However, green manures of different crops and cultivars may vary in their activity or efficacy against different pathogens and diseases (Larkin 2013).

Root diseases are responsible for large losses in melon cultivation worldwide and the way the soil is managed can affect the incidence of these diseases. In this study, the high incidence of root rot in the NT cultivation system in bare soil may be linked to the reduced quantity of dry matter found in this treatment, which can reduce the growth and development of antagonist microorganisms that can have suppressive effects against pathogens (Bettiol and Ghini 2005). When cover plants are desiccated, large quantities of organic matter are made available, and when in contact with the soil, the dry matter can be readily used as substrate by various microorganisms (Lobo Junior et al. 2009). Therefore, there are potential increases in number, diversity and activity of microorganisms that are antagonists to phytopathogens. In the current study, the decrease in the soil temperature observed in cover crop treatments in the NT system, induced by the plant residues mulching and shading the soil, may also have played an important role in the lower root rot incidence found in these treatments in comparison to the bare soil treatment. Similar results were also observed by Cunha et al. (2014). These authors demonstrated that soil covered by crop residues in the NT system, as well as the presence of weeds in subplots not weeded in the NT and CT system, increased mulching and shading in the soil, which resulted in lower soil temperatures when compared to those of bare soil and soil covered by polyethylene film. Mulching can also work as a physical barrier, blocking light, an essential element for the development of pathogen resistant structures, such as apothecia, which are produced by the pathogen Sclerotinia sclerotiorum in Phaseolus vulgaris, as previously reported by Lobo Junior et al. (2009). These researchers studied the carpogenic germination of S. sclerotiorum and relate the reduction in the number of apothecia formed on the soil (due to cover crop) as the most remarkable and immediate effect to reduce the severity of disease. The cover crop blocks the production of apothecia, which require light to complete its development and also contributed to the increase of parasitism of sclerotia (Görgen et al. 2009). The lower incidence of root rot of muskmelon grown in soil that was previously cultivated with sunn hemp and spontaneous vegetation + polyethylene film in the NT in comparison to the CT system can be attributed to the non disturbance of the soil. In non-disturbed soil, the sunn hemp residues have less contact with the soil, which reduces the decomposition rate. In contrast, in CT, the

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sunn hemp residues are incorporated into the soil through soil disruption, promoting decomposition of the plant material. A large amount of nitrogen is released in the soil during sunn hemp decomposition (Andrioli et al. 2008), which can favor the growth and development of antagonist microorganisms of pathogens that cause root rot (Botelho et al. 2001). Although in the present study it has not been verified that the sunn hemp residues, when incorporated in the soil, reduced root rot of muskmelon, Dantas et al. (2013), showed that the effect of sunn hemp, castor bean, cassava and neem and timing of incorporation of these materials on the incidence of root rot in muskmelon, verified that sunn hemp reduced disease incidence when the time of incorporation was 14 days. However, with the increase of incorporation time, there was an increase in the percentage of plants with root rot, especially in the time of 28 days. This can be explained by the Carbon/Nitrogen (C/N) ratio of these materials which provides for a more accelerated decomposition, releasing nutrients and chemical compounds more rapidly, which promotes a faster reduction of disease (Dantas et al. 2013). In the second trial, of the current study, the soil management with spontaneous vegetation resulted in the lowest incidence of root rot. That can be associated with the high diversity of weeds observed in the area, which probably contributed to the increase in number and diversity of antagonistic microorganisms in the soil which may disfavor soil-borne pathogens. Studies carried by Massenssini et al. (2014) suggested that weeds tend to be positively associated with soil microorganisms while crops may have neutral or negative associations. Therefore, in a condition of weed diversity, there may be a reduction in the diseases incidence caused by soil-borne pathogens due to the greater action of antagonistic microorganisms. The following weed species were identified in both trials: pigweed (Portulaca oleraceae), black pigweed (Trianthema portulacastrum), crabgrass (Digitaria bicornis), green carpetweed (Mollugo verticillata), spiny pigweed (Amaranthus spinosus), hairy woodrose (Merremia aegyptia), and Benghal dayflower (Commelina benghalensis). The association of spontaneous vegetation with polyethylene film resulted in the highest incidence of root rot, independently of the tillage system. That may be because the polyethylene film caused an increase in the soil temperature and humidity (Tosta et al. 2010), which can favor the development of root rot-causing fungi.

The pathogens isolated from symptomatic melon plants in both trials in this study are the same as previous reports from Andrade et al. (2005), who found F. solani and M. phaseolina as the predominant pathogens. Those were also the predominate fungi in melon plants cultivated in soil incorporated with diverse vegetal materials (Dantas et al. 2013). In the current study, F. solani was found to be the most predominant fungus possibly due to the great adaptation of this fungus to the local environmental conditions, such as high temperatures (PérezHernández et al. 2017). The reduction of root rot incidence may seem small at first glance. However, it can gradually decrease year after year, as was observed in root system diseases of wheat (Triticuma estivum) and barley (Hordeum vulgare) caused by Rhizoctonia solani (Schroeder and Paulitz 2006). Furthermore, Schillinger and Paulitz (2014) noticed suppression of R. solani AG-8 over time in the NT system, emphasizing that it is possible to show, in this type of study, that soilborne pathogens and root disease occurrences are dynamic over a long period of time and may be able to be suppressed by the soil’s natural microflora. The no-tillage system has three basic principles of soil management: planting without tillage, permanent (debris or living) coverage and crop rotation (Teófilo et al. 2012). Therefore, if rotation is not performed between the cycles of culture, there may be an increase in the incidence of the disease (ToledoSouza et al. 2008), as verified in the present study. Plant residues left on the soil surface can create a barrier that limits pathogen dispersion, as observed with Septoria glycines on soybeans (Almeida et al. 2015). However, in some cases, the NT system can increase the incidence of soilborne pathogens (Fernandes and Oliveira 1997; Toledo-Souza et al. 2008). The crop residues present in the soil can favor the survival of propagules and enhance the build-up of the pathogen population. Overall, the incidence of root rot increased from the first to the second trial, as did the occurrence of the fungi. The fact that the sequence of plants cultivated in the area was not altered could be the explanation for those results. Disease occurrence caused by soil-borne pathogens is favored when a crop rotation is not used in agricultural systems (Toledo-Souza et al. 2008). Moreover, high temperature and low precipitation observed during the trials in the current study could have favored some root rot fungi such as M. phaseolina and M. cannonballus. These fungi are known to thrive in

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semi-arid climates as they prefer to grow in higher temperatures (Bruton et al. 1987; Sales et al. 2007).

Conclusion The results suggest that the no-tillage system has the potential to control incidence of muskmelon root rot, but is necessary to realize crop rotation between the planting cycles. Although no-tillage system is not a traditional technique in melon production, presents itself as quite promising, when combined with appropriate crop rotation and can guarantee improvements in soil quality, being also an advantageous technique in semi-arid conditions, because it increases water infiltration rate and reduces soil water evaporation. Acknowledgements This work was supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior CAPES (Brazil). Compliance with ethical standards The research did not involve human participants. All authors have approved the submission of the manuscript; the findings have not been published or are not under consideration for publication elsewhere. This work was supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior CAPES (Brazil). Conflict of interest The authors declare that they have no conflict of interest.

References Allen, R. G., Pereira, L. S., Raes, D., & Smith, M. (1998). Crop evapotranspiration-Guidelines for computing crop water requirements-FAO Irrigation and drainage paper 56. FAO, Rome, 300(9), D05109. Almeida, A. M., Hau, B., Amorim, L., Bergamin, F. A., & Mariano, J. C. (2015). Tillage system effect on the epidemic of soybean brown spot. Tropical Plant Pathology, 40(6), 362–367. Altschul, S. F., Madden, T. L., Schaffer, A. A., Zhang, J., Zhang, Z., Miller, W., & Lipman, D. J. (1997). Gapped BLAST and PSI-BLAST: a new generation of protein database search programs. Nucleic Acids Research, 25(17), 3389–3402. Alvares, C. A., Stape, J. L., Sentelhas, P. C., Gonçalves, J. L. M., & Sparovek, G. (2014). Köppen’s climate classification 366 map for Brasil. Meteorologische Zeitschrift, 22(6), 711–728. Ambrósio, M. M. Q., Dantas, A. C., Martínez-Perez, E., Medeiros, A. C., Nunes, G. H. S., & Picó, M. B. (2015). Screening a variable germplasm collection of Cucumis melo L. for

seedling resistance to Macrophomina phaseolina. Euphytica, 206(2), 287–300. Andrade, D. E. G. T., Michereff, S. J., Biondi, C. M., Nascimento, C. W. A., & Sales Júnior, R. (2005). Freqüência de fungos associados ao colapso do meloeiro e relação com características físicas, químicas e microbiológicas dos solos. Summa Phytopathologica, 31(4), 327–333. Andrioli, I., Beutler, N. A., Centurion, J. F., Andrioli, F. F., & Coutinho, E. L. M. (2008). Produção de milho em plantio direto com adubação nitrogenada e cobertura do solo na pré-safra. Revista Brasileira de Ciência do Solo, 32(4), 1691–1698. Bettiol, W., & Ghini, R. (2005). Solos Supressivos. In S. J. Michereff, D. E. G. T. Andrade, & M. Menezes (Eds.), Ecologia e Manejo de patógenos radiculares em solos tropicais (pp. 125–143). Recife: UFRPE. Bonanomi, G., Antignani, V., Pane, C., & Scala, F. (2007). Suppression of soilborne fungal disease with organic amendments. Journal of Plant Pathology, 89(3), 311–324. Botelho, A. S., Rava, C. A., Leandro, W. M., & Costa, J. L. S. (2001). Supressividade induzida a Rhizoctonia solani Kuhn pela adição de diferentes resíduos vegetais ao solo. Pesquisa Agropecuária Tropical, 31(1), 35–42. Bruton, B. D., Jeger, M. J., & Reuveni, R. (1987). Macrophomina phaseolina infection and vine decline in cantaloupe in relation to planting date, soil environment, and plant maturation. Plant Disease, 71(3), 259–263. Bueno, C. J., Ambrósio, M. M. Q., & Souza, N. L. (2004). Controle de Fusarium oxysporum f. sp. lycopersici raça 2, Macrophomina phaseolina e Sclerotium rolfsii em microcosmo simulando solarização com prévia incorporação de couve (Br as si cae o le racea v a r. a c e p h a l a L . ) . S u m m a Phytopathologica, 30(3), 356–363. Carvalho, W. P., de Carvalho, G. J., Neto, D. O. A., & Teixeira, L. G. V. (2013). Desempenho agronômico de plantas de cobertura usadas na proteção do solo no período de pousio. Pesquisa Agropecuária Brasileira, 48(2), 157–166. Cohen, R., Horev, C., Burger, Y., Shirber, S., Hershenhorn, J., Katan, J., & Edelstein, M. (2002). Horticultural and pathological aspects of fusarium wilt management using grafted melons. HostScience, 37(7), 1069–1073. Cohen, R., Omari, N., Porat, A., & Edelstein, M. (2012). Management of Macrophomina wilt in melons using grafting or fungicide soil application: pathological, horticultural and economical aspects. Crop Protection, 35, 58–63. Cohen, R., Pivonia, S., Burger, Y., Edelstein, M., Gamliel, A., & Katan, J. (2000). Towards integrated management of Monosporascus wilt of melons in Israel. Plant Disease, 84(5), 496–505. Cunha, J. L. X. L., Freitas, F. C. L, Ambrósio, M. M. Q., Fontes, L. O., Nascimento, P. G. M. L., Guimarães, L. M. S. (2014). Comunidade microbiana do solo cultivado com pimentão nos sistemas de plantio direto e convencional associado ao manejo de plantas daninhas. Planta Daninha, 32(3), 543–554. Dantas, A. M. M., Ambrósio, M. M. Q., Nascimento, S. R. C., Senhor, R. F., Cézar, M. A., & Lima, J. S. S. (2013). Incorporation of plant materials in the control of root pathogens in muskmelon. Revista Agro@mbiente On-line, 7(3), 338–344. Darby, H. M., Stone, A. G., & Dick, R. P. (2006). Compost and manure mediated impacts on soilborne pathogens

Eur J Plant Pathol and soil quality. Soil Science Society of America Journal, 70(2), 347–358. Dias, R. C. S., Picó, B., Espinos, A., & Nuez, F. (2004). Resistance to melon vine decline derived from Cucumismelo sp. agrestis: genetic analysis of root structure and root response. Plant Breeding, 123(1), 66–72. Duniway, J. M. (2002). Status of chemical alternatives to methyl bromide for pre-plant fumigation of soil. Phytopathology, 92(12), 1337–1343. Everts, K. L. (2002). Reduced fungicide applications and host resistance for managing three diseases in pumpkin grown on a no-till cover crop. Plant Disease, 86(10), 1134–1141. Fao.Faostat (2015). Disponível em:< http://faostat.fao.org>. Accessed on march 24. Fao.Faostat (2016). Disponível em: < http://faostat.fao.org>. Acessed on january 25. Fernandes, F. T., & Oliveira, E. D. (1997). Principais doenças na cultura do milho. Embrapa Milho e Sorgo-Circular Técnica (INFOTECA-E). Gamliel, A., Grinstein, A., & Katan, J. (1996). Combining solarization and fumigants as feasible alternatives to methyl bromide. In Proc. Annu. Int. Res. Conf. Methyl Bromide Alternatives Emission Reduction, 3rd. Orlando FL (pp. 17–18). Görgen, C. A., Silveira Neto, A. N., Carneiro, L. C., Ragagnin, V., & Lobo Junior, M. (2009). Controle do mofo-branco com palhada e Trichoderma harzianum 1306 em soja. Pesquisa Agropecuária Brasileira, 44(12), 1583–1590. Guimarães, I. M., Sales Junior, R., Silva, K. J. P., Michereff, S. J., & Nogueira, D. R. S. (2008). Efeito de fluazinam no controle Monosporascus cannonballus, agente causal do declínio de ramas em meloeiro. Revista Caatinga, 21(4), 147–153. IBGE, Dados de melão. (2015). Available at: http://www.ibge.gov. br. Accessed on march 24. Jimenez, R. L., Gonçalves, W. G., Araújo Filho, J. D., Assis, R. L., Pires, F. R., & Silva, G. P. (2008). Crescimento de plantas de cobertura sobdiferentes níveis de compactação em um latossolo vermelho. Revista Brasileira de Engenharia Agrícola e Ambiental, 12(2), 116–121. Ko, W., & Hora, F. (1971). A selective medium for the quantitative determination of Rhizoctonia solani in soil. Phytopathology, 61(6), 707–710. Larkin, R. P. (2013). Green manures and plant disease management. CAB Reviews, 8(37), 1–10. Leslie, J. F., & Summerell, B. A. (2006). The Fusarium Laboratory Manual. Malden: Blackwell Publishing. Linhares, C. M. S., Freitas, F. C. L., Ambrósio, M. M. Q., Cruz, B. L. S., & Dantas, A. M. M. (2016). Efeito de coberturas do solo sobre a sobrevivência de Macrophomina phaseolina no feijão-caupi. Summa Phytopathologica, 42(2), 155–159. Lobo Junior, M., Brandão, R. S., Corrêa, C. A., Görgen, C. A., Civardi, E. A., & Oliveira, P. D. (2009). Uso de braquiárias para o manejo de doenças causadas por patógenos habitantes do solo. Embrapa Arroz e Feijão-Comunicado Técnico (INFOTECA-E). Lopes, C. A., Reis, A., & Boiteux, L. S. (2005). Doenças fúngicas (pp. 17–51). Embrapa Hortaliças: Doenças do tomateiro. Brasília. Massenssini, A. M., Bonduki, V. H. A., Tótola, M. R., Ferreira, F. A., & Costa, M. D. (2014). Soil microorganisms and their role in the interactions between weeds and crops. Planta Daninha, 32(4), 873–884.

Narayan, S., Kumar, V., & Singh, S. (2015). Studies on the effect of bio-pesticides on muskmelon wilt (Fusariumoxysporumf.sp. melonis). HortFlora Research Spectrum, 4(3), 250–254. Noling, J. W., & Becker, J. O. (1994). The challenge of research and extension to define and implement alternatives to methyl bromide. Journal of Nematology, 26(4S), 573–586. O’Donnell, K., Kistler, H. C., Cigelnik, E., & Ploetz, R. C. (1998). Multiple evolutionary origins of the fungus causing Panama disease of banana: concordant evidence from nuclear and mitochondrial gene genealogies. Proceedings of the National Academy of Sciences of the United States of America, 95(5), 2044–2049. O’Donnell, K., Sutton, D. A., Fothergill, A., McCarthy, D., Rinaldi, M. G., Brandt, M. E., Zhang, N., & Geiser, D. M. (2008). Molecular phylogenetic diversity, multilocus haplotype nomenclature, and in vitro antifungal resistance within the Fusarium solani species complex. Journal of Clinical Microbiology, 46(8), 2477–2490. Ochiai, N., Powelson, M. L., Dick, R. P., & Crowe, F. J. (2007). Effects of green manure type and amendment rate on Verticillium wilt severity and yield of Russet Burbank potato. Plant Disease, 91(4), 400–406. Oumouloud, A., El-Otmani, M., Chikh-Rouhou, H., Claver, A. G., Torres, R. G., Perl-Treves, R., & Alvarez, J. M. (2013). Breeding melon for resistance to Fusarium wilt: recent developments. Euphytica, 192(2), 155–169. Pereira Neto, J. V., & Blum, L. E. B. (2010). Adição de palha de milheto ao solo para redução da podridão do colo em feijoeiro. Pesquisa Agropecuária Tropical, 40(3), 354–361. Pérez-Hernández, A., Porcel-Rodríguez, E., & Gómez-Vázquez, J. (2017). Survival of Fusarium solani f. sp. cucurbitae and fungicide application, soil solarization, and biosolarization for control of crown and foot rot of Zucchini Squash. Plant Disease, 101(8), 1507–1514. Ribeiro Júnior, J. I. (2004). Análises estatísticas no Excel: guia prático, Viçosa (MG): Ed. Rossi, C. E. (2002). Adubação verde no controle de nematóides. Agroecologia Hoje, Botucatu, 2(14), 26–27. Salari, M., Panjehkeh, N., Nasirpoor, Z., & Abkhoo, J. (2012). Reaction of melon (Cucumis melo L.) cultivars to soil-borne plant pathogenic fungi in Iran. African Journal of Biotecnology, 11(87), 15324–15329. Sales, J. R., Beltrán, R., Vicent, A., Armengol, J., García-Jiménez, J., & Medeiros, E. V. (2007). Controle biológico de Monosporascus cannonballus com Chaetomium. Fitopatologia Brasileira, 32(1), 70–74. Schillinger, W. F., & Paulitz, T. C. (2014). Natural suppression of Rhizoctonia bare patch in a long-term no-till cropping systems experiment. Plant Disease, 98(3), 389–394. Schroeder, K. L., & Paulitz, T. C. (2006). Root diseases of wheat and barley during the transition from conventional tillage to direct seeding. Plant Disease, 90(9), 1247–1253. Silva, F. A. S. (2008). Sistema de Assistência Estatística– ASSISTAT versão 7.6 beta (em linha). Departamento de Engenharia Agrícola/DEAG, CTRN, Universidade Federal de Campina Grande/UFCG, Paraíba, Brasil, Campina Grande. Disponívelem http://www.assistat.com. Stapleton, J. J. (2000). Soil solarization in various agricultural production systems. Crop Protection, 19(8), 837–841. Stone, A. G., Scheuerell, S. J., & Darby, H. M. (2004). Suppression of soilborne diseases in field agricultural

Eur J Plant Pathol systems: organic matter management, cover cropping, and other cultural practices. In F. Magdoff & R. R. Weil (Eds.), Soil organic matter in sustainable agriculture (pp. 131–177). Florida: CRC Press. Stone, A. G., Vallad, G. E., Cooperband, L. R., Rotenberg, D., Darby, H. M., James, R. V., Stevenson, W. R., & Goodman, R. M. (2003). Effect of organic amendments on soilborne and foliar diseases in field-grown snap bean and cucumber. Plant Disease, 87(9), 1037–1042. Teixeira, C. M., Carvalho, G. J., Andrade, M. J. B., Silva, C. A., & Pereira, J. M. (2009). Decomposição e liberação de nutrientes das palhadas de milheto e milheto+ crotalária no plantio direto do feijoeiro. Acta Scientiarum Agronomy, 31(4), 647–653. Teodoro, R. B., Oliveira, F. L., Silva, D. M. N., Fávero, C., & Quaresma, M. A. L. (2011). Aspectos agronômicos de leguminosas para adubação verde no cerrado do Alto Vale do Jequitinhonha. Revista Brasileira de Ciência do Solo, 35(2), 635–643. Teófilo, T. M. S., Freitas, F. C. L., Medeiros, J. F., Fernandes, D., Grangeiro, L. C., Tomaz, H. V. Q., & Rodrigues, A. P. M. S.

(2012). Eficiência no uso da água e interferência de plantas daninhas no meloeiro cultivado nos sistemas de plantio direto e convencional. Planta Daninha, 30(3), 547–556. Toledo-Souza, E. D., Silveira, P. M., Lobo Junior, M., & Café Filho, A. C. (2008). Sistemas de cultivo, sucessões de culturas, densidade do solo e sobrevivência de patógenos de solo. Pesquisa Agropecuária Brasileira, 43(8), 971–978. Torres, J. L. R., Pereira, M. G., Andrioli, I., Polidoro, J. L., & Fabian, A. J. (2005). Decomposição e liberação de nitrogênio de resíduos culturais de plantas de cobertura em um solo de Cerrado. Revista Brasileira de Ciências do Solo, 29(4), 609–618. Tosta, P. A. F., Mendonça, V., Tosta, M. S., Machado, J. R., Tosta, J. S., & Medeiros, L. F. (2010). Utilização de coberturas de solo no cultivo de alface ‘Babá de Verão’ em Cassilândia (MS). Revista Brasileira de Ciências Agrárias, 5(1), 85–89. Weller, D. M. (2007). Pseudomonas biocontrol agents of soilborne pathogens: Looking back over 30 years. Phytopathology, 97(2), 250–256.