RESEARCH FOR ACTION
UNIVERSITÀ DEGLI STUDI DI TORINO
www.agrinewtech.com
M. Pugliese1, A. Cucu2, G. Gilardi2, M. L. Gullino2,3, A. Garibaldi2 1 AgriNewTech srl, Torino, Italy. E-mail: [email protected]
2 Agroinnova – Centre of Competence for the innovation in the agro-environmental field, University of Torino, Italy. 3 Department of Agricultural, Forest and Food Sciences (DISAFA), University of Torino, Italy.
EFFECT OF COMPOSTS AND BCAS ON LETTUCE FUSARIUM WILT
AND ON MICROBIAL COMMUNITIES
EUCLID Conference Avignon, September 12th, 2019
Lettuce Fusarium wilt, caused by Fusarium oxysporum f. sp. lactucae, represents a major problem in most lettuce production areas
worldwide. The seed transmission of this pathogen and the capacity of inoculums to survive in the soil for years, makes soil disinfection
only partially effective. The use of biological control agents (BCAs) and of suppressive composts starting from the nursery is considered
a more effective and sustainable strategy.
Composts, applied in nursery at 10% and in soil mixture before transplanting at 1
kg/m2, provided a consistent Fusarium wilt reduction from 51 to 69%. The
application of BCAs at the nursery level also provided a disease reduction from 44%
to 60% in the field trials (Table 2).
The use of composts and BCAs appears as an effective and safe strategy to implement sustainable crop protection strategies.
Two composts and different commercially available and experimental BCAs were applied (Table 1), in a naturally infested field
experiment, against lettuce wilting, over two lettuce cultivar ‘Novelsky’ cropping seasons (Fig. 1). The effects on rhizosphere and soil
indigenous total microbial communities, nitrifiers and different functional genes (fungal chitinase, bacterial 2,4-diacetylphloroglucinol
and HCN synthase) were also investigated.
Treatments Dosage Application time
on trays in nursery Application time in field
Bacillus subtilis QST 713 (Serenade max) 2.9X1010 cells/l water At day 5, 10, 15, 20 - Trichoderma asperellum ICC 012 + T. gamsii ICC 080 (Remedier) 1.2X106 cells/l water At day 5, 10, 15, 20 -
Pseudomonas putida strains FC7B+ FC8B +FC9B 1x107 (cells /ml water) At day 5, 10, 15, 20 - Green compost + Trichoderma sp. TW2 (ANT’s compost M) 8g/seedling;
1kg/1m2 of soil At day 0 -
At day 20 Green compost (ANT’s compost) 8 g/seedling;
1kg/1m2 of soil At day 0 -
At day 20 Trichoderma sp. TW2 1x107 (cells /ml) At day 5, 10, 15, 20 Azoxystrobin (Ortiva) 0.19 g active ingredient/l water At day 20
Table 1 - Treatments, dosage and timings applied in the trials.
Treatments Disease severity % Disease
reduction % Fresh weight g/12 plants Trial 1 Trial 2
Bacillus subtilis QST 713 (Serenade max) 24.5 ±1.6ab* 60ab 3135.6 ±128.9a 2727.2 ±371.5ab Trichoderma asperellum ICC 012 + T. gamsii
ICC 080 (Remedier) 28.6 ±2.7ab 54ab 2731.0 ±79.0a 2868.4 ±348.7ab
Pseudomonas putida strains FC7B+ FC8B +FC9B
31.65 ±2.6ab 49ab 3090.7 ±49.6a 1528.0 ±67.2bc
Green compost + Trichoderma sp. TW2 (ANT’s compost M)
19.15 ±2.9a 69 a 3256.3 ±267.6a 3766.0 ±481.6a
Green compost (ANT’s compost) 30.5 ±2.5ab 51ab 3323.9 ±146.7a 3747.6 ±130.1a Trichoderma sp. TW2 34.3 ±2.7b 44 b 2815.7 ±78.6a 1917.6 ±134.7bc Azoxystrobin (Ortiva) 22.3 ±4.0ab 64ab 3014.0 ±185.3a 3360.4 ±273.0a
Untreated control 61.7 ±3.5c 0 c 1745.7 ±93.0b 770.8 ±243.1c
Table 2 – Effect of the treatments with BCAs and composts on Fusarium wilt of lettuce.
Treatment
Bacillus subtilis - Serenade max - SM 5.063 a 5.435 a
Trichoderma spp. - Remedier - RM 4.221 c 4.120 d
Pseudomonas putida - Pp 3.985 c 4.326 c
ANT's compost M - CM 4.505 b 4.802 b
ANT's compost V - CV 3.986 c 4.328 c
Trichoderma sp. - TW2 3.647 d 3.903 d
Untreated control - C 3.616 d 3.875 d
P(F) Treat 0.000
Bacillus subtilis - Serenade max - SM 4.316 b 3.915 c
Trichoderma spp. - Remedier - RM 4.221 b 4.128 c
Pseudomonas putida - Pp 4.760 a 4.644 a
ANT's compost M - CM 4.809 a 4.408 b
ANT's compost V - CV 4.086 b 4.060 c
Trichoderma sp. - TW2 3.695 c 3.795 c
Untreated control - C 3.465 c 3.243 d
P(F) Treat 0.000
Bacillus subtilis - Serenade max - SM 3.962 d 2.915 c
Trichoderma spp. - Remedier - RM 4.297 c 3.180 bc
Pseudomonas putida - Pp 3.991 cd 3.414 b
ANT's compost M - CM 4.953 b 3.979 a
ANT's compost V - CV 4.534 c 4.117 a
Trichoderma sp. - TW2 5.667 a 3.926 a
Untreated control - C 3.767 e 2.839 c
P(F) Treat 0.000
Trichoderma (log copy gene g¯¹ dry soil)
Bacillus (log copy gene g¯¹ dry soil)
Pseudomonas (log copy gene g¯¹ dry soil)
Rhizosphere soil Bulk soil
Table 3 – Abundance of Bacillus sp., Trichoderma sp.
and Pseudomonas sp. genes in the rhizosphere and
bulk soil at the end of both trials.
*Different letters indicate significant differences between treatments according to Tukey’s HSD (p<0.05)
Figure 1 - Field trial on lettuce cv Novelsky.
Furthermore, the treatments improved the abundance of Bacillus sp., Trichoderma sp.
and Pseudomonas sp. in the rhizosphere and bulk soil (Table 3), while they did not
influence negatively the non-target microbial communities.