Jebagro and Demeter a quality alliance
Use of Nano Xtinger 10 GW (Trichoderma asperellum 5%, Trichoderma harzianum 5%) as a biological controller and as an antagonist microorganisms for management of the causative agent of Black Sigatoka (Mycosphaerrella fijiensis) in Banana (Musa paradisiaca) in Nicaragua 2020.
1Hebert Ocón Zúniga.
1 Researcher of Consulting and Professional Ocón Services for Biological Testing
ABSTRACT
This study was completed in November 2020 in “El Viejo “, a municipality in the department of Chinandega, Nicaragua. It was developed on Farm Santa Teresa with the aim of controlling Black Sigatoka disease (Mycosphaerrella fijiensis). The treatmentsevaluated in this study are T1 Nano Xtinger 10 GW 1.0 l.ha-1, T2 Nano Xtinger 10 GW 1.45 l.ha-1, T3 Nano Xtinger 10 GW 2.0 l.ha-1, T4 Serenade 1.34 SC 1.0 l.ha-1 and T5 Control. The arrangement of Complete Blocks was randomized with five treatments and five repetitions. The variables evaluated in this study are: incidence, severity, weighted average of infestation and thepercentage of biological efficacy of Black Sigatoka disease. The results indicate significant differences (P 0.05) within the variables studied. The results of T2 Nano Xtinger 10 GW 1.45 l.ha-1 show the lowest incidence level on Sigatokaat 8,0% 30 days after application (daa) as it only reached grade 1 severity with 9.52%, the percentage of efficacy on Sigatoka was 92.00% at 30 daa. It is important to note that T2 Nano Xtinger 10 GW presented WAI: 0.0952 at 30 daa; placing itself below the economic threshold which is 0.50. The data was stabilized using the Shapiro-Wilk normality test, and non-parametric Friedman tests.
Keywords: Mycosphaerrella fijiensis.
INTRODUCTION
Banana (Musa paradisiaca) is a polymorphic fruit that can contain 5-20 hands, each with 2-20 fruits, and is greenish-yellow in color. Edible plantains of vegetative parthenocarpy, meaning they develop an edible pulp without being pollinated. Most Musaceae fruits are edible and sterile, due to female sterility genes, triploidy and chromosomal structural changes (Almodóvar, 2001).
Bananas (Musa paradisiaca) are tropical fruits. They are ancient plants originating in southwestern India, where the largest number of clones are found,and America is their second center of origin. It is fourth most important fruit crop in the world. The largest production in international trade is carried out by Latin American countries and the Caribbean, producing 10 million tons, of which 30 million tons are traded worldwide (IICA, 2014).
On banana plantations, the fungal disease know as Black Sigatoka (Mycosphaerrella fijiensis) is one of the main diseases that cause severe damage to fruit size and quality loss, which in turn effects the profitability..
Due to the aforementioneddamage that Black Sigatoka (Mycosphaerrella fijiensis) is causing in Bananas, this fungal disease is of economic importance in cultivation. The company Demeter Nanotechnologies Inc, has conducted this research in order to assess the biological efficacy of Sigatoka through the preventive use of Nano Xtinger 10 GW (Trichoderma asperellum 5%, Trichoderma harzianum 5%), and to r to mitigate the occurrenceas well as severity of Black Sigatoka disease on Farm Santa Teresa, ” El Viejo” in Chinandega, Nicaragua.
| Grade | Description of leaf damage |
| 1 | Up 10 spots per banana leaf |
| 2 | Less than 5% diseased leaf area |
| 3 | From 6 to 15% diseased leaf area |
| 4 | From 16 to 33% diseased leaf area |
| 5 | From 34 to 50% diseased leaf area |
| 6 | More than 50% diseased leaf area |
The leading objetive was to evaluate the biological efficacy to a phytopathogenic fungus that affects the leaf area of bananas with Black Sigatoka disease by applying Nano Xtinger 10 GW in different doses at 1.0 l.ha-1, 1.45 l.ha-1 y 2.0 l.ha-1 on Farm Santa Teresa inWinter 2020. Other objetives are to determine the incidence and severity of Black Sigatoka in the foliar area of upper banana leaves.
MATERIAL AND METHODS
Location and description of place
This study was carried out at Farm Santa Teresa “El Viejo”, municipality of Chinandega, Nicaragua. This farm exports banana fruits to Europe and the U.S. The farm is located at an elevation of 47 meters above sea level. Its coordinates are 12° 40′ 00″ north latitude and 86° 10′ 00″ west longitude. The average anual temperature is 27 °C with an average anual rainfall of 1,846 mm and anaverage anual relative humidity at 74%.
Evaluated treatments
The following treatments are included in the evaluation: Nano Xtinger 10 GW (Trichoderama asperellum T. harzianum) and Serenade 1.34 SC (Bacillus subtilis).
Table 1. Evaluated treatment of essay
| Treatments | CFC | Doses (ha-1) |
| T1 Nano Xtinger 10 GW | 3 x 10 11 | 1.00 l |
| T2 Nano Xtinger 10 GW | 3 x 10 11 | 1.45 l |
| T3 Nano Xtinger 10 GW | 3 x 10 11 | 2.00 l |
| T4 Serenade 1.34 SC | 1 x 109 | 1.00 l |
| T5 Control | – | – |
Type of application
The application was carried out with a motor pump directed to the foliar area. For this purpose, a volume of 200 liters of water per hectare was used. To regulate the pH of water and hardness, Tri-fol Plus was used in an amout of 2 ml per liter of water.
Field evaluations
Measurements and evaluations have been performed at the regular intervals: first before application (0 dba), second (10 daa), third (20 daa) and fourth evaluation (30 daa). The method used was Modified Stover in evaluations in cultivation of Bananas for control of black Sigatoka.
Table 2. Modified Stover Scales
Source: Modified Stover Method.
Figure 1. Grades of Modified Stover to evaluate Black Sigatoka.
Variables evaluated
The variables that were evaluated in combination with Modified Stover are: incidence, severity, biological efficacy of Black Sigatoka and phytotoxicity in banana cultivation after application.
Phytotoxicity to banana cultivation
The phytotoxicity was evaluated after the application of biological fungicide Nano Xtinger 10 GW. 10 days after the application of the fungicide, the leaves of the banana crop showed no symptoms of phytotoxicity.
Table 3. Phytotoxicity scales in banana cultivation
| Grade | Percentage of damaged tissue |
| 0 | 0% leaf blade affected |
| 1 | 10% leaf blade affected |
| 2 | 20% leaf blade affected |
| 3 | 30% leaf blade affected |
| 4 | 40% leaf blade affected |
| 5 | 50% leaf blade affected |
| 6 | More than 51% leaf blade affected |
Experimental design
The experimental design was a Random Complete Block, the course consisted of 4 treatments, each treatment had an area of 64 square meters, the area of the block was 256 m2. The total experimental area was 1,120 m2.
Statistical analysis
The Statistical Analysis System (SAS) was used and data were normalized through a Levene Test and non-parametric Friedman tests were used. Analysis of variance was determined using Tukey’s Multiple Ranges with 95% confidence.
RESULTS
Incidence of Black Sigatoka
The Variance analysis shows that significant differences (P 0.05) within treatment evaluated in variable of incidence of Sigatoka.T2 Nano Xtinger 10 GW achieved the lowest figures with respectively 0.0%, 2.2% 8.0% at 10 daa, 20 daa and 30 daa . Meanwhile, T5 Control had a higher incidence with 17.58% at 30 daa (See Table 4).
Table 4. Percentage of incidence of Sigatoka (%)
| Treatment | 0 dba | 10 daa | 20 daa | 30 daa |
| T1 N.X 10 GW | 28.2 a | 22.8 a | 25.6 a | 22.9 a |
| T2 N. X 10 GW | 3.3 c | 0.0 d | 2.2 d | 8.0 c |
| T3 N.X 10 GW | 11.8 b | 2.5 c | 4.4 c | 18.8 b |
| T4 S. 1.34 SC | 9.4 b | 15.1 b | 10.0 b | 8.0 c |
| T5 Control | 9.0 b | 12.2 b | 15.0 b | 17.5 |
| C.V % | 13.57 | 15.11 | 11.54 | 15.12 |
| R2 | 0.9671 | 0.9679 | 0.973 | 0.9531 |
| Tukey (P 0.05) | * | * | * | * |
Source: SAS. Different letters from each other denote significant difference within treatments.
Severity of Black Sigatoka Grade 1
The analysis of variance indicates that there are significant differences (P 0.05) within treatments studied in terms of severity 1. T2 Nano Xtinger 10 GW acquires lowest severities with respectively 0.0%, 2.5% and 9.52% at 10 daa, 20 daa and 30 daa , and consequently surpasses T5 Control, which scores 9.66%, 11.74% and 20.15% at 10 dda, 20 dda and 30 daa (See Table 5).
Table 5. Porcentage of severity of grade 1
| Treatment | 0 dba | 10 daa | 20 daa | 30 daa |
| T1 N.X 10 GW | 26.1 a | 22.4 a | 25.4 a | 16.3 b |
| T2 N. X 10 GW | 3.2 d | 0.0 d | 2.5 d | 9.5 c |
| T3 N.X 10 GW | 9.6 b | 2.7 c | 5.1 c | 19.5 a |
| T4 S. 1.34 SC | 6.2 c | 13.8 b | 12.8 b | 5.4 d |
| T5 Control | 8.0 b | 9.6 | 11.7 | 20.1 a |
| C.V % | 5.1 | 7.22 | 6.55 | 4.33 |
| R2 | 0.9998 | 0.8986 | 0.7531 | 0.8887 |
| Tukey (P 0.05) | * | * | * | * |
Source: SAS. Different letters from each other denote Significant difference within treatments.
Severity of Black Sigatoka Grade 2 and 6
The analysis of variance indicates that there are significant differences (P 0.05) in grades of severity 2 and 6 of Black Sigatoka. It is notewothy that treatments 2 and 3 did not present any severity (0.0%) of grade 2 and 6 at 10 daa, 20 daa and 30 daa when T2 Nano Xtinger 10 GW was applied. However, in each case T4 Serenade 1.34 SC and T5 Control reached severity values of grade 2 with 2.7%, 5.3%, 12.4% and 7.8%.
Table 6. Porcentage of severidad. Grade 2 and 6
| Treatment | Grade 2 | Grade 6 | ||
| 0 dba | 10 daa | 30 daa | 30 daa | |
| T1 N.X 10 GW | 2.3 b | 0.0 b | 5.4 a | 0.0 b |
| T2 N. X 10 GW | 0.0 c | 0.0 b | 0.0 c | 0.0 b |
| T3 N.X 10 GW | 0.0 c | 0.0 b | 0.0 c | 0.0 b |
| T4 S. 1.34 SC | 6.2 a | 2.7 a | 2.7 b | 5.3 a |
| T5 Control | 5.0 a | 7.3 a | 12.4 a | 7.85 a |
| C.V % | 4.12 | 6.34 | 7.22 | 8.51 |
| R2 | 0.8765 | 0.9812 | 0.7654 | 0.9876 |
| Tukey (P 0.05) | * | * | * | * |
Source: SAS. Different letters from each other denote Significant difference within treatments.
Weighted Average Infestation of Sigatoka
The analysis of variance shows that there is a difference (P 0.05) in the variable of weighted average of infestation, T2 Nano Xtinger 10 GW turned out to be the lowest with 0.09, surpassing T4 Serenade 1.34 SC that obtained 0.27 of WAI at 30 daa. It is important to mention that even treatments 1 and 3 of Nano Xtinger 10 GW are at a low economic threshold, therefore, threshold is 0.50 of WAI. It is 5.0 % of infestation to make decisión to apply against to disease Black Sigatoka (See Table 7).
Table 7. Weighted Average Infestation of Sigatoka
| Treatment | 0 dba | 10 daa | 20 daa | 30 daa |
| T1 N.X 10 GW | 0.31 a | 0.22 | 0.25 | 0.27 |
| T2 N. X 10 GW | 0.03 d | 0 | 0.03 | 0.1 |
| T3 N.X 10 GW | 0.10 c | 0.03 | 0.05 | 0.2 |
| T4 S. 1.34 SC | 0.19 b | 0.19 | 0.12 | 0.27 |
| T5 Control | 0.17 b | 0.21 | 0.29 | 0.61 |
| C.V % | 4.33 | 8.5 | 2.68 | 3.84 |
| R2 | 0.8543 | 0.9871 | 0.8765 | 0.7765 |
| Tukey (P 0.05) | * | * | * | * |
Source: SAS. Different letters from each other denote Significant difference within treatments.
Biological Efficacy of Black Sigatoka
The analysis of variance indicates that there are significant differences (P 0.05) within studied treatments. T2 Nano Xtinger 10 GW obtained highest values of Biological Efficacy on Black Sigatoka disease with 100.0%, 98.0% and 92.0% at 10 daa, 20 daa and 30 daa , surpassing T5 Control, that had no control (0.0%) on Black Sigatoka disease at 10 daa, 20 daa and 30 daa .
Table 8. Percentage biological efficacy of Sigatoka
| Treatment | 10 daa | 20 daa | 30 daa |
| T1 Nano Xtinger 10 GW | 77.40 c | 75.20 c | 84.00 b |
| T2 Nano Xtinger 10 GW | 100.00 a | 98.00 a | 92.00 a |
| T3 Nano Xtinger 10 GW | 98.00 a | 96.00 a | 89.00 a |
| T4 Serenade 1.34 SC | 85.00 c | 90.00 b | 92.00 a |
| T5 Control | 0.00 d | 0.00 d | 0.00 c |
| C.V % | 7.97 | 10.35 | 8.48 |
| R2 | 0.7762 | 0.6724 | 0.8641 |
| Tukey (P 0.05) | * | * | * |
Source: SAS. Different letters from each other denote Significant difference within treatments.
The T2 Nano Xtinger 10 GW is a treatment that maintained low infestation on Black Sigatoka during all field trialss, showing a high biological efficacy (92.0%) of this control agent consisting of two beneficial microorganisms such as Trichoderma asperellum and Trichoderma harzianum, which are antagonists for Mycosphaerrella fijiensis disease in banana plants. Moreover, the same treatment 2, shows a low weighted average infestation with respect to the economic threshold of 5.0% according to Modified Stover. Meanwhile, T2 Nano Xtinger 10 GW reaches WAI 0.10 (1.0 %) at 30 days after fungicide application, remaining below 4.0%, below threshold established by this method.
CONCLUSIONS
- The use of T2 Nano Xtinger 10 GW resulted in 9.5% less incidence than T5 Control 30 days after application.
- In addition, T2 Nano Xtinger 10 GW classifies as grade 1, with 6% severity less than T5 Control, which obtained 20.1% severity according to Modified Stover at 30 daa. T2 never presented symptoms of severity in grades 2 and 6, presenting 0.0% in both grades evaluated.
- Furthermore, T2 Nano Xtinger 10 GW obtained a high biological efficacy on Black Sigatoka, (Mycosphaerrella fijiensis) reaching 92.0% and a WEI of 0.1, which would convert into 1.0%, making it far from applying, since it requires 2.0% or 5.0% in order to make decision to apply to control Sigatoka in banana cultivation.
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