The effectiveness of Biofumigants from Brassicaceae and Non-Brassicaceae to control root knot Nematodes on tomato

. Root-knot nematodes (Meloidogyne spp.) are considered as one of the main limiting factors in crop production systems. Currently, several eco-friendly root-knot nematodes control technologies have been developed, one of which is biofumigants. The purpose of this study was to determine the effectiveness of biofumigants from Brassicaceae and Non-Brassicaceae to control root-knot nematodes. The study was conducted using a one-factor Completely Randomized Design (CRD) with 5 treatments. The results showed that the application of biofumigants from both brassicaceae and non-brassicaceae had no significant effect on the height and number of leaves of tomato. The effectiveness of cabbage biofumigant suppressing the population of RKN in this study was 69.5% compared to control (untreatment). While the treatment of sorghum biofumigant was the better treatment as a biofumigant plant from Non-Brassicaceae with an effectiveness level of suppressing the population of RKN was 55.8% compared to control. While the effectiveness level of suppressing the population of RKN biofumigant tagetes was 36.6% compared to control.


Introduction
Root-knot Nematodes (RKN) can cause significant damage to plants because they affect the growth of the root system so that plant growth is inhibited due to lack of nutrient uptake from the soil and roots are at risk of secondary pathogens [1].Several control techniques have been used to eradicate or at least reduce the damage caused by root-knot nematodes.In general, the control technique that is often used is with chemically, namely nematicides.In addition, other control techniques that can be used are soil fumigation.Control techniques with fumigants (high doses of nematicides) include methyl bromide, DBCP, chloropisrine, etc. has long been used effectively to reduce the RKN population to below the economic threshold level [2].However, due to stricter regulations from the government, many of these nematicides have been phased out due to their toxic effects on the environment [3].Control of plant parasitic nematodes by fumigation (pesticide fumigant) is a control technique that is widely applied in several plants and has been shown to reduce the attack rate of plant parasitic nematodes transmitted through soil.Fumigant compounds are known to contribute to the emission of volatile organic compounds that have an impact on poor air quality for some plants [4].It was reported that the market turnover for fumigation in 2019 reached USD 938.61 million worldwide and is expected to continue to increase over the next 5 years with a growth of 5%.With soil fumigation included and its use is known to have been restricted to several countries around the world hence it is necessary to have alternative techniques for controlling root-knot nematodes that are environmentally friendly, one of which is by using biofumigation.
Biofumigation is a control technique by combining several plant materials, generally from the type of cabbage, which are mechanically cut and put into the soil.Cabbage plants are known to produce secondary metabolites in the form of glucosinolate (GSL) which are toxic to several pathogens and grasses [5].GSL secondary metabolite compounds can reduce the viability of RKN eggs (Meloidogyne incognita) through strong penetration of the cuticle layer [6].According to Anita and Biopestic [7] glucosinolate in the process will be hydrolyzed to produce isothiocyanite (ITS) which can act as a fungicide and nematicide.
In addition to using cabbage plants, several plants are also known to act as biofumigants, namely tagetes, sorghum and Sudan grass.Plants from the graminisae group such as sorghum and sudangrass are known to produce nematicidal cyanide through enzymatic hydrolysis of cyanogenic glycoside/dhurrin precursors.Sorghum seeds can secrete secondary metabolites dhurrin.The mechanism of inhibition of dhurrin against RKN is that after RKN infests plant roots, dhurrin is hydrolyzed by endogenous -D-glucoside glucohydrolase (dhurrinase) to liberate glucose and produce the unstable compound p-hydroxymandelonitrile, which is rapidly converted to toxin hydrogen cyanide (HCN) and p-hydroxybenzaldehyde by the enzymatic action of -hydroxynitrile lyase or at alkaline pH [8].Meanwhile, tagetes or kenikir known as allelopathic plants are known to produce α-terthienyl, which shows a potential biofumigation effect against root-knot nematodes [9].The roots of the Tagetes plant are known to release secondary metabolites in the form of α -terthienyl (thiophene -a sulfur polyacetylene compound).The mechanism of inhibition of -terthienyl, namely after photoactivation with near ultraviolet light (325-400 nm) α -terthienyl will react quickly by producing a type of reactive oxygen known as phytotoxic to insects and nematodes [10].This technique offers an attractive alternative for the management of plant parasitic nematodes, particularly root-knot nematodes.

Research preparation
At this stage, tomato are seeded in the Greenhouse of the Plant Protection Study Program for 15 days.The soil that has been infested by the Root-knot Nematodes (RKN) was taken from the soil of a former tomato plant belonging to a farmer from Sumberketempah Village, Kalisat District, Jember Regency which is endemic to RKN.

Research treatment
The mechanism of treatment was that cabbage, tagetes, and sorghum were chopped or cut pieces to a size between 3-4 cm, then mixed with RKN-infested soil at a dose of 0.4 kg of chopped plants/2 kg of soil (1:5).As for the nematicide with the active ingredient carbofuran, the recommended dose is 4 g/2 kg of soil.Soil that has been mixed with biofumigant is put into plastic bags without aeration, then tightly closed with a strong binding and stored for 14 days.After that, the plastic bags was opened and left for a day before the treated soil is transferred to polybags to be used as planting media.Then 15 days tomato seedlings of Tantyna F1 cultivar were planted into polybags containing treated soil, maintenance and observations were carried out for 30 days.

Screenhouse studies
The experimental design in this study used a completely randomized design (CRD).The main factor in this research is the biofumigation treatment of cabbage, tagetes, and sorghum, negative control and positive control where each treatment was repeated 5 times.Observation of growth on tomato plants was carried out by measuring plant height, number of leaves, and root weight on day 25.
Observations were made by calculating the RKN population in each treatment at 30 days after planting.The results of observations of the RKN population in each biofumigant treatment were compared with the observations of the RKN population in the negative control treatment to determine the effectiveness of the treatment.

Statistical analysis
Observational data were analyzed by one-way ANOVA using D-Staat software.The comparison between the means was carried out by Duncan's Multiple Range Test with a level of 5%.

Results and discussion
The results showed that all treatments did not have a significant effect on plant growth in terms of plant height and number of tomato leaves (Figure 1).The parameter of tomato plant height showed that treatment with carbofuran nematicide gave the highest yield, followed by treatment with cabbage biofumigant with a thin yield.This is because in the treatment with the nematicide carbofuran (Furadan 3G) in addition to chemical compounds that can kill nematodes, there are also growth regulators so that the highest tomato plant height data is obtained in that treatment.From the results of the study, it can also be concluded that the cabbage biofumigant treatment gave the best effect on plant height parameters compared to other biofumigant treatments, namely kenikir and sorghum.The use of cabbage biofumigants can have benefits such as potential for increased organic matter, better soil structure and nutrient release, all of which can increase plant vigor and growth [11].Meanwhile, the number of leaves (Figure 2) showed that the cabbage biofumigant treatment had the highest effect on the number of tomato leaves compared to other treatments.This is because the use of Brassicaceae plants such as cabbage is known to produce nitrogen for plant growth as well as P, K, Mg and C-Organic [12].Racmiati et al. [13] states that nitrogen fertilizers are needed by plants for the formation or growth of plants vegetative parts of plants such as leaves, stems and roots.For the parameters of root weight and the number of root-knot nematode populations in roots, it can be seen in Table 1.From the table it can be seen that the cabbage biofumigant treatment had the highest level of effectiveness in suppressing the Root-Knot Nematodes (RKN) population and had a significantly different effect compared to other biofumigant treatments.When compared with the control (without treatment), the effectiveness of suppression of the root-knot nematode was 69.5%.The results obtained are in accordance with the results of research conducted by Anita and Biopestic [7] on the biofumigation of cruciferous plant residues that can control root-knot nematodes.In this study, the effectiveness of suppression of root-knot nematodes was 60.6%.From Table 1, it can also be concluded that the sorghum biofumigant treatment is a treatment with a better RKN population suppression effectiveness for Non-Brassicaceae plants than the kenikir biofumigant treatment.This is because the secondary metabolite released by sorghum, namely dhurrin, has a mechanism that is more toxic to root-knot nematodes compared to tagetes which secretes a secondary metabolite -terthienyl which in general only inhibits the development of root-knot nematodes [9].The effectiveness level of suppression of root-knot nematodes in the treatment of sorghum biofumigant when compared to the control (without treatment) was 55.8%.While the effectiveness level of suppressing the population of RKN biofumigant tagetes is 36.6%compared to control.  1 it can also be concluded that the cabbage biofumigant treatment can significantly increase the wet weight of the roots compared to other treatments.This is in accordance with the statement of Racmiati et al. [13] previously that a fairly high nitrogen content, where cabbage has a high nitrogen content when compared to other organic material treatments, can help the formation and growth of not only leaves but also plant roots.

Conclusion
The biofumigant treatment from Brassicaceae, namely cabbage, was the best treatment because in addition to having the highest level of effectiveness in suppressing root-knot nematodes, it could also increase plant growth parameters in the form of plant height, number of leaves and wet weight of plant roots.The effectiveness of cabbage biofumigant suppressing the population of RKN in this study was 69.5% compared to control (untreatment).While the treatment of sorghum biofumigant was the better treatment as a biofumigant plant from Non-Brassicaceae with an effectiveness level of suppressing the population of RKN was 55.8% compared to control.While the effectiveness level of suppressing the population of RKN biofumigant tagetes was 36.6% compared to control.

Fig. 2 .
Fig. 2. The effect of biofumigant treatment on number of tomato leaves.

Table 1 .
The effect of biofumigant treatment on the suppression of root-knot nematode populations and root wet weight.