Development of Biorational Management Package of Root Knot Nematode Disease of Country Bean

A field experiment was conducted with a view to test the efficacy of Tricho-composts and integration of Tricho-composts, poultry refuse (PR), neem oilcake (NOC), saw dust burning (SDB) with chemical nematicide Furadan 5G (Carbofuran) for controlling root knot nematode of country bean through which growers will be Corresponding author Md. Iqbal Faruk, Principal Scientific Officer, Plant Pathology Division, Agricultural Research Institute, Joydebpur, Bangladesh.

a commercial crop both in ails (border) of the plots or main plots [2]. The crop is attacked by many pests and diseases causing marked yield loss. Among the diseases, root knot caused by Meloidogyne incognita is highly damaging and yield reducing factor of country bean throughout the country [3]. Due to only root-knot the crop suffers heavily, growth is retarded, fruit setting reduced, size and yield decreased and in serious condition, the plant die due to secondary infection with fungi and bacteria. In the late season the big size galls are easily visible at the base of the plants. A number of approaches aimed for controlling root -knot nematodes through application of nematicides [4 and 5], organic soil amendments [6, 7, 8, 9 and 10], cultural management, physical methods like soil solarization [11] and biological measures like Trichoderma spp, Pacecilomyces lilacinus, Pasturia penetrans and Pseudomonas aeruginosa [12, 13 and 14]. Country bean cultivar resistant to root-knot nematode is not available in Bangladesh. There are few synthetic chemical nematicides which have been used to control plant parasitic nematodes effectively. Although these are effective and fast acting, they are degrading to the environment, other beneficial soil micro flora and human health [15]. Therefore, alternate management options against the nematodes are to be sought.
Many researchers have focused on the use of organic amendments to control plant-parasitic nematodes [9, 16 and 17]. On the other hand biological control promises to be the most effective alternative for the management of root-knot nematode [18 and 19]. Bio-products contain bio -control agents (bacterium, fungus, virus, protozoan or alga) are host specific and are potential candidates for integrated pest management [20]. The free-living soil fungi Trichoderma spp. are potential nematode bio-control agents on many food, vegetable and cash crops [21 and 22]. Besides Trichoderma spp. is common soil beneficial bio-fertilizer belonging to plant growth promoting rhizobacteria have also been used for controlling rootknot nematodes [23 and 24]. Biological control of plant parasitic nematodes with antagonistic fungi is a promising technique which may be incorporated in integrated nematode management and gaining importance [25 and 26].
Under these circumstances,, the present study was designed to examine the nematicidal potential of locally developed bio-products viz. Tricho-compost-1 and Tricho-
Bangladesh Ltd. The collected inoculums were mixed with vermi-compost @ 1:20 (w/w) and kept for 7 days for multiplication of Trichoderma into the mixture and it's designated as Tricho-compost-1. Previously, collected and isolated virulent cultured of T. harzianum (TM7) by Plant Pathology Division, BARI was initially formulated in substrates containing a mixture of rice bran, wheat bran and mustard oilcake. The formulated Trichoderma was mixed with vermi-compost @ 1:20 (w/w) and kept for 7 days for multiplication of Trichoderma into the mixture and it's designated as Tricho-compost-2.

Field Experiment
The field trials were conducted in the fields of @ 20 g/pit (iv) Tricho-compost-2 @ 2 kg/pit + Furadan 5 G @ 20 g/pit, (v) Poultry refuse @ 5-6 kg/pit + Furadan 5 G @20 g/pit , (vi) Neem oil cake @ 500 g/pit + Furadan 5 G @ 20 g/pit (vii) Saw dust burning + Furadan 5 G @ 20 g/ pit and (viii) Farmers practices. The field experiments were laid out in randomized complete block design (RCBD) with 4 replications. The unit pit size was 2 m x 2 m keeping 1m distance from pit to pit. Standard cultivation procedures recommended by BARI were followed to grow country beanwith little modification. The experimental land was prepared with proper tillage and fertilizers were added during final land preparation. Requisite amount of poultry refuse and neem oil cake were incorporation with the soil 3 weeks before seed sowing whereas Tricho-composts were added in the soils 5 days before seed sowing. After application, the organic materials were properly mixed with the soil and kept moist for proper decomposition. In case of saw dust burning, 6 cm thick layer of dry saw dust cover with pit soil and burned the soil properly. After burning the ash were mixed with the soil. Furadan 5G was added at the time of seed sowing. To ensure inocula of the nematode, chopped severely galled roots of tomato infected with Meliodogyne incognita were mixed with the pit soils @100 gmpit -1 before seed sowing.
The country bean seeds variety BARI Shem-2 were sown in the pits and each pit received ten seeds. During crop season necessary weeding, irrigation and other intercultural operations were done as per recommendation of the crop. After 45-50 days seed sowing, 2 seedlings were kept in each pit and the rest of the seedlings from each pit was uprooted carefully without disturb the root system for data collection.

Data Collection and Analysis
Data on different parameters viz. plant height, plant weight, root length, root weight and yield were recorded. Gall index was recorded following 0-10 scale [27]. Data were analyzed statistically by using the MSTATC program. The treatment effects were compared by applying the least significant different (LSD) test at P=0.05 level.

Plant Growth
In both the years, plant growth parameter viz.
shoot length and shoot weight of country bean significantly enhanced by soil treatment with were not observed ( Table 2). The least effective treatment was SDB +Furadan 5G where the root weight was 5.28 gplant -1 ( Table 2).

Severity of Root-Knot Nematode Disease
In both the years, the severity of root-knot disease of country bean was reduced significantly over farmers practices due to soil treatment with Tricho-composts, integration Tricho-compost, poultry refuse (PR), neem oilcake (NOC) and saw dust burning (SDB) with Furadan 5G (Table 3). In the first year, the maximum average gall index value of 5.18 was recorded in the farmers' practices.
It was reduced to 1.50 to 2.00 due to application of different treatments. All the treatment gave significantly similar effect in reduction of root knot disease severity compared to farmers' practices (  Table 3. Effect of soil treatment with Tricho-compost, poultry refuse, neem oil cake and nematicide on the root knot nematode disease severity of country bean in soil inoculated with Meloidogyne incognita. In a column, similar letters (s) do not differ significantly at 5% level of probability. vegetable crops [21, 22, and 32]. In the present study soil amendments with organic soil amendments and nematicide gave the encouraging finding for the management root knot nematode and increasing yield of country bean. Many previous reviews have focused on the use of organic amendments to control plant-parasitic nematodes [16,17,9]. Soil amendment with poultry refuse or integration of poultry refuse with nematicde Furadan 5G has also been reported to be effective against root-knot nematode of tomato [37], brinjal [38], potato [39], bottle gourd [40] and jute [41]

Conclusion
The current study provides evidence that