Root-knot nematodes (Meloidogyne spp.) parasitize a wide range of annual and perennial crops, often impacting both the quantity and quality of marketable yields. These pests are also considered to be the most economically important plant-parasitic nematodes. In this study, the possibility as biological control agent of Monacrosporium thaumasium WHJ8 which nematode-trapping or predacious fungus was investigated.
1. The optimum cultivation condition of Monacrosporium thaumasium WHJ8 for liquid media is the most effect under the condition of PDA medium, 25℃ for temperature and pH 7.0. The agar media contained V8 juice 10% for solid culture had formation 7.3×107 conidia·mL-¹. The cultivation condition for spore formation is the most effect under the condition of carbohydrate sucrose 0.1% and nitrogen yeast extract 0.1%.
2. When manufacturing pre-formulation with M. thaumasium WHJ8, vermiculite, inorganic carrier was more produced conidia spore than cereals, organic carrier. In the test of inoculated methods for conidial spore formation ability, spray of conidial suspension plus nutrients (9.3×107 conidia·g-¹) was more efficacy than mix of cultured mycelium (3.6×105 conidia·g-¹). The formulation which manufactured with above inoculated methods designed M. thaumasium WHJ8 formulation was used to examine its effects.
3. M. thaumasium WHJ8 formulation shown high control efficacy to nematode number and egg mass on tomato root at pot test. In field test for melon, the control efficacy of M. thaumasium WHJ8 formulation was 63.3% and 62.3% at 30, 60 days, after treatment of M. thaumasium WHJ8 formulation which was treated 3 kg·10a-¹ at 15 days before planting.
4. To confirm storage stability of formulated product M. thaumasium WHJ8 formulation, this study was conducted under different storage conditions; low temperature(0℃), room temperature(25℃) and accelerated temperature of 50℃. The selected formulation was stored for 12 weeks under the given temperature and physical properties and cell amounts were analyzed. The physical properties and cell amounts of M. thaumasium WHJ8 formulation tested under two storage conditions, 0 and 25℃ were good, but under accelerated condition was a little affected.
M. thaumasium WHJ8 formulation was granule with brown color. Its physicochemical properties was pH 7.0, particle size of 8mesh 89% or more, hardness 0.5, bulk density 0.71 and moisture content is 12.4%
5. This study was performed to determine the acute oral toxicity of M. thaumasium WHJ8 formulation in SD rats. After the treatment, clinical signs and body weight change were observed for 14 days. All animals survived during the study and did not show any clinical signs. Body weight gain showed no significant difference between the control and treated rats.
These results indicated that M. thaumasium WHJ8 formulation could be potential biocide to root knot nematode.