Naturally occurring plant toxins, such as benzoates, have been shown to have insecticidal effects on some pest insects. In this study three commercially available benzoates, methyl benzoate (MB), ethyl benzoate (EB), and vinyl benzoate (VB), were assessed for their contact toxicity against Aphis gossypii Glover and its lacewing predator Chrysoperla carnea Stephens. Toxicity of 1% MB, EB, and VB showed 100%, 85% and 60% mortality of A. gossypii at 24 h. In addition, a mixture of MB and EB showed higher synergistic effect than mixtures of MB+VB or EB+VB against A. gossypii. Toxicity at 1% concentration of three benzoates against A. gossypii showed lower toxicity against the larvae of C. carnea after 72 h of exposure than A. gossypii. Our result suggest that benzoates have high potential as environmentally safe biopesticides for A. gossypii control.

Thrips is one of the serious insect pests in many economic crops, in which general managements rely mainly on chemical insecticides. However, the overuse of chemicals led to the development of insect resistance and environmental residual issues. Therefore, thrips management requires the consideration of alternative strategies which are less harmful to the environment and working on different target points. In this work, we isolated entomopathogenic fungi from soil, and identified them with morphological and molecular biology methods, followed by a preliminary virulence assay against Tenebrio molitor larvae. Selected fungal isolates were adjusted to 1×107 conidia/ml for an indoor virulence assay against thrips adults, and highly virulent isolates were added to a thrip-pathogenic fungal library. Biological characteristics of efficacious isolates were investigated comparing to a previously commercialized fungal isolate. This entomopathogenic fungal library could be used as a valuable resource for developing effective strains to control thrips in agricultural fields.

Thrips worms and root-knot nematodes occur in a variety of crops, and have shown a great deal of damage to farm income every year, and the damage is increasing every year. In order to solve these problems, a variety of biological materials are used in Korea to develop a control agent. However, there are very few products available that can satisfy the consumer's satisfactory control effect, efficacy, formulation stability and pesticide compatibility. In order to propose a biological control solution to these problems, this study was conducted to develop the optimal bioprocess technology and formulations suitable for the material by transferring the Aspergillus nigerF22 strain, which is effective for root-knot nematodes, at Chonnam National University. This study was conducted to investigate the efficacy of Aspergillus niger F22 20% suspension concentrate (Productname:NEMAFREE), which has excellent efficacy on root nematodes. The packing test result showed about 70-90% control effect. Soil fumigation and disinfection treatments after 4 days of planting were effective. In addition, we have developed a product to control the under powder pupa using Beauveria bassiana ERL836, an insect pathogenic microorganism, which has excellent control effect against resistant insect pupa. The main purpose of this study was to investigate the effect of insect pests on the under poor control of the pupa in the soil. In the pavement test, more than 70%(GR) formulation, which can be treated withch emical pesticides, and it is confirmed that synergy effect is in the control of Thrips worm.

Two groups of entomopathogenic bacteria, Xenorhabdus and Photorhabdus, are known to suppress insect immune responses by inhibiting eicosanoid biosynthesis. This study used these bacterial culture broths to develop novel biochemical insecticides against the diamondback moth, Plutella xylostella. Though the bacterial culture broths alone showed little insecticidal activity, they significantly enhanced pathogenicity of Bacillus thuringiensis against the fourth instar larvae of P. xylostella. Sterilization of the bacterial culture broth by autoclaving or 0.2 ㎛ membrane filtering did not influence the synergistic effect on the pathogenicity of B. thuringiensis. Three metablites identified in the culture broth of X. nematophila also showed similar synergistic effects. In field test, both entomopathogenic bacterial culture broth also enhanced the control efficacy of B. thuringiensis against P. xylostella.

Among the cultured products of Beauveria bassiana SFB-205 (KCCM 10892P), the supernatant showed the highest insecticidal activity against 2nd instars of Aphis gossypii (Aphididae) nymphs under glasshouse condition. The enzymes in the supernatant were confirmed as active materials, and the chitinase was finally selected as a QC factor for commercial production. However, the chitinase activity in the supernatant decreased by 11-folds due to the thermal stress at 50℃ for 2 h. To obtain thermal stability, the chitinase in the supernatant was adsorbed to a precipitable material and the pellet was freeze-dried (PCT/KR2007/005886). The adsorbent-A showed about 92.7% of harvesting efficiency which was higher than the other candidates. The chitinase activity of the freeze-dried powder was kept up about 82.0% of initial activity for the same thermal stress. Subsequently, an optimal formulation recipe was established to maximize long-term storage stability and efficacy. SFB-205 oil-based formulation was stable up to 18 months at room temperature. It showed 96.1% efficacy against 2nd instars of A. gossypii nymphs at 1 day after the treatment in the glasshouse. This novel approach can be a promising method to develop competitive biopesticies in the entomopathogenic fungi, even though it needs to be intensively studied.

Background : Adenophora triphylla var. japonica Hara. is one of the important oriental medicinal herbs being used to cure lung/respiratory diseases. It belongs to the five Sam (ginseng) including Panax ginseng, Salvia miltiorrhiza, Sophora flavescens, and Scrophularia buergeriana. In 2015, Korea produced 72 tons of medicinal herbs in a 14-hectare area and imported 24 tons valued at US$95,000. This study was carried out to investigate the effect of several biopesticides to control leaf spot of A. triphylla var. japonica Hara. Methods and Results : One year plants at the Department of Herbal Crop Research, NIHHS, RDA were used. The treatments used biopesticides such as plant extracts (BP), microbial agent (DM), microbial agent (PJ), sulfur powder (HS), and controlled chemicals (ST), while non treatment (NT) was used as control. After the early part of disease outbreak, the plants were treated four times with 7 days interval. The incidence of leaf spot, efficacy, phytotoxicity and control value were investigated. Based on the efficacy test, incidence of leaf spot is lowest at 15.6% in plant extracts (BP). Other biopesticides showed higher incidence - 16.7% for microbial agent (DM), 17.8% for microbial agent (PJ), 18.9% for sulfur powder (HS) and 71.1% for non treatment (NT), compared with 11.1% in controlled chemicals (ST). The microbial agent (PJ), sulfur powder (HS), plant extracts (BP) and microbial agent (DM) were not damaged in the phytotoxicity test. In the test of application dose, time and methods, the control value was highest in plant extracts (BP) at 78.1%, followed by microbial agent (DM) at 76.6%, microbial agent (PJ) at 75.0%, and sulfur powder (HS) at 73.4% , compared with controlled chemicals (ST) at 84.4%. Conclusion : It is possible to use biopesticides at the proper time to prevent leaf spot in Adenophora triphylla var. japonica Hara.

Field trial was conducted at the Research Farm of the Katsina State Agricultural and Rural Development Authority during the farming season of 2004 with a view to evaluate/determine the efficacy of some selected plant-derived biopesticides against the insect pests of cowpea as well as their effect on yield. The variety of the cowpea used was IT86D-719 and the plant derived biopesticides evaluated during the trial were chilli pepper, garlic, ginger, neem, sweetsop and tobacco. The experimental field was ploughed, harrowed and thereafter ridged before the commencement of the 2004 planting season. A total of twenty one (21) experimental plots were demarcated and arranged into seven treatment plots. The size of each plot was 5m~times4m while interspaces between adjacent plot and blocks were 1m and 2m, respectively. Results of the experiments showed that all the plant-derived biopesticide treatments were significantly (p>0.05) better than control treatment. The order of effectiveness of the treatments was tobacco (80-90%), sweetsop (75-85%), garlic (70-80), neem (72-78%), chilli pepper (60-70%) and ginger (30-50%). Furthermore, yield result corresponded positively with the effectiveness of the treatments. Results of the present finding suggest the use of tobacco, sweetsop and garlic as promising biopesticides in the control of cowpea insect pests.