Maize weevil is one of the most common and critical storage pest in the world. In this study, the insecticidal activity of the methanol extracts derived from Caesalpinia sappan was evaluated against adults of maize weevil, using by direct contact and fumigant methods. Based on the two methods, ethyl acetate fraction of the C. sappan extracts had 100% mortality against Maize weevil adults at 10 mg. The biological constituent of C. sappan extract was isolated by various chromatographic techniques and identified as juglone. On the basis of 72 h LD50 values, in the direct contact bioassay, the insecticidal activity of juglone (0.010 mg/cm2) was the most effective, followed by 1,4-NQ (0.018 mg/cm2) and menadione (0.087 mg/cm2). In a fumigant bioassay, the insecticidal activity of juglone (0.014 mg/cm2) was the most effective, followed by 1,4-NQ (0.015 mg/cm2) against maize weevil adults. On the other hand, menadione, lawsone, and 2-methoxy-1,4-NQ observed no insecticidal activity or weak. These results suggested that active compound of C. sappan materials could be used as biological control agent against maize weevil. Therefore, further research should be performed to the structure activity relationship of juglone and compared with its derivatives.

In this study, we evaluated the acaricidal activities of AP and its derivatives for their potentials as natural acaricides using the vapor phase and contact toxicity bioassays against Dermatophagoides spp. and Tyrophagus putrescentiae, and then compared with that of commercial acaricide such as benzyl benzoate. The acaricidal constituent of A. koreana was isolated by various chromatographic techniques and identified as 2’-H-4’-MAP. In the vapor phase toxicity bioassay, based on the LD50 values of 2’-H-4’-MAPand its derivatives against D. farinae, 2’-MAP (1.25 ㎍/㎠) was 8.0 times more effective than benzyl benzoate (10.00 ㎍/㎠), followed by 3’-MAP (1.26 ㎍/㎠), 4’-MAP (1.29 ㎍/㎠), 2’-H-4’-MAP (1.75 ㎍/㎠), and 2’-H-5’-MAP (1.96 ㎍/㎠). In the contact toxicity bioassay, 3’-MAP (0.58 ㎍/㎠) was 12.97 times more toxic than benzyl benzoate (7.52 ㎍/㎠), followed by 2’-MAP (0.64 ㎍/㎠), 2’-H-4’-MAP (0.76 ㎍/㎠), 4’-MAP (0.77 ㎍/㎠), and 2’-H-5’-MAP (1.16 ㎍/㎠). The acaricidal activities of 2’-H-4’-MAP derivatives against D. pteronyssinus and T. putrescentiae were similar to those against D. farinae. These results indicated that acaricidal activities of 2’-H-4’-MAP derivatives against the three mite species were changed with the introduction of hydroxyl (-OH) and methyl (-CH3) groups onto the acetophenone skeleton.

The behavioral responses of Plutella xylostella (Lepidoptera: Plutellidae) to four high power light emmitting diodes (HPLEDs) were tested at various illuminance intensity and light exposure time using a HPLED-equipped Y-maze chamber. Preference tests were conducted using the high power light emmitting diodes (HPLEDs) in the dark room at 27±0.5℃ and 60±0.5% relative humidity. Evaluated specific wavelengths were blue, green, yellow and red HPLEDs. The illuminance intensity was tested at 20, 40, 60, 80, and 100 lx and fixed at 30 min. As a result, the attraction rate of the green HPLED at 60 lx was the best effective (98.3%) to P. xylostella, followed by red HPLED of 60 lx (86.5%), yellow HPLED of 60 lx (83.6%), and blue HPLED of 40 lx (72.0%), respectively. Depending on the change of light exposure time (5, 10, 15, 20, and 25 min), green HPLED showed the potential attraction under the 15 min. These results may be used as information for developing an eco-friendly insect pest control system. Further research needs to be performed to evaluate the behavioral responses to single and multiple HPLED sources in the field.

The aim of this study is to observe the attraction of four colored lights against beet armyworm (Spodoptera exigua). The visual preference of the beet armyworm for light-emitting diodes (LEDs) was examined by LED equipped phototactic chamber in the dark room at 27 ± 0.5°C and 60 ± 5% relative humidity. Evaluated specific wavelengths of LEDs were blue (470 ± 10 nm), green (520 ± 5 nm), yellow (590 ± 5 nm) and red (625 ± 10 nm), and compared with that of the commonly luring lamp used fluorescent (380-800 nm) which served as controls. The light intensity was tested at 20, 40, 60, 80 and 100 lx, and light-exposure time was determined at 20, 40, 60, 80 and 100 min. All of the light treatments with 40 lx intensity and the 60 min light-exposure time showed the highest attraction rate to S. exigua. Based on attraction rate of the green LED (88.9%) was the most attractive to S. exigua, followed by blue LED (81.1%), yellow LED (63.3%) and red LED (56.7%). In comparisons with LED and fluorescent light, the attractive rate to green LED against beet worm was more effective than that of fluorescent (80%) light. Overall, these results indicated that the eco-friendly LED could be a more effective substitute for the chemical free insect pest control system because of the various advantages.

To evaluate potential attractive activity of high power light emitting diodes (HPLEDs) against Plutella xylostella (Lepidoptera: Plutellidae), the specific wavelengths, illuminance intensities (20, 40, 60, 80, 100 lux), and light exposure times were investigated at 5 minute intervals. The evaluated specific wavelengths were blue (450±10 nm), green (520±5 nm), yellow (590±5 nm), red (660±10 nm), and white (450-630 nm). Based on the highest attraction rate, the HPLEDs treated to 60 lux intensity against P. xylostella were significantly more attractive than other illuminance intensities when light exposure time was 10 min. Attraction rate under optimal conditions showed that the green HPLED had the highest attraction rate (98.3%), followed by red HPLED (89.3%), blue HPLED (86.7%), yellow HPLED (76.7%), and white HPLED (70.0%), respectively. These results indicated that phototatic effect of the green HPLED against P. xylostella showed the greatest attraction at 60 lux intensity and 10 min light exposure time. Further research needs to be performed to evaluate the phototatic behavioral responses to single and multiple HPLED sources in the field.

The object of this study is to observe the attraction of specific wavelengths against Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). The attractive effects was examined by the high power light-emitting diodes (HPLEDs) in the dark room at 27±0.5°C and 60±0.5% relative humidity. Evaluated specific wavelengths were blue (470±10 nm), green (520±5 nm), yellow (590±5 nm) and red (625±10 nm) HPLEDs. When a light exposure time was fixed at 60 min and tested with various illuminance intensity at 20, 40, 60, 80, and 100 lux, the attraction rate of the green HPLED at 80 lux was the most effective (94.4%) to B. tabaci, followed by yellow HPLED of 20 lux (78.9%), blue HPLED of 60 lux (71.1%), and red HPLED of 20 lux (60.0%), respectively. According to the change of light exposure time (10, 20, 30, 40, 50, and 60 min), green HPLED showed the potential attractive effects under the 40 min and 50 min. These results suggest that it is possible to develop a green HPLED trap for attracting, monitoring, and lighting system against B. tabaci.

Spodoptera exigua is a significant polyphagous pest in the greenhouse and open field. Our aim of this study was to evaluate light emitting diodes (LEDs) as the potential attractants against Spodoptera exigua on various wavelengths, light intensity, and light duration. The preference response to S. exigua was investigated by the laboratory and field-scale. The wavelengths of LEDs were composed as follows: blue (470 nm), green (520 nm), yellow (590 nm), red (625 nm) and white (450-620 nm). When the optimal light condition was investigated in the laboratory scale, the all light treatments attracted the highest number of S. exigua at 40 lux intensity and 60 min duration. Based on the wavelengths under optimal light condition, the white LED exhibited the highest attraction rate (91.1%), followed by green (88.9%), blue (81.1%), yellow (63.3%) and red (56.7%), respectively. In comparison with the selected white LED and yellow sticky traps in the field-scale, the white LED (81.3%) was about 16.26 times more attractive than yellow sticky trap (5.0%). These results clearly show that the white LED had the greatest attraction against S. exigua.