• Korean Journal of Organic Agriculture
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• v.20 no.1
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• pp.49-58
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• 2012

Greenhouse whitefly, $Trialeurodes$ $Vaporariorum$, is the most important insect pest in environmental friendly tomato production. Natural enemies, $Nesidiocoris$ $tenuis$ and environmental friendly agricultural materials (EFAM) are major control agents in Korea. The aim of the present work is to evaluate release time of $N.$ $tenuis$ in controlling of $T.$ $vaporariorum$ and to select environmental friendly agricultural materials (EFAM) to suppress both $T.$ $vaporariorum$ and $N.$ $tenuis$ which if the density were high causing necrotic rings. Six EFAM selected to control of $Trialeurodes$ $Vaporariorum$ in three times spray with seven days intervals. Three EFAM showed high mortality 67.7-70.5% in spray after release plot but low in release after spray plot. It should be careful to spray with $N.$ $tenuis$. When $N.$ $tenuis$ were early release at 7 days after transplanting which before occurring and establishment of greenhouse whitefly, it could suppress the density. Extracts of bead tree + matrin, matrin 1, Chrysanthemum showed high mortality on $T.$ $vaporariorum$ adults and $N.$ $tenuis$. The results suggested that this three EFAM could be control agents of the damage of necrotic rings from $N.$ $tenuis$.

• The Korean Journal of Pesticide Science
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• v.18 no.3
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• pp.196-201
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• 2014

This study was conducted to develop economic injury level (EIL) of sweet potato whitefly, Bemisia tabaci, on oriental melon. In greenhouse, seedlings of oriental melon were transplanted at June 8, 2010 and we inoculated adult B. tabaci with the density of 0, 1, 5, 10, or 20 per ten leaves at July 14. Adult of B. tabaci increased approximately twenty five-fold at 60 days after inoculation in the plot of 20 adults per ten leaves. The damages on leaves and fruits by B. tabaci were started to appear at 20 days after inoculation, and the damage rates of leaves or fruits were 28.5 or 31.5 percent at 60 days after inoculation, respectively, in the plot of inoculation with 20 adults per ten leaves. The yield of oriental melon was reduced as the inoculation density of B. tabaci increased, and the relationship between inoculation density of B. tabaci and the rate of damaged fruit could be described by a linear regression Y = 0.961x + 0.0562 ($R^2$ = 0.976). Based on the relationship, the economic injury level was 5.1 adults of B. tabaci per leaf and the control threshold estimated by 80% level of economic injury level was 4.1 adults per leaf for control of sweet potato whitefly.

• Korean journal of applied entomology
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• v.22 no.4 s.57
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• pp.233-236
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• 1983

Results obtained from the experiment conducted to determine the potential distribution of greenhouse white flies are summerized as follows; Hatching rate of eggs were significantly decreased when eggs were treated under $-5^{\circ}C$ for three days and no eggs were hatched when 4he eggs were treated at $10^{\circ}C$. for three days. Kate of pupation was also decreased when larvae were subjected to $-5^{\circ}C$ for three days and no pupation of larvae was of served when the larvae were under $-20^{\circ}C$ for three days. Emergency rate of pupae was decreased when pupae were under $-20^{\circ}C$. for three days and no emergence was observed when pupae were treated at the temperature of $-20^{\circ}C$ for three days. Survival rate of adults were greatly decreased when they were under $-7.5^{\circ}C$. for three days and the adults were completely dead when they were subjected to $-10^{\circ}C$. for three days. Therefore, it may be concluded that the greenhouse white flies may be overwintered, in the from of pupae at the middle-southern part of Korea, while they may overwinter in all developmental stages in Jeju Island and in southern tip coast area of Korea.

• Korean journal of applied entomology
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• v.46 no.3
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• pp.401-408
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• 2007

The feeding behaviors of 2 biotypes (type B and Q) of tobacco whitefly, Bemisia tobaci, were monitored using EPG technique on tomato and pepper plants treated 3 insecticides for controlling whiteflies, for examples, acetamiprid, spinosad and thiamethoxam. After treatment of three insecticides with recommended concentrations to tomato and pepper plants, EPG waveforms were recorded during 6 hours. The characteristic patterns of feeding behaviors investigated were as follows; time consumed by withdrawal of proboscis, total non-penetration time, total stylet pathway pattern time and total phloem feeding time. There was somewhat difference among 3 insecticides tested. As a result of investigation of total duration showed the stylet pathway activity due to the reaction against all tested insecticides, the Q biotype showed fewer time than those from the B biotype. The B biotype showed more frequent stylet pathway activity patterns during whole recording time and a shorter phloem ingestion time than those from the Q biotype. In result of prior up (non-penetration) time representing the reaction against the insecticide treated, the time of B biotype was more faster than that of the Q biotype, so it was considered that the B biotype was more sensitive to the tested insecticides. Therefore, our results revealed a clear difference in feeding behaviour between the B and Q biotypes of B. tabaci. Also, it was investigated that B biotype was susceptible to the 3 insecticides.

• The Korean Journal of Pesticide Science
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• v.7 no.3
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• pp.207-215
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• 2003

This study was carried out to evaluate toxicities of 3 registered insecticides to greenhouse whitefly(GWF), Trialeurodes vaporariorum and sweetpotato whitefly(SWF), Bemisia tabaci, B-biotype. Insecticide activities were evaluated by testing systemic action, residual effect in the laboratory, and control efficacy in the greenhouse. All experiments were tested at the recommended concentration(RC), half and a quarter concentrations of RC of each insecticides. Acetamiprid showed 45%, 42% ovicidal effect to greenhouse whitefly and sweetpotato whitefly at 40 ppm, respectively. Acetamiprid showed more than 97% larvicidal activities on the 3rd instars larvae of GWF and SWF at the recommended and its half concentrations. On the adults of the two whitefly species, acetamiprid and acetamiprid+ethofenprox showed more than 92% mortality even at half of recommended concentrations. Acetamiprid and acetamiprid+ethofenprox showed both residual effect and systemic activity. In the control efficacy test on GWF and SWF, 90% control values were obtained at the 3th day after treatments of acetamiprid and acetamiprid + ethofenprox by application with recommended concentration. These results indicate that acetamiprid and acetamiprid+ethofenprox can be used in the control of the two whitefly species in field.

• Korean journal of applied entomology
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• v.58 no.3
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• pp.209-218
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• 2019

This study was conducted to develop a technology for environmentally friendly control of sweet-potato whitefly, Bemisia tabaci, by controlling their behavior using a push-pull strategy in a tomato greenhouse. B. tabaci was attracted the most by yellow color, light source of 520 nm, whereas it avoided the complex light treatment of 450 + 660 nm. The two natural enemies of B. tabaci, Cyrtopeltis tenuis and Orius laevigatus, were attracted the most by 520 nm light source. B. tabaci was repelled by the volatile organic compounds ocimene and carvacrol and was the most attracted by methyl isonicotinate. When buckwheat was added into the tomato greenhouse, the density of C. tenuis was maintained at about 16 times higher than when untreated for 15 days. As a result of the combined treatment of push-pull strategy, the density per trap of B. tabaci was three times lower than when no treatment was applied, and the control of this pest increased with time and reached up to 68.7%.

• Horticultural Science & Technology
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• v.29 no.5
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• pp.420-432
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• 2011

Population dynamics of greenhouse whitefly, Trialeurodes vaporariorum (Westwood), were modeled and simulated to compare the temperature effects of air and tomato leaf inside greenhouse using DYMEX model simulator (pre-programed module based simulation program developed by CSIRO, Australia). The DYMEX model simulator consisted of temperature dependent development and oviposition modules. The normalized cumulative frequency distributions of the developmental period for immature and oviposition frequency rate and survival rate for adult of greenhouse whitefly were fitted to two-parameter Weibull function. Leaf temperature on reversed side of cherry tomato leafs (Lycopersicon esculentum cv. Koko) was monitored according to three tomato plant positions (top, > 1.6 m above the ground level; middle, 0.9 - 1.2 m; bottom, 0.3 - 0.5 m) using an infrared temperature gun. Air temperature was monitored at same three positions using a Hobo self-contained temperature logger. The leaf temperatures from three plant positions were described as a function of the air temperatures with 3-parameter exponential and sigmoidal models. Data sets of observed air temperature and predicted leaf temperatures were prepared, and incorporated into the DYMEX simulator to compare the effects of air and leaf temperature on population dynamics of greenhouse whitefly. The number of greenhouse whitefly immatures was counted by visual inspection in three tomato plant positions to verify the performance of DYMEX simulation in cherry tomato greenhouse where air and leaf temperatures were monitored. The egg stage of greenhouse whitefly was not counted due to its small size. A significant positive correlation between the observed and the predicted numbers of immature and adults were found when the leaf temperatures were incorporated into DYMEX simulation, but no significant correlation was observed with the air temperatures. This study demonstrated that the population dynamics of greenhouse whitefly was affected greatly by the leaf temperatures, rather than air temperatures, and thus the leaf surface temperature should be considered for management of greenhouse whitefly in cherry tomato grown in greenhouses.

• Korean journal of applied entomology
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• v.40 no.3
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• pp.203-209
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• 2001

Development and reproduction of the sweetpotato whitefly, Bemisia tabaci(B biotype) were investigated under different temperatures and host plants. Developmental periods from egg to pre-adult of whiteflies measured under four constant temperatures: they were 86.2 days at $15^{\circ}C$ and 17.0 days at $30^{\circ}C$. Lower threshold temperature and total effective temperature for the development of egg and nymph, and for the complete development (egg to emergence) were $10.1,\;11.6,\;11.1^{\circ}C$ and 110.3, 204.7, 317.3 degree days, respectively. The hatching and emergence rates were 87.0% at $25^{\circ}C$ and 76.7% at $20^{\circ}C$, which were higher than the results of other temperatures. The adult longevity was 23.6 and 14.0 days at $20^{\circ}C$ and $30^{\circ}C$, respectively. The highest average fecundity per female was 103.3 at $25^{\circ}C$. But there were no significant differences among the temperatures. The highest intrinsic rate of natural increase($r_{m}$) was 0.196 at $30^{\circ}C$ and the highest net reproduction rate ($R_{o}$) was 97.33 at $25^{\circ}C$. Developmental periods from egg to pre-adult of whiteflies were 21.2 on the tomato, 28.1 on red pepper, 22.2 on eggplant and 25.5 days on poinsetia. The hatching was highest (90.3%) on red paper and emergence rate was highest (89.6%) on eggplant. The longest longevity of adult female was 26.5 days on eggplant, and the average fecundity per female was greater on tomato and eggplant than on other host plants. The intrinsic rate of natural increase($r_{m}$) was the highest on tomato as 0.165 and the net reproduction rate ($R_{o}$) was the highest on eggplant as 106.1. As a result, the optimum range of temperature for the growth of B. tabaci was between $25^{\circ}C$ and $30^{\circ}C$, and the optimum host plant were tomato and eggplant among the plants tested.