• Korean journal of applied entomology
• /
• v.60 no.4
• /
• pp.339-355
• /
• 2021

Aphids can damage plants directly by absorbing their phloem sap and indirectly by transferring plant viruses and causing sooty mold. We compared the thermal effect on the development, survivorship, and reproduction of four cereal crop-damaging aphid species, Rhopalosiphum padi, Aulacorthum solani, Aphis craccivora, and Acyrthosiphon pisum using a life table analysis method. We investigated the stage-specific development period, survivorship, adult longevity, and fecundity of the above mentioned four aphids at 10, 15, 20, 25, and 30℃, respectively, and analyzed their life table parameters using the age-stage, two-sex life table analysis. A. solani nymphs could not complete their development to adulthood at 30℃. The intrinsic increase rate of R. padi was the highest at all tested temperatures except for that at 15℃ (0.12, 0.34, 0.47, and 0.32 at 10, 20, 25, and 30℃, respectively), and that of A. pisum displayed negative values at 30℃ (-0.04). It is speculated that R. padi would be a dominant species under high temperature conditions and A. solani is a highly adaptive species at low temperatures through the comparative analysis of the life table parameters of four aphid species damaging to cereal crops.

• Korean journal of applied entomology
• /
• v.62 no.3
• /
• pp.155-160
• /
• 2023

In this study, we investigated the functional response of aphid parasitoid, Aphidius colemani Viereck (Hymenoptera: Braconidae), on the green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae). Three carbon dioxide concentrations (400, 600, and 1000ppm) and seven host densities (2, 4, 8, 16, 32, 64, and 128) were used during a 24-h period. A type III functional response for A. colemani was fit separately for each CO₂ concentration. The estimated handling time (Th) under elevated CO₂ (600 ppm and 1000 ppm, 0.015 and 0.014 day) was shorter than that under ambient CO₂ (400 ppm, 0.017 day). The proportion of aphids that were parasitized showed the similar characteristic curve under three CO₂ concentrations. The highest parasitized rates for A. colemani were 0.57, 0.61, and 0.70 at 16, 32, and 32 aphid density under 400, 600, and 1000ppm, respectively. Although handling time of A. colemani was influenced by elevated CO₂ concentrations, the attach rate was not changed much.

• Korean journal of applied entomology
• /
• v.63 no.1
• /
• pp.33-42
• /
• 2024

The green peach aphid, Myzus persicae is a representative agricultural insect pest that is polyphagous and causes serious damage to tobacco, potatoes, peppers, cabbage, and peaches. In this study, we analyzed the level of development of insecticide resistance to λ-cyhalothrin, imidacloprid, and flupyradifurone and the point mutations (R81T, L1014F, M918L) in 12 field populations of M. persicae. In addition, the expression level of CYP6CY3, a cytochrome P450 gene, was analyzed through qRT-PCR. As a result, λ-cyhalothrin showed high resistance ratio (RR) of > 200 in all 12 populations. Imidacloprid and flupyradifurone showed high RR of >200 in YS, UR, HY, and WJ populations. The R81T was detected in approximately 50%, L1014F in approximately 33.3%, and M918L in 100% of the 12 populations. Additionally, the expression level of subunit CYP6CY3 was highest in imidacloprid-resistant population (YS). These results suggest that M918L point mutation can be used as λ-cyhalothrin-resistance molecular diagnostic and R81T point mutation and the high expression of CYP6CY3 can be used as imidacloprid-resistance molecular diagnostic markers.

• Korean journal of applied entomology
• /
• v.63 no.1
• /
• pp.53-61
• /
• 2024

The susceptibility of Aphis gossypii populations collected from three fields (WJ, CC, and GS) was evaluated to three insecticides (afidopyropen, chlorfenapyr and cyantraniliprole) and three binary mixtures. Three field populations showed resistance ratios of over 100 to all insecticides. The Combination Index (CI), %M_(synergism), Co-Toxicity Coefficient (CTC), Wadley Ratio (WR), Synergism Ratio (SR) and Abbott Ratio (AR) were used to evaluate combined effect of the insecticides. Afidopyropen + chlorfenapyr (CI ≤ 0.16; %M_(synergism) ≥ 94; CTC ≥ 764.5; WR ≥ 6.4; SR ≥ 6.9 and AR ≥ 1.1) showed a synergism in all filed populations. WJ and CC populations showed a synergism in all binary mixtures of insecticides, but GS population showed an antagonism for chlorfenapyr + cyantraniliprole (CI, 1.63; %M_(synergism), 30; CTC, 64.0; WR, 0.6 and AR, 0.54) and afidopyropen + cyantraniliprole (CI, 6.7; %M_(synergism), 1; CTC, 19.8; WR, 0.2 and AR ≤ 0.55). All mixtures (afidopyropen + chlorfenapyr, chlorfenapyr + cyantraniliprole and afidopyropen + cyantraniliprole) showed a control value of over 99% after 21 days of treatment in the field. This study highlights that binary mixtures of three insecticides serve as an effective control strategy for A. gossypii.

• Korean journal of applied entomology
• /
• v.55 no.2
• /
• pp.119-128
• /
• 2016

This study was conducted to develop temperature-driven models for a population model of turnip aphid, Lipaphis erysimi: nymphal development rate models and apterious adult's oviposition (larviparous) model. Nymphal development and the longevity and fecundity of adults were examined on cabbage at six constant temperatures (10, 15, 20, 25, 30, $35{\pm}1^{\circ}C$, 16L:8D). L. erysimi nymphs did not survive at $10^{\circ}C$. Development time of nymphs increased with increasing temperature up to $30^{\circ}C$ and thereafter slightly decreased, ranging from 18.5 d at $15^{\circ}C$ to 5.9 d at $30^{\circ}C$. The lower threshold temperature and thermal constant were estimated as $7.9^{\circ}C$ and 126.3 degree days, respectively. The nonlinear model of Lactin 2 fitted well for the relationship between the development rate and temperature of small (1+2 instar), large (3+4 instar) and total nymph (all instars). The Weibull function provided a good fit for the distribution of development times of each stage. Temperature affected the longevity and fecundity of L. erysimi. Adult longevity decreased as the temperature increased and ranged from 24.4 d at $20^{\circ}C$ to 16.4 d at $30.0^{\circ}C$ with abnormal longevity 18.2 d at $15^{\circ}C$, which was used to estimate adult aging rate model for the calculation of adult physiological age. L. erysimi showed a maximum fecundity of 91.6 eggs per female at $20^{\circ}C$. In this study, we provided three temperature-dependent components for an oviposition model of L. erysimi: total fecundity, age-specific cumulative oviposition rate, and age-specific survival rate.

• Korean journal of applied entomology
• /
• v.48 no.3
• /
• pp.301-310
• /
• 2009

For the comparing of mortality of the resistance and susceptible population of Myzus persicae, etofenprox was treated in the recommended concentration of 200ppm. Mortalities of resistance population were 16.7 and 36.7%, and susceptible population were 86.7 and 86.7% after 24 and 48 hours treatment, respectively. For the detect of cross resistance to other pyrethroids, 6 pyrethroids were examined. Mortalities of susceptible and resistance populations were 90 and 31% to deltamethrin, 92 and 23% to lambda cyhalothrin, 81 and 14% to cypermethrin, 70 and 20% to $\alpha$-cypermethrin, 29 and 28% to fenpropathrin, 84 and 29% to fenvalerate, respectively. It was showed that resistance populations were generally resistive to other pyrethroids. On the other hands, for recognized ecological characteristic of M. persicae susceptible and resistance populations life table was tested on the pepper leaves in the petri dish and on the plant in the pot. This results were showed that intrinsic rate of increase ($r_m$), net reproduction number ($R_0$) and generation time in day ($T_c$) were significantly different between two population in both tested. However, life span and reproduction period were slightly different between them. Otherwise, feeding behaviors were tested using EPG technique with non- and treated etofenprox. First potential drop time of susceptible and resistance population was 73.5 and 257.9 sec with non-treated and 93.3 and 1076.2 sec after treated, respectively. Electrical probing signals were 8.2 and 48.8 times with susceptible and resistance individuals after treated etofenprox, respectively. It was supposed that the resistance is more probings than susceptible population. After treated, total feeding time have more 6,728.9 sec on resistance than 965.5 sec on susceptible population. So, total non penetration time of susceptible population was 3,000 sec longer than resistance population.

• Korean journal of applied entomology
• /
• v.46 no.1 s.145
• /
• pp.37-42
• /
• 2007

To construct a life table and development model Schizaphis graminum (Rondani), its adult longevity and fecundity were studied at various constant temperatures ranging from 15 to $32.5^{\circ}C$, with $65{\pm}5%$ RH, and a photoperiod of 16L:8D. Adult longevity of the greenbug gradually increased with decreasing temperature below $32.5^{\circ}C$. Total fecundity was not significantly different at all temperatures except at $32.5^{\circ}C$. Daily fecundity gradually increased from $25.0^{\circ}C$. It was 3.6 at $27.5^{\circ}C$ and as temperatures either went down or up, it decreased to 1.4 at $15.0^{\circ}C$ and 0.4 at $32.5^{\circ}C$ Net reproduction rate (Ro) was highest with 47.6 at $25.0^{\circ}C$. The intrinsic rate of increase per day $(r_m)$ and the finite rate of increase per day $({\lambda})$ were highest with 0.4 and 1.5 at $30.0^{\circ}C$, respectively and the doubling time (Dt) was shortest with 0.98 at $32.5^{\circ}C$. The mean generation time (T) was 8.41 at $30.0^{\circ}C$.

• Korean journal of applied entomology
• /
• v.53 no.2
• /
• pp.193-197
• /
• 2014

Transgenic crops that produce insecticidal toxins have a great potential for controlling target pest insects, but there is a growing concern about unintended influences on non-target species. In the present study, the preferences and performance of non-target green peach aphid, Myzus persicae (Sulzer), on transgenic cabbages (Brassica oleracea) that produce Bt toxin (Cry1Ac1) and untransformed control plants were investigated as a part of risk assessment. In a free-choice situation, the number of nymphs larviposited by 10 winged adults over 3 days was $21.9{\pm}1.8$ and $22.5{\pm}2.2$ on transgenic and the control plants, respectively, indicating that the aphids did not discriminate between the two types of plants. In a performance assay, the development time (D) and intrinsic rate of increase (rm) of wingless aphids reared on transgenic and control plants were also similar (D, $5.8{\pm}0.2$ and $5.9{\pm}0.1$ (days) and rm, $0.7{\pm}0.1$ and $0.8{\pm}0.1$, for transgenic and control plants, respectively). These results suggest that M. persicae is not significantly affected by transgenic Bt cabbage.

• Korean journal of applied entomology
• /
• v.53 no.4
• /
• pp.449-456
• /
• 2014

Life table analysis and temperature-dependent development experiments were conducted to understand the biological characteristics of the cabbage aphid, Brevicoryne brassicae (Linnaeus) on detached Tah Tsai Chinese cabbage (Brassica campestris var. narinosa) leaves at seven constant temperatures (15, 18, 21, 24, 27, 30 and $33{\pm}1^{\circ}C$; $65{\pm}5%$ RH; 16L:8D). Mortality was lowest at $24^{\circ}C$ with 18% and 0% at $1^{st}{\sim}2^{nd}$ and $3^{rd}{\sim}4^{th}$ nymphal stages, respectively. The developmental period of $1^{st}{\sim}2^{nd}$ nymphal stage was 8.4 days at $18^{\circ}C$, and it decreased with increasing temperature. The developmental period of the $3^{rd}{\sim}4^{th}$ nymphal stage was 6.7 days at $18^{\circ}C$. The lower threshold temperature calculated using a linear model was $7.8^{\circ}C$, and the effective accumulative temperature was 120.1DD. Adult longevity was 14.9 days at $21^{\circ}C$, and total fecundity was observed 58.5 at $24^{\circ}C$. According to the life table, the net reproduction rate was 47.5 at $24^{\circ}C$, and the intrinsic rate of increase and the finite rate of increase were 0.36 and 1.43, respectively, at $27^{\circ}C$. The doubling time was 1.95d at $27^{\circ}C$, and mean generation time was 7.43d at $30^{\circ}C$.

• Korean journal of applied entomology
• /
• v.22 no.4 s.57
• /
• pp.237-243
• /
• 1983

A biological study was done on primary parasites and hyperparasites of cow-pea aphid, Aphis craccivora Koch, collected from Mt. Gyeryong and Daejeon area during the period from April to September 1983 was. The results of mummification of primary parasites, host selectivity between primary parasites and hyperparasites and ratio of mummification, no. of ar chegonia and longevity of important species were obtained as follows; Eight species of Aphidiidae were identified and listed and four of them, Binodoxys nearactaphidis Mackauer, Lipolexis scutellaris Mackauer, Lysiphlebus salicaphis(Fitch)and Trioxys hokkaidensis Takada found for the first time in Korea. Among the 509 mummies collected in the field, adult Aphidiid and adult hyperparasites were $44.8\%,\;and\;43.8\%$, respectively. Lysiphlebus ambiguus, Lysiphlebus salicaphis, Lysiphlebia japonica and Lipolexis scutellaris were a few of important species attacking cow-pea aphid and the rate of their occurrences were $31.6\%,\;18.8\%,\;16.7\%\;and\;11.4\%$, respectively. All the hyperparasites collected from cow-pea aphid were recorded for the first time in Korea; those were Lygocerus testaceimonus Kieffer, Protaphelinus nikolskajae (Jasnosh), Eucoila sp., Gastranscistrus sp., Ardilea convexa(Walker), Asaphes vulgaris Walker. Among the collected hyperparasites, Eucoila sp., A. vulgaris and A. Convexa were dominant species and their occurence rate was $39.9\%,\;34.1\%\;and\;19.7\%$, respectively. As a results of analysis on parasite-hyperparasite interrelationship in cow-pea aphid, Lipolexis scutellaris was attacked from 3 out of 6 hyperparasites and the others was attacked from almost all the hyperparasites. Lysiphlebus ambiguus was higher than Lysiphlebia japonica in the ability of parasitism. There was no difference between Lysiphlebus ambiguus(272) and Lysiphlebia japonica(279) in number of archegonia, but L. ambiguus$(66.9\%)$ was higher than L. japonica$(43.0\%)$ in the rate of mummification to archegonia. The longevity of Aphidiidae and hyperparasites was investigated by feeding honey. The results showed that hyperparasites had lived 15.8 to 21. 5 days, while Aphiidiidae lived only 2 to 3 days.