• Korean journal of applied entomology
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• v.48 no.4
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• pp.417-421
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• 2009

Monitoring was conducted to investigate the occurrence of Grapholita dimorpha Komai in Korean apple orchards using sex pheromone traps. G. dimorpa showed four peaks per year: early May, from late June to early July, from late July to mid August, and from late August to September. After adult emergence of the over-wintered G. dimorpha, G. dimorpha catches was decreased significantly and increased again after July. In G. molesta traps, G. molesta and G. dimorpha were trapped by 98.8 and 1.2%, respectively. Conversely in G. dimorpha traps, G. dimorpha and G. molesta were trapped by 99.7 and 0.3%, respectively. The 30.6% of the moths from the damaged apple fruits were G. dimorpha. This is the first report on G. dimorpha in apple orchards in Korea.

• Korean journal of applied entomology
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• v.51 no.4
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• pp.449-459
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• 2012

Fruit borers such as Grapholita molesta, G. dimorpha and Carposina sasakii are major pests of plum in Korea. Population densities and seasonal occurrence were monitored using the synthetic sex pheromone trap in Uiseong and Gyeongsan, two important major plum growing area in Korea. In 2010 and 2011, adults of G. molesta were caught from mid April with the peak of late April, and then undergone three more generations in Gyeongsan. Grapholita dimorpha appeared from late April and they showed three peaks until late September. Both Grapholita species occurred a few days later in Uiseong than in Gyeongsan where the latitude is $1^{\circ}$ lower. There was no difference of the phenological occurrence of C. sasakii between Gyeongsan and Uiseong, showing the same patterns of two or three peaks. Population size was in order of G. molesta, G. dimorpha and C. sasakii with 63:16:20 and 47:35:18 in Gyeongsan and 51:18:31 and 46:13:36 in Uiseong, in 2010 and 2011 respectively. There was no difference between the numbers of Grapholita species caught in the trap installed inside and outside of the orchards.

• Korean journal of applied entomology
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• v.52 no.4
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• pp.365-370
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• 2013

The plume fruit moth, Grapholita dimorpha Komai, a fruit tree pest occurring in the northeast Asia, was firstly reported to infest apple in Korea in 2009, but its direct damage to other fruit trees has been poorly studied. In this study, we investigated shoots and fruits of both peach and plum trees and compared their damage rates by G. dimorpha to those by G. molesta, a congeneric species. In order to discriminate the two moth species, we developed a molecular diagnosis method using species-specific primer sets on different PCR conditions and distinguished the two species collected from the damaged shoots or fruits. The shoots and fruits of peach were infested mostly by G. molesta. However, in plums, the shoots were damaged by G. molesta and the fruits mostly by G. dimorpha. In addition, these two species showed a clear difference in host preference in fruit damage, where 92.5% of the Grapholita moths collected in peach fruits were identified as G. molesta, but 97.0% of the moths in plum fruits were G. dimorpha. The difference of the damage between the two fruit trees may give important information for monitoring of the two moth species in these orchards.

• Korean journal of applied entomology
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• v.51 no.4
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• pp.479-484
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• 2012

The occurrence of plum fruit moth, Grapholita dimorpha, has been recently reported in apple orchards in Korea. It has been suspected that G. dimorpha and its related species, G. molesta, may occur simultaneously in other host plants. This study reports the occurrence of G. dimorpha in pear orchards of different localities in Korea. The identification of G. dimorpha was determined by morphological characters and the DNA marker. The cross-trapping of both species may be possible because the major sex pheromone (SP) compositions for the two species are similar. From the monitoring data, G. dimorpha and G. molesta were caught in SP lure traps of G. dimorpha and both species were also caught in SP lure traps of G. molesta. This cross-trapping of G. molesta to a SP lure of G. dimorpha varied significantly among pear orchards in different geographical localities. Furthermore, the occurrence peaks of the two species were not coincidental in all monitored orchards. These suggest that monitoring data obtained from each SP trap of both species in pear orchards may be mixed with two species, which would result in the over-estimation of population density and peak frequency on both species in pear orchards.

• Korean journal of applied entomology
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• v.60 no.1
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• pp.71-78
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• 2021

Trapping efficacy of lures obtained by mixing sex pheromone attractants of two or three species in a single dispenser were evaluated in peach and apple orchards for three lepidopteran fruit borers, Grapholita molesta (GM), Carposina sasaki (CS), and Conogethes punctiferalis (CP) which use different chemicals as their sex attractants. In the peach orchard, the trapping efficacy of the mixed lures of GM and CS attractants were reduced for GM trapping, compared with the single GM lure. The population fluctuation patterns of GM were highly correlated between the single lure and all the mixed lures. In the apple orchard, the efficacy of all the mixed lures were not reduced for GM trapping. The trapping efficacy of all the mixed lures for CS trapping were not reduced compared with the CS single lure in both the peach and apple orchards. In the peach orchard, the population fluctuation patterns of CS were highly correlated between the single lure and the mixed lures. The efficacy of the mixed lures for CP trapping could not be determined because of the small number of caught samples. The results indicated that mixed lures could be utilized for monitoring of the annual adult emergence of two species, GM and CS.

• Korean journal of applied entomology
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• v.47 no.3
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• pp.303-308
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• 2008

An unidentified moth was captured in sex pheromone traps of the oriental fruit moth, Grapholita molesta, especially at spring season in apple orchards and their vicinity. Though the captured males were similar in appearance to G. molesta males, they were easily distinguished by a matted difference in body size. Their occurrence pattern was also similar to that of overwintering G. molesta population from April to May, at which more males were captured in the pheromone traps installed in the vicinity of apple orchards than within apple orchards. After May, they were no longer captured in the pheromone traps. To investigate any larval damage due to this unidentified moth, molecular markers needed to be developed. Four PCR-RFLP markers originated from cytochrome b region of mitochondrial DNA could distinguish this unidentified moth from G. molesta.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.313-317
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• 2016

The congener and sympatric species, Grapholita molesta (Busck) and G. dimorpha Komai, are economically important pests against various Rosaceae fruit trees in Korea. In this study, we identified the species from the larvae of these two insects collected from damaged fruits of peach, plum, apple, pear, and quince by using a molecular diagnostic method and compared the distribution ratios of the two species within the fruits of each of these trees. Most (99.7%) of the larvae collected from peach fruits were identified as G. molesta, while all of the larvae found in plum fruits were G. dimorpha. Both species were found in the other three fruits, but G. molesta was significantly dominant in pear fruits. G. dimorpha was more abundant in apple and quince fruits, without any significant difference between the distribution ratios of two insects. The results suggest that development of further realistic strategies is necessary for the management of these two pests in Korean orchards.

• Korean journal of applied entomology
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• v.53 no.3
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• pp.239-246
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• 2014

Two congener species of Grapholita molesta and G. dimorpha have similar host ranges and adult occurrence patterns. In addition, the two species commonly use cis-8-dodecenyl acetate (Z8-12:Ac) and trans-8-dodecenyl acetate (E8-12:Ac) as their major sex pheromone components. The commercial lures made of the two components, therefore, suffer a mixed attraction of these two species. This study was conducted to assess any effect of their known minor sex pheromone components to reduce the mixed attraction. When cis-8-tetradecenyl acetate (Z8-14:Ac) was added to the commercial sex pheromone consisting of Z8-12:Ac/E8-12:Ac = 85/15, the attraction to G. dimorpha was not affected, but its attraction to G. molesta was significantly reduced. However, the addition of either dodecanyl acetate (12:Ac) or tetradedecanyl acetate (14:Ac) did not influence on the attraction of both species to the commercial lure. The addition of E8-14:Ac to 3-component sex pheromone, Z8-12:Ac/E8-12:Ac/Z8-14:Ac = 85/15/10, the attraction to G. dimorpha was rather significantly suppressed. From these results, the 3-component sex pheromone, Z8-12:Ac/E8-12:Ac/Z8-14:Ac = 85/15/10 was suggested as an improved composition of sex pheromone lure for G. dimorpha.

• Korean journal of applied entomology
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• v.47 no.1
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• pp.17-22
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• 2008

This survey was conducted from 1992 to 2005 in the major apple producing districts in southern part of South Korea including $4{\sim}8$ cities, to know the occurrence and damage level of two major pests, Carposina sasakii and Grapholita molesta that attack apple fruit. The fruit damage by G. molesta during the harvest period ranged from 0.02 to 1.64%. A tendency of higher damage of G. molesta was observed after 1997 compared with the previous years. The other hand, the fruit damage by C. sasakii was 0.02 to 1.30%, and the damage level was very low with fruit damage of < 0.3% except 1998. The orchard infested with G. molesta was 13 to 71 %, while 12 to 57% with C. sasakii. The rates of orchards where fruit damage by G. molesta was found were higher than those by C. sasakii after 1997. The tendency of fruit damage rates in the orchard where the most fruit damage was found was same with the trend of orchard rates infested with the pests. The maximum damage rate by G. molesta was 20.0% in 2005, while 4.5% by C. sasakii in 1998. The damaged shoot rates by the first generation G. molesta was $0.1{\sim}8.1%$, and it had a positive correlation with the rates of fruit damage during the harvest period. Consequently, it is concluded that G. molesta is dominant species compared with C. sasakii in commercial apple orchards recently.

• Korean journal of applied entomology
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• v.47 no.1
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• pp.37-44
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• 2008

Oriental fruit moth, Grapholita molesta, is a serious pest on apples. To control this pest in an environmentally friendly method, mating disruption strategy using sex pheromone has been developed. Area-wide application of mating disruption has been needed to be effective, with little understanding on how much size of apple cultivating area should be treated in one time application of the mating disruption technique. On this matter, we needed to determine a minimal mating active zone of G. molesta that should be applied with mating disrupters to be effective. Molecular markers to discriminate a specific population should be developed to trace population migration for reproductive behaviors. Here we developed two effective molecular markers using random amplified polymorphic DNA (RAPD) technique. Different field populations of G. molesta, based on locations and seasons, were analyzed with these markers. In a specific location, G. molesta populations varied in genetic composition with different seasons. Different local populations showed differential variation according to their relative distances among apple orchards. In overall, genetic variation among different populations became lessen with progression of seasons.