A research on determination of the population fluctuation and natural enemies of the pepper gall midge Asphondylia gennadii (Marchal) (Diptera: Cecidomyiidae) in greenhouse cultivation

The pepper gall midge Asphondylia gennadii (Marchal 1904) (Diptera: Cecidomyiidae), which was detected on pepper plant for the first time in our country in 1953 in Arsuz district of Hatay province, causes significant yield and quality loss by causing damage in greenhouse pepper production. In this study, the population fluctuation, natural enemies and the damage status of A. gennadii in greenhouse pepper cultivation were determined. At the same time, the hosts of A. gennadii were determined by sampling from the plants around the greenhouses. The study was carried out in greenhouses located in the Kumluca district of Antalya province in the 2020-2021 and 2021-2022 seasons. Samples were made from a total of six plastic greenhouses, three greenhouses in both seasons. In the study, 30 plants were randomly examined by weekly sampling starting from the planting date of the pepper plant in each greenhouse. As a result of the sampling, A. gennadii larvae and pupae were observed in the greenhouses between september and december, butany individuals could not be detected between january and may. Asphondylia gennadii individuals, which were detected again as of the second week of May, were observed in the greenhouses until the first week of july. In both seasons, the highest A. gennadii population was detected in may and june. Asphondylia gennadii larvae and pupa numbers were in the range of 0.03 – 1.9 larva/plant and 0.03 – 1.9 pupa/plant, respectively, in the 2020-2021 production season. In the 2021-2022 season, it was determined in the range of 0.03 – 0.53 larva/plant and 0.03 – 1.97 pupa/plant, respectively. In the greenhouses, the rates of indented plants were between 3.33% and 56.67%, the rates of indented flowers in all the flowers and fruits sampled were between 0.38% and 18.95%, and the rates of indented fruit were between 0.11 and 16.97%. In the 2021-2022 production season, the rates of indented plants were between 3.33% and 66.67%, the rates of indented flowers in all the flowers and fruits sampled were between 0.39% and 18.39%, and the rates of indented fruit were between 0.14 and 4.77%. In the study, three different parasitoid species were identified that fed as ectoparasites on A. gennadii individuals. These parasitoid species were determined as Eurytoma dentata Mayr 1878 (Hymenoptera: Eurytomidae), Sigmophora brevicornis Panzer 1804 (Hymenoptera: Eulophidae) and an unidentified species belonging to the Hymenoptera order Pteromalidae family. .The ratio of three different A. gennadii parasitoids were detected during the two seasons; 83.13% E. dentata, 14.46% S. brevicornis and 2.41% unidentified parasitoids were detected. In our study, only one E. dentata was observed in october, except for this exception, all parasitoids were observed in june, when the A. gennadii population was highest. In the study, A. gennadii population was also detected in Capparis spinosa Linnaeus (Capparidaceae) plants around the greenhouse. In the 2020-2021 production season, the first A. gennadii individuals were detected in C. spinosa buds in the second week of may and continued to be detected until the last week of june. In the 2021-2022 season, A. gennadii individuals, which were first detected in C. spinosa buds in the second week of november, continued to be seen until the last week of this month. Asphondylia gennadii individuals could not be detected in the C. spinosa plant from the end of november to the end of may, and the population started to appear again on the last day of may and continued to be detected until the first week of july. The numbers of larvae and pupae in C. spinosa buds of A. gennadii individuals were observed in the range of 0.2 – 2.3 larva/bud, 0.4 – 1.97 pupa/bud, respectively. It is thought that the findings obtained from the study will contribute to determine the appropriate control time against A. gennadii.