Study of tritrophic interactions in the pomegranate-carob moth-parasitoid system

Abedi, Zahra (2020) Study of tritrophic interactions in the pomegranate-carob moth-parasitoid system. Doctoral thesis, University of Mohaghegh Ardabili.

Text Abedi-Thesis- final.pdf Download (1MB)

Abstract

Research Aim: The carob moth, Ectomyeloisceratoniae(Zeller) (Lepidoptera Pyralidae), is the most important and effective factor in decreasing quality and quantity of pomegranate in Iran and many tropical and subtropical regions. The purpose of this research was to study, the effects of 11 commercial cultivars of pomegranate (Aban-Mahi, Esfahani-Daneghermez, Gabri, Gorche-Tafti, Malase-Danesyah, Malase-Yazdi,Shahvare-Daneghermez, Shahvare-Danesefid, Tabolarze-Mehrmahi, Tafti, and Toghe-Gardan) on life history variables, nutritional performance, and energy reserves of E. ceratoniae. Also, effects of four different developmental stages of pomegranate fruit (Hazelnut-size, Walnut-size, Juicy, and Ripe) were investigated on life table parameters, nutritional yield, and energy contents of E. ceratoniae intwo pomegranate cultivars, namely Shahvare-Danesefid and Esfahani-Daneghermez as susceptible and resistant cultivars, respectively. Moreover,the performance of Habrobraconhebetor Sayand Venturia canescensGravenhorst parasitizing E. ceratoniae were determined on five commercial cultivars of pomegranate, including Shahvare-Danesefid (relatively susceptible), Gabri and Tafti (moderately susceptible) and Esfahani-Danehghermez and Malase-Danehsyah (relatively resistant).Biochemical characteristics of the tested cultivars were assessed in order to understand any possible correlation between important demographic parameters and nutritional properties with biochemical features of pomegranate cultivars. Research method: TheE. ceratoniaelarvae were reared on each pomegranate cultivar in a growth chamber at 30 ± 1°C, 60 ± 5% RH, and a photoperiod of 14:10 (L:D) hours. The parasitoids rearedon fifth-instar larvae of E. ceratoniaeon each pomegranate cultivar at the same laboratory conditions. The life table parameters of E.ceratoniae and parasitoids analyzed with method using TWOSEX-MSChart. Anthocyanins of pomegranate cultivars were determined by HPLC.Other biochemical metabolites of pomegranate were measured by spectrophotometer. Findings: Our research showed that various pomegranate cultivars have significant effects on life history, demographical parameters, nutritional performance and energy reserves of E. ceratoniae. The shortest development time was observed on Shahvare-Danesefid cultivar and the longest was on Esfahani-Daneghermez and Malase-Danesyah cultivars. The highest intrinsic rate of increase was observed on Shahvare-Danesefid and the lowest was on Esfahani-Daneghermez. The results indicated that Shahvare-Danesefid was a relatively susceptible pomegranate cultivar and Esfahani-Daneghermez was the least appropriate (most resistant) cultivar for feeding of E. ceratoniae, which could be useful in the development of integrated pest management strategies for this pest. The Esfahani-Daneghermez cultivar can be recommended to be cultivated in regions where the damage of this pest is economically considerable. Significant differences were observed in developmental time and adult fecundity ofE. ceratoniae across various tested fruit stages in both pomegranate cultivars. The highest value of intrinsic rateof increase (r) was found in Juicy and lowest in Hazelnut-size stage of Shahvare-Danesefid. The highest rvalue was on Walnut-size and Juicy stages, and the lower rate was obtained from the feeding of E. ceratoniaeon Ripe and Hazelnut-size stages in Esfahani-Daneghermez. Results indicated Juicy (Shahvare-Danesefid) and Walnut-size stages(Esfahani-Daneghermez) were relatively susceptible pomegranate stages, and Hazelnut-size and Ripe stageswere unsuitable for feeding of E. ceratoniae in Shahvare-Danesefid and Esfahani-Daneghermez, respectively. Significant differences were observed in thelife history traits of H. hebetor and V. canescens onvarious pomegranate cultivars. The shortest development time of H. hebetorwas detected on Shahvare-Danehsefid cultivar and the longest period was on Malase-Danehsyah and Esfahani-Danehghermez cultivars. The highestr value of H. hebetor was observed on Shahvare-Danehsefid and the lowest was on Malase-Danehsyah. Also, the shorter development time of V. canescens was detected on Shahvare-Danesefid cultivar and the longer period was on Esfahani-Daneghermez cultivar. Six major anthocyanin compounds were detected in various pomegranate cultivars. Esfahani-Daneghermez cultivar showed the highest value of anthocyanin compounds. Conclusion: Shahvare-Danesefid cultivar was found to be the most suitable host in comparison with other cultivars in the pomegranate-carob moth-parasitoid interactions. The combination of pomegranate cultivars together with biological control agents could be proposed as an effective integrated pest management program against E. ceratoniae. Our findings may provide basic information for better understanding of the tritrophic interactions of the pomegranate-carob moth-parasitoid relationships.

Actions (login required)

View Item