Adaptation and establishment of Habrobracon hebetor Say in the population of stored moths pests of date, Ephestia kuehniella Zeller and Plodia interpunctella Hübner

Abstract

BackgroundHabrobracon hebetor (Hymenoptera: Braconidae) is a larval ectoparasitoid, mainly of pyralid moths of the stored pests of date, Plodia interpunctella Hübner and Ephestia kuehniella Zeller. It has some suitable characteristics for use in biological control of stored moth pests. The aim of this study was to compare the ability of H. hebetor establishment in the population of two important date storage moth pests P. interpunctella and E. kuehniella, and its role in their population fluctuations.ResultsThe population growth trends of two host species increased in the first 6 weeks and in the 17th to 22nd weeks of the 6-month period of conducting tests. The peaks of larval population of the two species were in the 10th and 21st weeks under temperature of 25 ± 2 °C, RH of 60 ± 5% and a photoperiod of 12:12, D:L. The pattern of fluctuation in the parasitism percentage in the larval population of the two moth species host was inconsistent with each other. The parasitism percentage was higher on the larval population of E. kuehniella than larval population of P. interpunctella. In E. kuehniella, the host population change rates were − 0.1 in the 10th and 15th weeks, while the highest rates were 0.1 and 0.8 in the 12th and 3rd weeks. The lowest level of parasitoid balance in the larval population of E. kuehniella and P. interpunctella was recorded in the 11th and 15th weeks, and the highest levels were recorded in the 20th and 24th weeks, respectively. The maximum probability rate of parasitoid non-establishment in E. kuehniella larval population was zero during the entire period and for P. interpunctella until the 22nd week.ConclusionIn fact, there was a strong correlation between establishment success and the severity of host and parasitoid populations. Only in the larval population of P. interpunctella, the maximum probability of failure of establishment was 11.5%, due to the occurrence of the maximum population of parasitized larvae and the minimum ratio of non-parasitic and parasitic larvae.