Investigation of relationship between biological and feeding traits of the carob moth, Ectomyelois ceratoniae Zeller (Lep.: Pyralidae), with some biochemical compounds of various hosts

The carob moth, Ectomyelois ceratoniae Zeller (Lep.: Pyralidae), is a polyphagous and destructive pest that causes considerable damage to various crops worldwide both before and after harvest. Host plant resistance is a critical component of integrated pest management and can be beneficial when used in conjunction with biological and chemical pest control approaches. The host type has a substantial effect on the biological characteristics and population growth parameters of E. ceratoniae. The purpose of this contribution is to evaluate the impact of eleven hosts, including peanut, apple, date, fig, olive, orange, pistachio, pomegranate, quince, and walnut, on the life history and nutritional indices of this pest.

The carob moth larvae were reared on each plant host in a growth room set at 30 ± 1 °C, 60 ± 5 % RH, plus a 14:10 (L:D) hour photoperiod. Daily observations and records were made of the duration of each stage, developmental period, and survival rate. TWO SEX-MSChart was used to evaluate the raw data based on the age-stage two-sex life table. Additionally, hosts' phytochemical metabolites were measured using a spectrophotometer. Correlations between demographic factors and nutritional properties with biochemical features of various hosts were then estimated.

The results indicated that various hosts substantially affected E. ceratoniae's demographic characteristics and nutritional indices. On walnut and artificial diets, the immature development period was the longest and shortest, respectively. Additionally, the intrinsic rate of increase (r) of E. ceratoniae was lowest on quince, orange, apple, olive, and highest on an artificial diet. Compared to larvae fed on other hosts, larvae reared on an artificial diet had the highest efficiency of conversion of ingested food (ECI) and efficiency of conversion of digested food (ECD). Furthermore, larvae-fed pistachio had a greater relative growth rate (RGR) than other tested hosts. The cluster analysis findings revealed that pomegranate and artificial diet treatments were relatively vulnerable hosts, whereas quince, orange, apple, and olive were the least suitable (most resistant) hosts for E. ceratoniae feeding. Significant variations in biochemical metabolites were observed between the various hosts in this study. Moreover, significant positive or negative associations between life history variables and nutritional indices plus biochemical features of various hosts were found. A significant negative correlation was observed between total phenolic content and total anthocyanin content of different hosts and E. ceratoniae fecundity, net reproductive rate (R0), intrinsic rate of increase (r), the efficiency of conversion of ingested food (ECI), and relative growth rate (RGR).

The findings may provide essential information for a better understanding of plant-herbivore interactions, which may aid in the development of effective integrated pest management (IPM) strategies for E. ceratoniae control.