Spodoptera littoralis is a highly polyphagous pest that attacks numerous important crops in the world and causes substantial economic losses to agricultural production. In the present study, the effects of different leafy vegetables, including Purslane, Chives, Parsley, Basil, Dill, Coriander, and Mint, were investigated on feeding responses and enzymatic activities of S. littoralis under laboratory conditions. Furthermore, the total contents of the three major secondary metabolites (phenolics, anthocyanins, and flavonoids) in the studied vegetables were determined. Our findings showed that the lowest and the highest approximate digestibility were on Basil and Purslane, respectively. The highest values of efficiency of conversion of ingested and digested food were achieved in larvae fed on Chives and Coriander, respectively, whereas the lowest values were recorded after feeding on Purslane. The highest and lowest relative growth rates were in larvae reared on Dill and Purslane, respectively. Furthermore, the highest amylolytic and proteolytic activities were in larvae fed with Coriander and Dill, respectively, while the lowest activities of these enzymes were on Purslane. In addition, correlation analysis revealed significant correlations between feeding characteristics and enzymatic activity of S. littoralis with biochemical compounds of the studied leafy vegetables. Our results suggest that Coriander is a suitable host, while Purslane displayed tolerance traits against S. littoralis, which can be used in sustainable management programs aiming to reduce chemical inputs.

The life history and digestive α-amylase activity of the Angoumois grain moth, Sitotroga cerealella Olivier (Lepidoptera: Gelechiidae) were studied on six wheat cultivars (Arg, Bam, Nai 60, Pishtaz, Sepahan and Shanghai) at 25 ± 1°C, relative humidity of 65 ± 5% and a photoperiod of 16:8 (L:D) h. A delay in the developmental time of S. cerealella immature stages was detected when larvae were fed on cultivar Sepahan. The maximum survival rate of immature stages was seen on cultivar Bam (93.33 ± 2.10%), and the minimum rates were on cultivars Nai 60 (54.66 ± 2.49%) and Sepahan (49.33 ± 4.52%). The highest realized fecundity and fertility were recorded for females which came from larvae fed on cultivar Bam (93.30 ± 2.10 eggs/female and 91.90 ± 3.10%, respectively); and the lowest ones were observed for females which came from larvae fed on cultivar Sepahan (49.30 ± 4.50 eggs/female and 67.4 ± 11.1%, respectively). The heaviest male and female weights of S. cerealella were observed on cultivar Bam (2.97 ± 0.02 and 4.80 ± 0.01 mg, respectively). The highest amylolytic activity of the fourth instar was detected on cultivar Bam (0.89 ± 0.04 mg maltose min−1), which had the maximum mean hundred-wheat weight (5.92 ± 0.19 g). One α-amylase isozyme was detected in the midgut extracts from the fourth instar larvae fed on different wheat cultivars, and the highest intensity was found in larvae fed on cultivar Bam. Correlation analyses showed that very high correlations existed between the immature period, fecundity and fertility on one side and inhibition of α-amylase, soluble starch content and hundred-wheat weight on the other. According to the obtained results, cultivar Sepahan is an unfavorable host for the feeding and development of S. cerealella.