Search

Background: Temperature alters host suitability for the development of parasitoids through direct (thermal effect) and indirect (parental effect) pathways. The effects of three temperature regimes on the development and survival of two parasitoid species, Citrostichusphyllocnistoides(Narayanan) and CirrospilusingenuusGahan (Eulophidae: Hymenoptera) of the citrus leafminer, PhyllocnistiscitrellaStainton (Lepidoptera: Gracillariidae) was evaluated. The experiment was conducted at 20, 25, and 30°C temperatures with 65 ± 2% relative humidity (R.H.) and 16h: 8h (L: D) photoperiod. Results: In C.phyllocnistoides, the pre-ovipositional period was longer at 20°C, while non- significant difference was observed in the pre-ovipositional period of C.ingenuusunder the effect of different temperatures (P> 0.05). The ovipositional period of C.phyllocnistoidesand C.ingenuuswas higher at 20°C and gradually decreased by increasing the temperature. Non- significant (P> 0.05) difference was found in post-ovipositional period of both parasitoid species. Both species exhibited the maximum fecundity at 25°C, while, the minimum fecundity was recorded at 30°C. However, the adult longevity of both parasitoid species was highest at 20°C and gradually decreased by increasing the temperature. In both parasitoids, the parasitism rate was highest at 25°C. Conclusion: This study highlighted the importance of thermal effects on some parasitoid species of insect pests to predict the future of trophic dynamics in global warming situations.

Background: The fall armyworm, Spodoptera frugiperda(J.E. Smith) (Lepidoptera: Noctuidae), was recorded for the first time in Pakistan in 2019, and now it has spread in several regions, i.e., Punjab and Sindh, affecting maize production. Farmers are using widely synthetic pesticides to control the pest. Further, the resistance development in insects and the non-target effect of chemicals on the environment and humans pose serious threats of using insecticides. The use of entomopathogenic fungi (EPF) is being considered an important tool in integrated pest management program. The main objective of this study was to check the impact of different conidial concentrations of Metarhizium anisopliaefungus on the nutritional physiology of S. frugiperda. Results: The dose-dependent effect of tested EPF was observed, and the highest concentration (1 × 109conidia/ml) considerably affected nutritional parameters. Reduced relative consumption rate (21.7%), relative growth rate (19.5%), the efficiency of conversion of ingested food (24.2%), and approximate digestibility (16.3%) were observed in treated larvae compared to the untreated by using a higher concentration of EPF. Pupal weight was also found lower (77.9 mg and 84.2 mg, respectively), when larvae were treated by 1 × 109and 1 × 108conidia/ml concentrations of EPF. Further, 46.7% of larvae were found dead with this conidial concentration. Conclusions: This study suggests that the application of a higher concentration of M. anisopliaecould be an effective option to control S. frugiperda. The EPF can enhance the integrated pest management programs and could be useful in reducing the environmental impact of synthetic insecticides.