Evaluation of the effectiveness of spirotetramat on the diaspine scale parlatoria pergandii in citrus orchards

Abstract

The control of Parlatoria pergandii (Comstock, 1881) was studied in citrus orchards at Belksiri (Gharb area), Morocco. Three concentrations of Spirotetramat (T0 = 0 L/Ha, T1 = 0.625 L/Ha, T2 = 0.755 L/Ha, and T3 = 1 L/Ha) were applied to 4 ha of Valencia late orchard (each dose for 1 ha of citrus). The insecticidal of Spirotetramat was evaluated on two stages of larvae (L1 and L2) of P. pergandii and three stages of females, F1, F2, and F3. Similarly, the rates of parasitism by Aphytis hispanicus on the females of three different stages were monitored to evaluate the impact of Spirotetramat on this natural enemy. Results showed that Spirotetramat was more effective on larvae than females. Of the females, 26.04% were parasitized, 65.81% were inhibited, and only 8.15% were intact after the treatment period. Of the larvae, 79.73% were inhibited, and only 20.27% survived after the treatment period. Finally, our study highlights that all the tested concentrations of this product were effective on the population of P. pergandii. On the other hand, this product showed a less negative impact on the parasitized females with the low concentration (0.625 L/Ha) compared to the high concentrations of the pesticide (T2 = 0.755 L/Ha and T3 = 1 L/Ha), especially for the female stages F2 and F3. Moreover, the impact on the water table will be less severe with a low concentration.