Rami Bou Hamdan* (1) Wajeh Kassis (2) and Mazen Bufaur (1)
(1). As-Suwayda Research Center, General Commission for Scientific Agricultural Research (GCSAR), Damascus, Syria.
(2). Department of Plant Protection, College of Agriculture, Damascus University, Syria.
(*Corresponding author: Rami Bou Hamdan. E-Mail: ramy.alswaida@gmail.com ).
Received:14/06/2022 Accepted: 2/10/2022
Abstract:
The study was conducted in 2019 at As-Suwayda Research Center in As-Suwayda governorate /Syria, to study the susceptibility of the codling moth Cydia pomonella to the Chlorpyrifos pesticide. The results shows that the Third-instar larvae of Cydia pomonella has developed a vigor tolerance to chlorpyrifos, and reached a resistance rate (RR) was (3.53, 3.55, 3.55) after (24, 48, 72) hours, respectively. The diapaused larvae of the codling moth (males and females) developed ultra vigor tolerance to chlorpyrifos, the resistance rate was (8.75, 9.52, 9.16) for male larvae and (8.86, 9.35, 8.95) for females after (24, 48, 72) hours, respectively, while ultra vigor tolerance was observed in the non-diapausing fifth-instar larvae, the resistance rate was (6.64, 7.7, 7.8) for males and (6.9, 8.16, 7.92) for females after (24, 48, 72) hours, respectively. We noted that the resistance rate of female larvae was higher than males, and the resistance rate of males and females of diapaused larvae was higher than third and non-diapausing fifth-instar larvae. Based on the results, we noted that the different larval instars showed tolerance to chlorpyrifos pesticide, while it didn´t reach to resistance, this calls for the pesticide shouldn´t be used extensively on pome trees, so that tolerance didn´t develop into resistance in the long term. In addition, the pesticide had to be used as part of a rotation cycle with other modern pesticides.
Key words: Cydia pomonella, larval instars, insecticide resistance, vigor tolerance, chlorpyrifos, Syria
Full paper in Arabic: pdf