The Sublethal Effects of Thiamethoxam, Hexaflumuron, and Acetamiprid Insecticides on the Growth Period, Reproduction, and Life Table of the Two-Spot Ladybirds (Adalia bipunctata Linnaeus, Col. Coccinellidae) Feeding on Common Pistachio Psylla
Akbar Rajabi (MSc)1, Sultan Ravan (PhD)2, Mehdi Basirat (PhD)*3
1 Former Graduate Student of Zabol University and Eexpert of Pistachio Research Center,
Horticultural Sciences Research Institute, Agricultural Research, Education
and Extension Organization (AREEO), Rafsanjan, Iran
2 Member of Scientific Board of Zabol University, Zabol. Iran
3 Member of Scientific Board, Pistachio Research Center, Horticultural Sciences Research Institute,
Agricultural Research, Education and Extension Organization (AREEO), Rafsanjan, Iran
Received: 12.05.2020 Accepted: 02.09.2020
Introduction: The common pistachio psylla, Agonoscena pistaciae Burckhardt & Lauterer (Hemiptera: Aphalaridae) is the key pest of pistachio trees in Iran. Controlling this pest is conducted by using chemical pesticides; this results in the destruction of the natural enemies of this pest and its outbreak. Adalia bipunctata Linnaeus (Col.: Coccinellidae) is one of the predators of pistachio psylla. Given the usage of three common pesticides i.e. thiamethoxam, hexaflumuron, and acetamiprid in pistachio gardens, the present study aims to investigate the sublethal effects of these three pesticides on the biological indictors of A. bipunctata (two-spot ladybirds) in controlled conditions.
Materials and Methods: In the present study, the effects of thiamethoxam, hexaflumuron, and acetamiprid pesticides have been investigated on some of the biological indicators and life table of this ladybird in controlled laboratory conditions (temperature of 27.5± 1 degrees centigrade, relative humidity of 65± 5 percent, and a photoperiod of 16 hours of light and 8 hours of darkness). This experiment has been conducted by immersing the ladybird’s eggs in a toxic solution with sub-lethal concentrations. In order to investigate the sublethal effects of the insecticides, the growth period of immature and adult stages and the daily spawning rate of adult insects were investigated.
Results: The length of the pre-adult period in thiamethoxam, hexaflumuron, acetamiprid and control treatments were 16.69, 16.07, 16.34 and 15.58 (days) respectively.
The insecticide treatments were significantly different from the control. The net fertility rate was higher in control and hexaflumuron treatments; they were significantly different from those of thiamethoxam and acetamiprid. The net reproduction rate (R0) in thiamethoxam, hexaflumuron, acetamiprid and control treatments were respectively 41.87, 110.94, 62.2 and 153.7 (female/female/generation); a significant difference was observed between insecticides and control treatments. The highest intrinsic rate of population increase (rm) was 0.151 (per day) in the control treatment; this was significantly different from that of the other treatments. The mean generation times (T) in thiamethoxam, hexaflumuron, acetamiprid and control treatments were respectively 42.98, 44.67, 38.12 and 33.01 (days); the treatments were significantly different.
Conclusion: The usage of these three pesticides in pistachio gardens reduces population growth indices and reproductive parameters of A. bipunctata ladybird. However, the side effects of hexaflumuron pesticide are less than the other two pesticides. This information can be used in the integrated control management of this pest.
►Please cite this article as follows:
Rajabi A, Ravan S, Basirat M. The sublethal effects of thiamethoxam, hexaflumuron, and acetamiprid insecticides on the growth period, reproduction, and life table of the two-spot ladybirds (Adalia bipunctata Linnaeus, Col. Coccinellidae) feeding on common pistachio psylla. Pistachio and Health Journal. 2020; 3 (3): 33-44.