Biological and biochemical effects of some insecticides on traits of orange pulvinaria scale, Pulvinaria aurantii Ckll. (Hemiptera: Coccidae) and mealybug ladybird, Cryptolaemus montrouzieri (Coleoptera: Coccinellidae)

Hallaji Sani1, Mohamadfazel (2020) Biological and biochemical effects of some insecticides on traits of orange pulvinaria scale, Pulvinaria aurantii Ckll. (Hemiptera: Coccidae) and mealybug ladybird, Cryptolaemus montrouzieri (Coleoptera: Coccinellidae). Doctoral thesis, University of Mohaghegh Ardabili.

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Abstract

Research Aim: The orange pulvinaria scale, Pulvinaria aurantii Ckll. is the most important scale of citrus in the northern Iran. The lethal effect of chlorpyrifos, pyripropoxyfen, acetamiprid and palazin, alone and combined with emulsifying oil, was evaluated on first instar of P. aurantii. Research method: The experiment was conducted under natural condition in a randomized complete block design with 10 treatments and 3 replications, and treatments effect was compared 1, 7, 14 and 21 days after spraying. Moreover, the effect of these insecticides was investigated on some biological traits and activity of some detoxification enzymes (alpha-esterase, beta-esterase and glutathion-S-transferase) in the scale and third instar larvae of Cryptolaemus montrouzieri Muls. was evaluated ( 26±1ºC, 75±5% RH, photoperiod of 14:10 h). Moreover, The effect of chlorpyrifos, pyriproxyfen and acetamiprid was examined on life table parameters of the Pulvinaria scale. Findings: The results on the first instar nymphs in natural condition showed that chlorpyrifos, pyriproxyfen and acetamiprid and palizin treated with oil caused the highest mortality. Pyriproxyfen had a more negative effect on P. aurantii life table parameters than other insecticides. The LC50 values of chlorpyrifos, pyriproxyfen and acetamiprid, respectively, were 215.1, 92.8 and 126.7 ppm, respectively. The intrinsic rate of increase in pyriproxyfen treatment (0. 160 / day) decreased compared to the control treatment (0.801 / day). The lowest activity of enzymes was recorded in chlorpyrifos treatment. The longest hatching time (8.13 days) was obtained in chlorpyrifos and the shortest in control (4.80 days).Among the treatments, the shortest life of the adult insect was observed in chlorpyrifos (53.50 days). Conclusion: Chlorpyrifos showed the greatest decrease in alpha-esterase activity and acetamiprid decreased the glutathione S-transferase activity in the third instar larvae. Palizin had less negative effect on shoemaker beta-ester activity than the other three insecticides. The results of the present study showed that among these compounds, palizin and oil are the most suitable insecticides for citrus pest control in integrated pest management programs.

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