scholarly journals The effects of Kingbo biopesticide on Tetranychus urticae Koch female adults

2013 ◽  
Vol 28 (3) ◽  
pp. 195-202 ◽  
Author(s):  
Irena Medjo ◽  
Dejan Marcic
Keyword(s):  
Tetranychus Urticae ◽  
Spider Mite ◽  
Sublethal Effects ◽  
Recovery Potential ◽  
Petri Dishes ◽  
Set Up ◽  
Two Spotted Spider Mite ◽  
Tetranychus Urticae Koch ◽  
Laboratory Bioassays ◽  
Concentration Series

Toxic and sublethal effects of the biopesticide Kingbo (oxymatrine 0.2% + psoralen 0.4%) on female adults of two-spotted spider mite (Tetranychus urticae Koch) were investigated in two laboratory bioassays. The assays were set up in four replicates on bean leaf discs (30 mm in diameter) placed on moistened cotton wads in Petri dishes. Preovipositional females were then released on them and treated directly with the biopesticide at a concentration series using a Potter device (2 ml liquid, 100 kPa air pressure, 2.7 ? 0.2 mg/cm2 aqueous deposit). Each replicate included 4-7 Petri dishes containing a total of 20-35 females. In the first assay, females were exposed to continuous acaricidal activity on treated discs over a period of 96 h; in the second assay, they were exposed for 24 h and then transferred to untreated discs and kept there for the next 72 h. Kingbo toxicity to females, expressed as LC50, was significantly higher in the first bioassay (14.83 ?l/l) than in the second one (26.39 ?l/l). Total gross fecundity of females in the first assay was reduced by 37-95% and net fecundity by 48-97%, depending on concentration; in the second assay, the respective fecundity reductions were 15-87% and 23-91%. We found that a 24 h exposure to the biopesticide Kingbo was sufficient for sustaining significant toxic and sublethal effects. Further research should provide additional data on the recovery potential of T. urticae populations.

Sublethal effects of chlorfenapyr on the life table parameters of two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae)

2018 ◽  
Vol 23 (7) ◽  
pp. 1342 ◽  
Author(s):  
Niloufar Sangak Sani Bozhgani ◽  
Hamid Ghobadi ◽  
Elham Riahi
Keyword(s):  
Life Table ◽  
Tetranychus Urticae ◽  
Spider Mite ◽  
Sublethal Effects ◽  
Pest Mite ◽  
Two Spotted Spider Mite ◽  
Experimental Treatments ◽  
Tetranychus Urticae Koch ◽  
Sublethal Concentrations ◽  
Lethal Doses

The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) is a well-known pest mite with an extensive host range worldwide. The control of T. urticae populations mostly relies on the application of synthetic acaricides or pesticides. Chlorfenapyr is a broad spectrum insecticide/miticide effective against agriculturally important pests. In this study, sublethal effects (LC10, LC20 and LC30) of this insecticide on demographic parameters of T. urticae based on the age-stage, two-sex life table theory were investigated under laboratory conditions [25 ± 2 °C, 60 ± 5 % RH and 16:8 (L:D) h]. According to the obtained results, the LC50 value for females of T. urticae was 47.66 ppm. The egg incubation, protonymph, as well as deutonymph durations of both sexes were significantly reduced as a consequence of treatment with LC20 and LC30 of chlorfenapyr. In addition, our results indicated that oviposition period in LC10 lasted 9.62 days, which was closer to the control (9.73 days); while it significantly decreased with increasing the concentration from LC20 to LC30. Furthermore, LC20 and LC30 treatments decreased the fecundity of females by 55.5% and 61.6%, respectively. The values of both intrinsic (r) and finite rates of increase (λ) at LC20 and LC30 was significantly inferior to other experimental treatments. It could be concluded that along with the lethal doses, the sublethal concentrations of chlorfenapyr profoundly reduced the population growth rate of T. urticae.

scholarly journals Effects of local isolates of Beauveria bassiana (Balsamo) Vuillemin on the two-spotted spider mite, Tetranychus urticae (Koch) (Acari: Tetranychidae)

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Cenk Yucel
Keyword(s):  
Tetranychus Urticae ◽  
Beauveria Bassiana ◽  
Spider Mite ◽  
Lethal Effect ◽  
Probit Analysis ◽  
Plant Feeding ◽  
Wide Range ◽  
Two Spotted Spider Mite ◽  
Short Time ◽  
Tetranychus Urticae Koch

Abstract Background The two-spotted spider mite, Tetranychus urticae (Koch) (Acari: Tetranychidae), is a widely distributed plant-feeding pest that causes significant yield losses in a wide range of crops. Newly developed or improved environmentally friendly biocontrol agents serve as an alternative to traditional pest control tools. Experiment of the effects of 2 local fungal isolates of Beauveria bassiana (BGF14 and BCA32) was carried out against T. urticae under laboratory conditions. Results Both tested isolates had lethal effect in a short time after application, and this effect increased as time progressed. BGF14 and BCA32 isolates caused T. urticae mortality rates ranging from 25.88 to 61.92 and 32.36 to 62.03% when applied at the concentrations between 1×105 and 1×108 conidia/ml, respectively. According to the Probit analysis performed on the effect of fungi on T. urticae adults, the LC50 values of BGF14 and BCA32 isolates on the 7th day after inoculation were 2.6×106 and 6.3×104 conidia/ml, respectively, and the LT50 values for both fungi applied at a concentration of 108 conidia/ml were 2.14 and 2.23 days, respectively. Conclusions The 2 isolates of B. bassiana (BGF14 and BCA32) had the potentials to suppress T. urticae population and can be recommended as promising biocontrol agent candidates for control of T. urticae.

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