The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), and the carmine spider mite, Tetranychus cinnabarinus (Boisduval), are two of the most important mite pests of different host plants in Egypt. These mites are spreading rapidly because of their resistance to acaricides; therefore, it was necessary to develop a new biological control tactics for mite management. Plant extracts, such as garlic extract (Allium sativum Linn.), may represent easy, available and viable alternative, because they are considered to be minimum-risk pesticides. A series of laboratory and semi-field experiments were considered to determine the susceptibility of adult mite females to different concentrations of garlic aqueous extract (G.A.E.). Mortality was measured upon treatment with five concentrations ranging from 1 to 25% W/V. Female mortality increased with concentration, T. urticae was more tolerant than T. cinnabarinus through laboratory studies as maximum mortality values were 90% and 100% after 24 hours using concentration 25% W/V, respectively. The chemical composition of the Allium sativum aqueous extract was characterized by GC/MS analysis which revealed the occurrence of 33 compounds, of which the major compound was identified as 2-Furancarboxaldehyde,5-(hydroxymethyl). The efficacy of G.A.E. was evaluated against T. urticae and T. cinnabarinus under semi-field conditions. Highest reduction (89.75 %) in T. urticae population was recorded by using concentration 50% W/V one day after treatment (DAT). T. cinnabarinus was more tolerant under the semi-field conditions as the reduction was (80.14 %) using the same concentration. G.A.E. is effective in the control of both tetranychids. It is promising candidates for biological control of these two mite pests.
Experiments were conducted in the laboratory to assess the ability and stability of garlic (Allium sativum Linn.) aqueous extract to control the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), and the carmine spider mite, Tetranychus cinnabarinus (Boisduval) in Egypt. Natural plant extracts, as (Allium sativum Linn.), have minimum-risk to the environment, so they can considered as an easy alternative to pesticides. Seven concentrations ranging from 2000 to 40000 ppm garlic were used to measure extract toxicity. Data showed that the maximum mortality values were 83.33and 86.67 % after 7 days, for T. urticae, and T. cinnabarinus, respectively. The effect of storage periods on the efficacy of different six concentrations of aqueous garlic extract on the same mite species was studied. Results indicated that the extract acaricidal activity decreased throw time for all tested concentrations. After four weeks it lost about 30% of its activity. Garlic aqueous extract significantly reduced egg deposition and egg hatchability of T. urticae and T. cinnabarinus. Regarding mites' mortality and fecundity, there were no statistically significant differences between the two species. These experiments demonstrated that garlic aqueous extract is effective in the control of both tetranychid mite pests.
The efficacy of Fenugreek, Trigonellafoenum graecum, Celery, Apium graveolens Laurel, Laurus nobilis and Thyme, Thymus vulgaris extracts, against the four stored grains pests, rice weevil, Sitophilus oryzae, cowpea beetle, Callosobruchus maculatus, mould mite, Tyrophagus putrescentiae and house dust mite, Dermatophagoides farinae were investigated. Mortality (%) increased with increasing concentrations, exposure periods and varying from plant to plant. Petroleum ether extract of A. graveolens induced 100% mortality after two, eight and seven days of exposure for C. maculates, S. oryzae and D. farinae, respectively. Foenum graecum caused 100% mortality after four, five and seven days for S.oryzae, D. farinae and T. putrescentiae, respectively and 93.3% for C. maculates after five days. Petroleum ether extract of L. nobilis caused 100% mortality to C. maculatus, T. putrescentiae and D. farina but declined to48% with S. oryzae. T. vulgaris caused a complete reduction in F1-progeny for C. maculatus but had no effect against S. oryzae moderate effect on T. putrescentiae and D. farinae. A. graveolens and T. foenumgraecum were the most toxic plants followed by L. nobilis; while T. vulgariswas the least. For all plants, petroleum ether extracts were more effective in mortality percentage and reduction in F1-progeny than acetone extracts.
The biology and life table of three acarid mite, Caloglyphus manure Eraky&Osman, Sancassania (Caloglyphus) berlesei (Michael) and Tyroghagus putrescentiae (Schank) fed on the eggmasses of root-knot nematode Meloidogyn. incognita (Kofoid
Abdou, D.A.M., M.M. Elbokl, A.E.M. Abd Elmageed and M.G. Habashy. 2023. Lethal and Sublethal Effects of Mixed Pesticides on Tetranychus urticae Koch and its Predator Phytoseiulus persimilis. Arab Journal of Plant Protection, 41(1): 40-47. https://doi.org/10.22268/AJPP-41.1.040047 Tetranychus urticae Koch is considered one of the most economically important pests on a wide range of crops in orchards worldwide. T. urticae control has been largely based on the utilization of acaricides. Sublethal effects of Romectin gold 32.8% SC (Abamectin 2.8% + Imidaclopride 30%) and AgriFlix 18.56% SC (Thiamethoxam 15.24% + Abamectin 3.23%) were studied on toxicity index and life-table parameters of T. urticae. LC25 concentration of Romectin gold and AgriFlix that were 0.0019 and 0.013 ppm, respectively, were utilized for sublethal studies. All acaricides showed a significant effect on T. urticae. Results obtained indicated that Romectin gold was the compound that had the higher effect on adult females of T. urticae and its predatory mite P. persimilis than AgriFlix. Sublethal concentrations of Romectin gold and AgriFlix may influence the durability of pre-adult stages, longevity, and biological parameters of T. urticae. The duration of life cycle of both females and males decreased significantly compared to the control with no significant effect between the two tested compounds. At the same time, Romectin gold produced the highest life cycle and life span. AgriFlix significantly decreased the pre-oviposition period with the lowest time of 1.10 days compared with 2.00 days for the control. To the contrary, Romectin gold had no significant effect on the preoviposition period. On the other hand, treatments with both Romectin gold and AgriFlix decreased significantly the oviposition period compared with the control. Romectin gold and AgriFlix significantly reduced the total number of eggs produced per female. AgriFlix acaricide decreased the total number and the daily rate of eggs produced by 73.36 and 65.05%, respectively. Results showed that exposure of females to sublethal concentrations of Romectin gold and AgriFlix reduced the net reproductive rate (R0), while intrinsic rate (rm) was increased compared to the control. Similarly, the finite rate of increase (exprm) for the control was significantly higher than that for Romectin gold and AgriFlix. Additionally, it was found that mean generation time (T) of the control was significantly shorter than that of Romectin gold and AgriFlix. Meanwhile, sex ratio was the same for control, Romectin gold and AgriFlix. Keywords: Sublethal effects, toxicity index, Life-table parameters, Abamectin, Imidaclopride and Thiamethoxam.
The use of synthetic acaricides is becoming increasingly hazardous to non-target organisms. Plant-derived natural products are alternative candidates with general low toxicity to human and environment. Two extracts and nine phenolic compounds (1-9) from the leaves of the Brazilian pepper tree (Schinus terebinthifolius Raddi) were investigated for their acaricidal effects against two tetranychid mites, Tetranychus cinnabarinus (carmine spider mite) and Tetranychus urticae (two-spotted spider mite). After 7-days of treatment, the ethyl acetate fraction demonstrated remarkable mortality against T. cinnabarinus (86.67%) while, the n-hexane fraction showed the highest mortality against T. urticae (96.67%) at 200 μg/mL. Among the tested compounds, afzelin (2) and protocatechuic acid (7) exhibited remarkable activity. Regarding T. cinnabarinus, afzelin showed the highest mortality (86.67%), toxic activity (LC50 22.32 μg/mL and toxicity index, Ti 0.972), and the fastest lethality by time. Whereas, protocatechuic acid achieved the highest mortality (96.67%), the lowest LC50 (0.232 μg/mL, Ti 73.71), and fastest lethality by time against T. urticae. This study reported a promising in vitro acaricidal activity of the phytoconstituents of the Brazilian pepper tree and suggested its isolated compounds, such as afzelin and chatechuic acid, as alternative leads for the development of echo-friendly acaricides.
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