Adults Of Two-spotted Spider Mite Research Articles

Acaricidal activity of the chinaberry, Melia azedarach L. (Lamiaceae) essential oil against Tetranychus urticae Koch

ABSTRACT The two-spotted spider mite, Tetranychus urticae Koch, is the worst pest for strawberries among all arthropod pests in Iran. In this study, essential oils from the flowering branches and fruits of the chinaberry, Melia azedarach L. were analysed using gas chromatography-mass spectrometry, and the acaricidal activity of the oil was evaluated in fumigation tests against T. urticae. Forty-three constituents were identified and Methanecarbothiolic acid (10.80%), Ethyl Acetate (9.24%), 2-Propanone, 1-fluor (9.01), Acetic acid, 1-methylethyl ester (8.33%) and n-Propyl acetate (8.02%) were the main constituents The mites were susceptible to the oil using the fumigation method. The results stated that M. azedarach oil had high toxicity on eggs and adults of two-spotted spider mite (LC50 was 18.27 and 13.63 µL L−1 for eggs and adults, respectively) with LT50 of 12.05 h. In addition, all tested concentrations had oviposition deterrent activity and repellency on adults of this mite. For the practical use of this oil as a novel acaricide, however, further investigations are needed to evaluate the effects on non-target organisms and the cost-benefit ratio for the formulation of a product to be used on protected crops such as strawberry in the greenhouse condition.

Phytochemical and acaricidal study of the Kermani lemongrass, Dracocephalum polychaetum Bornm. (Lamiaceae) essential oil against Tetranychus urticae Koch

ABSTRACT Mites cause significant damage to various crops, often requiring synthetic acaricides for their control. However, the frequent use of these products, resistance problems and severe problems with contamination occur. Therefore, one of the promising solutions is plant acaricides, which can be developed based on essential oils. Thus, the objective of this work was the extraction and characterization of the essential oil from the leaves of Kermani lemongrass, Dracocephalum polychaetum, and acaricidal evaluation of the oil and its major compound using the application by fumigation on female adults of Tetranychus urticae. The composition of the essential oil was analysed by GC-MS. The major components in the oil were 1-octen-3-ol (11.27%), 6-methyl-5-hepten-2-one (11.06%), linalool (9.89), and nonanal (9.64%), respectively. The impact of essential oil of this plant on fumigant toxicity, LT50, oviposition deterrent activity, and repellency against T. urticae was studied at different concentrations. The results stated that D. polychaetum oil had high toxicity on eggs and adults of two-spotted spider mite (LC50 was 60.30 and 50.87 µL L−1 for eggs and adults, respectively) with LT50 of 8.02 h. In addition, all tested concentrations had oviposition deterrent activity and repellency in adults of this mite.

Toxicity and Control Efficacy of an Organosilicone to the Two-Spotted Spider Mite Tetranychus urticae and Its Crop Hosts.

Simple SummaryThe organosilicone is commonly used as surfactant ingredient in agriculture. Some pilot studies showed pesticidal activities of some organosilicone surfactants. This study examined the toxicity of an organosilicone, Silwet 408, to the two-spotted spider mite Tetranychus urticae and explored the field usage of this chemical in pest control. We tested this chemical on eggs, nymphs, and adults of T. urticae. We applied a two-sprays strategy to enhance the field control efficacy based on the high toxicity of Silwet 408 to nymphs and adults and the lack of toxicity to eggs of T. urticae. However, their phytotoxicity should be taken under consideration. Our study improved our understand of the toxicity and safety of organosilicone surfactants. The results provide a basis for the usage of this chemical in mite control.Organosilicone molecules represent important components of surfactants added to pesticides to improve pest control efficiency, but these molecules also have pesticidal properties in their own right. Here, we examined toxicity and control efficacy of Silwet 408, a trisiloxane ethoxylate-based surfactant, to the two-spotted spider mite (TSSM), Tetranychus urticae and its crop hosts. Silwet 408 was toxic to nymphs and adults of TSSM but did not affect eggs. Field trials showed that the control efficacy of 1000 mg/L Silwet 408 aqueous solution reached 96% one day after spraying but declined to 54% 14 days after spraying, comparable to 100 mg/L cyetpyrafen, a novel acaricide. A second spraying of 1000 mg/L Silwet 408 maintained control efficacy at 97% when measured 14 days after spraying. However, Silwet 408 was phytotoxic to eggplant, kidney bean, cucumber, and strawberry plants, although phytotoxicity to strawberry plants was relatively low and declined further seven days after application. Our study showed that while the organosilicone surfactant Silwet 408 could be used to control the TSSM, its phytotoxicity to crops should be considered.

Evaluation of entomopathogenic fungi for the control of Tetranychus urticae (Acari: Tetranychidae) and the effect of Metarhizium brunneum on the predatory mites (Acari: Phytoseiidae)

The efficacy of the entomopathogenic fungi (EPF), Metarhizium brunneum (strains ARSEF 4556 and V275), Metarhizium flavoviride UPH-0288, Lecanicillium lecanii UPH-0241, and Beauveria bassiana UPH-1103 against the different developmental stages of the two spotted spider mite (TSSM), Tetranychus urticae, was investigated at 1×107conidia/ml concentration in detached leaf Petri dish and whole plant pot assays. One of the most virulent strains, M. brunneum V275 (=Novozymes Met52/F52), was screened using a range of doses against adult female predatory mites, Phytoseiulus persimilis and Neoseiulus californicus. All the EPF tested killed 11.8–14.3% and 12.8–17% of the TSSM eggs in Petri dish and pot assays, respectively. They also caused 57.3–90.3% and 29.5–67.5%, mortality of the mobile stages in the Petri dish and pots trials, respectively. TSSM adults were generally more susceptible to the EPF than the juveniles. Adult mortality was >80% for all strains except M. flavoviride which caused 67% mortality. Predatory female mites were also susceptible to M. brunneum V275 with mortality being dependent on the dose and predator species; thus mortality at 1×106, 1×107 and 1×108conidia/ml was 57.5, 80.5, and 99.5% for P. persimilis and 51.5, 75.0, and 90.5% for N. californicus, respectively. However, subsequent biological stages (eggs and juveniles) were not affected by the fungal pathogen, and the number of new generation mobile stages increased 3–9-fold compared with the initial number of released predatory mites. The current study thus shows that M. brunneum V275 application with the releases of predatory mites have the potential to suppress T. urticae.

Phytochemical and Acaricidal Study of the Galbanum, Ferula gumosa Boiss. (Apiaceae) Essential Oil Against Tetranychus urticae Koch (Tetranychidae)

The two-spotted spider mite, Tetranychus urticae Koch, one of the major pests of various agricultural plants, causes many problems with agricultural, horticultural and ornamental plants. In recent years, using plant-derived compounds such as essential oils and extracts were attended to their insecticidal and acaricidal properties. The galbanum, Ferula gummosa is a native plant of central Asia, was identified as an acaricide plant for the first time of this study. The composition of the essential oil was analyzed by GC-MS. The major components in the oil were β-pinene (50.1%), α- pinene (14.9%) and δ-3-Carene (6.7%). The impact on essential oil of this plant on fumigant toxicity, LT50, oviposition deterrent activity and repellency against T. urticae was studied at different concentrations. The results stated that F. gummosa oil had high toxicity on eggs and adults of two-spotted spider mite (LC50 was 6.98 and 6.52 μL L-1 for eggs and adults, respectively). In addition, all tested concentrations had oviposition deterrent activity and repellency on adults of this mite.

Efficiency of Orius minutus for control of Tetranychus urticae on selected potato cultivars

The influence of host plant traits of five potato cultivars: Savalan, Agria, Morene, Kondor and Diamant on the population density of two-spotted spider mite (TSM) Tetranychus urticae Koch, and ovipositional preference, predation rate and life history parameters of its predator Orius minutus L. were studied under laboratory conditions (23 ± 1°C, 50 ± 5% RH and 14L:10D). The density of TSM adults on Savalan, Agria and Morene was significantly lower than on Kondor and Diamant. In both no-choice and free-choice experiments, the females of the predator laid more eggs on TSM-infested leaves of Savalan (6 eggs/leaf and 24 eggs/plant) than on Agria, Morene, Kondor and Diamant. In predation rate experiments, the females of O. minutus consumed more TSM on the infested leaves of Savalan (32 TSM/predator during 48 hours) than on Agria, Morene, Kondor and Diamant. In performance experiments, the predator nymphs developed faster when reared on TSM-infested leaves of Savalan (16 days) than on Kondor and Diamant. Moreover, the survival rate, from egg to adult, of O. minutus on TSM-infested leaves of Savalan (52.8%) was better than on Kondor and Diamant. The fecundity of O. minutus reared on TSM-infested leaves of Savalan (11.7 eggs/female) was significantly higher than on Agria, Morene, Kondor and Diamant. The intrinsic rate of natural increase and the population growth rate of O. minutus were highest when reared on TSM-infested leaves of Savalan (rm = 0.089 day−1 and λ = 1.094 day−1). These results suggest that using Savalan cultivar integrated with O. minutus could result in improved efficacy of this predator and lead to effective and more sustainable management of T. urticae in potato fields.

Toxicity and Oviposition Deterrence and Repellency of Mentha pulegium (Lamiacaeae) Essential Oils against Tetranychus urticae Koch (Teteranychidae)

The two-spotted spider mite, Tetranychus urticae Koch, one of the major pests of various agricultural plants, causes many problems on agricultural, horticultural and ornamental plants. In recent years, using plant-derived compounds such as essential oils and extracts was attended for their insecticidal and acaricidal properties. Mentha pulegium is a native plant of temperate Asia, was identified as an acaricidal plant for the first time in this study. The impact of essential oil of this plant on fumigant toxicity, LT50, oviposition deterrent activity and repellency against Tetranychus urticae was studied at different concentrations. The results stated that M. pulegium oils had high toxicity on eggs and adults of two-spotted spider mite (LC50 was 2.57 and 2.25 μL L−1 for eggs and adults, respectively). In addition, all tested concentrations had oviposition deterrent activity and repellency on adults of this mite.

The effects of Kingbo biopesticide on Tetranychus urticae Koch female adults

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.

Patch Retention Time in an Omnivore, Dicyphus hesperus is Dependent on Both Host Plant and Prey Type

We examined patch residence times for an omnivorous predator, Dicyphus hesperus on a variety of plants and prey. Individual D. hesperus were placed in cages containing either mullein, tomato, pepper or chrysanthemum plants, and either no prey, Mediterranean flour moth eggs, greenhouse whitefly pupae or two-spotted spider mite adults. Patch residence times were typically greater than 24 h. The probability of remaining on the patch was greatest on mullein and tomato, followed by chrysanthemum and least on pepper, whereas probability of remaining on the patch was greatest when flour moth eggs were present, and least when no prey were available. Patch residence time in D. hesperus was determined by both the prey, and the species of plant, in an independent fashion. Our results reinforce the notion that for omnivores, the patch itself is as important as the prey that it harbors.