THE EFFECT ON THE TWO-SPOTTED SPIDER MITE, TETRANYCHUS URTICAE, OF DICOFOL CONCENTRATION AND DEPOSIT DISTRIBUTION ON THE LEAF SURFACE

1968 ◽  
Vol 100 (7) ◽  
pp. 777-781 ◽  
Author(s):  
R. W. Fisher ◽  
N. G. Morgan
Keyword(s):  
Field Strength ◽  
Tetranychus Urticae ◽  
Adult Female ◽  
Active Ingredient ◽  
Spider Mite ◽  
Leaf Surface ◽  
Egg Laying ◽  
Low Volume ◽  
Two Spotted Spider Mite ◽  
Toxicity Effects

AbstractDicofol was applied to bean leaf discs in various ways. The number of drops per disc, the concentration of dicofol in each drop, and the size of the drops were related to egg laying and mortality of adult female mites placed on the discs. Under the conditions of the experiment, an increase in concentration above normal field strength (0.046% active ingredient) had little effect, even though the deposits were discontinuous and similar to those expected from low-volume spraying. Repellency of dicofol to mites was reaffirmed and toxicity effects were significant when about one-quarter of the leaf surface was covered by deposit.

Should I lay or should I wait? Egg-laying in the two-spotted spider mite Tetranychus urticae Koch

2013 ◽  
Vol 92 ◽  
pp. 24-30 ◽  
Author(s):  
Gwendoline Clotuche ◽  
Camille Turlure ◽  
Anne-Catherine Mailleux ◽  
Claire Detrain ◽  
Thierry Hance
Keyword(s):  
Tetranychus Urticae ◽  
Spider Mite ◽  
Egg Laying ◽  
Two Spotted Spider Mite ◽  
Tetranychus Urticae Koch

DIEL PERIODICITY IN SENSITIVITY OF TETRANYCHUS URTICAE (ACARINA: TETRANYCHIDAE) TO DICOFOL

1967 ◽  
Vol 99 (3) ◽  
pp. 281-284 ◽  
Author(s):  
R. W. Fisher
Keyword(s):  
Tetranychus Urticae ◽  
Spider Mite ◽  
Egg Laying ◽  
Diel Periodicity ◽  
Two Spotted Spider Mite

AbstractThe two-spotted spider mite, Tetranychus urticae Koch, showed a pronounced two-peak diel periodicity of susceptibility to dicofol, in a natural regimen of light: dark. The first occurred between 0200 and 0500 hours and the second between 1300 and 1800 hours. Mortality dropped sharply after sunrise (0441 hours) and again an hour before sunset (2002 hours). Lowest mortality occurred near midday. Egg-laying was inversely related to mortality over the 24-hour period.

Ethyl formate and phosphine fumigations on the two-spotted spider mite, Tetranychus urticae and their biochemical responses

2019 ◽  
Vol 62 (1) ◽  
Author(s):  
Kyeongnam Kim ◽  
Yong Ho Lee ◽  
Gayoung Kim ◽  
Byung-Ho Lee ◽  
Jeong-Oh Yang ◽  
...  
Keyword(s):  
Tetranychus Urticae ◽  
Respiratory Chain ◽  
Spider Mite ◽  
Ethyl Formate ◽  
Treated Group ◽  
Effective Control ◽  
Molecular Approaches ◽  
Significant Difference ◽  
Target Sites ◽  
Two Spotted Spider Mite

Abstract Two spotted spider mite, Tetranychus urticae, is a polyphagous pest to a variety of plants and they are hard to be controlled due to occurrence of resistance to acaricides. In this study, biochemical evaluation after ethyl formate (EF) and phosphine (PH3) fumigation towards T. urticae might help officials to control them in quarantine purposes. PH3 fumigation controlled eggs (LC50; 0.158 mg/L), nymphs (LC50; 0.030 mg/L), and adults (LC50; 0.059 mg/L) of T. urticae, and EF effectively affected nymphs (LC50; 2.826 mg/L) rather than eggs (LC50; 6.797 mg/L) and adults (LC50; 5.836 mg/L). In a longer exposure time of 20 h, PH3 fumigation was 94.2-fold more effective tool for control of T. urticae than EF fumigant. EF and PH3 inhibited cytochrome c oxidase (COX) activity differently in both nymphs and adults of T. urticae. It confirmed COX is one of target sites of these fumigants in T. urticae and COX is involved in the respiratory chain as complex IV. Molecular approaches showed that EF fumigation completely down-regulated the expression of cox11 gene at the concentration of LC10 value, while PH3 up-regulated several genes greater than twofold in T. urticae nymphs treated with the concentration of LC50 value. These increased genes by PH3 fumigation are ndufv1, atpB, para, and ace, responsible for the expression of NADH dehydrogenase [ubiquinone] flavoprotein 1, ATP synthase, and acetylcholinesterase in insects, respectively. Lipidomic analyses exhibited a significant difference between two fumigants-exposed groups and the control, especially an ion with 815.46 m/z was analyzed less than twofold in the fumigants-treated group. It was identified as PI(15:1/18:3) and it may be used as a biomarker to EF and PH3 toxicity. These findings may contribute to set an effective control strategy on T. urticae by methyl bromide alternatives such as EF and PH3 because they have shared target sites on the respiratory chain in the pest.

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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