Control of two–spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) by some selected chemicals

1970 ◽  
Vol 25 ◽  
pp. 15-18 ◽  
Author(s):  
S Hossain ◽  
MM Haque ◽  
N Nader

The experiment was conducted to study the effectiveness of four commonly used chemicals viz., deltamethrin, cypermethrin, malathion and sulphur against two-spotted spider mite (TSSM), Tetranychus urticae Koch on potted bean plants and on excised leaf discs. Mite population remained significantly lower in all treated plots except malathion treatment. The population of T. urticae differed significantly due to different chemicals and it remained lower up to 4th week on single-sprayed plants, which again increased. But in double-sprayed plants mite population was checked and remained significantly lower. The estimated LC50 values for cypermethrin, malathion, deltamethrin and sulphur were 2.9956, 15.8663, 0.5386 and 20.7045 nl.cm-2 respectively when the chemicals were sprayed before mite release. But the LC50 values for these chemicals sprayed after mite release were estimated 1.8110, 8.2746, 0.2192 and 6.8308 nl.cm-2. The use of chemicals is essential for better yield of crops. Among the four tested chemicals the pyrithroids (cypermethrin and deltamethrin) were found more effective against the TSSM than the other two. Key words: Two-spotted spider mite, Tetranychus urticae, bean, deltamethrin, cypermethrin, malathion, sulphur Univ. j. zool. Rajshahi Univ. Vol.25 2006 p.15-18

1970 ◽  
Vol 27 ◽  
pp. 51-54 ◽  
Author(s):  
Mst Mursalin Parvin ◽  
Mohd Mainul Haque

Three predators Scolothrips sexmaculatus Pergande, Phytoseiulus persimilis Athias - Henriot and Stethorus punctillum Weise were used to control two-spotted spider mite, Tetranychus urticae Koch on potted bean plants. Mite population increased exponentially on the untreated plants, but on the predator treated plants, increase of mite population was checked and remained within minimum number. Early release of predator checked the mite population earlier and kept it lower than on late released plants. All the three predators may be used as bio-control agents against two-spotted spider mite. Key words: Control, Tetranychus urticae, Scolothrips sexmaculatus, Phytoseiulus persimilis, Stethorus punctillum and bio-control agents.   doi:10.3329/ujzru.v27i0.1954 Univ. j. zool. Rajshahi Univ. Vol. 27, 2008 pp. 51-54


1970 ◽  
Vol 15 ◽  
pp. 127-132 ◽  
Author(s):  
M Khalequzzaman ◽  
Mina Mondal ◽  
M Fazlul Haque ◽  
M Sajedul Karim

The relative abundance Tetranychus urticae and Phytoseiulus persimilis as well as voracity of the predator were conducted on potted eggplants. After six weeks of release of ten female T. urticae in control plants, the highest mite population reached at 184.21 / leaf, against 67.92 and 107.48 / leaf in plants which received two predators after 1st and 3rd week respectively. After nine weeks the number of mite / leaf reduced to 13.21 and 23.97 / leaf after 1st and 3rd week of introduction of the predator, the control population was 81.32. Adult P. persimilis as single predator fed 8.2, 15.4 and 20.6 T. urticae eggs after 24, 48 and 72 h respectively. Again a single predator when tested separately fed 5.4, 10.8 and 14.6 T. urticae larvae after 24, 48 and 72 h respectively. A single adult predator fed on 3.6, 7.0 and 12.0 adult T. urticae after the same durations. When varying number (10, 20, 30, 40 and 50) of prey (larvae or adults) were provided to a single predator it fed 5.0, 6.6, 6.8, 9.0 and 9.4 larvae against 3.2, 3.2, 3.4, 3.6 and 3.6 adults respectively. Key words: Predation, spider mite, eggplant, voracity, release.   doi: 10.3329/jbs.v15i0.2152 J. bio-sci. 15: 127-132, 2007


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Cenk Yucel

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.


Sign in / Sign up

Export Citation Format

Share Document