scholarly journals Biological effects of three bacterial species on Tetranychus urticae (Acari: Tetranychidae) infesting eggplant under laboratory and greenhouse conditions

Acarologia ◽  
2020 ◽  
Vol 60 (3) ◽  
pp. 587-594
Author(s):  
Mahmoud M. Al-Azzazy ◽  
Abdullah S. Alsohim ◽  
Carl E. Yoder
Keyword(s):  
Tetranychus Urticae ◽  
Biological Effects ◽  
Bacterial Species ◽  
Predatory Mite ◽  
Phytoseius Plumifer ◽  
New Strategy ◽  
Acinetobacter Sp ◽  
Two Spotted Spider Mite ◽  
Mite Mortality ◽  
Efficiency Rate

This study evaluated the efficacy of three bacterial species. Acinetobacter sp. (concentration 2.237×108 cfu/ml), Bacillus subtilis (concentration 2.470×108 cfu/ml) and Bacillus qassimus (concentration 3.320×108 cfu/ml) were tested against the two-spotted spider mite, Tetranychus urticae, infesting eggplants under laboratory and greenhouse conditions. In addition, we studied their side effects on the predatory mite, Phytoseius plumifer. The highest efficiency rate on T. urticae was observed with Acinetobacter sp. sprays. Three days after treatment, mite mortality reached 87.15 and 77.29 % under laboratory and greenhouse conditions, respectively. Moreover, the mortality rates were significantly lower (72.22 and 67.11 % and 70.74 and 65.19 %) using B. subtilis and B. qassimus under lab and greenhouse conditions, seven days after treatment. The predatory mite, P. plumifer, showed higher tolerance than T. urticae to the three bacterial preparations. The results of this study indicated that Acinetobacter sp. has a strong efficacy on T. urticae and slightly affected the predatory species herein tested. This study introduces a potentially new strategy for biological control of phytophagous mites.

The pathogenicity of entomopathogenic fungus Acremonium hansfordii to two-spotted spider mite, Tetranychus urticae and predatory mite Neoseiulus barkeri

2018 ◽  
Vol 23 (11) ◽  
pp. 2173
Author(s):  
Su-Qin Shang ◽  
Yao-Nian Chen ◽  
Ying-Lu Bai
Keyword(s):  
Tetranychus Urticae ◽  
Entomopathogenic Fungus ◽  
Spider Mite ◽  
Crop Yields ◽  
Predatory Mite ◽  
Experimental Conditions ◽  
Neoseiulus Barkeri ◽  
Preoviposition Period ◽  
Two Spotted Spider Mite ◽  
F1 Generation

The two-spotted spider mite, Tetranychus urticae, is an important mite pest worldwide. It often leads to reduced crop yields or poor marketability of the produce and has already developed resistance to many acaricides. In this study, the pathogenicity of the entomopathogenic fungus (EPF), Acremonium hansfordii, to T. urticae and its side effects on the predatory mite Neoseiulus barkeri were compared. The toxicity of A. hansfordii was evaluated on T. urticae at 1.0×104, 1.0×106, 1.0×108 conidia/mL concentrations and predatory mite N. barkeri at 1.0×108 conidia/mL under experimental conditions at 25±1°C, 75±5% RH and 16L: 8D photoperiod. The effects of EPF on the development of the F0 and F1 generation of predatory mites were also assessed at 1.0×108 conidia/mL concentration. The results showed that the corrected mortality of T. urticae at three tested concentrations were 36.67%, 53.67% and 66.33% within 11d, and the median lethal time were 14.39 d, 9.84d and 7.99d, respectively. The corrected mortality of N. barkeri was only 3.9% after 11d at 1×108 conidia/mL concentration. Some hyphae of A. hansfordii were detected on the surface of treated T. urticae but not on N. barkeri body after 7d. After N. barkeri females were treated with 1.0×108 conidia/mL, the preoviposition period of the F0 generation was prolonged 1.56 times and the other life history parameters have no significant differences; similar patterns were also shown in the F1 generation. A. hansfordii showed strong pathogenicity against T. urticae but did not significantly adversely influence N. barkeri. Therefore, the combination of A. hansfordii and N. barkeri has the potential to be used for the control of T. urticae in the future. 

scholarly journals Results of the Single Release Efficacy of the Predatory Mite Neoseiulus californicus (McGregor) against the Two-Spotted Spider Mite (Tetranychus urticae Koch) on a Hop Plantation

2020 ◽  
Vol 11 (1) ◽  
pp. 118
Author(s):  
Matej Vidrih ◽  
Anja Turnšek ◽  
Magda Rak Cizej ◽  
Tanja Bohinc ◽  
Stanislav Trdan
Keyword(s):  
Tetranychus Urticae ◽  
Spider Mite ◽  
Biological Control Agent ◽  
Spider Mites ◽  
Predatory Mite ◽  
Control Agent ◽  
Neoseiulus Californicus ◽  
Future Research ◽  
Starting Point ◽  
Two Spotted Spider Mite

In 2015, we studied the efficiency of the predatory mite Neoseiulus californicus (McGregor) for suppression of the two-spotted spider mite Tetranychus urticae in a field experiment at a hop plantation. We randomly arranged four treatments in a three-block experiment. Fungicides were used in all treatments; insecticides were used in all treatments except the predatory mite treatment and acaricides were used in only two treatments. A single inundative release of the mite N. californicus was carried out on 4 July. On four different dates (10 June, 17 July, 29 July and 9 August), we counted the eggs and the mobile stages (larvae, nymphs and adults) of the two-spotted spider mite in all four treatments. In the treatment with the predatory mite, we established the fewest eggs and mobile stages of T. urticae 14 days after the release of the predator. The selected acaricides in our research acted in a primarily ovicidal manner, but we did not detect satisfactory effects on the mobile stages of the two-spotted spider mite. This result suggests the emergence of resistance of two-spotted spider mites to the acaricides hexythiazox and abamectin. Our research established comparable effects of the predatory mite N. californicus and acaricides, and further improvement of the efficiency would require release of the natural enemy into a hop plantation in mid-June, followed by a second release three weeks later. The costs of acaricide use in our experiment were from 12.7-fold (two sprayings of hexythiazox, and a single spraying with abamectin) to 17.8-fold (single treatments of hexythiazox and abamectin) lower than those of a single release of the biological control agent in question. The results of our study represent a starting point for future research, which could achieve satisfactory results in suppressing two-spotted spider mites on a hop plantation by repeated use of the predatory mite N. californicus.

scholarly journals Variability of infestation of rose varieties by the spider mite Tetranychus urticae under conditions of application of Phytoseiulus persimilis or acaricides

2021 ◽  
Vol 104 (4) ◽  
pp. 218-222
Author(s):  
V. V. Moor ◽  
A. I. Anisimov ◽  
E. G. Kozlova*
Keyword(s):  
Biological Control ◽  
Tetranychus Urticae ◽  
Spider Mite ◽  
Biological Control Agent ◽  
Ornamental Plants ◽  
Phytoseiulus Persimilis ◽  
Predatory Mite ◽  
Control Agent ◽  
Pest Mite ◽  
Two Spotted Spider Mite

The two-spotted spider mite Tetranychus urticae is a dangerous polyphagous pest of agricultural and ornamental plants. In a commercial greenhouse treated with acaricides or biological control using predatory mite Phytoseiulus persimilis individual varieties of roses differed significantly in terms of the average annual infestation by the pest mite. On the poorly populated rose varieties, the biological control agent application was more effective as compared to the acaricides. To effectively control the pest, the required predatory mite rates were 4.6–8.7 times higher on varieties with a minimal spider mite infestation (Aqua and Deep Water) as compared to the maximal pest infestation (Heaven and Brazil).

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