scholarly journals Occurrence of Two-Spotted Spider Mite (Tetranychus urticae Koch) on Potentilla fruticosa Cultivars

2016 ◽  
Vol 24 (2) ◽  
pp. 25-30
Author(s):  
Piotr Szafranek

Abstract Potentilla fruticosa L. (Rosaceae Juss.) is one of the most popular deciduous shrubs cultivated in Poland. Among pests identified so far on P. fruticosa, a serious threat is caused by two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae). During three-year study, the occurrence of two-spotted spider mite T. urticae on four cultivars of P. fruticosa: ‘Goldfinger’, ‘McKay’s White’, ‘Uman’ and ‘Pink Beauty’ grown in field conditions was compared. While conducting experiment, weather conditions were monitored. The number of eggs and motile forms of two-spotted spider mite were recorded separately. The most attractive cultivar to spider mite was ‘Goldfinger’. The largest amount of motile forms of mites and their eggs were found on the leaves of this cultivar in all three years of study. The least number of pests occurred on the cv. ‘Pink Beauty’. However, differences in the abundance of this pest on all studied cultivars were variable during the growing seasons.

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258198
Author(s):  
Ian M. Scott ◽  
Tim McDowell ◽  
Justin B. Renaud ◽  
Sophie W. Krolikowski ◽  
Ling Chen ◽  
...  

In southern Ontario, Canada, the two-spotted spider mite (Tetranychus urticae) is an emerging pest of soybean (Glycine max) due to the increasing incidence of warmer, drier weather conditions. One key strategy to manage soybean pests is breeding resistant cultivars. Resistance to pathogens and herbivores in soybean has been associated with isoflavonoid phytoalexins, a group of specialized metabolites commonly associated with root, leaf and seed tissues. A survey of 18 Ontario soybean cultivars for spider mite resistance included evaluations of antibiosis and tolerance in relation to isoflavonoid and other metabolites detected in the leaves. Ten-day and 4-week trials beginning with early growth stage plants were used to compare survival, growth, fecundity as well as damage to leaves. Two-spotted spider mite (TSSM) counts were correlated with HPLC measurements of isoflavonoid concentration in the leaves and global metabolite profiling by high resolution LC-MS to identify other metabolites unique to the most resistant (R) and susceptible (S) cultivars. Within 10 days, no significant difference (P>0.05) in resistance to TSSM was determined between cultivars, but after 4 weeks, one cultivar, OAC Avatar, was revealed to have the lowest number of adult TSSMs and their eggs. Other cultivars showing partial resistance included OAC Wallace and OAC Lakeview, while Pagoda was the most tolerant to TSSM feeding. A low, positive correlation between isoflavonoid concentrations and TSSM counts and feeding damage indicated these compounds alone do not explain the range of resistance or tolerance observed. In contrast, other metabolite features were significantly different (P<0.05) in R versus S cultivars. In the presence of TSSM, the R cultivars had significantly greater (P<0.05) concentrations of the free amino acids Trp, Val, Thr, Glu, Asp and His relative to S cultivars. Furthermore, the R cultivar metabolites detected are viable targets for more in-depth analysis of their potential roles in TSSM defense.


2020 ◽  
Vol 21 (supplement 1) ◽  
Author(s):  
Ebrahim A.A ◽  
Abdallah A.M ◽  
Aiad K.A.

Neoseiulus californicus is considered a promising agent for successful controlling the two spotted spider mite, Tetranychus urticae Koch. Vertimec, in selective doses, used to reduce the number of the two-spotted spider mite population withoutaffecting the survival of the predator. An open area was selected in El-Mahala district, El-Gharbia governorate to evaluate the utilizing of Vertimec followed by releasing N. californicus to control the population number of the two-spotted spider mite during unsuitable weather conditions for N. californicus, and activating the role of N. californicus to suppress the population number of T. urticae. An open area divided into two equal areas. The first area was allocated without Vertimec treatment and the second area was left for Vertimec treatment. The two areas are cultivated watermelon variety Sikata. The results obtained from releasing the predatory mite, N. californicus did not provide an advantage to prevent the two-spotted spider mite, T. urticae from exceeding the economic threshold level and subsequently deteriorated watermelon plant. In addition, the results obtained from spraying Vertimic pesticide before releasing the predatory mite N. californicus and duplicate the release of N. californicus was better of that obtained by releasing the predatory mite without using Vertimic in terms of suppressing the two-spotted spider mite, T. urticae.


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.


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