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Molecular mechanisms of Tetranychus urticae chemical adaptation in hop fields.

Piraneo TG, Bull J, Morales MA, Lavine LC, Walsh DB, Zhu F - Sci Rep (2015)

Bottom Line: Here, we investigated resistance ratios and distribution of multiple resistance-associated mutations in field collected T. urticae samples compared with a susceptible population.However, P450-mediated detoxification was observed and is a putative mechanism for abamectin resistance.Molecular mechanisms of T. urticae chemical adaptation in hopyards is imperative new information that will help growers develop effective and sustainable management strategies.

View Article: PubMed Central - PubMed

Affiliation: Irrigated Agriculture Research and Extension Center, Washington State University, Prosser, WA 99350, USA.

ABSTRACT
The two-spotted spider mite, Tetranychus urticae Koch is a major pest that feeds on >1,100 plant species. Many perennial crops including hop (Humulus lupulus) are routinely plagued by T. urticae infestations. Hop is a specialty crop in Pacific Northwest states, where 99% of all U.S. hops are produced. To suppress T. urticae, growers often apply various acaricides. Unfortunately T. urticae has been documented to quickly develop resistance to these acaricides which directly cause control failures. Here, we investigated resistance ratios and distribution of multiple resistance-associated mutations in field collected T. urticae samples compared with a susceptible population. Our research revealed that a mutation in the cytochrome b gene (G126S) in 35% tested T. urticae populations and a mutation in the voltage-gated sodium channel gene (F1538I) in 66.7% populations may contribute resistance to bifenazate and bifenthrin, respectively. No mutations were detected in Glutamate-gated chloride channel subunits tested, suggesting target site insensitivity may not be important in our hop T. urticae resistance to abamectin. However, P450-mediated detoxification was observed and is a putative mechanism for abamectin resistance. Molecular mechanisms of T. urticae chemical adaptation in hopyards is imperative new information that will help growers develop effective and sustainable management strategies.

No MeSH data available.


Related in: MedlinePlus

Pie charts illustrating proportions of different levels of Resistant Ratio (RR) for field collected T. urticae samples.(A) Abamectin resistance; (B) Bifenazate resistance. Low level of resistance, RR < 10; moderate level of resistance, RR = 10–100; high level of resistance, RR >100.
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f3: Pie charts illustrating proportions of different levels of Resistant Ratio (RR) for field collected T. urticae samples.(A) Abamectin resistance; (B) Bifenazate resistance. Low level of resistance, RR < 10; moderate level of resistance, RR = 10–100; high level of resistance, RR >100.

Mentions: The toxicities of abamectin and bifenazate were assessed for T. urticae populations collected from 13 and 12 hopyards, respectively (Tables 2 and 3). In the bioassays with abamectin, the LC50s ranged from 1.36 to 26.05 mg a.i./L and the resistant ratios (RRs) compared with the susceptible strain varied from 5.96 to 114.25 (Table 2). Low resistance levels (RR < 10) were observed in 10.5% of the surveyed populations, 10.5% had high resistance (RR > 100), and the majority of the surveyed populations (79%) exhibited moderate resistance (RR = 10–100) to abamectin (Fig. 3A). The RR of the T. urticae population in the organic hopyard (Granger 2) compared with the susceptible population was 11.23, which is the 3rd lowest resistance among surveyed populations and the highest level of mortality (100%) at the field rate. Samples collected from the Granger 4 hopyard showed the lowest resistance ratio (RR = 5.96) compared with the susceptible population. There were three 1st year (baby) hopyards (Prosser 3, 4, and 5) surveyed in 2013. The RRs of samples collected from these baby hopyards ranged from 21.80 to 114.25, exhibiting a moderate to high degree of resistance (Table 2). There were multiple collections from certain hopyards (Prosser 2, 3 and 4) during the course of summer 2013. Specifically, six collections were taken from the Prosser 2 hopyard starting from middle of June till just prior to harvest in late August during which abamectin was applied twice10. The RR increased 6-fold from the middle of July to mid-August (Table 2). The RRs in samples collected from Prosser 3 and 4 increased 1.7-fold and 2.3-fold in four and five weeks, respectively. The highest resistance level to abamectin was recorded at the Prosser 4 (RR = 114.25) (Table 2).


Molecular mechanisms of Tetranychus urticae chemical adaptation in hop fields.

Piraneo TG, Bull J, Morales MA, Lavine LC, Walsh DB, Zhu F - Sci Rep (2015)

Pie charts illustrating proportions of different levels of Resistant Ratio (RR) for field collected T. urticae samples.(A) Abamectin resistance; (B) Bifenazate resistance. Low level of resistance, RR < 10; moderate level of resistance, RR = 10–100; high level of resistance, RR >100.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664861&req=5

f3: Pie charts illustrating proportions of different levels of Resistant Ratio (RR) for field collected T. urticae samples.(A) Abamectin resistance; (B) Bifenazate resistance. Low level of resistance, RR < 10; moderate level of resistance, RR = 10–100; high level of resistance, RR >100.
Mentions: The toxicities of abamectin and bifenazate were assessed for T. urticae populations collected from 13 and 12 hopyards, respectively (Tables 2 and 3). In the bioassays with abamectin, the LC50s ranged from 1.36 to 26.05 mg a.i./L and the resistant ratios (RRs) compared with the susceptible strain varied from 5.96 to 114.25 (Table 2). Low resistance levels (RR < 10) were observed in 10.5% of the surveyed populations, 10.5% had high resistance (RR > 100), and the majority of the surveyed populations (79%) exhibited moderate resistance (RR = 10–100) to abamectin (Fig. 3A). The RR of the T. urticae population in the organic hopyard (Granger 2) compared with the susceptible population was 11.23, which is the 3rd lowest resistance among surveyed populations and the highest level of mortality (100%) at the field rate. Samples collected from the Granger 4 hopyard showed the lowest resistance ratio (RR = 5.96) compared with the susceptible population. There were three 1st year (baby) hopyards (Prosser 3, 4, and 5) surveyed in 2013. The RRs of samples collected from these baby hopyards ranged from 21.80 to 114.25, exhibiting a moderate to high degree of resistance (Table 2). There were multiple collections from certain hopyards (Prosser 2, 3 and 4) during the course of summer 2013. Specifically, six collections were taken from the Prosser 2 hopyard starting from middle of June till just prior to harvest in late August during which abamectin was applied twice10. The RR increased 6-fold from the middle of July to mid-August (Table 2). The RRs in samples collected from Prosser 3 and 4 increased 1.7-fold and 2.3-fold in four and five weeks, respectively. The highest resistance level to abamectin was recorded at the Prosser 4 (RR = 114.25) (Table 2).

Bottom Line: Here, we investigated resistance ratios and distribution of multiple resistance-associated mutations in field collected T. urticae samples compared with a susceptible population.However, P450-mediated detoxification was observed and is a putative mechanism for abamectin resistance.Molecular mechanisms of T. urticae chemical adaptation in hopyards is imperative new information that will help growers develop effective and sustainable management strategies.

View Article: PubMed Central - PubMed

Affiliation: Irrigated Agriculture Research and Extension Center, Washington State University, Prosser, WA 99350, USA.

ABSTRACT
The two-spotted spider mite, Tetranychus urticae Koch is a major pest that feeds on >1,100 plant species. Many perennial crops including hop (Humulus lupulus) are routinely plagued by T. urticae infestations. Hop is a specialty crop in Pacific Northwest states, where 99% of all U.S. hops are produced. To suppress T. urticae, growers often apply various acaricides. Unfortunately T. urticae has been documented to quickly develop resistance to these acaricides which directly cause control failures. Here, we investigated resistance ratios and distribution of multiple resistance-associated mutations in field collected T. urticae samples compared with a susceptible population. Our research revealed that a mutation in the cytochrome b gene (G126S) in 35% tested T. urticae populations and a mutation in the voltage-gated sodium channel gene (F1538I) in 66.7% populations may contribute resistance to bifenazate and bifenthrin, respectively. No mutations were detected in Glutamate-gated chloride channel subunits tested, suggesting target site insensitivity may not be important in our hop T. urticae resistance to abamectin. However, P450-mediated detoxification was observed and is a putative mechanism for abamectin resistance. Molecular mechanisms of T. urticae chemical adaptation in hopyards is imperative new information that will help growers develop effective and sustainable management strategies.

No MeSH data available.


Related in: MedlinePlus