Twospotted Spider Mite Populations Research Articles

Leaf disc-mediated oral delivery of small molecules in the absence of surfactant to the two-spotted spider mite, Tetranychus urticae.

The two-spotted spider mite (TSSM), Tetranychus urticae, is a chelicerate herbivore with a wide host range and strong ability to develop pesticide resistance. Experimental TSSM populations are easy to maintain, and the recent publication of the complete TSSM genome sequence and development of RNA interference-based reverse genetics protocols make this species an ideal chelicerate model for the study of pesticide resistance and plant-herbivore interactions. In such studies, treated leaf discs are often used for oral delivery of test compounds. When preparing these leaf discs, the organosilicone surfactant Silwet L-77 is used to promote wetting of the leaf surface and distribution of the test compound across the entire leaf surface. Here, we examined the toxicity of Silwet L-77 and found it to be toxic to TSSMs. We then developed a novel means of preparing leaf discs in which a polypropylene sheet rather than Silwet L-77 was used to ensure distribution of a tracer dye across the entire leaf surface. These leaf discs were then successfully used to deliver the tracer dye into the midgut of TSSMs. No significant differences were observed in the survival, fecundity, or feeding activity of TSSMs fed on leaf discs treated with water via our novel method compared with those fed on untreated leaf discs. Thus, our novel method of preparing leaf discs eliminates concerns regarding the bioactivity of surfactants in TSSMs, and we anticipate that it will be useful for improving oral delivery-based bioassays that use TSSMs.

SEASONAL ABUNDANCE OF THE TWO SPOTTED SPIDER MITE, Tetranychus urticae KOCH ON FOUR COTTON CULTIVARS AT DAKAHLIA GOVERNORATE, EGYPT

The two spotted spider mite (TSM), Tetranychus urticae Koch (Acari: Tetranychidae) is one of the major mite pests on agricultural crops worldwide. The present work aims to study abundance of TSM and the most common predatory phytoseiid species, Typhlodromips capsicum Mostafa (Acari: Phytoseiidae) on four cotton cultivars viz. Giza 45, Giza 86, Giza 87 and Giza 92 mostly cultivated in Egypt during two successive growing seasons 2016 and 2017 at Aga district, Dakahlia Governorate, Egypt in relation to prevailing atmospheric temperature and relative humidity. Also, the synchronization of TSM and T. capsicum under field conditions on the above-mentioned investigated cotton cultivars was investigated. Obtained results showed that TSM populations were significantly (P≤ 0.05) higher on the cotton cultivars Giza 45 and Giza 92 in comparison with the other investigated ones (Giza 86 and Giza 87) during the two investigated seasons 2016 and 2017. Populations of the phytoseiid species, T. capsicum did not significantly affected by the tested cotton cultivars. There were positive correlations between the changes of TSM and T. capsicum populations and temperature while the correlations with relative humidity were positively insignificant during the two investigated growing seasons. Good synchronization between TSM and T. capsicum populations on tested cotton cultivars was detected during the first and second seasons. These results showed that cotton cultivars, predatory mites and weather factors are of the most important factors affecting the populations of T. urticae on the investigated cotton cultivars.

Comparison of susceptibility of two Iranian populations of Tetranychus urticae Koch (Acari: Tetranychidae) to spirodiclofen

Two-spotted spider mite, Teranychus urticae (Acari: Tetranychide), is one of the most important agricultural pests throughout the world. The high reproductive potential, short life cycle, combined with frequent acaricide applications has resulted in resistance development to a wide range of acaricides. Resistance to acaricides has an important role in inefficiency of chemical control of this pest. In the present study, the susceptibility of two populations of two-spotted spider mite collected from Karaj (KrS) and Mahallat (MhR) to spirodiclofen was investigated. The bioassay was conducted using a leaf-dip method on same-age protonymphs. Bioassay results showed that there was a significant difference between LC 50 values of KrS and MhR populations. The resistance ratio was obtained as 22.19. The synergistic effects of triphenyl phosphate (TPP), piperonyl butoxide (PBO) and diethyl maleate (DEM) were assessed using residual contact vial (RCV) bioassay method. Results of the synergistic studies showed significant differences between LC 50 values of spirodiclofen with spirodiclofen + PBO and spirodiclofen + TPP in MhR population. The most synergistic effect in MhR population was related to PBO. The results of enzyme assays revealed that the most ratio activity in MhR population to KrS population was related to cytochrome P450 monoxygenase (3.02) and the lowest ratio activity was related to glutathione S-transferase (GST) (1.40). These results confirmed that esterase and cytochrome P450 monoxygenase are probably involved in resistance of T. urticae to spirodiclofen.

Biocontrol of Spider Mites in California Strawberry Production

ABSTRACTField experiments were conducted in 2013 and 2014 to evaluate the predation efficacy of four commercially available predatory mites (Phytoseiidae): Phytoseiulus persimilis, Neoseiulus californicus, N. fallacis, and Amblyseius andersoni, for control of twospotted spider mite (Tetranychus urticae Koch) and Lewis spider mite (Eotetranychus lewisi) in strawberries. In the 2013 experiment, a grower standard treatment (P. persimilis and N. californicus) was compared to single treatments of each phytoseiid species. The 2014 experiment excluded N. fallacis as a treatment, but all other treatments are the same as in 2013. For both seasons, all treatments decreased both two-spotted and Lewis spider mite populations immediately after releases equivalently. However, none of the treatments tested were able to keep twospotted and Lewis spider mite populations below the economic threshold level. These findings indicate that several releases will be needed throughout the growing season in order to maintain spider mite levels below the economic thresholds.

Intercropping garlic plants reduces Tetranychus urticae in strawberry crop.

The effect of aromatic plants on number of twospotted spider mite (TSSM), Tetranychus urticae Koch, when intercropped with strawberry were assessed in the field. During the first year, chives (Allium schoenoprasum L.), coriander (Coriandrum sativum L.), fennel (Foeniculum vulgare Mill.), garlic (Allium sativum L.), oregano (Origanum vulgare L.), or sweet marjoram (Origanum majorana L.) were intercropped with strawberry. Assessments were performed on TSSM populations by taking six samples from July 20 to September 20, 2012. During the second year, garlic plants were intercropped between rows of strawberry at three densities in greenhouse and field. Mobile forms and eggs numbers (only in field) of TSSM were evaluated from April 18 to June 05 (greenhouse) and June 06 to August 14, 2013 (field). It was found that intercropping with garlic caused a greater reduction of TSSM (up to 52%) in strawberry plants when higher populations of TSSM occurred in the field. TSSM reduction was found in one sample when fennel and chives were intercropped with strawberries (42 and 50% reduction, respectively); this also occurred when populations of TSSM were higher. The three densities of garlic plants (one, two and three rows among the strawberry rows) reduced TSSM mobile forms by 49, 53 and 60% (greenhouse) and 44, 51 and 65% (field), and eggs by 38, 43 and 64% (field), respectively. The results suggest that intercropping garlic plants between strawberry rows is a promising strategy to reduce TSSM populations.

Interactions between natural enemies: Effect of a predatory mite on transmission of the fungus Neozygites floridana in two-spotted spider mite populations

Introducing the predatory mite Phytoseiulus persimilis into two-spotted spider mite, Tetranychus urticae, populations significantly increased the proportion of T. urticae infected with the spider mite pathogen Neozygites floridana in one of two experiments. By the final sampling occasion, the number of T. urticae in the treatment with both the predator and the pathogen had declined to zero in both experiments, while in the fungus-only treatment T. urticae populations still persisted (20–40 T. urticae/subsample). Releasing P. persimilis into crops in which N. floridana is naturally present has the potential to improve spider mite control more than through predation alone.

Effect of two-spotted spider mite population (Tetranychus urticae Koch) on growth parameters and yield of the summer apple cv. Katja

Warabieda W. (2015): Effect of two-spotted spider mite population (Tetranychus urticae Koch) on growth parameters and yield of the summer apple cv. Katja. Hort. Sci. (Prague), 42: 167–175. The effect of two-spotted spider mite populations (Tetranychus urticae Koch) on the yield and growth parameters of the early-season apple cv. Katja was evaluated during a 3-year study. In the case of the colonisation of apple trees exceeding 1,462, 2,760 and 1,548 cumulative mite days (CMDs) in the subsequent years of research, a significant reduction of the cumulative yield (14 kg/tree) and of the cumulative trunk cross sectional area increase (5.7 cm2) was observed. No significant effect of spider mites on the average weight of the fruit was observed, while the pest affected fruit colouration. The calculated values of economic injury level were 60.5, 155.5 and 51.8 CMDs in subsequent years of the study, respectively. These values are much lower than the action threshold recommended in Poland and elaborated for the European red mite – Panonychus ulmi (Koch) on apple trees. The results suggest that the tolerance of early-season apple cultivars to T. urticae may be lower when compared to late-season varieties infested with P. ulmi; therefore, the decision to implement pest management for two-spotted spider mite should be taken at a lower infestation threshold than previously thought.

BIOLOGICAL STUDY OF TWO SPOTTED SPIDER MITE Tetranychus sp. (ACARI: TETRANYCHIDAE) ON THREE LEAF PHASES OF MUNG BEAN AND ADZUKI BEAN FOR MITE MASS REARING

Two-spotted spider mite (TSM) Tetranychus sp. is one of prey mites for phyotoseiid mite mass rearing. Based on previous research that TSM population developed well on Mung bean ( V igna radiata ) and Adzuki bean ( V . angularis ) as host plants, confirmed growth and development of TSM on both beans. Research was aimed to observe biology of TSM on three phases of Mung bean and Adzuki bean leaf such as at primary leaf unrolled completely (V1), at the 1 st trifoliate unrolled completely (V2), and at the 2 nd trifoliate unrolled completely (V3). Pre adult stadia, life cycle, male and female longevity, female fecundity of TSM, and trichome density were observed on petri dishes contained each leaf phase of beans. Result showed that three leaf phases of beans did not influence significantly in all biological variables, except fecundity. TSM fecundity was the highest on V3 phase of Mung bean (86.90). Trichome density on Mung bean leaf surface per mm² was lower than Adzuki bean. Trichome density of upper leaf surface of V3 phase of Mung bean (10.53) and Adzuki bean (3.07) were lower than V1 (13.20; 12.40) and V2 phase (6.20; 5.27). V3 phase of Mung bean was most suitable for TSM mass rearing. Key words: fecundity, leaf phase, mass rearing, trichome density, two-spotted spider mite

Resistance mechanisms to abamectin in Iranian populations of the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae)

The toxicity of abamectin to the Iranian populations of two-spotted spider mite, Tetranychus urticae, collected from Isfahan (ISR) and Guilan (GUS2) provinces were assayed using the residual contact vial (RCV) bioassay. The results interestingly showed more than 12755-fold resistance to abamectin in the ISR population of T. urticae compared with the susceptible GUS2 population. The synergistic effects of Triphenyl Phosphate (TPP), Piperonyl Butoxide (PBO) and Diethyl Maleate (DEM) were carried out to determine the involvement of esterase, mixed functional oxidase (MFO) and glutathione S-transferase (GST) in resistance mechanisms, respectively. Due to very high levels of resistance in the ISR population, it was not possible to calculate LC50 value nor to accurately assess the effects of synergists on this population. When alpha-naphthyl acetate (alpha-NA) was used as a substrate, the difference in esterase activity between the ISR and GUS2 populations was statistically significant, but low. Kinetic studies also indicated that the alpha-NA hydrolyzing esterases in the ISR population were different from those of the GUS2 population. Activity of GST in the ISR population was 2-fold more than that in the GUS2 population, and Km and Vmax values of the ISR population to a 1-choloro-2,4-dinitrobenzene (CDNB) substrate were 1.44 and 1.21 times lower and higher than those of the susceptible counterpart, respectively. The amount of heme content in the ISR population was 1.26 times more than that in the GUS2 population. Finally, comparing the nucleotide sequences of one of the transmembrane regions of the glutamate-gated chloride channel (GluCl1) from the two studied populations showed no substitutions in the deduced amino acid sequence of this region in the ISR population.

Effects of soft soap and abamectin on the two spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) and predatory mite Phytoseiulus persimilis A-H (Acari: Phytoseiidae) under laboratory conditions

Soft soap at three dosages (3 ml/L, 5 ml/L and 7 ml/L) and abamectin (12.5 mg/100L) were applied to bean plants determine their residual effects on the predatory mite, Phytoseiulus persimilis A-H (Acari: Phytoseiidae) later released for the control of the two-spotted spider mite (TSSM), Tetranychus urticae Koch (Acari: Tetranychidae) under laboratory conditions. The contact toxicity of soft soap and abamectin were evaluated and classified according to IOBC(International Organization for Biological Control) standards. The soap at 3 ml/L and 5 ml/L did not supress TSSM populations and could not provide satisfactory control when compared with soap at 7ml/L and abamectin. The efficacy of soap at 5 ml/L with P. persimilis gave sufficient control of TSSM when compared with soap at 3 ml/L with P. persimilis, and the predator alone. Both the soap at 7 ml/L and abamectin in combination with the predatory mite gave satisfactory control of TSSM ,but in the abamectin treatment, the predatory mite population was not observed due to harmful effects of abamectin. However, use of soft soap at suitable dosage, with or without predatory mite, gave encouraging results for controlling TSSM but was moderately toxic at 5 ml/L and 7 ml/L P. persimilis in contact toxicity testing by causing 50.0 % and 42.3 % mortality, respectively, to adulst of P. persimilis. In addition, abamectin at 12.5 and 25 mg/L (ppm) dosages was evaluated as harmful (T) to adults of P. persimilis. Separately, soft soap caused no phytotoxicity to host plants. However, its phytotoxicity needs to be further investigated under greenhouse and field conditions.

POSSIBILITIES OF STRAWBERRY COMPLEX PROTECTION AGAINST FUNGAL DISEASES AND TWO-SPOTTED SPIDER MITE USING STROBILURIN FUNGICIDES

New fungicides from strobilurin group, such as Signum 33 WG and Zato 50 WG were tested for the control of strawberry fungal diseases in field conditions. The effect of tested fungicides on two-spotted spider mite population was also evaluated. Both fungicides have a broad spectrum of activity. The effectiveness of Signum 33 WG used in the control of grey mould was good and ranged from 80 to 92%. The application of Signum 33 WG significantly increased the strawberry yield. It was higher than yield from control plots and the same as from plots treated with standard fungicide. Signum 33 WG used in the program of grey mould protection significantly decreased the level of leaf spot and powdery mildew. The effectiveness was over 80% and about 70% in the control of leaf spot and powdery mildew, respectively. The second tested fungicide - Zato 50 WG was very effective in the control of both leaf diseases. The efficacy was above 90%. Two-spotted spider mite population was similar on plants treated with Signum 33 WG and with standard fungicide, Euparen Multi 50 WG.

Evaluation of Persistence of Selected Miticides Against the Twospotted Spider Mite, Tetranychus urticae

Twospotted spider mite, Tetranychus urticae, is a major arthropod pest in greenhouses. Greenhouse producers typically use miticides to control twospotted spider mite (TSM) populations. This study, which involved two replicated experiments, was designed to assess the persistence or longevity and efficacy of translaminar miticides with the active ingredient (a.i.) etoxazole, chlorfenapyr, abamectin, and spiromesifen by applying these miticides to either butterfly bush (Buddleia davidii) or marigold (Tagetes erecta) plants, depending on the experiment, and then artificially infesting the plants with TSM. Based on percent mortality and number of live and dead TSM, several miticides provided adequate control of TSM even after having been applied to the test plants 14 days before being artificially infested with TSM. This suggests that these miticides have extended residual activity. The etoxazole 10 to 12 μm and etoxazole water-dispersible formulations provided control (greater than 85% mortality) of TSM over the course of Expt. 1 with four or less live TSM recovered from treated plants across the three evaluation times (21, 28, and 42 days). Spiromesifen, in Expt. 2, was significantly more effective against both the nymph (89% to 99.2%) and adult (37.3% to 87.9%) stages of the TSM than the other miticides and killed more nymphs (165 to 227) than the other treatments. In general, none of the miticides provided consistent or adequate control of TSM adults across all three evaluation times (49, 56, and 70 days).

High Tunnel Tree Fruit Production: The Final Frontier?

High tunnel production systems typically use horticultural crops that are annually or biennially herbaceous, high in value, short in stature, and quick to produce. At best, tree fruits may fit only one of these criteria–high value. Sweet cherry (Prunus avium) may command high enough values in premium market niches to make high tunnel production strategies worth attempting. Furthermore, sweet cherry production can be a risky endeavor, even in optimal climates, due to the potentially devastating effects of preharvest rain that cause fruit cracking. Consequently, environmental modification by tunnels in regions like the Great Lakes provides a significant risk reduction. Additional potential benefits, such as protection from frosts, diseases, insects, wind scarring, etc., add further production value. Multi-bay high tunnels were constructed in 2005 at two Michigan State University experiment stations, over established and newly planted sweet cherry trees on dwarfing rootstocks, to study and optimize the effects of production environment modification on vegetative and reproductive growth, marketing season extension, and protection of cherries from diseases, insect pests, and/or physiological disorders. Results with tunnels thus far include premium fruit quality and high crop value; increased leaf size and terminal shoot growth; decreased radial trunk growth; decreased chemical pesticide inputs; decreased incidence of cherry leaf spot (Blumeriella jaapii) and bacterial canker (Pseudomonas syringae); increased incidence of powdery mildew (Podosphaera clandestina); inconclusive effects on brown rot (Monolinia fructicola); no or reduced infestation by plum curculio (Conotrachelus nenuphar) or cherry fruit fly (Rhagoletis cingulata); dramatically reduced japanese beetle (Popillia japonica) damage; and increased black cherry aphid (Myzus cerasi) and two-spotted spider mite (Tetranychus urticae) populations.

High Tunnel Tree Fruit Production: The Final Frontier?

High tunnel production systems typically use horticultural crops that are annually or biennially herbaceous, high in value, short in stature, and quick to produce. At best, tree fruits may fit only one of these criteria–high value. Sweet cherry (Prunus avium) may command high enough values in premium market niches to make high tunnel production strategies worth attempting. Furthermore, sweet cherry production can be a risky endeavor, even in optimal climates, due to the potentially devastating effects of preharvest rain that cause fruit cracking. Consequently, environmental modification by tunnels in regions like the Great Lakes provides a significant risk reduction. Additional potential benefits, such as protection from frosts, diseases, insects, wind scarring, etc., add further production value. Multi-bay high tunnels were constructed in 2005 at two Michigan State University experiment stations, over established and newly planted sweet cherry trees on dwarfing rootstocks, to study and optimize the effects of production environment modification on vegetative and reproductive growth, marketing season extension, and protection of cherries from diseases, insect pests, and/or physiological disorders. Results with tunnels thus far include premium fruit quality and high crop value; increased leaf size and terminal shoot growth; decreased radial trunk growth; decreased chemical pesticide inputs; decreased incidence of cherry leaf spot (Blumeriella jaapii) and bacterial canker (Pseudomonas syringae); increased incidence of powdery mildew (Podosphaera clandestina); inconclusive effects on brown rot (Monolinia fructicola); no or reduced infestation by plum curculio (Conotrachelus nenuphar) or cherry fruit fly (Rhagoletis cingulata); dramatically reduced japanese beetle (Popillia japonica) damage; and increased black cherry aphid (Myzus cerasi) and two-spotted spider mite (Tetranychus urticae) populations.

Evaluation of the predatory mite Phytoseiulus macropilis (Acari: Phytoseiidae) as a biological control agent of the two-spotted spider mite on strawberry plants under greenhouse conditions

The predatory mite Phytoseiulus macropilis is a potential biological control agent of the two-spotted spider mite (TSSM) Tetranychus urticae on strawberry plants. Its ability to control TSSM was recently assessed under laboratory conditions, but its ability to locate and control TSSM under greenhouse conditions has not been tested so far. We evaluated whether P. macropilis is able to control TSSM on strawberry plants and to locate strawberry plants infested with TSSM under greenhouse conditions. Additionally, we tested, in an olfactometer, whether odours play a role in prey-finding by P. macropilis. The predatory mite P. macropilis required about 20 days to achieve reduction of the TSSM population on strawberry plants initially infested with 100 TSSM females per plant. TSSM-infested plants attract an average of 27.5 +/- 1.0% of the predators recaptured per plant and uninfested plants attracted only 5.8 +/- 1.0% per plant. The predatory mites were able to suppress TSSM populations on a single strawberry plant and were able to use odours from TSSM-infested strawberry plants to locate prey in both olfactometer and arena experiments. Hence, it is concluded that P. macropilis can locate and reduce TSSM population on strawberry plants under greenhouse conditions.

Twospotted Spider Mite Population Level, Distribution, and Damage on Ivy Geranium in Response to Different Nitrogen and Phosphorus Fertilization Regimes

Twospotted Spider Mite Population Level, Distribution, and Damage on Ivy Geranium in Response to Different Nitrogen and Phosphorus Fertilization Regimes

Biological control of twospotted spider mite, Tetranychus urticae, with predatory mite, Neoseiulus californicus, in strawberries

Greenhouse and field experiments were conducted from 2005 to 2007 to determine the effectiveness of different release times with the predatory mite, Neoseiulus californicus (McGregor), for control of the twospotted spider mite (TSSM), Tetranychus urticae Koch, in strawberries (Fragaria x ananassa Duchesne). The effect of N. californicus releases over time and on development of TSSM populations during a growing season were evaluated. Our hypothesis was that repeated applications of N. californicus, which is currently recommended by biological control companies, might be unnecessary to attain season-long control of TSSM. In greenhouse trials, three treatments consisting of releases of N. californicus at five-day intervals: day 0, day 5, and day 10, and an untreated control were evaluated. The treatment releases significantly reduced TSSM below the control within five days of each release. Neoseiulus californicus significantly reduced TSSM in treatments with high densities (leaflets with > or =40 TSSM) below that of treatments with lower densities (leaflets with < or = 10 TSSM) demonstrating that if released at a predator: prey ratio of 1:10, timing of release does not alter the effectiveness of N. californicus in controlling TSSM. However, we found that if the ratio of predator: prey remains adequate, N. californicus is a more efficient predator at high TSSM densities. Field studies included three treatments consisting of releases of N. californicus at one-month intervals. All treatments significantly reduced TSSM compared with the control plots (no releases). Releases applied early in the season sustained TSSM significantly below those in the control plots for the whole season. Our results indicate that one release of N. californicus is able to sustained control of TSSM in strawberry throughout a growing season if released when TSSM populations are low early in the season in the southeastern United States.

Effects of extending the light phase on diapause induction in a Japanese population of the two-spotted spider mite, Tetranychus urticae

Artificial lighting is a merit of a 'plant factory', which might be utilized to suppress an increase in pest population. We investigated the effects of extending the light phase on diapause induction in the two-spotted spider mite (TSSM), Tetranychus urticae. TSSM were reared at 18 degrees C under light phases ranging from 2 to 64 h combined with a constant dark phase of 16 h in aluminum bottles, with white light emitting diodes attached inside to minimize fluctuations in air temperature between the light and dark phases. Diapause was induced in adult TSSM females when the light phase was 24 h or shorter, and diapause induction was inhibited when the light phase extended over 32 h. The development of deutonymphs was delayed under a diapause-inducing photoperiod. Diapause inducing photoperiods may suppress an increase in the TSSM population, by slowing down development and reproduction.

THE RESIDUAL AND DIRECT EFFECTS OF REDUCED-RISK AND CONVENTIONAL MITICIDES ON TWOSPOTTED SPIDER MITES, TETRANYCHUS URTICAE (ACARI: TETRANYCHIDAE) AND PREDATORY MITES (ACARI: PHYTOSEIIDAE)

The residual effects of several reduced-risk and conventional miticides were evaluated in strawberries (Fragaria × ananassa Duchesne) on the twospotted spider mite (TSSM), Tetranychus urticae Koch (Acari: Tetranychidae) and on 2 predatory mites, Neoseiulus californicus McGregor and Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae). Experiments were conducted in the laboratory and greenhouse. The greenhouse experiments also tested the direct effects of the miticides on TSSM. The efficacy of conventional and reduced-risk miticides was evaluated on strawberry leaf discs and on whole plants for control of TSSM. Furthermore, the residual effects of these miticides were evaluated on whole strawberry plants against selective predatory mites. For TSSM, 5 treatments were evaluated: a conventional miticide; fenbutatin-oxide (Vendex®) and 3 reduced-risk miticides; binfenazate (Acramite 50WP®), activated garlic extract (Repel®), sesame seed and castor oil (Wipeout®), and a water-treated control. For predatory mites, the residual effects of only Acramite® and Vendex® were evaluated. Acramite® was the most effective acaricide in reducing TSSM populations in both the laboratory and greenhouse experiments. Vendex® and Wipeout® were also effective in the laboratory, but did not cause significant reduction of TSSM in the greenhouse. Repel® was the least effective of the 4 pesticides evaluated. Neither Acramite® nor Vendex® had a significant effect on either predatory mite species. However, there appeared to be more predatory mites on the Vendex®-treated plants than on the Acramite®-treated plants. There were significantly more predatory mites of both species on the cue plants, which were inoculated with TSSM versus the non-cue plants, which were not inoculated.

Determination of the resistance level of two-spotted spider mite (Tetranychus urticae Koch) populations in apple orchards in Isparta province against some pesticides

Determination of the resistance level of two-spotted spider mite (Tetranychus urticae Koch) populations in apple orchards in Isparta province against some pesticides