Effect of pesticide mixtures on the predatory mite Phytoseiulus persimilis A.H. (Acarina, Phytoseiidae) in the laboratory

The acaricide hexythiazox (Acorit^® SC, 100 g a.i.l^–1), the fungicide triadimefon (Bayleton spezial^® WG, 52 g a.i.kg^–1) and the insecticide heptenophos (Hostaquick^® EC, 550 g a.i.l^–1), were tested in the laboratory for their side-effects on the predatory mite Phytoseiulus persimilis A.H. The pesticides were either applied separately at a range of concentrations or in admixture to detached bean leaves using a Potter Tower to deposit 2 mg spray solution per cm². No significant differences in the mean mortality rate of the phytoseiid or in the mean reproduction per female was found between the different treatments. Total effect values ranged from 5.4 to 38.7% after separate application of the test products and from 8.9 to 25.5% after treatment with the various pesticide mixtures.     

Rainforest habitat resistance to the migration of Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) in south-eastern Queensland

Abstract  This paper tests the hypothesis that habitat differences affect the migratory ability of the Chilean predatory mite, Phytoseiulus persimilis , an introduced biological control agent of the spider mite, Tetranychus urticae . It is suggested that habitat resistance accounts for the species' inability to invade rainforests in south-eastern Queensland, Australia. Like its prey, P. persimilis migrates to distant plants on air currents. To test our hypothesis, populations of the Chilean predatory mite were established on potted bean plants in both remnant rainforest and adjacent open fields, and their migration monitored using sticky traps. Overall it was found that prey populations on leaves were similar in both habitats, but those of predators were about 20% lower in rainforest. However, the numbers of both predators and prey caught on sticky traps in rainforest were about 6% and 25%, respectively, of those caught in open fields, indicating a strongly reduced rate of aerial migration in the forest. The number of P. persimilis caught on the sticky traps increased with increasing populations of predators on foliage. Thus, dense vegetation inhibits the movement of air currents and inhibits colonisation by both predators and, to a lesser extent, spider mites. These results suggest that the inhibition of aerial migration is one reason for lower numbers of P. persimilis in forest habitats, both because its own vagility is restricted, and because its prey is less able to disperse.     

智利小植绥螨密度对朱砂叶螨产卵能力的影响

智利小植绥螨是朱砂叶螨的专性捕食者。本研究在室内,研究了智利小植绥螨密度对朱砂叶螨存活及生殖的影响。智利小植绥螨对朱砂叶螨存活干扰结果表明:干扰后24 h各处理朱砂叶螨的死亡率均显著高于对照,且死亡率随干扰密度增大而提高,10头捕食螨/叶碟处理高达76.67%,为对照处理的14.38倍。但是干扰48 h后对叶螨存活影响不大。对朱砂叶螨产卵干扰结果表明:干扰后各时间段朱砂叶螨单雌产卵量均随智利小植绥螨干扰密度的增加而降低。干扰24 h后,除1头捕食螨/叶碟处理与对照差异不显著外,其他各处理均与对照有显著差异。干扰48 h后,10头捕食螨/叶碟处理的叶螨单头产卵量是2.80粒,仅为对照的28.5%。但是干扰96h后,除10头捕食螨/叶碟处理与对照差异显著外,其余各处理与对照均差异不显著。本研究还分析了干扰对96 h内朱砂叶螨单雌总产卵量影响,处理5头/叶碟和10头/叶碟均显著低于对照,并且10头/叶碟显著低于5头/叶碟;1头/叶碟和3头/叶碟与对照相当,但是均显著高于10头/叶碟。结果显示,智利小植绥螨密度对朱砂叶螨有较强的生殖干扰作用,并且捕食螨密度越大,干扰作用越强,后代增殖潜能越小。     

Ontogenetic shifts in intraguild predation on thrips by phytoseiid mites: the relevance of body size and diet specialization

In greenhouse agroecosystems, a guild of spider mite predators may consist of the oligophagous predatory mite Phytoseiulus persimilis Athias-Henriot, the polyphagous predatory mite Neoseiulus californicus McGregor (both Acari: Phytoseiidae) and the primarily herbivorous but facultatively predatory western flower thrips Frankliniella occidentalis Pergande (Thysanoptera: Thripidae). Diet-specialization and the predator body size relative to prey are crucial factors in predation on F. occidentalis by P. persimilis and N. californicus. Here, it was tested whether the relevance of these factors changes during predator ontogeny. First, the predator (protonymphs and adult females of P. persimilis and N. californicus): prey (F. occidentalis first instars) body size ratios were measured. Second, the aggressiveness of P. persimilis and N. californicus towards F. occidentalis was assessed. Third, survival, development and oviposition of P. persimilis and N. californicus with F. occidentalis prey was determined. The body size ranking was P. persimilis females > N. californicus females > P. persimilis protonymphs > N. californicus protonymphs. Neoseiulus californicus females were the most aggressive predators, followed by highly aggressive N. californicus protonymphs and moderately aggressive P. persimilis protonymphs. Phytoseiulus persimilis females did not attack thrips. Frankliniella occidentalis larvae are an alternative prey for juvenile N. californicus and P. persimilis, enabling them to reach adulthood. Females of N. californicus but not P. persimilis sustained egg production with thrips prey. Within the guild studied here, N. californicus females are the most harmful predators for F. occidentalis larvae, followed by N. californicus and P. persimilis juveniles. Phytoseiulus persimilis females are harmless to F. occidentalis.     

Toxicity of the herbicide glufosinate-ammonium to predatory insects and mites of Tetranychus urticae (Acari: Tetranychidae) under laboratory conditions

The toxicities of the herbicide glufosinate-ammonium to three predatory insect and two predatory mite species of Tetranychus urticae Koch were determined in the laboratory by the direct contact application. At a concentration of 540 ppm (a field application rate for weed control in apple orchards), glufosinate-ammonium was almost nontoxic to eggs of Amblyseius womersleyi Schicha, Phytoseiulus persimilis Athias-Henriot, and T. urticae but highly toxic to nymphs and adults of these three mite species, indicating that a common mode of action between predatory and phytophagous mites might be involved. In tests with predatory insects using 540 ppm, glufosinate-ammonium revealed little or no harm to larvae and pupae of Chrysopa pallens Rambur but was slightly harmful to eggs (71.2% mortality), nymphs (65.0% mortality), and adults (57.7% mortality) of Orius strigicollis Poppius. The herbicide showed no direct effect on eggs and adults of Harmonia axyridis (Pallas) but was harmful, slightly harmful, and harmless to first instars (100% mortality), fourth instars (51.1% mortality), and pupae (24.5% mortality), respectively. The larvae and nymphs of predators died within 12 h after treatment, suggesting that the larvicidal and nymphicidal action may be attributable to a direct effect rather than an inhibitory action of chitin synthesis. On the basis of our data, glufosinate-ammonium caused smaller effects on test predators than on T. urticae with the exception of P. persimilis, although the mechanism or cause of selectivity remains unknown. Glufosinate-ammonium merits further study as a key component of integrated pest management.     

Evaluation of predatory mites and Acramite for control of twospotted spider mites in strawberries in north central Florida

Greenhouse and field experiments were conducted from 2003 to 2005 to determine the effectiveness of two predatory mite species, Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus (McGregor), and a reduced-risk miticide, Acramite 50 WP (bifenazate), for control of twospotted spider mite, Tetranychus urticae Koch, in strawberries (Fragaria x ananassa Duchesne). In greenhouse tests, three treatments consisting of releases of P. persimilis, N. californicus, and an untreated control were evaluated. Both species of predatory mites significantly reduced twospotted spider mite numbers below those found in the control during the first 3 wk of evaluation. However, during week 4, twospotted spider mite numbers on the plants treated with P. persimilis increased and did not differ significantly from the control. Field studies used releases of P. persimilis and N. californicus, applications of Acramite, and untreated control plots. Both N. californicus and P. persimilis significantly reduced populations of twospotted spider mite below numbers recorded in the control plots. During the 2003-2004 field season P. persimilis took longer than N. californicus to bring the twospotted spider mite population under control (< 10 mites per leaflet). Acramite was effective in reducing twospotted spider mite populations below 10 mites per leaflet during the 2003-2004 field season but not during the 2004-2005 field season, possibly because of a late application. These findings indicate that N. californicus releases and properly timed Acramite applications are promising options for twospotted spider mite control in strawberries for growers in north Florida and other areas of the southeast.     

Attraction of Phytoseiulus persimilis (Acari: Phytoseiidae) towards volatiles from various Tetranychus urticae-infested plant species

Plants infested with the spider mite Tetranychus urticae Koch, may indirectly defend themselves by releasing volatiles that attract the predatory mite Phytoseiulus persimilis Athias-Henriot. Several plants from different plant families that varied in the level of spider mite acceptance were tested in an olfactometer. The predatory mites were significantly attracted to the spider mite-infested leaves of all test plant species. No differences in attractiveness of the infested plant leaves were found for predatory mites reared on spider mites on the different test plants or on lima bean. Thus, experience with the spider mite-induced plant volatiles did not affect the predatory mites. Jasmonic acid was applied to ginkgo leaves to induce a mimic of a spider mite-induced volatile blend, because the spider mites did not survive when incubated on ginkgo. The volatile blend induced in ginkgo by jasmonic acid was slightly attractive to predatory mites. Plants with a high degree of direct defence were thought to invest less in indirect defence than plants with a low degree of direct defence. However, plants that had a strong direct defence such as ginkgo and sweet pepper, did emit induced volatiles that attracted the predatory mite. This indicates that a combination of direct and indirect defence is to some extent compatible in plant species.     

Disease prevalence and transmission of Microsporidium phytoseiuli infecting the predatory mite, Phytoseiulus persimilis (Acari: Phytoseiidae)

Isolated colonies of the predatory mite, Phytoseiulus persimilis, were used to gain information regarding prevalence and transmission of Microsporidium phytoseiuli. Two colonies of P. persimilis were reared on spider mite (Tetranychus urticae)-infested bean plants in isolated cages. Disease prevalence of predators from Colony 1 remained relatively low (between 0 and 15%) over 57 weeks of observation whereas disease prevalence of predators from Colony 2 increased over 3 months (from 12 to 100%). Disease prevalence among predators from Colony 1 had increased to 100% 2 months after weekly sampling had ceased for this colony and periodic sampling confirmed that disease prevalence among individuals of both colonies remained at 100%. Microsporidian spores were not detected in randomly chosen samples of T. urticae prey mites that were removed and examined biweekly during this period. Although numerous microsporidian spores were observed in smear preparations of fecal pellets examined by light microscopy, spores were not observed on leaf surfaces or predator feces when examined by SEM. The latter appeared as intact aggregates composed of numerous dumbbell-shaped crystals and it is unlikely that spores are liberated from intact fecal pellets onto leaf surfaces. Vertical transmission of M. phytoseiuli was 100%; horizontal transmission was low (14.3%) and occurred only when immature P. persimilis were permitted to develop in contact with infected immature and adult predators. The mean number of eggs produced per mated pair was highest when uninfected females were mated with uninfected males (63.2 eggs per mated pair). Although mean egg production decreased when one or both parents were infected, not all differences were significant. Male predatory mites did not contribute to infection of their progeny. Results suggest that routine examination of P. persimilis for microsporidian spores is essential for the management of M. phytoseiuli within P. persimilis colonies. Low disease prevalence and lack of obvious disease signs or symptoms, as in the case of M. phytoseiuli, increase the probability that these pathogens will escape notice unless individuals are routinely examined for pathogens.     

Efficacy and persistence of rosemary oil as an acaricide against twospotted spider mite (Acari: Tetranychidae) on greenhouse tomato

Efficacy of rosemary, Rosmarinus officinalis L., essential oil was assessed against twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), as well as effects on the tomato, Lycopersicum esculatum Mill., host plant and biocontrol agents. Laboratory bioassay results indicated that pure rosemary oil and EcoTrol (a rosemary oil-based pesticide) caused complete mortality of spider mites at concentrations that are not phytotoxic to the host plant. The predatory mite Phytoseiulus persimilis Athias-Henriot is less susceptible to rosemary oil and EcoTrol than twospotted spider mite both in the laboratory and the greenhouse. Rosemary oil repels spider mites and can affect oviposition behavior. Moreover, rosemary oil and rosemary oil-based pesticides are nonpersistent in the environment, and their lethal and sublethal effects fade within 1 or 2 d. EcoTrol is safe to tomato foliage, flowers, and fruit even at double the recommended label rate. A greenhouse trial indicated that a single application of EcoTrol at its recommended label rate could reduce a twospotted spider mite population by 52%. At that rate, EcoTrol did not cause any mortality in P. persimilis nor did it affect their eggs. In general, EcoTrol was found to be a suitable option for small-scale integrated pest management programs for controlling twospotted spider mites on greenhouse tomato plants.     

Toxicity of bifenazate and its principal active metabolite, diazene, to Tetranychus urticae and Panonychus citri and their relative toxicity to the predaceous mites, Phytoseiulus persimilis and Neoseiulus californicus

Bifenazate is a novel carbazate acaricide discovered by Uniroyal Chemical (now Chemtura Corporation) for the control of phytophagous mites infesting agricultural and ornamental crops. Its acaricidal activity and that of its principal active metabolite, diazene, were characterized. Bifenazate and diazene had high toxicity and specificity both orally and topically to all life stages of Tetranychus urticae and Panonychus citri. Acute poisoning was observed with no temperature dependency. No cross-resistance was found to mites resistant to several other classes of acaricides, such as tebufenpyrad, etoxazole, fenbutatin oxide and dicofol. Bifenazate remained effective for a long time with only about a 10% loss of efficacy on T. urticae after 1 month of application in the field. All stages of development of the predatory mites, Phytoseiulus persimilis and Neoseiulus californicus, survived treatment by both bifenazate and diazene. When adult females of the two predatory mite species were treated with either bifenazate or diazene, they showed a normal level of fecundity and predatory activity in the laboratory, effectively suppressing spider mite population growth. Even when the predators were fed spider mite eggs that had been treated previously with bifenazate, they survived. These findings indicate that bifenazate is a very useful acaricide giving high efficacy, long-lasting activity and excellent selectivity for spider mites. It is, therefore, concluded that bifenazate is an ideal compound for controlling these pest mites.     

THE OCCURRENCE OF PHYTOSEIULUS PERSIMILIS ATHIAS-HENRIOT (ACARINA:PHYTOSEIIDAE) IN AN ORCHARD IN VICTORIA

b
High numbers of the predatory mite, Phytoseiulus persimilis , were found on apple and nectarine trees in a commercial orchard at Werribee, Victoria in February 1981. In the following season, again it was not detected on trees or broad-leaved weeds in the orchard until late summer. Slide-dip tests on the Werribee population of P. persimilis and a population originating from strawberries in Sydney, New South Wales, showed that azinphos-methyl was equally toxic to the 2 strains and DDT was considerably less toxic to both.     

Improved control capacity of the mite predator Phytoseiulus persimilis (Acari: Phytoseiidae) on tomato

The predatory mite Phytoseiulus persimilis is frequently reported to perform poorly on greenhouse tomatoes. As the predators are mass-reared on another host plant (bean), we supposed that they are poorly adapted to tomato, a plant densely packed with poisonous and sticky glandular hairs. This hypothesis was tested by comparing the control capacity of a stain of P. persimilis directly obtained from a mass rearing with the same strain after four generations on tomato. Both strains were released in a tomato crop in two identical compartments of a greenhouse and the population dynamics of prey (a tomato strain of Tetranychus urticae) and predator were recorded at weekly time intervals. It was found that the strain previously exposed to a tomato environment performed better than the unexposed strain: (1) its population increased faster; (2) the prey population declined faster; and (3) the damage to new-grown tomato leaves was considerably lower. To investigate the causes of the difference in performance between the exposed and unexposed strains, oviposition and survival rates were assessed on a diet of two-spotted spider mites on tomato leaf sections. In addition, the unexposed strain was tested on a diet of two-spotted spider mites on bean leaf sections. The difference in oviposition rates of both predator strains was small compare to the overall mean. However, the oviposition rate of the first generation of predators since transfer from bean to tomato dropped to less than half of the original value. Moreover, mortality in the first generation increased from 14% to 89%, whereas it decreased to 0% after four generations. Future research should clarify whether these changes in life history are due to selection or to physiological adaptation.     

Does pollen availability mitigate the impact of pesticides on generalist predatory mites?

The effect of the provision of pollen on the impact of pesticides on the predatory mite Kampimodromus aberrans was assessed at individual and population levels. In the laboratory we evaluated the influence of pollen amount and pollen application frequency on lethal and sub-lethal effects of chlorpyrifos and spinosad. In a potted plant experiment, the effects of pesticides and pollen were assessed on predatory mite population abundance. In the laboratory, survival and fecundity of predatory mites were reduced by insecticides, and spinosad was more toxic than chlorpyrifos. In the same experiment, high pollen application frequency alleviated the sub-lethal effect induced by chlorpyrifos. On potted plants, pollen applications reduced the impact of chlorpyrifos on K. aberrans, whereas without pollen applications the impact of spinosad and chlorpyrifos on the predatory mite population was similar. Results obtained here highlight that the provision of fresh pollen is of particular importance for predatory mites when pesticides are applied.     

Interactions in a tritrophic acarine predator– prey metapopulation system: prey location and distance moved by Phytoseiulus persimilis (Acari: Phytoseiidae)

The between-plant movement of the predatory mite Phytoseiulus persimilis was studied in a greenhouse. The aims were to determine the distance moved by P. persimilis and the response of the predator to the location of a plant infested with two-spotted spider mite, Tetranychus urticae. In addition, we tested whether the predator exhibits random movement between plants or whether its dispersal is oriented. We found that a high proportion of the predators released on a central plant were able to reach plants at the periphery provided the plants were connected to the central plant with 'bridges'. The results further showed that P. persimilis does not disperse randomly to the surrounding plants. The distribution of immigrants was influenced by the position of an infested plant in the neighbourhood, but light/shadow effects in the greenhouse may also influence the choice of direction. The likely implications of the findings for biological control are discussed. © Rapid Science Ltd. 1998     

Volatile spider-mite pheromone and host-plant kairomone, involved in spaced-out gregariousness in the spider mite Tetranychus urticae

ABSTRACT. From the host plant-spider mite complex Phaseolus lunatus—Tetranychus urticae Koch a volatile chemical is emitted that acts as a kairomone for the predatory mite Phytoseiulus persimilis Athias-Henriot (Sabelis et al. , 1984a). This kairomone is apparently a byproduct of a vital physiological process and/or it has a function in the biology of the spider mite as well.
The spider mite—host plant complex also emits a volatile spider-mite dispersing pheromone. This is shown in the present study where spider mites were introduced into an odour patch on a horizontal screen in a vertical airflow olfactometer. When spider-mite infested leaves of Lima bean are offered, the spider mites walk mainly straight and soon reach the edge of the screen. On the other hand, when clean Lima bean leaves are offered, the mites walk tortuously most of the time and reach the edge of the screen much later. Artificially damaged plants elicit the same response as undamaged plants. Differences in spider-mite behaviour are observed in the vertical airflow olfactometer when odour of either clean or spider-mite infested leaves is offered. A comparison of the behaviour in these two situations with that when no odour was offered suggests that Lima bean leaves emit a volatile kairomone that activates T. urticae and makes them return after losing the stimulus. A Y-tube olfactometer experiment confirms the existence of this kairomone.
At a low ratio of dispersing pheromone to plant kairomone, the spider mites behave as if only kairomone is present, walking mainly tortuously. At a high ratio they disperse. No aggregation-pheromonal effect is observed.
The possibility that the spider-mite dispersing pheromone acts as a kairomone for P. persimilis is discussed.     

Differential Effects of Plant Species on a Mite Pest (Tetranychus Urticae) and its Predator (Phytoseiulus Persimilis): Implications for Biological Control

The influence of plant species on the population dynamics of the spider mite pest, Tetranychus urticae, and its predator, Phytoseiulus persimilis, was examined as a prerequisite to effective biological control on ornamental nursery stock. Experiments have been done to investigate how the development, fecundity and movement of T. urticae, and the movement of P. persimilis were affected by plant species. A novel experimental method, which incorporates plant structure, was used to investigate the functional response of P. persimilis. Development times for T. urticae were consistent with published data and did not differ with plant species in a biologically meaningful way. Plant species was shown to have a major influence on fecundity (P < 0.001) and movement of the pest mite (P < 0.01), but no influence on the movement of the predator. The movement of both pest and predator was shown to be related to the density of the adult pest mites on the plant (P < 0.001). Plant structure affected the functional response, particularly in relation to the ability of the predator to locate prey at low densities. The impact of these findings on the effective use of biological control on ornamental nursery stock is discussed.     

Biological, Chemical and Integrated Control of Two-spotted Spider Mite Tetranychus urticae on Dwarf Hops

Chemical, biological and integrated programmes for the control of two-spotted spider mite, Tetranychus urticae, were compared on dwarf hops in 1997 and 1998. In both years integrated control, which consisted of an application of the ovicidal acaricide clofentezine followed by a release of the predatory mite Phytoseiulus persimilis at 10 individuals per plant, was the most effective treatment. Similar numbers of spider mites were recorded on plots that were treated with P. persimilis only or with a single application of the acaricide tebufenpyrad, and plots with either of these treatments had higher levels of infestation than the plots under integrated control. The highest numbers of spider mites were found on the untreated plots. This study indicates that integrated control of T. urticae using clofentezine in conjunction with P. persimilis is likely to be more effective than an approach based on chemical or biological measures only. It is suggested that an integrated system would have the added benefit over a pesticide-only programme of reducing pressure on the pest for the selection of strains resistant to acaricides.     

The impact of insecticides applied in apple orchards on the predatory mite Kampimodromus aberrans (Acari: Phytoseiidae)

Kampimodromus aberrans is an effective predatory mite in fruit orchards. The side-effects of insecticides on this species have been little studied. Field and laboratory experiments were conducted to evaluate the effects of insecticides on K. aberrans. Field experiments showed the detrimental effects of etofenprox, tau-fluvalinate and spinosad on predatory mites. Spider mite (Panonychus ulmi) populations reached higher densities on plots treated with etofenprox and tau-fluvalinate than in the other treatments. Single or multiple applications of neonicotinoids caused no detrimental effects on predatory mites. In the laboratory, spinosad and tau-fluvalinate caused 100 % mortality. Etofenprox caused a significant mortality and reduced fecundity. The remaining insecticides did not affect female survival except for imidacloprid. Thiamethoxam, clothianidin, thiacloprid, chlorpyrifos, lufenuron and methoxyfenozide were associated with a significant reduction in fecundity. No effect on fecundity was found for indoxacarb or acetamiprid. Escape rate of K. aberrans in laboratory was relatively high for etofenprox and spinosad, and to a lesser extent thiacloprid. The use of etofenprox, tau-fluvalinate and spinosad was detrimental for K. aberrans and the first two insecticides induced spider mite population increases. The remaining insecticides caused no negative effects on predatory mites in field trials. Some of them (reduced fecundity and repellence) should be considered with caution in integrated pest management programs.     

The effect of chrysanthemum leaf trichome density and prey spatial distribution on predation of Tetranychus urticae (Acari: Tetranychidae) by Phytoseiulus persimilis (Acari: Phytoseiidae)

The effect of plant architecture, in terms of leaf hairiness, and prey spatial arrangement, on predation rate of eggs of the spider mite, Tetranychus urticae Koch, by the predatory mite Phytoseiulus persimilis Athias-Henriot was examined on cut stems of chrysanthemums. Three levels of leaf hairiness (trichome density) were obtained using two different chrysanthemum cultivars and two ages within one of the cultivars. The number of prey consumed by P. persimilis was inversely related to trichome density. At low prey densities (less than ten eggs per stem), prey consumption did not differ in a biologically meaningful way between treatments. The effect of prey spatial arrangement on the predation rate of P. persimilis was also examined. Predation rates were higher in prey patches on leaves adjacent to the release point of P. persimilis, but significantly greater numbers of prey were consumed in higher density prey patches compared to low density patches. The predators exhibited non-random searching behaviour, spending more time on leaves closest to the release point. The implications of these findings for biological control and predator-prey dynamics are discussed.     

Comparison of single and combination treatments of Phytoseiulus persimilis, Neoseiulus californicus, and Acramite (bifenazate) for control of twospotted spider mites in strawberries

Greenhouse and field experiments were conducted from 2003 to 2005 to determine the effectiveness of combining releases of two predatory mite species, Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus (McGregor), and a reduced-risk miticide, Acramite (bifenazate), for control of twospotted spider mite (TSSM) (Tetranychus urticae Koch) in strawberries. In the greenhouse experiment, a combination treatment of P. persimilis and N. californicus was compared with single treatments of each species, Acramite application, and untreated control. All treatments significantly reduced TSSM numbers compared with the control. Field studies employed two approaches: one investigating the same five treatments as the greenhouse experiment and a second, comparing combination treatments of P. persimilis/N. californicus, Acramite/N. californicus, and Acramite/P. persimilis to single treatments of each and to control plots. Among the combination treatments, the P. persimilis/N. californicus treatment significantly reduced TSSM numbers compared with the control, but was not as effective as N. californicus alone during the 2003-2004 field season. Also, combination treatments of Acramite/N. californicus, and Acramite/P. persimilis significantly reduced TSSM populations compared with the control. These findings indicate that all three combination treatments are promising options for TSSM control in strawberries for growers in northern Florida and other strawberry producing areas of the world.