Status of Aceria guerreronis Keifer (Acari: Eriophyidae) as a Pest of Coconut in the State of Sao Paulo, Southeastern Brazil

The coconut mite, Aceria guerreronis Keifer, is one of the main pests of coconut palms (Cocos nucifera) in northeastern Brazil. The objective of this study was to evaluate the levels of the coconut mite and other mites on coconut palms in the state of S?o Paulo and to estimate the possible role of predatory mites in the control of this pest. The effect of cultivated genotypes and sampling dates on the mite populations was also estimated. We sampled attached fruits, leaflets, inflorescences, and fallen fruits. The coconut mite was the main phytophagous mite found on attached and fallen fruits, with average densities of 110.0 and 20.5 mites per fruit, respectively. The prevalent predatory mites on attached and fallen fruits were Proctolaelaps bulbosus Moraes, Reis & Gondim Jr. and Proctolaelaps bickleyi (Bram), both Melicharidae. On leaflets, the tenuipalpids Brevipalpus phoenicis (Geijsks) and Tenuipalpus coyacus De Leon and the tetranychid Oligonychus modestus (Banks) were the predominant phytophagous mites. On both leaflets and inflorescences, the predominant predatory mites belonged to the Phytoseiidae. Neoseiulus baraki (Athias-Henriot) and Neoseiulus paspalivorus (De Leon), predators widely associated with the coconut mite in northeastern Brazil and several other countries, were not found. The low densities of the coconut mite in S?o Paulo could be related to prevailing climatic conditions, scarcity of coconut plantations (hampering the dispersion of the coconut mite between fields), and to the fact that some of the genotypes cultivated in the region are unfavorable for its development.     

Correlation between Olfactory Responses, Dispersal Tendencies, and Life-history Traits of the Predatory Mite Neoseiulus Womersleyi (Acari: Phytoseiidae) of Eight Local Populations

To investigate the relationship between foraging behavior and life-history traits of the predatory mite Neoseiulus womersleyi, the olfactory responses, dispersal ratios from a prey patch, predation rates, fecundity, and developmental times in eight local populations of N. womersleyi were investigated. Significant differences among local populations were found in all these traits except fecundity. None of the life-history traits correlated with foraging behavior. A significant positive correlation was found only between the olfactory response and the dispersal ratio. These results suggested that predatory mites with low olfactory responses would stay in a prey patch longer than predatory mites with high olfactory responses.     

Hyperpredation by generalist predatory mites disrupts biological control of aphids by the aphidophagous gall midge Aphidoletes aphidimyza

Biological control of different species of pest with various species of generalist predators can potentially disrupt the control of pests through predator-predator interactions. We evaluate the impact of three species of generalist predatory mites on the biological control of green peach aphids, Myzus persicae (Sulzer) with the aphidophagous gall midge Aphidoletes aphidimyza (Rondani). The predatory mites tested were Neoseiulus cucumeris (Oudemans), Iphiseius degenerans (Berlese) and Amblyseius swirskii Athias–Henriot, which are all commonly used for pest control in greenhouse sweet pepper. All three species of predatory mites were found to feed on eggs of A. aphidimyza, even in the presence of abundant sweet pepper pollen, an alternative food source for the predatory mites. In a greenhouse experiment on sweet pepper, all three predators significantly reduced population densities of A. aphidimyza, but aphid densities only increased significantly in the presence of A. swirskii when compared to the treatment with A. aphidimyza only. This stronger effect of A. swirskii can be explained by the higher population densities that this predator reached on sweet pepper plants compared to the other two predator species. An additional experiment showed that female predatory midges do not avoid oviposition sites with the predator A. swirskii. On the contrary, they even deposited more eggs on plants with predatory mites than on plants without. Hence, this study shows that disruption of aphid control by predatory mites is a realistic scenario in sweet pepper, and needs to be considered when optimizing biological control strategies.     

Functional response of Neoseiulus barkeri Hughes on two-spotted spider mite (Acari: Tetranychidae)

Generalist predatory mites are the common phytoseiid fauna in many agroecosystems, but little attention has been paid to their potential as biological control agents. In this study, we determined the functional responses of adult females of the generalist predator Neoseiulus barkeri Hughes on eggs, larvae, and adults of the two-spotted spider mite, Tetranychus urticae Koch, in the laboratory. Predation experiments were conducted on pepper leaf discs over a 24 h period at 25±1°C, 70–80% RH and 16L:8D photoperiod. Prey densities ranged 5 to 80 eggs, or 5 to 40 larvae, or 1 to 8 female adults of T. urticae per disc. The predation rate of N. barkeri adult females on T. urticae eggs was the same as on its larvae, but the predation rate on adult females was much lower. The role of generalist predatory mites in integrated and biological control of greenhouse pests was discussed.     

Influence of species of host plants on the predation of thrips by Neoseiulus cucumeris, Iphiseius degenerans and Orius laevigatus

A leaf-disc bioassay was used to compare the predation levels of two species of predatory mites (Neoseiulus cucumeris (Oudemans) and Iphiseius degenerans (Berlese)) and a predatory bug (Orius laevigatus (Fieber)), on the thrips Frankliniella occidentalis (Pergande) and Heliothrips haemorrhoidalis (Bouché), feeding on a range of susceptible plant species from twelve plant families. The predatory bug, O. laevigatus, reduced the number of thrips to a greater extent than the predatory mites and all three predators showed greater levels of predation on F. occidentalis than on H. haemorrhoidalis. The level of predation caused by each predator varied among the species of plants; the variation was greater on the plant hosts of H. haemorrhoidalis than of F. occidentalis.     

Relative contribution of biotic and abiotic factors to the population density of the cassava green mite, Mononychellus tanajoa (Acari: Tetranychidae)

The cassava green mite, Mononychellus tanajoa, is a key pest of cassava, Manihot esculenta Crantz (Euphorbiaceae), and it may be kept in check by naturally occurring predatory mites of the family Phytoseiidae. In addition to predatory mites, abiotic factors may also contribute to regulate pest mite populations in the field. Here, we evaluated the population densities of both M. tanajoa and the generalist predatory mite Euseius ho DeLeon (Acari: Phytoseiidae) over the cultivation cycle (11 months) of cassava in four study sites located around the city of Miranda do Norte, Maranhão, Brazil. The abiotic variables rainfall, temperature and relative humidity were also recorded throughout the cultivation cycle of cassava. We determined the relative importance of biotic (density of E. ho) and abiotic (rainfall, temperature and relative humidity) factors to the density of M. tanajoa. The density of M. tanajoa increased whereas the density of E. ho remained constant throughout time. A hierarchical partitioning analysis revealed that most of the variance for the density of M. tanajoa was explained by rainfall and relative humidity followed by E. ho density and temperature. We conclude that abiotic factors, especially rainfall, were the main mechanisms driving M. tanajoa densities.     

Effects of thermal stress on lipid peroxidation and antioxidant enzyme activities of the predatory mite,Neoseiulus cucumeris (Acari: Phytoseiidae)

Changes in temperature are known to cause a variety of physiological stress responses in insects and mites. Thermal stress responses are usually associated with the increased generation of reactive oxygen species (ROS), resulting in oxidative damage. In this study, we examined the time-related effect (durations for 1, 2, 3, and 5 h) of thermal stress conditions—i.e., relatively low (0, 5, 10, and 15 °C) or high (35, 38, 41, and 44 °C) temperatures—on the activities of antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD), peroxidase (POX), glutathione S-transferases (GSTs), and total antioxidant capacity (T-AOC) of the predatory mite Neoseiulus cucumeris. Also the lipid peroxidation (LPO) levels of the predatory mite were measured under thermal stress conditions. The results confirmed that thermal stress results in a condition of so-called oxidative stress and the four antioxidant enzymes play an important role in combating the accumulation of ROS in N. cucumeris. CAT and POX activity changed significantly when the mites were exposed to cold and heat shock, respectively. The elevated levels of SOD and GSTs activity, expressed in a time-dependent manner, may have an important role in the process of antioxidant response to thermal stress. However, the levels of LPO in N. cucumeris were high, serving as an important signal that these antioxidant enzyme-based defense mechanisms were not always adequate to counteract the surplus ROS. Thus, we hypothesize that thermal stress, especially extreme temperatures, may contribute much to the generation of ROS in N. cucumeris, and eventually to its death.     

Comparison of the predation capacities of two soil-dwelling predatory mites,Gaeolaelaps aculeifer and Stratiolaelaps scimitus (Acari: Laelapidae), on three thrips species

Soil-dwelling predatory mites are natural enemies of various soil pest insects and mites. Both Gaeolaelaps aculeifer (Canestrini) and Stratiolaelaps scimitus (Womersley) are commercialized natural enemies of thrips, but there is little information on the predation rate of these predatory mites on different thrips species. We compared their predation capacities on three thrips species, Frankliniella occidentalis, F. intonsa, and Thrips palmi, which are major pests of various horticultural plants. The predatory rate of G. aculeifer was higher than that of S. scimitus. Both predator species fed on more T. palmi thrips than F. occidentalis or F. intonsa thrips, which may be attributable to the smaller body size of T. palmi than the other thrips. Predation rates of female adults were 2.6–2.8 times higher than those of deutonymphs in both species. Predation rates were not separated according to the various developmental stages (i.e., second instar larva, pupa, or adult) of thrips; however, deutonymphs fed on fewer adults than larvae or pupae of F. occidentalis. Our results suggest that both G. aculeifer and S. scimitus are active predators that can prey during any of their developmental stages and on any species of thrips tested.     

Effect of long-term feeding history on functional and numerical response of Neoseiulus californicus (Acari: Phytoseiidae)

The functional and numerical responses of the predatory mite Neoseiulus californicus to eggs and protonymphs of Tetranychus urticae were studied on excised strawberry leaflet discs under laboratory conditions (25 ± 1°C, 75–85% RH and 16L : 8D). Four strains of the phytoseiid were compared: three originated from a long-term mass-rearing with different food (T. urticae, Dermatophagoides farinae and Quercus spp. pollen) and under controlled conditions, while the fourth was directly collected from a natural environment and therefore considered a wild strain. The different nutritional histories affected the responses of N. californicus on tetranychids. On the whole, the wild strain gave better performance. When egg prey was administered this strain and the one mass-reared on two-spotted spider mites showed similar functional as well as numerical responses; on the contrary, when protonymphs were furnished, the wild strain did not differ from that mass-reared on pollen. The strain previously fed on house dust mites gave the worst performance and also showed the lowest percentages of females in the progeny. The functional responses obtained were predominantly type II curves. In all cases considered, no stored energy was allocated for reproduction and, with the exception of the wild strain on eggs, the prey was exploited less efficiently as the consumption increased. In spite of the differences evidenced in this experiment all strains were characterized by high predation and oviposition rates. Thus the results obtained suggest no drawbacks in the use of mass-reared N. californicus as biocontrol agents. © Rapid Science Ltd. 1998     

Functional response of Neoseiulus californicus (Acari: Phytoseiidae) to Tetranychus urticae (Acari: Tetranychidae) on strawberry leaves

Neoseiulus californicus (McGregor) is a predatory mite employed for biological control of the agricultural pest Tetranychus urticae (Koch). We explored whether environmental differences, in this case the trichome densities of abaxial leaf surfaces of strawberry cultivars (‘Maehyang’ and ‘Sulhyang’ varieties) affect the functional response of adult female N. californicus preying on immature stages (egg, larva and nymph) of T. urticae. We also evaluated the functional response of N. californicus to eggs of T. urticae at different temperatures (15, 20, 25, 30 and 35°C). We conducted a logistic regression of the proportion of prey consumed as a function of initial prey density to identify functional response types, and used nonlinear least‐squares regression and the random predator equation to estimate attack rates and handling times. The functional response of adult female N. californicus to T. urticae was not influenced by non‐glandular trichomes on abaxial leaves but was affected by temperature. Overall, adult female N. californicus exhibited a type 2 functional response to T. urticae. The handling time of N. californicus was highest (1.9970 h) against T. urticae nymphs. The attack rate did not change much at 15–30°C, but was significantly higher at 35°C. The handling time decreased significantly with increasing temperature at 15–35°C. At 35°C, the attack rate was highest (0.2087) and the handling time was lowest (0.9511 h).     

Use of spinosad and predatory mites for the management of Frankliniella occidentalis in low tunnel‐grown strawberry

Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) is a major pest of strawberry. The efficacy of three species of predatory mites, Typhlodromips montdorensis (Schicha), Neoseiulus cucumeris (Oudemans) (both: Acari: Phytoseiidae), and Hypoaspis miles (Berlese) (Acari: Laelapidae), and their compatibility with spinosad for the control of this thrips was evaluated in commercial strawberry in spring. Low tunnel‐grown strawberry was treated with ‘water then mites’, ‘spinosad then mites’, or ‘mites then spinosad’. Predatory mites were released as single‐, two‐ and three‐species combinations. Overall, spinosad‐treated plants had fewer thrips than water‐treated plants (control). In all treatment regimes, each species of predatory mite reduced the number of thrips relative to those plants that received no mites. Predatory mites were most effective in reducing thrips when released after spinosad was applied. Any multiple‐species combination of predatory mites reduced thrips numbers more than single‐species releases. The two‐species combination of T. montdorensis (foliage inhabiting) and H. miles (soil dwelling) was the most effective in suppressing thrips. The next most effective combination was a three‐species release. Of multiple‐species combinations, the two‐species combination of T. montdorensis and N. cucumeris was the least effective in suppressing thrips numbers. The spinosad and mites only temporarily reduced the numbers of F. occidentalis. This suggests that further application of predatory mites, spinosad, or both is required to maintain F. occidentalis populations below an economically damaging level.     

Mite pests and their predators on seven vegetable crops (Arachnida: Acari)

During this study the frequency of occurrence and dominance of phytophagous and predatory mites harboring seven vegetable crops in Egypt, namely common bean, cowpea, eggplant, okra, squash, sweet pepper and sweet potato during 2017–2018 were investigated to identify predatory mites that might be useful for the biological control of the phytophagous mites. Three phytophagous and nine predatory mite species were surveyed. The two spotted spider mite Tetranychus urticae Koch of the family Tetranychidae was the dominant pest on these vegetables, while phytoseiids Phytoseiulus persimilis (Athias- Henriot), Typhlodromips swirskii (Athias- Henriot) and Euseius scutalis Chant were the dominant predators. The population of the native or indigenous phytoseiid mite fauna in Egypt such as Phytoseiulus persimilis could be considered as a good biocontrol agent and a part of the Integrated Pest Management (IPM) program in the future. Mite fauna of Egypt especially local populations of Phytoseiulus persimilis can be considered for implementation in future Integrated Pest Management (IPM).     

Effect of spinosad and predatory mites on control of Frankliniella occidentalis in three strawberry cultivars

Western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), is a major pest of strawberry, Fragaria × ananassa Duchesne (Rosaceae). Spinosad is highly efficacious against F. occidentalis, and spinosad is believed to be compatible in an integrated pest management program. This study determined whether F. occidentalis could be controlled with predatory mites [Typhlodromips montdorensis (Schicha), Neoseiulus cucumeris (Oudemans) (both Acari: Phytoseiidae), and Hypoaspis miles (Berlese) (Acari: Laelapidae)] and spinosad in strawberry. In the glasshouse, three strawberry cultivars (Camarosa, Camino Real, and Albion) were sprayed once with spinosad at the recommended rate (80 ml 100 l^?1 rate, 0.096 g a.i. l^?1) or with water (control). Thrips adults were released onto plants 24 h after spraying and predatory mites released 6 days later. Spinosad significantly reduced thrips numbers compared with water. All three mite species reduced F. occidentalis numbers, and spinosad had no effect on predatory mites. Though H. miles could not be counted, the numbers of thrips in treatments with H. miles were lower than those in treatments without the mite. Thrips numbers were lowest on Camino Real and highest on Camarosa. These results suggest that the use of Camino Real with spinosad applications followed by releases of predatory mites can significantly reduce thrips numbers.     

Alternating temperatures affect life table parameters of Phytoseiulus persimilis, Neoseiulus californicus (Acari: Phytoseiidae) and their prey Tetranychus urticae (Acari: Tetranychidae)

Increasing energy costs force glasshouse growers to switch to energy saving strategies. In the temperature integration approach, considerable daily temperature variations are allowed, which not only have an important influence on plant growth but also on the development rate of arthropods in the crop. Therefore, we examined the influence of two constant temperature regimes (15 °C/15 °C and 20 °C/20 °C) and one alternating temperature regime (20 °C/5 °C, with an average of 15 °C) on life table parameters of Phytoseiulus persimilis and Neoseiulus californicus and their target pest, the two-spotted spider mite Tetranychus urticae at a 16:8 (L:D) h photoperiod and 65 ± 5 % RH. For females of both predatory mites the alternating temperature regime resulted in a 25–30 % shorter developmental time as compared to the corresponding mean constant temperature regime of 15 °C/15 °C. The immature development of female spider mites was prolonged for 7 days at 15 °C/15 °C as compared to 20 °C/5 °C. With a daytime temperature of 20 °C, no differences in lifetime fecundity were observed between a nighttime temperature of 20 and 5 °C for P. persimilis and T. urticae. The two latter species did show a higher lifetime fecundity at 20 °C/5 °C than at 15 °C/15 °C, and their daily fecundity at the alternating regime was about 30 % higher than at the corresponding mean constant temperature. P. persimilis and T. urticae showed no differences in sex ratio between the three temperature regimes, whereas the proportion of N. californicus females at 15 °C/15 °C (54.2 %) was significantly lower than that at 20 °C/5 °C (69.4 %) and 20 °C/20 °C (67.2 %). Intrinsic rates of increase were higher at the alternating temperature than at the corresponding mean constant temperature for both pest and predators. Our results indicate that thermal responses of the studied phytoseiid predators to alternating temperature regimes used in energy saving strategies in glasshouse crops may have consequences for their efficacy in biological control programs.     

Effect of pollen supplement on intraguild predatory interactions between two omnivores: The importance of spatial dynamics

Arthropods often engage in complex trophic interactions such as intraguild predation (IGP), true omnivory (i.e., feeding on plants and prey), and apparent competition. Theoretical treatments of the effects of such interactions on herbivore populations have been concerned almost entirely with equilibrium conditions. Yet these interactions are common in non-equilibrium settings such as agroecosystems, where they are likely to have a strong influence on pest populations. We therefore tested short-term effects of IGP and food supplementation on interactions between two predators (the phytoseiid mite Neoseiulus cucumeris and the anthocorid bug Orius laevigatus) and their shared prey, Frankliniella occidentalis, on strawberry plants. All three consumers feed on strawberry pollen, both mites and bugs prey on thrips, and the bug also feeds on the mites (IGP). Strong IGP on mites (IG prey) by the bugs (IG predator) was recorded in structurally-simple arenas. In a more complex setting (whole-plants), however, the intensity of IGP differed among plant structures. Likewise, pollen supplementation reduced both IGP and predation on thrips in a structurally simple setting. In the whole-plant experiment, IGP was more intense on pollen-bearing than pollen-free flowers. The study illustrated how spatial dynamics, generated when consumers track food sources differently in the habitat and possibly when herbivorous and IG prey alter their distribution to escape predation, led to site-specific configuration of interacting populations. The intensity of resulting trophic interactions was weakened by food supplementation and by increased complexity of the habitat.     

Susceptibility to deltamethrin in the predatory mites Neoseiulus californicus and Phytoseiulus macropilis (Acari: Phytoseiidae) populations in protected ornamental crops in Brazil

Knowledge of inter and intra-specific variation in the susceptibility of natural enemies to pesticides could help to better design integrated pest management strategies. The objective of this research was to evaluate the susceptibility to deltamethrin in populations of the predatory mites Neoseiulus californicus (McGregor) and Phytoseiulus macropilis (Banks) populations collected from protected ornamental crops in Brazil. The susceptibility to deltamethrin was characterized against immature and adult stages of both species. The impact of this insecticide was also measured by estimating the intrinsic rate of increase (r _i). The immature and adult stages of N. californicus were approximately 3,600 and 3,000-fold more tolerant to deltamethrin than those of P. macropilis. However, high variability in the susceptibility to this insecticide was detected among P. macropilis populations, with resistance ratios of up to 3,500-fold. The selection of deltamethrin-resistant strains of P. macropilis could be exploited in applied biological control programs.     

Functional responses of Iphiseius degenerans and Neoseiulus teke (Acari: Phytoseiidae) to changes in the density of the cassava green mite, Mononychellus tanajoa (Acari: Tetranychidae)

The functional responses of protonymph and adult female Iphiseius degenerans and Neoseiulus teke to increasing density of three stages of their prey, the cassava green mite (CGM), Mononychellus tanajoa, were studied on excised cassava leaf discs under laboratory conditions. The responses obtained were predominantly sigmoid type III curves with the highest plateau when both stages of I. degenerans and N. teke were preying on CGM eggs. In all cases, the predation rate of the former species exceeded that of the latter. The empirical data were fitted by four different models. From the models, the attack coefficient (a) and handling time (T _h) were estimated. For a given predator stage (protonymph or adult female), the predator's attack coefficient declines and handling time increases as the prey gets larger. For a given prey stage, the predator's attack coefficient increases and handling time decreases as the predator stage becomes larger.     

A novel method for protecting slow-release sachets of predatory mites against environmental stresses and increasing predator release to crops

Slow-release sachets of predatory mites are widely employed for controlling small pest arthropods in protected crops. However, environmental stresses can adversely affect the performance of such sachets. To solve this problem, we developed plant-attached shelters that hold sachets of Neoseiulus californicus (McGregor) or Amblyseius swirskii (Athias-Henriot). We conducted laboratory experiments to reveal whether sheltered sachets can protect predators against pesticides and drenching. The numbers of each predator in unsheltered sachets were drastically decreased after spraying with a non-selective pesticide (methidathion), and after continuous spraying (four days) with water, whereas the numbers in the sheltered sachets were not seriously affected by these factors. We also found that more predators (at least for N. californicus) were released from sheltered sachets at different temperatures (25 and 17 °C) than from unsheltered sachets. These results indicate sheltered sachets to be potentially useful for protecting predatory mites against environmental stresses and enhancing their release to crops.     

Evaluation of the predatory mite Amblyseius hainanensis (Acari: Phytoseiidae) and artificial rainfall for the management of Brevipalpus obovatus (Acari: Tenuipalpidae)

Brevipalpus obovatus Donnadieu is an important pest mite on tea plants in South China. In the current study, predatory mites of B. obovatus in the tea gardens of Guangzhou were extensively surveyed. In total, 13 species of predatory mites (four families with seven genera) were recorded. The population proportion of Amblyseius hainanensis Wu et Qian was the highest (68.6?%), followed by that of Anystis baccarum (L.) (8.4?%) and A. theae Wu (6.3?%). The effects of starvation time, habitat size and pest population density on the predatory efficiency of the most dominant species, A. hainanensis, feeding on B. obovatus were assessed. In addition, the effectiveness of artificial rainfall in reducing B. obovatus populations was evaluated. After starvation for 48?h, the predatory efficiency of A. hainanensis was significantly higher than those that had been starved for 24 or 72?h when 30-50 B. obovatus eggs were made available. The predation of A. hainanensis on B. obovatus also increased with increasing prey density. The number of prey attacked by A. hainanensis in a 3.2?cm(2) habitat was significantly higher than in a 6.3?cm(2) habitat. The average predation of A. hainanensis was 31.7 eggs per day when offered 100 B. obovatus eggs on a tea leaf. This decreased to 17.8 eggs per day when four A. hainanensis shared 100 B. obovatus eggs. B. obovatus populations can be reduced by artificial rainfall, with the reduction affected by rainfall intensity. With an intensity of 40?mm in 15?min, 90.2?% mortality of B. obovatus occurred; lower mortalities were recorded (13.3 and 29.8?%) when the intensity was 2 or 4?mm in 15?min. Combination of the predatory mite A. hainanensis and artificial rainfall for the integrated pest management of B. obovatus is discussed.     

Biological control of aphids in the presence of thrips and their enemies

Generalist predators are often used in biological control programs, although they can be detrimental for pest control through interference with other natural enemies. Here, we assess the effects of generalist natural enemies on the control of two major pest species in sweet pepper: the green peach aphid Myzus persicae (Sulzer) and the western flower thrips Frankliniella occidentalis (Pergande). In greenhouses, two commonly used specialist natural enemies of aphids, the parasitoid Aphidius colemani Viereck and the predatory midge Aphidoletes aphidimyza (Rondani), were released together with either Neoseiulus cucumeris Oudemans, a predator of thrips and a hyperpredator of A. aphidimyza, or Orius majusculus (Reuter), a predator of thrips and aphids and intraguild predator of both specialist natural enemies. The combined use of O. majusculus, predatory midges and parasitoids clearly enhanced the suppression of aphids and consequently decreased the number of honeydew-contaminated fruits. Although intraguild predation by O. majusculus on predatory midges and parasitoids will have affected control of aphids negatively, this was apparently offset by the consumption of aphids by O. majusculus. In contrast, the hyperpredator N. cucumeris does not prey upon aphids, but seemed to release aphids from control by consuming eggs of the midge. Both N. cucumeris and O. majusculus did not affect rates of aphid parasitism by A. colemani. Thrips were also controlled effectively by O. majusculus. A laboratory experiment showed that adult predatory bugs feed on thrips as well as aphids and have no clear preference. Thus, the presence of thrips probably promoted the establishment of the predatory bugs and thereby the control of aphids. Our study shows that intraguild predation, which is potentially negative for biological control, may be more than compensated by positive effects of generalist predators, such as the control of multiple pests, and the establishment of natural enemies prior to pest invasions. Future work on biological control should focus on the impact of species interactions in communities of herbivorous arthropods and their enemies.