Location,reproduction and movement of Neoseiulus californicus (Acari: Phytoseiidae) during the autumn,winter and spring in orchards in the south of France

Field samples and experiments conducted in apple orchards in the south of France showed that Neoseiulus californicus (McGregor) searched for prey on the trees and in the ground cover as late as mid-November 1993, and at least as early in the spring as the end of February 1994. Overwintering females fed, expanded and produced viable eggs within 7.9±0.3 (SE) days given the natural light regime, adequate food and temperatures of 17.0±20.6°C. The first generation of N. californicus developed in the field during March and April 1994. N. californicus nymphs, females and males readily moved over bare ground and through a grass ground cover to trap plants located on stakes 1 m above the ground. In the laboratory, the rate of movement of adult females on 0.5 mm copper wire was a linear function of temperature above a threshold of 11.9±0.9°C. At 25°C they travelled 10 m per h. The migration rate of N. californicus to trap plants on stakes placed in an orchard 13 Apr. increased in 2 weeks from 0.07 to 0.57 predators/trap plant/degree-day, while the migration rate to plants placed directly in the ground cover was 1.45 predators/trap plant/degree-day. The largest population of N. californicus in April occurred on Barley, Hordeum murinum L. This plant produces pollen in April and May, and may be useful in biocontrol programs.     

Short-term changes in consumption and oviposition rates of Neoseiulus californicus strains (Acari: Phytoseiidae) after a diet shift

Short-term effects on consumption and oviposition rates of four strainsof Neoseiulus californicus (McGregor) after a diet shiftwere evaluated. The new feeding conditions experienced by the predators weresixfixed densities of eggs or protonymphs of Tetranychusurticae Koch placed on excised strawberry leaflet discs andmaintained under laboratory conditions (25±1°C,75–85% RH, 16L: 8D). The observations were made on the first and thefifthday of the experiment. The phytoseiids came from three long-term mass-rearedstrains fed on T. urticae, Dermatophagoides farinaeHughes,or Quercus spp. pollen, respectively. The fourth strainwascollected directly in a strawberry field. Time since diet transfer can be addedto the factors (i.e. feeding history and prey density) already known to affectthe functional and numerical responses of N. californicus,both when it feeds on prey eggs and protonymphs. If consumption rates wereaveraged over all strains and densities, 9.04 and 11.41 eggs, and 6.97 and 6.48protonymphs were consumed on the first and the fifth day, respectively. If thesame was done for oviposition rates, predators feeding on eggs produced 1.46and2.36 eggs/female/day, whereas predators feeding on protonymphs produced 1.35and2.29 eggs/female/day. Time had the greatest impact on the functional responseofthe strain that had previously fed on tetranychids, while an effect of time onthe numerical response was detectable in all strains.     

Predatory behaviors of Neoseiulus californicus and Galendromus helveolus (Acari: Phytoseiidae) attacking Oligonychus perseae (Acari: Tetranychidae)

Predatory behaviors of Neoseiulus californicus (McGregor) and Galendromus helveolus (Chant) attacking Oligonychus perseae Tuttle, Baker and Abbatiello on avocado leaves were videotaped and analyzed. Behaviors were recorded for “fresh” predators that were used ≤ 48 hr post receipt from a commercial insectary and “cold stored” predators that were maintained at 12°C for ≈ 14 days. Fresh and cold stored G. helveolus were observed to attack O. perseae only after invading webbed nests. Conversely, fresh and cold stored N. californicus employed three different modes of predatory attack: (1) intercepting and attacking migrant O. perseae outside of web nests; (2) attacking prey through nest webbing; or (3) invading and attacking O. perseae inside nests. Predatory efficacy of both N. californicus and G. helveolus was reduced following cold storage, as both species engaged in certain predatory behaviors less frequently in comparison to predators that were not stored at low temperatures. Our observed results for N. californicus and G. helveolus attacking O. perseae are interpreted in relation to the chaetotaxy hypothesis, which proposes that phytoseiid invasion efficiency and propensity of webbed nests is facilitated by dorsal setal lengths. This revised version was published online in July 2006 with corrections to the Cover Date.     

Food scarcity reduces female longevity of <Emphasis Type="Italic">Neoseiulus californicus</Emphasis> (Acari: Phytoseiidae)

A commercial strain of Neoseiulus californicus (Spical^®) has a conspicuously long postoviposition period in comparison with other strains of N. californicus or other phytoseiid mites. In many insects and mites, life span is shorter for multiple-mated females than for single-mated females, and is shorter under poor prey conditions than under ample prey conditions. We previously showed that the postoviposition period of multiple-mated females was 40% shorter than that of single-mated females, but that it was never shorter than 30 days. Here we focused on the effect of prey abundance on the postoviposition period. We examined three groups of multiple-mated females: mites that were fed ample prey (group I), mites that were subjected to repeated cycles of 2 days of fasting followed by 2 days of ample prey (group II), and mites that were subjected to repeated cycles of 4 days of fasting followed by 2 days of ample prey (group III). The postoviposition periods of groups II and III were 90% shorter than that of group I. Also the total adult longevity was significantly shorter in groups II and III than in group I. Total egg production in group III was about half that in groups I and II, although the oviposition periods in groups II and III were significantly longer than that in group I. These results suggest that the prolonged postoviposition period in single-mated females of the Spical strain may only appear under laboratory conditions, without multiple mating or starvation.     

Effects of starvation on reproduction of the predacious mite <Emphasis Type="Italic">Neoseiulus californicus</Emphasis> (Acari: Phytoseiidae)

Effects of starvation on gravid females of Neoseiulus californicus were investigated at 20°C and 85% RH. When females that had been reared with abundant prey were swapped, just after laying their first egg, to conditions without any prey and water, they laid 1.8 eggs and survived for 4.3 days. In the body of well-fed females, an egg with eggshell and/or two oocytes were observed in the ventral and dorsal regions, respectively. The larger oocyte had two roundish nuclei and abundant yolk granules, and was enveloped with a vitelline membrane. These two nuclei were not fused but were just close to each other. The smaller oocyte had a nucleus, but had not yet formed yolk granules and vitelline membrane. Females after 12 h starvation had an egg in the ventral region and an oocyte in the dorsal region of the body. After more than 24 h starvation females maintained an oocyte in the dorsal region of the body, but had no egg in the ventral region. The oocyte was filled with abundant yolk granules and contained two irregular nuclei when females were starved for 24 h, but when starved for more than 36 h it contained one irregular nucleus. These findings suggest that (1) gravid females maintained an oocyte in the dorsal region after laying two eggs during starvation, (2) the oocyte was not absorbed during starvation, (3) the oocyte advanced vitellogenesis and the fusion of two nuclei, and (4) the vitellogenic oocyte was not enveloped with an eggshell and had not started embryogenesis.     

Suseptibility of the Predatory Mite,Neoseiulus californicus (Acari: Phytoseiidae), to Seven Insecticides

Susceptibility of the predatory mite, Neoseiulus californicus (McGregor) (Acari: Phytoseiidae), to the field rates of seven commercial insecticides was evaluated in laboratory bioassays. In direct treatments with lufenuron, novaluron, pyrifluquinazon, and sulfoxaflor, 82–88% of N. californicus adult females survived 168 h after exposure. Females exposed to these four insecticides produced 14–19% fewer eggs compared to females in the control group. Eclosion of eggs deposited by treated females was not affected. The percentage of eggs that hatched and larval survival following direct exposure to these four insecticides were not seriously reduced. A total of 72–82% of immature N. californicus survived on leaf discs with residues of lufenuron, novaluron, pyrifluquinazon, and sulfoxaflor matured to adults. Emamectin benzoate, lepimectin and spirotetramat were highly toxic to both N. californicus adult females and larvae. Based on these results, lufenuron, novaluron, pyrifluquinazon and sulfoxaflor are promising candidates for use in integrated pest management programs where N. californicus is a major natural enemy.     

Temperature‐dependent developmental model of Neoseiulus californicus (McGregor) (Acari,Phytoseiidae)

The developmental time and survival of immature stages of Neoseiulus californicus were studied at nine constant temperatures (12, 16, 24, 24, 28 32, 36, 38 and 40°C), 60–70% RH, and a photoperiod of 16 : 8 (L : D) h. The total mortality of immature N. californicus was lowest at 24°C (4.5%) and highest at 38°C (15.2%). The total developmental time decreased with increasing temperature between 12°C (18.38 days) and 32°C (2.98 days), and increased beyond 32°C. The relationship between the developmental rate and temperature was fitted by five nonlinear developmental rate models (Logan 6, Lactin 1, 2 and Briere 1, 2). The nonlinear shape of temperature development was best described by the Lactin 1 model (r² = 0.98). The developmental variation of each stage was well described by the three‐parameter Weibull distribution model (r² = 0.91–0.93). The temperature‐dependent developmental models of N. californicus developed in this study could be used to determine optimal temperature conditions for its mass rearing, to predict its seasonal population dynamics in fruit tree orchards or greenhouse crops, or to develop a population dynamics model of N. californicus.     

Life tables of the predatory mite Neoseiulus cucumeris (Acari: Phytoseiidae) on two pest mites as prey,Aculops lycopersici and Tetranychus urticae

Abstract

Studies on the life history and life table parameters of Neoseiulus cucumeris Oudemans (Acari: Phytoseiidae) were carried out under laboratory conditions of 25?±?1?°C and 65?±?5% RH; 30?±?1?°C and 60?±?5% RH; 35?±?1?°C and 55?±?5% RH. As prey, immature stages of tetranychid spider mite T. urticae Koch (Acari: Tetranychidae) and the moving stages of the Tomato Russet Mite A. lycopersici (Massee) (Acari: Eriophyideae) were selected. The predatory phytoseiid mite, Neoseiulus cucumeris (Oudemans) was able to develop successfully from egg to adult stage through the entire life history on both preys. The higher of different temperatures and relative humidities shortened the development and increased reproduction and prey consumption and vice versa. The maximum reproduction (3.91, and 3.09 eggs/♀/day) was recorded at 35?°C and 65% RH, while the minimum (2.12, and 1.90 eggs/♀/day) was at 25?±?1?°C and 55?±?5% RH. when N. cucumeris fed on A. lycopersici and T. urticae, respectively. The reproductive rate on eriophyid was significantly higher than previously recorded on tetranychid. Life table parameters indicated that feeding of phytoseiid mite N. cucumeris on tomato russet mite A. lycopersici led to the highest reproduction rate (rm?=?0.268, 0.232 and 0.211 females/female/day), while feeding on T.urticae gave the lowest reproduction rate (rm?=?0.159, 0.143 and 0.131) at 35?°C and 55% RH, 30?°C and 60% RH and 25?°C and 65% RH, respectively. The population of N. cucumeris multiplied (36.81, 28.71 and 20.47) and (24.60, 19.58 and 14.62 times) in a generation time of (20.10, 23.20 and 25.14) and (22.35, 25.36 and 27.79 days) when a predator fed on A. lycopersici and T. urticae at the same temperature above mentioned, respectively. These results suggest that the two mites, particularly A. lycopersici, proved to be suitable prey for N.cucumeris, as a facultative predator.     

Mating, cross-mating and related behaviours of Neoseiulus californicus and Neoseiulus fallacis (Acari: Phytoseiidae)

The pairings of Neoseiulus californicus (McGregor) and Neoseiulus fallacis (Garman) from western North America were monitored for tending by adult males, males in the mating position and oviposition and the activity of female deutonymphs and adults. The N. fallacis × N. californicus (♂ × ♀) tests had fewer males tending the deutonymphs but more in the mating position with new females than the reciprocal test. Afterwards, most of the females appeared gravid and approximately 20% produced an egg. Some eggs did not hatch but others became adult males, which mated with their mothers, but no eggs were produced. F1 males tended and mated with new N. fallacis females which had normal offspring. When held with new N. californicus females, F1 males tended the deutonymphs but were not seen mating and no eggs were laid. The pairings of N. californicus× N. fallacis had more males tending, less in the mating position and the females appeared non-gravid and produced no eggs. When same-species males were added to females held with F1 males for 15–20 days, normal levels and sexes of the progeny were produced. The female and male adults of N. fallacis were more active (ambulatory) than those of N. californicus. In within-species tests, the males had a high activity except while tending and mating, the female deutonymphs were inactive and the just mated females were more active than the ovipositing females. The timing of the tending and mating differed in the cross-pairings. Overall, these and other life-history data show that these two mites are distinct species, but that their males are promiscuous in tending and mating. This revised version was published online in November 2006 with corrections to the Cover Date.     

Neoseiulus Californicus (Acari: Phytoseiidae) as a Potential Control Agent of Tetranychus Urticae (Acari: Tetranychidae): Effect of Pest/Predator Ratio on Pest Abundance on Strawberry

Neoseiulus californicus (McGregor) is a promising agent for successful Tetranychus urticae Koch control through conservation techniques, in strawberry crops in La Plata (Buenos Aires, Argentina). In prey–predator interaction, initial relative densities have an important effect on system dynamics. The economic threshold level (ETL) used for this pest in the present study was 50 active mites per leaflet. In our laboratory experiments, initial T. urticae to N. californicus ratio had a significant effect on the population abundance of T. urticae at a 7-day period. When pest/predator ratio was 5/1 (at initial pest densities from 5 to 15 females/leaflet) the final number of active T. urticae/leaflet was significantly lower than the ETL, while at 20 females/leaflet this number did not differ from the ETL. At 7.5/1 ratio, the final number of active T. urticae/leaflet, at initial pest densities from 5 to 15 females/leaflet, reached the ETL without surpassing it. At 10/1 and 15/1 ratios, pest densities exceeded the ETL only at 15 initial T. urticae/leaflet. Most greenhouse and field observations were consistent with the predictions of a graphical model based on experimental results. This predator was very effective in limiting pest densities at a 7-day period and within the range of pest–predator ratios and absolute densities used in this study. Conservation of N. californicus promoting favorable pest/predator ratios may result in early control of T. urticae.     

Biological control of strawberry tarsonemid mite Phytonemus pallidus and two-spotted spider mite Tetranychus urticae on strawberry in the UK using species of Neoseiulus (Amblyseius) (Acari: Phytoseiidae)

Two species of Neoseiulus, N. californicus and N. cucumeris, showed potential for biocontrol of phytophagous mites on strawberry. N. californicus controlled Tetranychus urticae on potted strawberry plants in a gauze-sided glasshouse at temperatures comparableto early summer in the UK (8–20°C). Both species of phytoseiid reducednumbers of the tarsonemid Phytonemus pallidus on potted strawberry plants under glasshouse conditions (15–23°C). In several experiments reductions in the range of 71–81% in numbers of tarsonemid active stages and eggs, compared to non-release plants, were obtained. The importance of establishing a suitable predator: prey ratio at an earlystage was demonstrated in an experiment where an initial ratio of 1 N. cucumeris: 10 P. pallidus gave a greater degree of controlthan 1:20 or 1:40.     

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

We assessed the reproductive responses of adult female Iphiseius degenerans and Neoseiulus teke to increasing density of three stages of their prey, Mononychellus tanajoa, on cassava leaf discs under laboratory conditions. The oviposition rates increased with number of prey consumed per predator per day with a maximum of approximately two eggs per day for I. degenerans and four eggs per day for N. teke. The oviposition rate of N. teke was higher when consuming eggs than other prey stages. Neoseiulus teke was more efficient than I. degenerans in converting consumed prey into egg production. The data were adequately described by simple mathematical models.     

Factors affecting ambulatory dispersal in the predaceous mite Neoseiulus californicus (Acari: Phytoseiidae)

Experiments conducted in the laboratory showed that different biotic and abiotic factors affected the ambulatory dispersal behaviour of Neoseiulus californicus. The experimental set-up comprised dwarf alfalfa (Medicago polymorpha) infested or unifested by Tetranychus urticae. Temperatures were measured with thermocouples. Trials were performed at three temperatures, three prey densities, three light intensities, two relative humidities (RHs) and two vegetative states of alfalfa plants, turgid and withered. Deutonymphs were the most dispersive followed by young ovipositional females. High temperatures (35°C), high light intensities (40 000 lux) and drought-stressed alfalfa increased the dispersal of N. californicus. The availability of food in the environment and high moisture (80% RH) slowed down dispersion. The main factors which seem to elicit dispersal behaviour are the deprivation of food and high temperatures which result in an increase in the walking speed of the mite. In addition, other factors tested either increase or reduce the ambulatory dispersal of N. californicus. According to our results, individuals could move from ground cover into apple trees before spring. © 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).     

温度对加州新小绥螨以截形叶螨为猎物的发育及繁殖的影响

在15～35℃、RH80%～85%条件下,研究了加州新小绥螨Neoseiulus (Amblyseius) californicus (Mcgregor)以截形叶螨Tetranychus truncatus Ehara为猎物时,不同螨态的发育和实验种群生命表。结果表明,加州新小绥螨在此温度范围内能完成世代发育,世代发育历期随着温度升高而逐渐缩短。该螨能适应35℃的高温条件,雌性的发育历期最短仅为6.14d。平均产卵期和平均寿命均随着温度的上升逐渐缩短。20℃～25℃时,该螨的平均产卵量最大,达53.73粒/雌。净增殖率在20℃时最高(48.2525),且雌雄性比最大。15℃时内禀增长率和周限增长率均最低,分别为0.0638和1.0659,种群倍增时间最长(10.8669d),35℃时内禀增长率和周限增长率均最高,分别为0.1954和1.2158,种群倍增时间最短(3.5477d)。     

Use of polypropylene bags for mass rearing Neoseiulus baraki (Acari: Phytoseiidae), a predatory mite of Aceria guerreronis Keifer (Acari: Eriophyidae)

An efficient, low cost and practicable mass rearing method for the predatory mite, Neoseiulus baraki Athias-Henriot (Acari: Phytoseiidae) was developed using a bag made of two-ply polypropylene (gauge 150, 24 cm × 36 cm) sheets. Introducing 20 N. baraki females into the bag produced a mean number 5218 ± 212.10 offspring in 6 weeks with a 260-fold increase of the initial population.     

How feeding on mixed pollens of cattail and saffron affects Neoseiulus cucumeris (Acari: Phytoseiidae) performance

Predatory phytoseiid mite, Neoseiulus cucumeris (Oudemans) is a commercially available biocontrol agent against various pests of greenhouse crops, and it can feed on different diets, including small arthropods and pollen. This generalist predatory mite was reared on the mixture of two different plant pollens including cattail (35%), and saffron (65%) for 10 generations. The effects of mixed diet on the biological parameters of N. cucumeris were evaluated under laboratory conditions at 25 ± 1 °C, 60 ± 5% RH, and a photoperiod of 16:8 (L: D) h every 5 generations (G1, G5, and G10). In addition, the predation ability of nymphs and adults of N. cucumeris encountering the natural prey, Tetranychus urticae Koch was evaluated after 10 generations. The results showed that the quality of mass-reared N. cucumeris on a mixed diet of cattail and saffron pollens did not decrease up to 10 generations of rearing. The intrinsic rate of increase (r) of the predator in G1, G5, and G10 was 0.180, 0.189, and 0.199 day⁻¹, respectively. In addition, the r value was 0.181 day⁻¹ after switching this predator to T. urticae, and it had a high potential of predation (513 prey/generation). The results of this study revealed that rearing N. cucumeris for 10 generations on a mixed diet of saffron and cattail pollens did not affect the performance of the predator negatively.     

Distortion of the spermathecae of phytoseiid mites (Acari: Phytoseiidae) in slide preparation

The shape and dimensions of the spermathecae are taxonomically important characteristics in phytoseiid mites. In experiments with Neoseiulus californicus (McGregor) and Typhlodromus pyri Scheuten, the shape of the cervix of the spermatheca changed considerably and its diameter was increased by 42–49% when mites were flattened, compared to being mounted with 140m spacers underneath the coverslips. Dimensions of the dorsal shield were also affected by flattening, increasing by 3–5%.     

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.     

Life-history of predatory mites Neoseiulus californicus and Phytoseiulus persimilis (Acari: Phytoseiidae) on four spider mite species as prey, with special reference to Tetranychus evansi (Acari: Tetranychidae)

The commercially available strains of Phytoseiulus persimilis Athias-Henriot, the biological control agent of Tetranychus urticae Koch, perform poorly in the Western Mediterranean, probably because they are not well adapted to local climatic conditions. For that reason, efforts are being focused on the development of a biological control programme using native phytoseiid mites. Four species of red spider mites can be found in vegetable crops in eastern Spain: T. urticae, Tetranychus turkestani Ugarov and Nikolski, Tetranychus ludeni Zacher and the recently introduced Tetranychus evansi Baker and Pritchard. To evaluate their potential role as biological control agents, the present study evaluates the life-history of local populations of Neoseiulus californicus (McGregor) and P. persimilis when fed on T. urticae, T. turkestani, T. evansi, and T. ludeni in the laboratory. Results indicate that N. californicus and P. persimilis are able to feed and complete their development on the four tested red spider mite species. The predators may exhibit a particularly high capacity for population increase when fed on T. urticae, T. turkestani, and T. ludeni, thus may be able to provide effective control of these species in the field. When fed T. evansi, however, predator performance was poor; significant increase in development and preoviposition times, and a reduction in oviposition period and fecundity were recorded. The resultant low capacity for population growth suggests poor ability of the two tested predators to suppress T. evansi populations on commercial crops. It is unlikely therefore that P. persimilis and N. californicus, now being widely used to control T. urticae in greenhouse crops in Central Europe, will be able to halt any spread of T. evansi to greenhouse crops in temperate areas.