Compatibility of Orius laevigatus Fieber (Hemiptera: Anthocoridae) with Neoseiulus Amblyseius cucumeris Oudemans (Acari: Phytoseiidae) and Iphiseius Amblyseius) degenerans Berlese (Acari: Phytoseiidae) in the biocontrol of Frankliniella occidentalis Pergande (Thysanoptera: Thripidae)

The compatibility of Orius laevigatus Fieber with Neoseiulus (Amblyseius) cucumeris Oudemans as predators of Frankliniella occidentalis Pergande was assessed in 24 h tests on French bean leaf discs. At varying densities of N. cucumeris and F. occidentalis in the presence of a single female O. laevigatus, it was found that O. laevigatus fed on both other organisms to a similar extent, thus raising questions as to the suitability of this combination of predators in the biocontrol of F. occidentalis. In similar trials assessing the compatibility of O. laevigatus with Iphiseius (Amblyseius) degenerans Berlese, O. laevigatus preyed on F. occidentalis to a greater extent than on I. degenerans. It is hypothesized that O. laevigatus and I. degenerans could be used simultaneously in the biocontrol of F. occidentalis with minimal interference between them.     

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.     

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.     

Effects of founder population size on the performance of Orius laevigatus (Hemiptera: Anthocoridae) colonies

Orius laevigatus (Hemiptera: Anthocoridae) is a key predator of thrips and is mass reared in large numbers for use in biological control. The aim of this study was to evaluate the effect of founder population size on the biological and behavioral performance of O. laevigatus over time. Laboratory lines were started from 1, 10 and 50 founder couples from 750 adults collected in the field and their performance was evaluated at the 5th–6th and 10th–11th generations. Adaptation to the captive rearing situation occurred in the 10 and 50 founder couples lines while it failed in the 1 founder couple line. The intrinsic rate of natural increase (r_m) increased and the period for doubling the population (D) decreased over the generations in the 10 and 50 founder couples lines, while (r_m) decreased and (D) increase in the 1 founder couple line. Also, consumption of Frankliniella occidentalis prey was significantly lower for females from the 1 founder couple line at the 5th generation compared to females from the 10 and 50 founder couples lines. Females of laboratory lines of all founder couples did not respond to odours from thrips infested plants during the 5th and 10th generations, whereas wild females strongly reacted to these odours. We suggest that the lack of reaction to infested plant volatiles may be due to the artificial rearing method where mass reared predators do not experience an infested crop. The results showed that the 1 founder couple line differed from the 10 and 50 founder couples lines, suggesting that bottlenecking had an effect at that level. However, no difference was found between the 10 and 50 founder couples lines which suggest that these founder numbers can be used to start laboratory-reared O. laevigatus lines without a significant loss in quality of its relevant biological characteristics.     

Developmental and reproductive fitness of Orius laevigatus (Hemiptera: Anthocoridae) reared on factitious and artificial diets

The developmental and reproductive fitness of the polyphagous predator Orius laevigatus (Fieber) (Hemiptera: Anthocoridae) was compared on two factitious foods and four artificial diets. Adults fed factitious foods (Ephestia kuehniella Zeller eggs and Artemia franciscana Kellogg cysts) performed better than those fed artificial diets. Among the artificial diets, a diet composed of liver and ground beef scored better than meridic diets based on egg yolk. Within the egg yolk-based artificial diets, the developmental fitness varied proportionally with the amount of egg yolk present in the diet. A food switching experiment, in which nymphs and adults of the predator were fed either E. kuehniella eggs or an egg yolk-based artificial diet, showed that the impact of adult food on reproductive capacity was greater than that of nymphal food. An optimal adult food was able to wholly compensate for deficiencies incurred by an inferior artificial diet in the nymphal stage. A strong correlation was found between oocyte counts, lifetime oviposition, and the number of eggs laid after 8 d. A rapid dissection assay may thus be effective to reliably and economically assess the fitness of O. laevigatus as a function of the diet. This method also may prove useful as part of quality assurance procedure for commercially produced predators.     

Taxonomy and biological control: Neoseiulus cucumeris (Acari: Phytoseiidae), a case study

The predatory mite Neoseiulus cucumeris (Oudemans) (Acari: Phytoseiidae) is an important biological control agent of thrips and other small pests worldwide. Yet, despite its economic importance, this species is poorly defined taxonomically and cannot be reliably separated from other species on the basis of morphology alone. Neoseiulus cucumeris has been reported from Australia, although considerable confusion exists as to whether the Australian material is actually N. cucumeris or a presumed endemic species, Neoseiulus bellinus (Womersley). A morphological investigation of N. bellinus and several geographical 'strains' of N. cucumeris demonstrated that: (i) N. bellinus is a distinct species, the males of which can be morphologically separated from those of N. cucumeris , using setal and cheliceral lengths and number of teeth on the fixed digit; and (ii) N. cucumeris , or a morphologically identical species, is present in Australia. Despite behavioural differences, there are no significant morphological differences between the 'strains' of N. cucumeris . Biosystematic research is a more reliable method of species separation, and such a method is suggested for future work with phytoseiid mites.     

Comparison of attraction to LED wavelengths between two strains of Orius laevigatus (Fieber) (Hemiptera: Anthocoridae)

Inter-strain variation in attraction to specific LED wavelengths has been studied previously. Here, we report on differences in attraction of two commercialized strains (Biobest and Koppert) of Orius laevigatus to 10 or 11 different LED wavelengths. We found a significant difference in attraction patterns among the tested wavelengths between the two insect strains; for the Biobest strain, attraction was the highest in 365 and 385 nm wavelengths, while for the Koppert strain, it was the highest in 365, 385, 395, and 405 nm wavelength. As both strains showed highest attraction rate at a wavelength of 385 nm, lights with this output could be used in field pest management strategies.     

Nutritional value of brine shrimp cysts as a factitious food for Orius laevigatus (Heteroptera: Anthocoridae)

Decapsulated cysts of the brine shrimp Artemia franciscana were assessed as a factitious food for rearing the anthocorid predator Orius laevigatus. Developmental and reproductive traits of O. laevigatus reared for a single generation on A. franciscana from three geographical locations or on gamma-irradiated eggs of the Mediterranean flour moth Ephestia kuehniella were compared. There was no effect of diet on nymphal survival but nymphal period on E. kuehniella eggs (12.2 days) was 0.7-1.6 days shorter than on the Artemia diets. The predator developed 0.5-1 day faster on cysts from San Francisco Bay (USA) than on cysts from Great Salt Lake (USA) or Macau (Brazil). Fecundity on brine shrimp cysts from different locations was similar to that on flour moth eggs (142-187 eggs/female). The biochemical composition of decapsulated cysts from San Francisco Bay was compared with that of E. kuehniella eggs. Depending on the type of analysis, Artemia cysts contained higher or similar amounts of protein as compared with E. kuehniella eggs, but amino acid patterns were generally similar. Flour moth eggs were almost three times richer in fatty acids than brine shrimp cysts, with some marked differences in fatty acid profiles. Because nutrient imbalances in a diet may be expressed only after several generations of rearing, the predator was cultured for three consecutive generations on A. franciscana cysts from San Francisco Bay. In the third generation on brine shrimp cysts, nymphs took 18% longer to develop, and adults were shorted-lived and about 60% less fecund than those maintained on E. kuehniella eggs. Brine shrimp cysts may be used as a supplement in the mass production of O. laevigatus but may not be a suitable food for long-term culturing of the predator.     

Life table and predation of Neoseiulus longispinosus (Acari: Phytoseiidae) on Oligonychus coffeae (Acari: Tetranychidae) infesting tea

Life table and predation of the predatory mite Neoseiulus longispinosus (Evans) on the red spider mite (RSM), Oligonychus coffeae (Nietner), a major pest of tea in India, were studied in the laboratory. Developmental time from egg to adult varied from 4 to 14 days at 30 to 15 °C, respectively; at 35 °C no larva survived. Survival of immature stages was more than 94 % at all temperatures. Threshold temperature for development of immature stages of females and males was 10 and 9.9 °C, respectively, and thermal constant was 84.03 degree-days for females and 80 for males. Sex ratio was female biased and temperature (20–30 °C) had no clear effect on sex determination. Egg hatchability was 73 % at 35 °C and >97 % at lower temperatures. Average number of eggs laid per female/day was higher at 30 °C than at 20 or 25 °C. The highest net reproductive rate (R ₀) was 40.7, at 20 °C. Mean generation time (T) decreased from 28 to 13 days with temperature increasing from 20 to 30 °C. Weekly multiplication (6.5) and intrinsic rate of natural increase (r _m ) (0.268) were highest at 30 °C. Males lived longer than females at every temperature tested. Longevity was highest at 20 °C (50 days for females and 55 for males). Survival and longevity were adversely affected by temperature above 30 °C. Daily consumption of prey increased with the advancement of predator’s life stages; adult females consumed the highest numbers of prey items, preferably larvae and nymphs.     

Toxicity of three acaricides to Tetranychus urticae (Tetranychidae: Acari) and Orius insidiosus (Anthocoridae: Hemiptera)

Management for twospotted spider mite, Tetranychus urticae Koch, populations in peanut, Arachis hypogaea L., relies on acaricides. The outcomes of acaricide applications are most predictable when complete information on their toxicity and specificity is available. Specifically, the degrees to which acaricides impact different stages of T. urticae and natural enemies combined determine the overall efficacy of an acaricide application. The objectives of this study were to determine stage-specific direct and residual efficacies of three acaricides (fenpropathrin, etoxazole, and propargite) against T. urticae, and the direct and residual toxicity of the acaricides to Orius insidiosus (Say) adults. Direct toxicity of acaricides to T. urticae was measured on peanut cuttings. All acaricide treatments caused significant mortality to a mixed stage population of T. urticae, and mortality did not differ among the acaricides 7 d after treatment. When toxicity to eggs was tested, the proportion of eggs that hatched for all acaricide treatments was significantly lower than the control, with etoxazole and propargite causing 100% mortality. Exposure to acaricide residues caused < 30% mortality of T. urticae adults 1 and 2 d after treatment and was not significantly different from the control. Fenpropathrin and propargite caused 100% mortality and etoxazole caused > 50% mortality of O. insidious adults after direct exposure to the acaricides. Residual toxicity of acaricides to O. insidiosus adults varied but remained toxic to O. insidiosus longer than to T. urticae. Fenpropathrin had the longest residual effect on O. insidiosus adults, causing > 95% mortality after 14 d; etoxazole and propargite caused < 30% mortality after 14 d.     

Bionomics of a polyphagous predator:Orius laevigatus (Het.: Anthocoridae)

The main characteristics of the imaginal and preimaginal development and the reproduction ofOrius laevigatus were studied at 15, 20, 25 and 30°C. Temperature greatly influences the developmental and reproductive biology of this species. The lowest developmental threshold is 10,6°C. Reproduction is greatly reduced at 15°C relative to the higher temperatures tested. O. laevigatus is well adapted to relatively high temperature conditions. The best development and reproduction rates are observed between 20 and 30°C with a theoretical optimum at 26°C.

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Résumé Les principales caractéristiques du développement pré-imaginal et imaginal ainsi que la reproduction d'Orius laevigatus sont étudiées à des températures de 15, 20, 25 et 30°C. La température influence considérablement le développement embryonnaire et post-embryoannaire de cette espèce. Le zéro théorique de développement se situe à 10,5°C. Les capacités reproductrices sont fortement perturbées à des températures inférieures à 15°C. Les résultats montrent queO. laevigatus est une espèce adaptée à des conditions thermiques relativement élevées. C'est entre 20 et 30°C, avec un optimum de 26°C, que s'expriment le mieux les capacités de développement et de reproduction de ce prédateur.

     

Functional response of Neoseiulus cucumeris (Oudemans) (Acari: Phytoseiidae) to Bemisia tabaci (Gennadius) on tomato leaves

Bemisia tabaci (Gennadius) is an important invasive pest of vegetables and other horticultural plants worldwide. In this study, the functional response of Neoseiulus cucumeris (Oudemans) to different stages of immature B. tabaci was evaluated under laboratory conditions. Predation experiments were conducted on tomato leaf discs (2.5?cm diameter) over a 24-h period at 26?±?1°C and 65?±?5% relative humidity with a L16:D8 photoperiod. The prey densities ranged from 5 to 90 immature stages (eggs and first- to fourth-instar nymphs) of B. tabaci per leaf disc. The results showed that the egg stage of B. tabaci was the most susceptible prey stage and that the mated female adult mite (3-day-old) was a more effective predator than the male adult mite. The functional response of adult N. cucumeris followed a Type II trend curve as shown in a logistic regression model. Adult N. cucumeris exhibited different predation tendencies towards prey in different stages of immaturity. The daily maximum number of eggs, first-, second- and third-instar nymphs of B. tabaci killed by a single female over a 24-h period (26?±?1°C, 65?±?5% RH and L16:D8 photoperiod) were 8.5, 5.2, 3.0 and 2.1, respectively, whereas the number killed by a single male was 6.0, 4.0, 2.3 and 1.8, respectively. The results of this study could help determine an effective B. tabaci biocontrol measure that employs a natural predator.     

有益真绥螨与巴氏新小绥螨的集团内捕食和同类相残作用

【目的】有益真绥螨Euseius utilis是北方地区广泛分布的一种多食性植绥螨,而巴氏新小绥螨Neoseiulus barkeri目前在我国广泛应用于农业害虫的生物防治中。本研究旨在对巴氏新小绥螨在本地的应用进行风险评估及为与有益真绥螨的联合释放提供依据。【方法】本研究在室内通过一系列实验,比较了实验室饲养的巴氏新小绥螨和采自内蒙古农业大学校园的有益真绥螨的雌成螨对同种或异种未成熟螨的捕食量、存活时间及产卵量的差异,检测了有益真绥螨与巴氏新小绥螨两种植绥螨相互之间的攻击强度以及种内和种间的相互作用。【结果】两种植绥螨都难以刺吸同种或异种植绥螨的卵,而对同种或异种植绥螨幼螨的捕食量最大,其次是对若螨。在无共同食物的情况下,有益真绥螨雌成螨对同种植绥螨幼螨的攻击性比对异种植绥螨幼螨的攻击性强(BreslowDay检验:χ~2=13.84,df=1,P0.001),且有益真绥螨对同种植绥螨幼螨的捕食量(9.10±1.65头)高于对异种植绥螨幼螨的捕食量(5.31±1.43头)(T检验:t=5.487,P0.001),巴氏新小绥螨对异种植绥螨幼螨的捕食量(7.48±0.75头)高于对同种植绥螨幼螨的捕食量(4.75±0.58头)(T检验:t=9.110,P0.05)。【结论】有益真绥螨更倾向于捕食同种幼螨而发生同类相残;巴氏新小绥螨更倾向于捕食异种幼螨而发生集团内捕食。     

Effect of different diets on reproduction,longevity and predation capacity of Orius insidiosus (Say) (Hemiptera: Anthocoridae)

Orius insidiosus is a generalist predator for which diet influences important biological traits like reproduction and predation. We tested the effects of different diets alone or in combination on reproduction, longevity and predation capacity of this predator. The diets tested were: no food (control); pollen; Frankliniella occidentalis (Pergande) nymphs and adults; F. occidentalis nymphs and adults and pollen; Anagasta kuehniella (Zeller) eggs; A. kuehniella eggs and pollen; A. kuehniella eggs; F. occidentalis nymphs and adults and A. kuehniella eggs, F. occidentalis nymphs and adults and pollen. The pre-oviposition period was shortest when the diet consisted of pollen and prey (A. kuehniella and/or F. occidentalis), of the two prey species together or of only A. kuehniella eggs. The highest values for the length of the oviposition period (50.1, 48.0, 46.3 and 46.1 days), daily fecundity (3.8, 3.9, 4.0 and 4.2 eggs/female/day), total fecundity (190.3, 187.7 185.2 and 193.6 eggs/female) and longevity (52.1, 49.9, 48.7 and 48.0 days) were found with diets consisting of only A. kuehniella eggs. Pollen did not improve any of the performance parameters of the predator when offered exclusively or as a complementary food. The results show that selection of a proper diet can strongly improve reproduction, longevity and predation capacity of O. insidiosus. An important finding is that A. kuehniella eggs, which can easily be produced in large quantities, are an excellent factitious prey for mass production of O. insidiosus.     

利用功能反应模型评价球孢白僵菌对东亚小花蝽捕食二斑叶螨的影响

[目的]天敌昆虫和生防菌剂的应用都是害虫生物防治的有效手段,在生产中通过两者联合进行害虫的生物防治具有极强的应用前景和潜在的防控增效作用,然而生防菌对天敌的安全性评价是必不可少的.本研究旨在评估球孢白僵菌Beauveria bassiana与东亚小花蝽Orius sauteri联合应用进行害虫生物防治的可行性.[方法]...     

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.     

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.     

两种植绥螨的同类相残和集团内捕食作用

巴氏新小绥螨(Neoseiulus barkeri)和黄瓜新小绥螨(N.cucumeris)是两种多食性植绥螨,主要捕食叶螨和蓟马等,目前在我国广泛应用于农业生物防治中.本文研究了这两种植绥螨种内的同类相残(cannibalism)和种间的集团内捕食作用(intraguild predation)以及相互之间的攻击强度,以明确两者之间的相互关系,为合理构建天敌组合及评估生物防治的作用提供依据.结果显示:两种植绥螨对同种或异种幼螨的捕食量最大,其次是若螨,而对卵的捕食量极低.两种植绥螨对异种幼螨或若螨的捕食量均极显著高于对同种幼螨或若螨的捕食量.可见,无其他猎物存在情况下,两种植绥螨同时发生时更倾向于发生种间的集团内捕食.而巴氏新小绥螨对异种幼螨或若螨的捕食量均高于黄瓜新小绥螨对异种幼螨或若螨的捕食量,并且巴氏新小绥螨和黄瓜新小绥螨相比,巴氏新小绥螨对异种幼螨的攻击性更强,因此当这两种植绥螨发生集团内捕食时,巴氏新小绥螨是潜在的集团内捕食者,而黄瓜新小绥螨是潜在的集团内猎物.