The predation consequence of continuous breeding vs starting a new colony of a polyphagous insect predator

The predation rates of a recently collected population of the mirid Macrolophus pygmaeus versus one continuously bred in the laboratory, reared under the same conditions for three generations, were compared in 24-h choice experiments using first to fourth instar nymphs of the aphid Myzus persicae on aubergine and sweet pepper. On aubergine, the mean wet weights for first, second, third and fourth instar nymphs of M. persicae were 46%, 36%, 8% and 14% greater, respectively, compared with aphids on pepper. Adult females from a recently collected field population of M. pygmaeus (MpK) consumed more second and third instars compared with first and fourth instars on aubergine and pepper (79% and 88% of biomass consumed, respectively). M. pygmaeus females (MpV) from a population maintained in the laboratory for more than 15 years consumed more first and second instar nymphs on aubergine. On pepper, consumption by MpV females was relatively constant between instars and unlike other combinations, where third instars contributed the greatest amount of biomass consumed (43–60%), fourth instars contributed the most biomass consumed (51%). The total aphid biomass consumed by the MpK population was twofold greater on pepper and 4.7-fold greater on aubergine when compared with the MpV population. The MpK population consumed more aphid biomass on aubergine compared with pepper while the reverse was the case for the MpV population. Such intraspecific differences may have a significant influence on their efficacy as predators in biological control systems.     

Associations betweenFrankliniella spp. andOrius niger populations in cotton

The distribution of theFrankliniella speciesF. occidentalis (Pergande) andF. intonsa (Trybom) (Thysanoptera: Thripidae), and of the predatory bugOrius niger (Wolff) (Hemiptera: Anthocoridae), in various organs of the cotton plant, as well as prey — predator interactions between thrips andO. niger, were investigated over 6 years in cotton fields in the eastern Mediterranean region of Turkey. The highest number of larvae ofFrankliniella spp. were found inhabiting bolls, whereas the adults colonized mainly flowers. The majority of predatory bug nymphs were present on leaves, followed by bolls, whereasO. niger adults visited mostly flowers. The thrips larvae were most likely preyed upon on flowers and squares, and bolls were safe plant parts for thrips, with a low predation rate. An intermediate but relatively high predation rate occurred on cotton leaves. In further field experiments, the effects of insecticide treatment on the relationships betweenO. niger andFrankliniella spp. were investigated. These trials revealed that a higher correlation existed between the numbers of adultO. niger in flowers andFrankliniella spp. in non-treated cotton fields than in insecticide-treated fields. The proportions of prey/predator in flowers ranged from 1.53 to 19.28 and were below four thrips per predator at most sampling dates in some of the non-treated cotton fields. It is concluded thatO. niger is an effective predator that can play an important role in suppressing population increase ofFrankliniella spp. in cotton. http://www.phytoparasitica.org posting May 12, 2006.     

巴氏钝绥螨对芦笋上烟蓟马捕食效能研究

本文研究巴氏钝绥螨Amblyseius barkeri（Hughes）对芦笋上烟蓟马Thrips tabaci Lindeman 1龄若虫的捕食功能反应及干扰作用。结果表明：巴氏钝绥螨雌成螨对烟蓟马1龄若虫的日捕食量随温度的升高和猎物数的增加而增加。在猎物密度为3～24头.皿-1范围内,15、20、25、30、35℃下日均捕食量分别为2.00～3.75、2.67～4.75、2.75～5.25、3.00～11.50、3.00～18.33头。5种温度下的功能反应符合Holling-Ⅱ和Holling-Ⅲ模型。处于产卵期的雌成螨捕食能力最强,产卵期雌成螨、第2若螨、第1若螨、雄成螨和产卵结束后的雌成螨的日捕食量分别为3.00～16.00、1.74～12.92、1.75～6.93、2.60～6.25、2.75～5.00头。巴氏钝绥螨个体间存在干扰反应,平均捕食量和捕食率均随捕食螨数量的增加而减少。在蓟马数按比例随捕食螨数量增加或不变的情况下的干扰反应模型分别为E=0.5316P-1.1177、E=0.1550P-0.3614。     

烟盲蝽对不同密度斜纹夜蛾初龄幼虫的捕食和搜寻行为

为评价动植食性烟盲蝽对害虫的控制作用,本文通过室内试验研究了烟盲蝽在斜纹夜蛾幼不同密度虫斑块上的捕食和搜寻行为。在盆栽烟草植株上设置不同猎物密度,每株分别接0、5、10、20和30头1龄斜纹夜蛾幼虫于同一叶片上,然后接入1头烟盲蝽雌成虫,观察记录烟盲蝽的行为及其发生时间。结果表明,烟盲蝽对猎物的捕食量随猎物密度增大而增加;对猎物被捕食的时间进行Cox比例风险模型拟合表明,低密度猎物斑块上的幼虫被烟盲蝽捕食的风险大于高密度猎物斑块。烟盲蝽在猎物斑块上的行为以搜寻和刺吸猎物、植物为主,用于梳理和休息的时间较少;在低密度猎物斑块上,搜寻和刺吸植物的时间占较大比例;而在高密度猎物斑块上,刺吸猎物的时间占较大比例。烟盲蝽在斑块上的驻留时间随猎物密度增大而延长,在高密度猎物斑块上的驻留时间显著长于在低密度斑块上。研究结果说明,烟盲蝽对斜纹夜蛾初龄幼虫的捕食强度与猎物密度有关,密度越高,捕食得越多,但花费的时间更多,从而导致对高密度猎物的捕食效率低于对低密度猎物的捕食。     

Biology and predation rate of the sarcophagid fly,Agria mamillata a predator of European small ermine moths

Abstract

The biology of the univoltine, predatory sarcophagid fly Agria mamillata (Pandellé) was studied in a population of Yponomeuta evonymellus(L.) (Yponomeutidae) attacking Prunuspadus L. in the Valais, Switzerland. Clarification of the literature records suggests that A. mamillata is oligophagus, attacking five Yponomeuta species in the Palaearctic. The adult flies emerged in May. The presence of host odour was advantageous to elicit mating. After a preoviposition period of 19 days, the ovolarviparous females deposited eggs/first instar larvae on the cuticle of late fifth instar prey larvae, or on cocoons of prey pupae. The potential fecundity averaged 40 eggs per female. Reid data indicated that females of the predator laid more eggs in tents with higher prey density. Larval development lasted 11 days. Rain stimulates mature predator larvae to leave the tents of Y. evonymellus to pupate in the soil. Pupation was observed between early July and mid August. Predation rates ( = number of prey eaten per predator) were estimated from laboratory food consumption tests and from the number of predator larvae and predated cocoons in prey tents in the field. It was shown that a single predator consumed an average of five Y. evonymellus individuals. Field data indicated that predation rates cannot increase with higher numbers of prey available. It was shown that the number of prey eaten per predator decrease with higher predator densities per tent in the field.     

巴氏钝绥螨对椭圆食粉螨的捕食效能

在实验室RH85%、5个常温(16、20、24、28℃和32℃)条件下,研究了巴氏钝绥螨的雌成螨、雄成螨、若螨对椭圆食粉螨的捕食效能。结果表明:各个温度下的功能反应均属于HollingⅡ型。温度相同时,雌成螨的捕食能力最大,若螨其次,雄成螨的捕食能力最弱。温度对各螨态的捕食能力有一定的影响,在试验温度范围内,各螨态对椭圆食粉螨的捕食能力(a/Th值)随温度升高而增大,28℃时捕食能力最大。在椭圆食粉螨密度固定时,巴氏钝绥螨的平均捕食量随着其自身密度的提高而逐渐减少。     

Competition between Solanum nigrum and pepper in the presence of Meloidogyne incognita

The influence of the root-knot nematode Meloidogyne incognita (Kofoid & White) Chitwood on the competitive relationships between pepper (Capsicum annuum L.) and Solanum nigrum L. (black nightshade) was investigated in a glasshouse experiment. Seven competition treatments were set up: two intraspecific for the crop and the weed and five interspecific treatments in which the emergence of S. nigrum plants was progressively delayed with respect to that of the pepper. Nematodes reproduced in every inoculated plant and their multiplication rates were high in both pepper and S. nigrum. The parasite reduced all growth and yield parameters of the crop, but did less harm to the weed. The negative effect of S. nigrum on pepper peaked in the treatment in which the weed and pepper plants emerged together. S. nigrum was a stronger competitor than pepper under both nematode-infested and nematode-free conditions. The effect of nematodes on pepper yield was less than that of competition, but both appeared to be additive.     

Prey consumption by the mealybug predator <Emphasis Type="Italic">Spalgis epius</Emphasis> on pink hibiscus mealybug (<Emphasis Type="Italic">Maconellicoccus hirsutus</Emphasis>)

The pink hibiscus mealybug Maconellicoccus hirsutus (Green) (Hemiptera: Pseudococcidae) is a major pest of economically important crops. The apefly Spalgis epius (Westwood) (Lepidoptera: Lycaenidae) is a potential predator of various species of mealybugs. Studies of its preying potential and preference for prey stages on M. hirsutus are incomplete. An investigation was undertaken to determine the daily prey consumption and preference for prey stages by different larval instars of S. epius reared on M. hirsutus in the laboratory. During the 8-day larval development period with four larval instars of S. epius, the daily prey consumption increased from the first to the seventh day and decreased on the eighth day prior to the prepupal stage. Generally, there was a significant difference in the prey consumption on different days. The 1st to 4th instar larvae of S. epius consumed, respectively, a mean of 181.3, 679.1, 1770.4 and 4333.0 eggs or 19.1, 67.7, 153.0 and 639.0 nymphs or 2.72, 6.26, 13.8 and 32.1 adults of M. hirsutus. When an S. epius larva was fed on M. hirsutus eggs, nymphs and adults separately, it consumed a mean of 6952.6 eggs, 878.8 nymphs or 53.9 adults during its entire development. A single larva of S. epius consumed 2358.3 eggs, 151.2 nymphs and 34.3 adults of M. hirsutus during its entire development when the prey stages were offered all together. The study revealed that S. epius is a voracious predator of M. hirsutus and thus could be utilized as a potential biological control agent.     

绿盲蝽对冬枣不同生长期的为害

为了解绿盲蝽对其重要果树寄主冬枣的为害特点,通过对各生长期叶、蕾、花、幼果等易受害部位接虫试验,研究绿盲蝽对冬枣的为害规律及其对冬枣坐果的影响。结果显示,不同生长期各部位的被害率和刺点数均随着接虫数的增加而增大。嫩叶期最幼嫩的部位顶芽和第1片叶被害率均为100%,第4、5片叶的被害率均为0;相同接虫密度下,花的刺点数显著高于蕾和幼果;花蕾并存时,花的刺点数显著高于蕾,而被害率无显著差异。花期受害后,坐果数显著降低,其中接1、2、3、4、5头绿盲蝽坐果数分别降低了49.49%、59.60%、84.85%、94.95%、94.87%。研究表明,绿盲蝽对冬枣的为害有明显趋嫩和趋花性,花期受害后对产量的影响最大,应加强对花、幼果期绿盲蝽种群的控制。     

Untersuchungen zum Einfluss von Temperatur und Licht auf die Fra?leistung von Macrolophus pygmaeus (Rambur, 1839) (Heteroptera: Miridae) an verschiedenen Wei?e Fliege-Arten

Whiteflies are one of the major pests in greenhouse cultivation. Traditional methods of pest control involve the use of pesticides, which may lead to the emergence of resistive vermin. Therefore and in the context of growing health- and environmental awareness alternative ways of pest control should be considered. One alternative approach is the deployment of natural antagonists to the vermin. An effective use of those organisms within pest control requires studies on their biology, their behaviour and their climatic tolerance. Biology and behaviour of the studied insects are presented in a synopsis of the scientific literature. For this paper laboratory experiments on the predation rate of the beneficial organism M. pygmaeus were conducted on different whitefly species under various conditions of both, temperature and light. The treatment was carried out on eggs and larval stages of the whitefly species T. vaporariorum and B. tabaci with a photoperiod of 9 and 16 h light and under temperatures of 11?C22°C. On infestation by T. vaporariorum a high effectiveness (68,4?C79,7%) of M. pygmaeus is shown under all tested light- and temperature conditions. On infestation of B. tabaci the effectiveness of M. pygmaeus was lower (8,5?C46,1%). For unknown reasons those two species did not reproduce in the rearing. The high predation rate of M. pygmaeus on eggs and larval stages of T. vaporariorum proved that M. pygmaeus can be effectively deployed at low (11?C13°C) and intermediate (18?C22°C) temperatures under both, short day- and long day conditions. Especially at low temperatures and short day conditions M. pygmaeus so far turns out to be a useful supplement or alternative.     

Infraspecific variation ofSolanum nigrum L. andS. villosum Miller,important crop weeds in Israel

Solarium nigrum L. is represented in Israel by subsp.nigrum, andS. villosum Miller by subsp.villosum and subsp.puniceum (Kirschleger) Edmonds. OnlyS. villosum subsp.villosum is apparently native. Major distinctive characters of the species and subspecies are the type of indumentum, shape of calyx lobes, and color of leaves and ripe fruits. The significance ofSolanum spp. as weeds is emphasized.     

Morphological and molecular characterization of Fusarium spp. associated with yellowing disease of black pepper (Piper nigrum L.) in Malaysia

Yellowing disease is one of the most important diseases of black pepper (Piper nigrum L.). To characterize the pathogen(s) responsible for yellowing disease of black pepper in Malaysia, 53 isolates of Fusarium were collected from the roots of diseased black pepper plants and from rhizosphere soils from major growing areas in Sarawak and Johor. A total of 34 isolates of F. solani and 19 isolates of F. proliferatum were obtained and identified based on morphological characteristics and molecular techniques. DNA sequencing of the internal transcribed spacers (ITS1 and ITS2) and 5.8S ribosomal DNA regions was conducted to identify Fusarium species. Nucleotide sequence analysis of the ITS regions revealed that this molecular technique enabled identification of Fusarium at the species level as F. solani and F. proliferatum. In a pathogenicity test on 3-month-old black pepper plants, F. solani was pathogenic, but F. proliferatum was not. On the basis of morphology, DNA sequences and pathogenicity of the fungal isolates from the diseased plants, we showed that yellowing disease on black pepper is caused by F. solani     

Prey stage preference,mutual interference and switching of Amblyseius swirskii (Acari: Phytoseiidae) on Eotetranychus frosti (Acari: Tetranychidae) and Cenopalpus irani (Acari: Tenuipalpidae)

Abstract

Prey stage preference, mutual interference, and switching of Amblyseius swirskii Athias-Henriot on Eotetranychus frosti (McGregor) (Tetranychidae) and Cenopalpus irani Dosse (Tenuipalpidae) were evaluated under laboratory conditions on apple leaves. The results of no-choice experiments on the two prey revealed that the predator A. swirskii consumed significantly more eggs than other prey stages. The predator consumed about 46% and 57% of the initial density of eggs of E. frosti and C. irani, respectively. In choice experiments the mean consumption rate of A. swirskii females significantly differed among each of the pests’ life stages. The negative value of the interference coefficient in the mutual interference analysis showed an inverse relationship between the predator density and per capita searching efficiency. The prey preference by predator was not dependent on the relative abundance of prey, as it did not switch from of E. frosti when it became rare to another prey which was more abundant except for the ratio 20E. frosti:60C. irani. The results of this study revealed that A. swirskii could be utilized as an effective predator in the integrated management of E. frosti and C. irani; particularly, its heavy preference for E. frosti could play a considerable role in control of it.     

Life table and some feeding features of Nephus kreissli fed on Planococcus ficus

In this study certain biological and prey consumption features of the predator of mealybug, namely Nephus kreissli Fürsch & Uygun (Coleoptera: Coccinellidae), fed on vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), were determined under the laboratory conditions. Experiments were performed in the acclimatized room under 28?±?1°C, 60?±?10% r.h. and a photoperiod of 16:8 h(L:D) conditions. To determine the biological features of the coccinellid, predator individuals were continuously observed from egg stage to end of adult stage. The development, survival and fecundity of N. kreissli were determined and all the measured data were recorded daily. The total development time from egg to the eclosion of adult stage was determined as 31.6?±?0.4 days. The lifespan of males and females was 66.0?±?3.8 and 65.8?±?3.5 days, respectively; and a single female laid 122.6 eggs. The raw data related to life history were analyzed by using the age-stage, two-sex life table. The intrinsic rate of increase, the net reproductive rate, and the mean generation time were 0.0709?±?0.0036 d^?1, 53.1?±?9.5 offspring and 55.8?±?1.3 days, respectively. The first and second instars of N. kreissli preferred egg stages of P. ficus to other stages of mealybug. On the other hand, third and fourth instars and adult predators preferred the second and third instar nymphs and adult females of the prey. It was determined that the egg consumption of N. kreissli increased with the development of larval stages, and that the highest consumption was recorded in its fourth instar.     

Aphid aqueous-extract as a source of host searching kairomones for the aphidophagous predatorCoccinella septempunctata L. (Col., Coccinellidae)

AdultCoccinella septempunctata, a coccinellid predator of the bean aphidAphis fabae Scop., responded to aqueous extract containing kairomones of the prey. The crude aphidextract was topically dropped onto either clean leaves ofVicia faba or clean Petri-dishes. After application of aqueous-extract at different aphid densities, the predator showed variations in the attractivity and searching behaviour in comparisons with control. The variations are summarized as follows: (1) the aqueous-extract of aphids attract or directC. septempunctata adults to the treated vials at all aphid densities. The number of attracted or directed coccinellid adults was directly proportional with aphid concentrations; (2) the predatorC. septempunctata adult intensified its searching behaviour by increasing the total path length walked; (3) the number of turns exhibited is significantly higher as compared with those of control; and (4) the arrested time spent by coccinellid adults with treated plant is much more than that with clean plant at all aphid densities. The present results show that the aphid aqueous-extract contains the active ingredients (kairomone) which induce considerable changes in the searching pattern of the predator coccinellid adults.     

Aphid aqueous-extract as a source of host searching kairomones for the aphidophagous predatorCoccinella septempunctata L. (Col., Coccinellidae)

AdultCoccinella septempunctata, a coccinellid predator of the bean aphidAphis fabae Scop., responded to aqueous extract containing kairomones of the prey. The crude aphidextract was topically dropped onto either clean leaves ofVicia faba or clean Petri-dishes. After application of aqueous-extract at different aphid densities, the predator showed variations in the attractivity and searching behaviour in comparisons with control. The variations are summarized as follows: (1) the aqueous-extract of aphids attract or directC. septempunctata adults to the treated vials at all aphid densities. The number of attracted or directed coccinellid adults was directly proportional with aphid concentrations; (2) the predatorC. septempunctata adult intensified its searching behaviour by increasing the total path length walked; (3) the number of turns exhibited is significantly higher as compared with those of control; and (4) the arrested time spent by coccinellid adults with treated plant is much more than that with clean plant at all aphid densities. The present results show that the aphid aqueous-extract contains the active ingredients (kairomone) which induce considerable changes in the searching pattern of the predator coccinellid adults.     

Effects of host plant morphological features on the functional response of Adalia bipunctata (Coleoptera: Coccinellidae) to Myzus persicae (Hemiptera: Aphididae)

The effect of three selected plants on the functional response of Adalia bipunctata to different densities of Myzus persicae was examined in Petri-dish arenas. Logistic regression indicated a type II functional response on all plants. The maximum number of prey killed per day by females was 65.4 at a density of 130 preys on sweet pepper. On the other hand, handling time was significantly longer on tomato than on eggplant or sweet pepper (0.35 h vs. 0.24 h and 0.21 h, respectively). This laboratory study suggests that plant characteristics influence the ability of A. bipunctata to respond to changes in prey density.     

Functional response of the coccinellid predator <Emphasis Type="Italic">Adalia fasciatopunctata revelierei</Emphasis> to walnut aphid (<Emphasis Type="Italic">Callaphis juglandis</Emphasis>)

The functional response types and parameters of 3rd and 4th instar larvae, and adult females and males of a coccinellid predator, Adalia fasciatopunctata revelierei (Mulsant) (Col.: Coccinellidae), were evaluated at five different densities of Callaphis juglandis (Goeze) (Hemiptera: Aphididae) in order to understand their role for the aphid’s biological control. Experiments were carried out in petri dishes at 25 ± 1°C, 60 ± 10% r.h. and 16L:8D photoperiod in a controlled temperature room. All tested stages exhibited a Type II response determined by a logistic regression model. The attack rate (α) and handling time (T _h ) coefficients of a Type II response were estimated by fitting a “random-predator” equation to the data. Although the estimates of α for all stages of A. fasciatopunctata revelierei tested were similar, the longest T _h was obtained for 3rd instar larva because of the lower consumption rate at densities above 40 prey/day. Results indicated that the adult female has the highest predation of C. juglandis followed by 4th instar larvae, adult males and 3rd instar larvae. However, further field-based studies are needed to draw firm conclusions.     

Experimental studies on Tuta absoluta (Meyrick) in protected tomato crops in France: biological control and integrated crop protection

Tuta absoluta is a pest from South America which has been detected in many European and Mediterranean countries since 2006. It was identified in Corsica and the South of France in late 2008, and by 2010 this Lepidopteran species had spread to further tomato‐production areas. The pest is present mainly on tomatoes in protected and field crops, and damage on leaves and fruit can be so severe that it can lead to total destruction of the plant. Since 2010, studies have been carried out in experimental insect‐proof glasshouses with artificial infestations of the pest. The objective was to gain better knowledge of this emergent pest and to develop adapted control strategies under the conditions of the South‐East of France. Integrated pest management is widely used on tomato crops in France, and the predator Macrolophus pygmaeus and the parasitoid Trichogramma achaeae were studied, alone and in combination. The possible effect of the concurrent prey Trialeurodes vaporariorum on the impact of the predator on T. absoluta was also studied. The best results were obtained when the two beneficials were released in combination, even in the presence of whiteflies T. vaporariorum.     

Influence de la densité et de la période de concurrence de Solanum nigrum L. sur la tomate de semis direct, en relation avec le désherbage

Effects of density and period of competition by Solanum nigrum L. on direct seeded tomatoes in relation to weed control The effects of density and period of competition from Solanum nigrum L. were measured in direct seeded tomatoes given weed control treatments currently used in south-east France. S. nigrum emerging after a diquat treatment at the 2–3 leaf stage of the crop and thinned to low densities (<12.8 plants ha^?1) at the 5–6 leaf stage of the crop caused significant yield loss if left to compete with the crop until harvest. Yield reduction was smaller if the same weed densities were present only until the onset of flowering. The regression curves of yield on weed density differed as annual climatic variations affected sowing date and plant growth; a comparison between years was made using the relation ‘crop yield × weed biomass/crop biomass’. Significant interactions between weed density and period of competition were found with yield of both green and red fruit. For late sown crops with low densities of S. nigrum two weed control treatments at the 5–6 leaf stage and at the onset of flowering were sufficient to prevent yield loss.