Biological Control Of Aphids Research Articles

Controle biológico natural de pulgões (Hemiptera: Aphididae) em lavoura de trigo por parasitóides (Hymenoptera, Aphidiinae), no município de Medianeira, PR, Brasil

Aphids constitute one of the main phytosanitary problems in wheat crops in southern Brazil , and are the target of a biological control program with parasitoids implemented in Brazil since the 1970’s. In spite of the initial success quickly achieved, no recent study exists for the west region of the State of Parana that evaluates the current status of aphid biological control; therefore, this was the object of the present work. Weekly surveys were conducted in a commercial wheat crop in Medianeira, PR. The aphids were identified and, when parasitization was verified, they were analyzed until emergence of the parasitoid. The population of aphids did not reach the mean value of 1 insect/tiller, with predominance of Rhopalosiphum padi (53%), followed by Sitobium avenae and R. maidis (19.5%) and Metopolophium dirhodum (8%), which were verified mostly from the wheat elongation stage. The parasitoids were observed starting at the wheat flowering season (about 3 months after planting), and only two species of braconids, Lysiphlebus testaceipes (97.3%) and Diaeretiella rapae (2.7%), were identified, whose population growth followed the aphids population of, keeping the same trend after the number of aphids in the field was reduced.

The entomopathogenic fungus Verticillium lecanii (Deuteromycetes, Moniliaceae). The proteins hydrophobins and the biological control of aphids (Homoptera, Aphididae): Literature review)

International literature review on the biological control of aphids using the entomopathogenic fungus Verticillium lecanii is given. Attention is directed on the fungal proteins hydrophobins for their role in Biotechnology as well as Biocontrol of Pests of Agricultural and horticultural importance.

The Feeding Behavior of the Bigeyed Bug, Minute Pirate Bug, and Pink Spotted Lady Beetle Relative to Main Strawberry Pests

Laboratory assays were performed to determine the impact of three predators, the bigeyed bug, Geocoris punctipes Say, minute pirate bug, Orius insidiosus (Say), and the pink spotted lady beetle, Coleomegilla maculata fuscilabris (Mulsant), on two herbivores, the cotton aphid, Aphis gossypii Glover, and the twospotted spider mite (TSM), Tetranychus urticae Koch, using strawberry (Fragaria ananassa Duchesne) leaflets as a substrate. Both herbivores are considered important strawberry pests worldwide. Daily and hourly consumption of a single prey species studied were conducted as well as a preference for prey test. All stages of the bigeyed bug, minute pirate bug, and pink spotted lady beetle fed on the cotton aphid and TSM. The pink spotted lady beetle had a higher rate of consumption for both the cotton aphid and TSM, and therefore, may be a more effective predator of both prey species. The bigeyed bug and minute pirate bug (third instar and adult) prefer TSM over cotton aphids based on handling time. In contrast, the pink spotted lady beetle (third instar and adult) prefers aphids over mites. Results from these experiments indicated that the pink spotted lady beetle seems to be a good predator to incorporate into an existing biological control program for cotton aphid and TSM on strawberries. Better understanding of these three predators will lead to their more efficient use for biological control of aphids and TSM.

Quality Assessment of Selected Commercially Available Whitefly and Aphid Biological Control Agents in the United States

Quality Assessment of Selected Commercially Available Whitefly and Aphid Biological Control Agents in the United States

Biological control of cereal aphids in north america and mediating effects of host plant and habitat manipulations.

The predator and parasitoid fauna associated with cereal aphids is described, emphasizing the fauna associated with classical biological control efforts against the greenbug and Russian wheat aphid. We focus on literature from North America and include work from Europe and elsewhere when it is desirable to draw contrasts between approaches that affect cereal aphid biological control. Effects on natural enemies of cereal aphids are described that appear associated with plant traits that are innate, bred, or induced by aphid feeding. Examples of habitat manipulations, within and bordering cereal fields and within the broader landscape in which cereal production resides, affecting predators and parasitoids of cereal aphids are presented. These mediating effects of host plant and habitat manipulations on cereal aphid biological control provide significant and underexplored avenues to optimize cereal aphid management.

The value of the ITS2 region for the identification of species boundaries between Alloxysta hyperparasitoids (Hymenoptera: Charipidae) of aphids

1) Alloxystinae are major secondary parasitoids of aphids, important in both their ecology and pest management. 2) Two radically differing views of alloxystine taxonomy exist in the literature, in one of which the group is very diverse, in the other it consists of a few variable species. 3) We sequenced a variable nuclear gene region (ITS2) for 28 specimens of a morphologically clearly defined group which, in one view belong to a single species and in the other to four species. We find that the four putative species each carry a different unique allele with no intraspecific variation. We show that the probability of the observed distribution of alleles under the assumption of a single interbreeding population is very small and we reject the view that all specimens belong to a single biological species. 4) We discuss the implications of our results for aphid - parasitoid community ecology and the biological control of aphids with parasitoids.

Aspectos biológicos dos estágios imaturos de Pseudodorus clavatus (Fabricius) (Diptera: Syrphidae) alimentados com Schizaphis graminum (Rondani) (Hemiptera: Aphididae) em diferentes temperaturas

Os aspectos biológicos de Pseudodorus clavatus (Fabricius), alimentada com Schizaphis graminum (Rondani), foram avaliados em diferentes temperaturas, visando obter informações para o controle biológico de afídeos. Ovos do predador foram individualizados em discos de folhas de sorgo, mantidos em placas de Petri, às temperaturas de 16, 19, 22, 25, 28 e 31 ºC e 12h de fotofase. Ninfas e adultos de S. graminum foram oferecidos ad libitum. Avaliou-se o número de ínstares, a duração e sobrevivência de cada ínstar, bem como das fases larval e pupal e do período de larva a adulto de P. clavatus. A temperatura base e a constante térmica também foram estimadas. A duração dos três ínstares de P. clavatus variou na razão inversa da temperatura. Houve redução das fases larval (14,9 para 4,9 dias) e pupal (17,2 para 4,2 dias) e do período de larva a adulto (31,7 para 8,8 dias) quando as larvas foram mantidas a 16ºC e 31ºC, respectivamente. As temperaturas bases estimadas foram de 10,8; 11,0 e 10,8ºC para as fases larval, pupal e para o período de larva a adulto, respectivamente. Em todas as temperaturas estudadas a sobrevivência do primeiro ínstar foi superior a 78% e do segundo e terceiro instares foi superior a 94%. As sobrevivências da pupa e do período de larva a adulto foram maiores a 22ºC e menores a 16ºC e 31ºC. O desenvolvimento completo de P. clavatus, alimentada com S. graminum, foi possível em todas as temperaturas testadas, que variaram de 16ºC a 31ºC.

Field evaluation of herbivore-induced plant volatiles as attractants for beneficial insects: methyl salicylate and the green lacewing, Chrysopa nigricornis.

Synthetic methyl salicylate (MeSA), a herbivore-induced plant volatile (HIPV), was demonstrated to be an attractant for the green lacewing, Chrysopa nigricornis, in two field experiments conducted in a Washington hop yard. Significantly greater numbers of C. nigricornis were trapped on MeSA-baited sticky cards (mean: 2.8 +/- 0.4/card/week) than on unbaited cards (0.45 +/- 0.15) during June-September. Cards baited with two other HIPVs, hexenyl acetate and dimethyl nonatriene, did not attract more C. nigricornis than did unbaited traps (0.30 +/- 0.10, 0.44 +/- 0.15, respectively). MeSA-baited Unitraps captured 1.9 +/- 0.5 C. nigricornis/trap/week during July-August compared to 0.20 +/- 0.20/trap/week in methyl eugenol-baited traps and 0.03 +/- 0.03/trap/week in unbaited traps. The potential use of MeSA in enhancing C. nigricornis populations in Washington hop yards as an aid to conservation biological control of aphids and mites is discussed.

Species diversity, abundance, and phenology of aphid natural enemies on spring wheats resistant and susceptible to Russian wheat aphid

The species composition, relativeabundance, and seasonal dynamics of selectednatural enemies of cereal aphids were monitoredin spring wheat fields in Moscow, Idaho in 1997and 1998. Trials also examined the potentialimpact of resistance to Russian wheat aphid(RWA), Diuraphis noxia (Mordvilko)(Homoptera: Aphididae) in wheat, on aphidbiological control agents. Natural enemypopulations were monitored on two springwheats: D. noxia susceptible variety`Centennial' and resistant genotype `IDO488'. Field plots were artificially infested withadult D. noxia, and sampled for cerealaphids and parasitoids weekly. Coccinellidpredators were monitored once in 1997 and twicein 1998. The coccinellids Hippodamiaconvergens Guerin, Coccinellaseptempunctata L., C. transversoguttataBrown and C. trifasciata Mulsant weredetected. No significant differences in adultor immature coccinellid densities were observedbetween the D. noxia resistant andsusceptible genotypes. During both years, themost abundant primary hymenopteran parasitoidswere Diaeretiella rapae (M'Intosh), Aphidius ervi Haliday, A. avenaphis(Fitch), and Lysiphlebus testaceipes(Cresson), Aphelinus varipes (Foerster),Aphidius colemani Viereck, Aphidiuspicipes (Nees), Aphidius sp., Monoctonus washingtonensis Pike & Stary, Praon gallicum Stary, Praon occidentaleBaker, and Praon sp. were also detected. Numbers of both D. noxia and D.rapae were significantly greater on Centennialthan on IDO488 in both years. When all speciesof cereal aphids and parasitoids areconsidered, the total percentage parasitism wasnot significantly different between thegenotypes. There was no interaction betweenD. noxia resistance and the populationdensity of the predators or parasitoidsmonitored. These results suggest that the D. noxia resistant line had no adverse impacton natural enemies under the conditions ofthese field experiments.

The Conflicting Values and Differing Priorities of Biological Control

The Conflicting Values and Differing Priorities of Biological Control

Intraguild Predation among the Hoverfly Episyrphus balteatus de Geer (Diptera: Syrphidae) and Other Aphidophagous Predators

Abstract Aphidophagous predators compete for the same prey species. During their foraging activity they frequently encounter heterospecific aphid predators. These situations can lead to intraguild predation and may disrupt biological control efforts against aphids where more than one predator species is present. We investigated the behavior of larvae of the hoverfly Episyrphus balteatus de Geer and its interaction with three other aphid predators: the ladybird Coccinella septempunctata L., the lacewing Chrysoperla carnea Stephens, and the gall midge Aphidoletes aphidimyza (Rondani). Interspecific interactions between predators were examined in arenas of different sizes and in the presence of extraguild prey. The outcome of interactions between E. balteatus larvae and the other predators depended predominantly on the relative body size of the competitors. Relatively large individuals acted as intraguild predators, while relatively smaller individuals became intraguild prey. Eggs and first- as well as second-instar larvae of E. balteatus were highly susceptible to predation by all other predators, whereas pupae of E. balteatus were preyed upon only by the larvae of C. carnea. Interactions between A. aphidimyza and E. balteatus were asymmetric and always favored the latter. Eggs and first- as well as second-instar larvae of E. balteatus sustained intraguild predation irrespective of the size of the arena or the presence of extraguild prey. However, the frequency of predation on third-instar larvae of E. balteatus was significantly reduced. This study indicated that the same species can be both intraguild predator and intraguild prey. It is suggested that combinations of predators must be carefully chosen for success in biological control of aphids.

Alternaria alternata, a new pathotype pathogenic to aphids

A fungus, identified as Alternaria alternata, was isolated from dying or dead aphids and proved to be pathogenic. It was isolated from different parts of Greece from aphid specimens on cultivated plants, ornamentals and weeds. In the laboratory, disease development started with the germination of spores on the insect integument and the subsequent growth of mycelium. The fungus formed apical and intercalary, globose or lobate appressoria which were firmly attached onto the host exoskeleton and facilitated entrance of the mycelium into the insect body. Under favorable conditions of temperature (15–35 °C) and relative humidity (100%), infected aphids died in 2–4 days. A characteristic brown discoloration accompanied the death of the insects. Both mycelial growth and sporulation were profuse on dead specimens. The pathogen infected all 26 aphid species tested but was unable to infect other insects (Drosophila melanogaster and Ceratitis capitata) or aphid host plants. There were significant differences in mortality rate among aphid species only during the first two days after inoculation. It is suggested that A. alternata may be a good candidate to be exploited for the biological control of aphids.

Predation on immature parasitoids and its impact on aphid suppression.

Many predatory arthropods eat both unparasitized herbivores and herbivores that are parasitized and contain the immature stages of endoparasitoids, a form of intraguild predation. Thus, the biological control of herbivorous arthropods can be either enhanced or disrupted by introducing a predator species to an existing host-parasitoid system. We evaluate the impact of introducing a predator, the convergent ladybird beetle, Hippodamia convergens, on the biological control of the cotton aphid, Aphis gossypii, by the parasitoid Lysiphlebus testaceipes, under field conditions. Predation on immature parasitoids by H. convergens was intense: 98-100% of aphid mummies were consumed by the end of the experiment, and H. convergens substantially reduced immature parasitoid populations. Despite the negative impact of H. convergens on aphid parasitoids, aphid population suppression was greatest in treatments containing both H. convergens and parasitoids. The parasitoid alone or in combination with H. convergens suppressed cotton aphids in a density-dependent manner and increased total plant leaf area and biomass, H. convergens did not substantially alter the percentage of aphids mummified by parasitoids and showed a partial feeding preference for unparasitized aphids over aphid mummies. We conclude that under conditions where a predator shows both a partial preference for unparasitized hosts and high levels of predation on unparasitized hosts, we may expect the predator to improve suppression of herbivores even if it produces high levels of intraguild predation. While intraguild predation is an important ecological interaction in the early-season cotton agroecosystem, it does not disrupt cotton aphid biological control.

Adult Coccinellid Activity and Predation on Aphids in Spring Cereals

Improved understanding of coccinellid activity and predation on aphids in the field could clarify their potential in aphid biological control. Our objective was to determine the influence of abiotic and biotic factors on activity and predation by adults of three coccinellid species (Hippodamia convergens Guerin-Meneville, H. tredecimpunctata tibialis (Say), and Coleomegilla maculata DeGeer) in spring cereal fields. The proportion of time coccinellids spent searching was correlated with air temperature, aphid density, and time of day. The relationship between searching and these variables differed among species. Mean walking speed ranged from 66.4 cm/min for C. maculata to 83.2 cm/min for H. tredecimpunctata and increased with temperature for all species. The frequency of short flights (<2 m) by beetles increased with temperature and decreased with increasing aphid density for all species, but the relationship of short flight frequency to these variables differed among species. The frequency of long flights (>2 m) was similar for all species and influenced by temperature and calendar date. The frequencies with which aphids were encountered and eaten were correlated with aphid density and temperature for H. convergens and H. tredecimpunctata. Despite over 250 h spent observing adult coccinellid behavior in the field, predation data were insufficient to develop a useful predation model.

Dispersal and Dispersion of Aphids (Homoptera: Aphididae) and Selected Natural Enemies in Spatially Subdivided Greenhouse Environments

Matrices of potted plants within greenhouses generate spatially subdivided habitats that may influence the spread of arthropod pests and the abilities of natural enemies to locate them. Thus, the goals of current research were to quantify dispersal of the aphids Myzus persicae (Sulzer) and Aphis gossypii (Glover) in potted chrysanthemum [ Dendranthema grandiflora (Tzvelev)] greenhouses; assess the relationship between dispersal capabilities and population dispersion of aphids; and determine the influence of spatial structure on the behavior of 2 aphid natural enemies, Chrysoperla rufilabris (Burmeister) and Aphidius colemani Viereck. Replicated studies conducted in greenhouses revealed no significant differences between M. persicae and A. gossypii displacement distances, diffusion constants, and dispersion indices. Studies of the effects of localized aggregations on M. persicae population dynamics revealed decreasing rates of population increase with increasing aphid densities. Natural-enemy displacement distances and diffusion constants were significantly greater for adult A. colemani compared with 3rd instars of C. rufilabris . In addition, the percentage of A. colemani observed to be actively searching for aphids was significantly higher than the percentage of C. rufilabris larvae. Differences in dispersal capability and searching activity may explain why A. colemani successfully located 97% of all aphid-infested pots compared with the 49% located by C. rufilabris within 10 h of their release. These results suggest that aphid biological control in chrysanthemum greenhouses may be enhanced by releasing sufficient numbers of natural enemies from points &ap;2 times their displacement distance 10 h after their releases. These distances are 325 cm apart among benches for A. colemani and 68 cm apart within benches for C. rufilabris .

INTRAGUILD PREDATION AMONG APHID PREDATORS: CHARACTERIZATION AND INFLUENCE OF EXTRAGUILD PREY DENSITY

Intraguild predation (IGP), a common interaction in invertebrates and vertebrates, affects the abundance and distribution of many species. Several parameters influence the magnitude and direction of IGP: feeding specificity, size, mobility, and aggressiveness of the protagonists, as well as extraguild prey density. Under laboratory conditions, we studied IGP among three species of aphid predators, Aphidoletes aphidimyza (Diptera: Cecidomyiidae), Chrysoperla rufilabris (Neuroptera: Chrysopidae), and Coleomegilla maculata lengi (Coleoptera: Coccinellidae), which commonly attack the potato aphid (extraguild prey) Macrosiphum euphorbiae (Homoptera: Aphididae). We characterized the levels and symmetry of IGP among the various stages of the predators in the absence of extraguild prey. The aphid specialist A. aphidimyza was more vulnerable to IGP than C. rufilabris and C. maculata, two generalist predators. The C. maculata/C. rufilabris interaction was symmetric (mutual IGP), whereas the C. maculata/A. aphidimyza and C. rufilabris/A. aphidimyza interactions were asymmetric, in favor of the coccinellid and the lacewing, respectively. Sessile and low mobility stages of all species were extremely vulnerable to IGP. Generally, the larger sized individual won confrontations. For similar sizes, lacewing larvae were superior to coccinellid larvae. We also tested whether IGP decreases when extraguild prey are introduced into the system. Data from five predator combinations revealed three types of responses: (1) an exponential decrease in IGP (lacewing instar I vs. coccinellid instar I); (2) a constant IGP (lacewing instar III vs. coccinellid instar I); (3) a constant IGP at low densities decreasing at high densities (lacewing instar III vs. gall midge old larva). Four theoretical scenarios are derived from these responses. Each is discussed according to the ecological attributes of the protagonists. This study shows that IGP is influenced by factors inherent to the predators and external factors such as extraguild prey density. The results are discussed further in the context of aphid biological control.

Biological and chemical characterization of a kairomone excreted by the bean aphids, Aphis fabae Scop. (Hom., Aphididae) and its effect on the predator Metasyrphus corollae Fabr. I. Isolation, identification and bioassay of aphid‐kairomone

Abstract: The results obtained are summarized as follows: (1) the active compounds of aphid's odour stimulated the syrphid females to deposit significantly higher percentages of eggs. These chemical compounds could be isolated by the solvent n‐pentane. (2) Gas chromatography mass spectral analysis of n‐pentane fractions of aphid's odour revealed the presence of several active peaks of hydrocarbon compounds. The active peaks ranged from docosane (C22) to octacosane (C28). Also, GC‐mass spectral analysis of n‐pentane fractions of the aphid‐extract supernatant showed the same chain of hydrocarbon compounds which is present in the aphid odour. (3) Bioassay of the different cosane compounds showed that the different concentrations of tricosane, tetracosane, pentacosane and hexacosane have a kairomonal effect on the syrphid females and the second concentration of C23CII, C24CII, C25CII and C26CII stimulated the syrphid females to deposit a significantly higher percentage of eggs. While hexacosane (C26) was the most abundant hydrocarbon compound in aphid kairomone, tricosane (C23) was the most active hydrocarbon compound. (4) Bioassay of the different mixtures of cosane compounds showed that HCM1, HCM2, HCM3, HCM4, HCM5 and HCM6 have a kairomonal effect on the syrphid females. The highest percentage of eggs was laid under the effect of the fourth mixture (HCM4) which contains tricosane (C23), tetracosane (C24), pentacosane (C25), hexacosane (C26) and octacosane (C28). (5) The chain of non‐volatile hydrocarbon compounds of aphid‐kairomone is secreted along with the cornicle secretion which contains volatile compounds. This kairomone stimulate the oviposition of syrphid females when it is received mechanically by the antennae. (6) The present study showed the importance of the different mixtures of cosane compounds as aphid‐kairomone. The use of aphid‐kairomone could be promising in aphid biological control instead of the heavy use of insecticides.

An artificial non-flying mutation to improve the efficiency of the ladybird Harmonia axyridis in biological control of aphids

The use of coccinellids in the biological control of aphids is restricted to the release of larvae because adults tend to fly away. Non-flying adults may stay longer in one place and so they and their progeny could give longer term protection to plants. This work is an attempt to produce a non-flying population by the use of a chemical mutagen and selection of adults with wing malformations through their subsequent generations. These adults are characterized by open elytra and extended wings. Some general features of this mutation were disclosed. The mutation is either unexpressed or results in malformed wings. It also seems recessive and lethal when homozygous. The adults with the mutation suffered a high level of mortality and a drastic reduction in reproductive capacity that prevents their mass rearing for biological control. This study revealed a negative relationship between wing malformations and reproductive capacity. Nevertheless, when adults with the mutation were released in greenhouses containing cucumbers infested with the aphid Aphis gossypii, they remained on the plants in higher numbers and laid eggs over a longer period of time than the control adults but their progeny were less numerous.

Ontogenetic change of prey preference in the generalist predator Zelus renardii and its influence on predator–predator interactions

1. Two field experiments were conducted to test the hypothesis that the intensity of predation by a generalist predator on two species of prey changes with the developmental stage of the predator. The generalist predator studied was Zelus renardii Kolenati (Hemiptera: Reduviidae) and the prey were the lacewing larva, Chrysoperla carnea Stephens, and the cotton aphid, Aphis gossypii Glover.2. Zelus renardii and lacewings feed on aphids, thereby acting as potential competitors. In addition, Z. renardii feeds on lacewings. Thus, Z. renardii is an intraguild predator of lacewings.3. Zelus renardii exhibited changes in prey preferences across developmental stages. The older stages of Z. renardii exerted greater mortality on lacewings and fed on larger lacewing larvae than did the younger stages.4. Lacewings suppressed aphid population growth strongly. In contrast, none of the stages of Z. renardii was an effective control agent of the cotton aphid.5. The addition of Z. renardii frequently disrupted the effective control of aphids generated by lacewings. In one of the two replicates of the experiment, the disruption increased with the developmental stage of Z. renardii, paralleling the increase in lacewing mortality.6. Although the developmental stage of Z. renardii can influence the prevalence of intraguild predation and the intensity of the disruption of the aphid biological control, these experiments have demonstrated that even the youngest instars of Z. renardii can cause substantial lacewing mortality and release aphid populations from regulation.

施設栽培ピーマンにおける主要害虫の総合防除に関する研究 １．ヤマトクサカゲロウを用いたアブラムシ類防除

施設栽培ピーマンにおける主要害虫の総合防除に関する研究 １．ヤマトクサカゲロウを用いたアブラムシ類防除