Chrysoperla Carnea Larvae Research Articles

Functional response estimations of Chrysoperla carnea to different densities of Aphis craccivora and Gynaikothrips ficorum nymphs.

The functional responses of Chrysoperla carnea larvae were evaluated at different seven densities of the 3rd instar nymphs of Aphis craccivora and Gynaikothrips ficorum in order to find out the relationship between predator densities and its prey by the, and also to find out their capability for biological control of aphids and thrips. Results revealed that all tested larval instars of Ch. carnea exhibited a type II response in relation to the prey. Moreover, the coefficients of attack rate (a) and handling time (Th) was differed among various growing instars of predator and for the prey species. The 3rd instar larvae of Ch. carnea manifested the highest attacking rate (1.23 and 1.22) on the 3rd instar nymphs of A. craccivora and G. ficorum, respectively. In addition it exhibited the highest maximum predation (Na max) (50.00 and 52.63) on A. craccivora and G. ficorum nymphs, respectively as compared with the other treatments. Accordingly, Ch. carnea could be considered as a promising bio-control agent for A. craccivora and G. ficorum management.

Risk Assessment of the Biological Control Product «Gulløyelarver» with the Active Organism Chrysoperla Carnea

Gulløyelarver (green lacewing larvae, Chrysoperla carnea) is a product for biological control. The application is for use against aphids in green-houses and tunnels.
 Gulløyelarver was used in Norway from 1985-1993. An assessment in 2001 concluded however that the use of products with Chrysoperla carnea could represent an environmental risk since it was not known if the species in the products were the same as the ones with natural occurrence in Scandinavia.
 In this regard, The Norwegian Food Safety Authority would like VKM to perform an assessment of possible risks related to health and environment in light of possible new data.
 VKM’s conclusions are as follows:
 Health:
 The larvae of Chrysoperla carnea have hollow jaws through which they can inject digestive enzymes into their prey. In contact with humans, the larvae are capable of delivering painful bites which may cause local swelling. Such bites are however not considered dangerous, and can be avoided with preventive measures.
 Allergic asthma and rhino conjunctivitis has been reported in persons working in the production of biological agents with Chrysoperla carnea, but it is the opinion of VKM that such effects are not likely to be relevant for users of the agents.
 Environment:
 A previous assessment in 2001 concluded that the use of products with Chrysoperla carnea represented an environmental risk because of the risk of genetic interference with natural populations of the species in Norway.
 Lacewings belonging to the Chrysoperla carnea complex are considered established and indigenous in Norway, and a recent study by the Norwegian Institute for Agricultural and Environmental Research (Bioforsk) strongly suggests that the lacewings in the commercial products belong to the same cryptic species complex as individuals sampled in Norway. In case the species in the products is different from those present in Norway, any genetic interference with local populations in Norway is prevented by differences in duetting songs.
 If an invertebrate biological control agent is indigenous and has limited direct or indirect effect on the environment, it is the opinion of VKM that it could be authorized for release in greenhouses or plastic tunnels.
 Chrysoperla carnea is polyphagous and cannibalistic. They prefer aphids, but may also consume other insects and mites. It is however the opinion of VKM that the environmental risk from this will be minimized in greenhouses and tunnels where the release will be in a contained environment and directed against aphid colonies.
 Establishment, host range and dispersal ability should be carefully reviewed, even if the species is indigenous. Chrysoperla carnea may establish in the greenhouse and plastic tunnels and may also possess the ability to disperse and survive in the field. However, it is the opinion of VKM that the direct and indirect effects of this are at most moderate, although it cannot be completely excluded that Chrysoperla carnea species in the products might also have properties that have not been reviewed.

Glandular trichomes affect mobility and predatory behavior of two aphid predators on medicinal cannabis

Medicinal cannabis (Cannabis sativa L.) is a growing agro-industrial sector with the end product required to be free of pesticides. C. sativa is covered by specialized hairs called trichomes, namely, two types of non-glandular and three types of glandular trichomes. Despite the great importance of biological pest control in medicinal cannabis little is known about the impact of cannabis trichomes on natural enemies mobility and their interaction with prey. In the current study, by employing a video recording set-up, we determined the mobility of Aphidoletes aphidimyza and Chrysoperla carnea larvae and their interaction with the aphid pests Phorodon cannabis and Aphis gossypii on C. sativa leaf disks and inflorescences. As benchmark, we tested the same parameters on sweet pepper leaf disks, a benign host plant for both predators, and without trichomes. It was found, that A. aphidimyza females readily oviposited on P. cannabis colonies developing on C. sativa plants. On C. sativa leaves, covered by non-glandular trichomes, the larvae of both predators were able to move and prey upon aphids. On C. sativa inflorescences, where glandular trichomes prevailed, the larvae of A. aphidimyza were generally inactive while the C. carnea larvae were still able to move and interact with prey albeit to a lesser degree compared to the cannabis leaves. We suggest that the use of A. aphidimyza and C. carnea in augmentative biological control programs in medicinal cannabis should depend on the croṕs growth stage; the former should be employed during the vegetative while the latter during the vegetative and flowering crop stages.

Use of Chrysoperla carnea larvae to control whitefly (Aleyrodidea: Hemiptera) on tomato plant in greenhouse

In the last ten years, whitefly has presented a serious risk to vegetables most commonly the tomatoes and natural products in the field. Another significant issue is associated with the pest management control system and insect preferences for the tomato plants. In these lines we investigate Predatory efficiency capability and capacity of Chrysoperla carnea with whitefly Bemisia tabaci in a greenhouse were study at Hyderabad, Pakistan. Larvae of Chrysoperla carnea were used against whitefly in a greenhouse. Adult, eggs and nymph of Bemisia tabaci is affected by Chrysoperla carnea. In this experiment used different numbers of larvae is attached to tomatoes plants to measure the efficiency of Chrysoperla carnea larvae. The overall mean population of whitefly indicates positive correlation with the number of larvae introduced. Highest overall mean whitefly population is observed in Un-Treated (13.11±1.614) and (4.012±0.804), the lowest count found in 10larvae/plant (7.400±0.904) and (1.363±0.561) for adult and nymph respectively. Up to 50% mortality is observed as compared to untreated plants. During this experiment, a strong negative correlation is observed between Chrysoperla carnea applied/plant and whitefly population (-0.808) and (-0.978) in adult and nymph respectively. Data also clearly showed decreased from start and after introduced Chrysoperla carnea larvae to tomato plants. Keywords: Chrysoperla carnea; Bemisia tabaci; larvae; mortality; tomato http://dx.doi.org/10.19045/bspab.2020.90227

Predatory ability of generalist predators on eggs, young nymphs and adults of the invasive Halyomorpha halys in southern Europe

Halyomorpha halys (Stal, 1855) is an invasive pest causing serious damage to agricultural crops in Europe and the USA. Very little is known about H. halys predators in Europe. This survey evaluated the potential of generalist predators/omnivorous species by means of predation bioassays in tri-dimensional arenas, where the predator had to locate H. halys prey items on the leaves of a bean plant. Eleven species of different taxa were tested and the prey items consisted in fresh eggmasses, 1st and 2nd instar nymphs. One species was also tested against adults. Some predators were species commercially available as biocontrol agents against plant pests, other predators were wild, captured in habitats shared with H. halys. All tested specimens were starved 24 h before starting the experiment. The survivorship of control prey items in predator-excluding cages was compared to that of predator treatment groups to determine the effect of predator presence. According to the results, the generalist species showed a quite low acceptance of H. halys prey items, since only two species caused 80% mortality on at least one item (Eupholidoptera chabrieri and Rhynocoris iracundus) and mortality due the other species never exceed 60%. Among commercially available species only Adalia bipunctata adults and Chrysoperla carnea larvae were effective, predating the eggs and 1st instar nymphs, respectively. Among the field collected specimens, the orthopteran E. chabrieri and the predatory hemipterans R. iracundus, Nagusta goedelii and Himacerus mirmicoides showed efficacy against 1st instar nymphs, E. chabrieri and R. iracundus showed efficacy against 2nd instar nymphs, whereas only E. chabrieri and N. goedelii predated the eggs. R. iracundus was also tested on the adults and successfully predated them. By identifying some of the species that can exploit H. halys as a suitable prey in southern Europe, the present investigation provides an important contribution for conservation biological control of this pest.

The Role of Chrysoperla carnea (Steph.) (Neuroptera: Chrysopidae) as a Potential Dispersive Agent of Noctuid Baculoviruses.

Simple SummaryBaculoviruses (BV) infect several lepidopteran pests of economic importance, such as the beet armyworm Spodoptera exigua. The joint use of microbiological and macrobiological strategies may improve the efficacy of control. Laboratory bioassays were developed to evaluate the interactions between two BVs: the multiple nucleopolyhedroviruses of S. exigua (SeMNPV) and Autographa californica (AcMNPV), and the predator Chrysoperla carnea. The excretion products of the predator’s larvae (drops) and adults (meconia) were microscopically examined after the ingestion of BV-infected S. exigua larvae. For both types of excreta and BVs, viral occlusion bodies (OBs) (resistance forms) were observed. These OBs were infective to healthy S. exigua larvae when applied in water suspension and in direct deposition. The virulence of meconia was higher in suspensions (higher viral load), while larval drops were more virulent in direct application due to their liquid nature and their easiness of consumption. The fitness of C. carnea was slightly affected by the consumption of both BV-infected prey. No preference was shown between healthy and BV-infected S. exigua, and both were preferred vs. the aphid Macrosiphum euphorbiae. Our findings present C. carnea, and particularly its larvae, as a promissory candidate for BV dispersion in the field.Baculoviruses (BV) are highly effective against lepidopteran pests of economic importance such as Spodoptera exigua. The combined use of entomopathogens and macrobiological control agents requires the study of their relationships. Laboratory bioassays were developed to evaluate the interactions between the multiple nucleopolyhedroviruses of S. exigua (SeMNPV) and Autographa californica (AcMNPV), and the predator Chrysoperla carnea. The microscopic examination of predator’s excreta (larval drops and meconia) after the ingestion of BV-infected S. exigua revealed the presence of viral occlusion bodies (OBs). The reinfection of S. exigua larvae with BVs-contaminated excreta by using OBs water suspensions or by direct application both yielded high mortality values but different speed-of-kill results. Meconia killed before in suspensions due to their higher viral load and larval excretion drops did so in direct application due to their liquid nature and their easiness of consumption. The prey-mediated ingestion of SeMNPV and AcMNPV triggered slight effects in C. carnea, which were probably derived from the food nutritional quality. Chrysoperla carnea larvae did not discriminate between healthy and BV-infected S. exigua, while a preference was shown for S. exigua (healthy or infected) vs. Macrosiphum euphorbiae. Our findings present C. carnea, and particularly its larvae, as a promissory candidate for BV dispersion in the field.

Laboratory Evaluation of the Effect of Insecticides on Chrysoperla carnea (Neuroptera: Chrysopidae), Forficula auricularia (Dermaptera: Forficulidae), Adalia bipunctata (Coleoptera: Coccinellidae) and Harmonia axyridis (Coleoptera: Coccinellidae)

The effect of 8 biopesticides and 23 synthetic pesticides on the eggs and larvae of Chrysoperla carnea (Stephens, 1836), adults of Forficula auricularia Linnaeus, 1758, larvae of Adalia bipunctata (Linnaeus, 1758) and adults of Harmonia axyridis (Pallas, 1773) have been evaluated under laboratory conditions. All of the tested biopesticides were harmless (causing mortality < 30%) or only slightly harmful (causing mortality 30–79%) to the tested natural enemies. The tested synthetic fungicides were harmless or slightly harmful, with the exception of myclobutanil, which was moderately harmful (causing mortality 90–99%) to A. bipunctata larvae. The tested synthetic insecticides were harmless or slightly harmful to C. carnea eggs and F. auricularia larvae. Various results were obtained for neonicotinoids ranging from the harmful effects (causing mortality > 99%) of thiacloprid on A. bipunctata larvae and H. axyridis adults to the harmless effects of acetamiprid on F. auricularia adults and C. carnea eggs. Thiacloprid, dodine and chlorpyrifos-methyl had effects on the behaviour of F. auricularia adults. The results confirmed the selectivity of the tested biopesticides that had no negative effects on the tested natural enemies.

Functional Response of Chrysoperla carnea (Neuroptera: Chrysopidae) on Myzus persicae Nymphs (Hemiptera: Aphididae)

Effectiveness of natural enemies greatly depends on their functional responses, one of the key components in the selection of biological control predators. The aim of this study was to describe the functional response of third-instar Chrysoperla carnea Stephens (Neuroptera: Chrysopiade) on fourth-instar Myzus persicae Sulzer (Hemiptera: Aphididae). We determined the type of functional response by logistic regression analysis, which suggested that C. carnea exhibited a type III functional response. The handling time estimated was of 0.0066 (±0.0026) and, attack coefficient “a” is made a function of prey density(a = bNo). Chrysoperla carnea larvae ate an increasingly larger number of M. persicae nymphs as the prey density increased. We obtained an initial accelerated response, because C. carnea became more efficient at finding M. persicae. Roger's model did forecast correctly the expected number of eaten preys, but, the value of Th overestimated the maximum number “T/Th” of preys eaten by one C. carnea predatory larva.

Evaluation of the Bio-insecticidal Effects of Three Extracts on the Larvae of the Green Lacewing Chrysoperla carnea (Stephen) under the Laboratory Conditions

Aims: To control aphids without the misdeeds of the chemical insecticides. To make sure of the harmlessness of three bio-aphicides.
 Study Design: Experimental device in complete random block with three replications.
 Place and Duration of Study: Laboratory of bio-insecticidal entomology, Regional Center of Agricultural Research of Kenitra, INRA- Morocco and the Biodiversity and Natural Resources Laboratory of Sciences Faculty, Ibn Tofail kenitra, morocco. The experiments were done between March and December 2017.
 Methodology: The present study highlighted the lethal and sublethal effects of three bio-aphicides plants collected from the Gharb region of morocco: Capsicum frutescens, Nerium oleander and Melia azedarach, tested in five concentrations of their plant material against Chrysoperla carnea larvaes. Adding to these concentrations, two controls were used: one without any treatment (blanc) and another treated with a chemical insecticide (Deltamethrine).
 Results: The obtained results indicated that the aqueous extract of the Nerium oleander was harmful to the larvae of the Chrysoperla carnea. Indeed, the insecticidal activity of different concentrations increased with the exposure time, reaching about 10; 16 and 20% of mortality, respectively by applying 10; 15 and 20 g/20 ml after three days of exposure. However, low concentrations of 2 and 5 g/20 ml caused no effect whatever the duration of exposure. Also, the corrected mortality rate caused by the aqueous extract of Nerium oleander, at the concentrations tested is much lower than that caused by the insecticide Deltamethrin.
 Conclusion: Nerium oleander plant is harmful to the larvae of the Chrysoperla carnea at concentrations of 10; 16 and 20%. At these concentrations, the aqueous extracts of hot pepper and melia are not haurmful to the larvae of the green lacewing, so they can be recommended as a biological insecticide. Moreover, other works on these two extracts are outstanding in our laboratory.

Activity of Flonicamid and Two Neonicotinoid Insecticides against Bemisia tabaci (Gennadius) and Its Associated Predators on Cotton Plants

The sweet potato whitefly, Bemisia tabaci (Genn.), is a world-wide pest causing severe damages to numerous economic crops and has acquired resistance to most of conventional insecticides, particularly organophosphates and pyrethroids. Hence, Flonicamid, thiamethoxam and imidacloprid were evaluated for their efficacy against different developmental stages of B. tabaci on cotton plants under laboratory and field conditions at Sakha Agricultural Research Station, Egypt, during the cotton growing seasons of 2016 and 2017. Their side effects on the predacious stages of the associated predators i.e., the larvae of Chrysoperla carnea, both adults and larvae of Coccinella spp. and Scymnus spp., and true spiders were studied in the field as well. Results of the laboratory trials indicated that flonicamid provided no insecticidal activity on B. tabaci eggs, while thiamethoxam was significantly the most effective with LC50 value of 37.38 mg a.i.L-1. Thiamethoxam possessed the highest toxic effect against the 2nd instar nymphs followed by imidacloprid and flonicamid recording LC50 values of 30.37, 136.41, and 226.54 mg a.i.L-1, respectively. Under the field conditions, the activity of thiamethoxam did not differ significantly from that of imidacloprid recording from 83.19 ــ 93.24% and from 77.02 ــ 82.48% control of adults and immature stages of B. tabaci, respectively. Flonicamid demonstrated sufficient control, where it resulted in 75.67 to 80.64% and 64.97 to 69.58% reduction in the adults and immature stages, respectively. All the tested insecticides were more effective against adults than immature whitefly. Flonicamid was significantly the most harmless to the associated predators causing 21.01 to 23.75% reduction. Thiamethoxam and imidacloprid resulted in 35.24 to 49.96% reduction in the associated predator's population. These results suggest that flonicamid, thiamethoxam and imidacloprid could be successfully incorporated in IPM programs to control B. tabaci under the field conditions.

Day length constrains the time budget of aphid predators

Phenology shifts and range expansions cause organisms to experience novel day length - temperature correlations. Depending on the temporal niche, organisms may benefit or suffer from changes in day length, thus potentially affecting phenological adaptation. We assessed the impact of day length changes on larvae of Chrysoperla carnea (Stephens) and Episyrphus balteatus (De Geer), both of which prey on aphids. Larvae of E. balteatus are night-active, whereas those of C. carnea appear to be crepuscular. We subjected both species in climate chambers to day lengths of 16 : 8 L : D and, to circumvent diapause responses, 20 : 4 L : D. We recorded development times and predation rates of both species. E. balteatus grew 13% faster in the 16 : 8 L : D treatment and preyed on significantly more aphids. In contrast, C. carnea grew 13% faster in the 20 : 4 L : D treatment and higher predation rates in 20 : 4 L : D were marginally significant. Our results show that day length affects development and predation, but that the direction depends on species. Such differences in the use of day length may alter the efficiency of biocontrol agents in a changing climate.

Associational resistance or susceptibility: the indirect interaction between chemically‐defended and non‐defended herbivore prey via a shared predator

Many organisms possess chemical defences against their natural enemies, which render them unpalatable or toxic when attacked or consumed. These chemically‐defended organisms commonly occur in communities with non‐ or less‐defended prey, leading to indirect interactions between prey species, mediated by natural enemies. Although the importance of enemy‐mediated indirect interactions have been well documented (e.g. apparent competition), how the presence of prey chemical defences may affect predation of non‐defended prey in terrestrial communities remains unclear. Here, an experimental approach was used to study the predator‐mediated indirect interaction between a chemically‐defended and non‐defended pest aphid species. Using laboratory‐based mesocosms, aphid community composition was manipulated to include chemically‐defended (CD) aphids Brevicoryne brassicae, non‐defended (ND) aphids Myzus persicae or a mixed assemblage of both species, on Brassica oleracea cabbage plants, in the presence or absence of a shared predator (Chrysoperla carnea larvae). Aphid population growth rates, aphid distributions on host plants and predator growth rates were measured. In single‐species treatments, C. carnea reduced M. persicae population growth rate, but had no significant impact on B. brassicae population growth rate, suggesting B. brassicae chemical defences are effective against C. carnea. Chrysoperla carnea had no significant impact on either aphid species population growth rate in mixed‐species treatments. Myzus persicae (ND) therefore experienced reduced predation in the presence of B. brassicae (CD) through a predator‐mediated indirect effect. Moreover, predator growth rates were significantly higher in the M. persicae‐only treatments than in either the B. brassicae‐only or mixed‐species treatments, suggesting predation was impaired in the presence of B. brassicae (CD). A trait‐mediated indirect interaction is proposed, consistent with associational resistance, in which the predator, upon incidental consumption of chemically‐defended aphids is deterred from feeding, releasing non‐defended aphids from predatory control.

Do Chrysoperla carnea and Adalia bipunctata influence the spread of Cucurbit aphid‐borne yellows virus and its vector Aphis gossypii?

AbstractThe effects of two aphidophagous predators, the larvae of Chrysoperla carnea and the adults of Adalia bipunctata, on the spread of Cucurbit aphid‐borne yellows virus (CABYV) transmitted by the cotton aphid Aphis gossypii were studied under semi‐field conditions. Aphids and natural enemies were released inside insect‐proof cages with a CABYV‐infected cucumber plant placed in the centre of the cage and surrounded by 48 healthy cucumber seedlings. The spatiotemporal dynamics of the virus and vector were evaluated in the short (7 days) and long term (14 days) in the presence and absence of each predator. The spatial analysis by distance indices methodology, together with other indices measuring the dispersal around a single focus, was used to assess the spatial pattern and the degree of association between the virus and vector.The presence of C. carnea larvae and A. bipunctata adults induced A. gossypii dispersal after 14 days but not after 7 days. The reduction of the initial aphid population established in the plant located in the centre of each cage was always higher for C. carnea than for A. bipunctata. There was some evidence that the natural enemies affected the spread of CABYV, though more so for C. carnea than for A. bipunctata.This study suggests an influence of both predators on the spread of the aphid, mainly in the long term, but only weak effect of predators in the spread of the viral disease was demonstrated.

Lethal and sublethal effects of pesticides on Chrysoperla carnea larvae (Neuroptera: Chrysopidae) and the influence of rainfastness in their degradation pattern over time.

The predator Chrysoperla carnea is a model species for the study of non-target effects of pesticides under different scenarios: registration of plant protection products under the European Union and effects of the Bt toxin. Laboratory and persistence studies were carried out with six pesticides currently used in corn crops in Spain that were applied at their maximum field recommended concentrations. The assessed end-points were larval mortality, survivorship until adult stage, duration of the larval and pupal periods, fecundity, fertility and sex ratio of the emerged adults. Based on the total effect (lethal and sublethal) caused to L3 larvae in contact with fresh residues in the laboratory, pendimethalin was harmless (IOBC 1), lambda-cyhalothrin, abamectin, and hexythiazox were slightly harmful (IOBC 2), deltamethrin was moderately harmful (IOBC 3) and chlorpyrifos was harmful (IOBC 4). Afterwards, the residues of the two most toxic pesticides in the lab (deltamethrin and chlorpyrifos) were aged under greenhouse conditions (22±2°C, 40±10% R.H., 16.9 μmol m(-2) s(-1) UV radiation) in the presence and absence of artificial rainfall (10lm(-2)h(-1), applied 24h after pesticide application). Deltamethrin was classified as short lived (IOBC A) in both cases. However, degradation of chlorpyrifos residues was accelerated in the presence of rainfall, leading to the classification as slightly persistent (IOBC B), while in absence of rainfall it behaved as persistent (IOBC D). Every pesticide can be recommended for inclusion in corn IPM programs where the predator is present except chlorpyrifos that exhibited high direct toxicity in the lab and prolonged residual action even in the presence of rainfall.

Survival and Reproduction ofChrysoperla carnea(Stephens)1Fed Different Diets

Abstract. Larvae of Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) are effective predators for controlling insect pests of various crops. Increased awareness of the nutritional substrate that promotes their development will help in management of this predator for biological control of pests. Developmental time, reproduction, and survival rate of C. carnea feeding on seven diets were recorded: eggs of Trichoplusia ni (Hubner) (Lepidoptera: Noctuidae), Plutella xylostella (L.) (Lepidoptera: Plutellidae), and Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae); larvae of T. ni and P. xylostella; and aphids Brevicoryne brassicae (L.) and Rhopalosiphum padi (L.) (Hemiptera: Aphididae). The intrinsic rate of growth (rm), net reproductive rate (R0), and finite rate of augmentation (λ) were greater when the lacewing larvae were fed B. brassicae (rm = 0.198, R0 = 1171, λ = 1.21) and R. padi (rm = 0.198, R0 = 1181, λ = 1.21) aphids; generation time (T) was greater when they ate eggs of T. ni (T = 38....

The effect of Chrysoperla carnea (Neuroptera: Chrysopidae) and Adalia bipunctata (Coleoptera: Coccinellidae) on the spread of cucumber mosaic virus (CMV) by Aphis gossypii (Hemiptera: Aphididae).

The effects of two aphidophagous predators, the larvae of Chrysoperla carnea and adults of Adalia bipunctata, on the spread of cucumber mosaic virus (CMV) transmitted in a non-persistent manner by the cotton aphid Aphis gossypii were studied under semi-field conditions. Natural enemies and aphids were released inside insect-proof cages (1 m × 1 m × 1 m) with a central CMV-infected cucumber plant surrounded by 48 healthy cucumber seedlings, and the spatiotemporal dynamics of the virus and vector were evaluated in the short and long term (1 and 5 days) in the presence and absence of the natural enemy. The spatial analysis by distance indices methodology together with other indices measuring the dispersal around a single focus was used to assess the spatial pattern and the degree of association between the virus and its vector. Both natural enemies significantly reduced the number of aphids in the CMV-source plant after 5 days but not after 1 day. The CMV transmission rate was generally low, especially after 1 day, due to the limited movement of aphids from the central CMV-source plant, which increased slightly after 5 days. Infected plants were mainly located around the central virus-infected source plant, and the percentage of aphid occupation and CMV-infected plants did not differ significantly in absence and presence of natural enemies. The distribution patterns of A. gossypii and CMV were only coincident close to the central plant. The complexity of multitrophic interactions and the role of aphid predators in the spread of CMV are discussed.

Functional Response ofChrysoperla carnea(Neuroptera: Chrysopidae) onTrialeurodes vaporariorum(Hemiptera: Aleyrodidae) Eggs

Abstract. The functional response of the third instar larvae of Chrysoperla carnea (Stephens) on densities of Trialeurodes vaporariorum (Westwood) eggs was evaluated under controlled conditions. A functional type Il response (Holling's disk) was observed. Holling and Livdahl & Stiven models gave similar values for estimating parameters of the Holling's disk equation; however, estimates produced by the Rogers were higher. According to the results obtained of predation, C. carnea has considerable potential for the control of T. vaporariorum.

Predation capacity and prey preference of Chrysoperla carnea on Pieris brassicae

The predation capacity and prey preference of larvae of Chrysoperlacarnea (Stephens) (Neuroptera: Chrysopidae) on eggs or larvae of Pieris brassicae (Linnaeus) (Lepidoptera: Pieridae) in the absence and presence of cabbage aphids as an alternative prey were evaluated in laboratory experiments at 25°C. Both instars preyed upon butterfly eggs and larvae as well as on cabbage aphids with the third instar being the most voracious. The lacewings had a strong preference for caterpillars to butterfly eggs. In the presence of the aphids the predation on P. brassicae eggs or larvae was either completely abandoned or reduced by about 70%, respectively, by second instar lacewings and either reduced by about 80% or maintained, respectively, by third instar lacewings. Both instars thus had a clear preference for aphids compared to eggs of P. brassicae. However, second instar lacewings preferred aphids to caterpillars whereas the opposite was the case for third instar lacewings. The results indicate that 3rd instar C. carnea has a potential as biocontrol agent against P. brassicae.

Impact of snowdrop lectin ( Galanthus nivalis agglutinin; GNA) on adults of the green lacewing, Chrysoperla carnea

Based on the finding that Galanthus nivalis agglutinin (GNA) has direct negative effects on larvae of Chrysoperla carnea, laboratory experiments were conducted to investigate its toxicity to the adults. While the ingestion of GNA dissolved in an artificial diet did not affect adult longevity, there were concentration-dependent negative effects on the pre-oviposition period, daily fecundity and total fecundity (number of eggs laid). When GNA was ingested by larvae of C. carnea, it caused a significant extension of larval development time. Adults that had emerged from GNA-fed larvae did not differ from those that developed from control larvae in terms of adult fresh weight, pre-oviposition period and daily or total fecundity. However, fertility (proportion of hatching eggs) was significantly decreased in adults raised from GNA-treated larvae. Western blots revealed that GNA ingested by larvae of C. carnea was partly transferred to the adult stage and was subsequently excreted or digested within a few days. Our toxicity studies (Tier-1 tests) clearly established a hazard of GNA to adult C. carnea when administered to larvae or adults at high concentrations. Implications of these toxicity data for the non-target risk assessment of GNA-expressing transgenic crops are discussed.

Kairomone Formulations as Reinforcing Agents for Increasing Abundance of Chrysoperla cornea (Stephens) in Cotton Ecosystem

Adults and larvae of Chrysoperla carnea (Stephens) utilize different kairomones for oviposition, prey selection and acceptance. The larval kairomones containing scale extracts fortified with tricosane along with the eggs of Corcyra cephalonica (Stainton) as the supplementary diet, and the adult kairomone, acid hydrolyzcd L-tryptophan were studied to increase the predatory activity of the C. carnea in cotton ecosystem at three locations during 2002-2004. Controls were maintained with the two releases of C. carnea and without any treatment. In all the locations, the number of eggs, larvae, pupae or adult C. carnea was more than the treated control and control. The number of aphids, jassids, and the incidence of bollworm were significantly less in kairomone treated plots, compared to other plots. However, no difference was observed in the activity of coccinellids predators. The scope for utilizing the kairomones as reinforcing agents for C. carnea is discussed.