Carnea Larvae Research Articles

ROLE OF Chrysoperla carnea (Stephens) RELEASE IN THE BIOCONTROLLING OF Cassida vittata Vill. AND Scrobipalpa ocellatella Boyd. LARVAE AS WELL AS ENHANCING THE ASSOCIATED ARTHROPOD PREDATOR POPULATIONS IN COMPARISON WITH CONVENTIONAL INSECTICIDES APPLICATIONS IN SUGAR BEET FIELDS

The current study was carried out at the Experimental Farm of Sakha Agricultural Research Station, Kafr El-Sheikh Governorate during 2016/2017 and 2017/2018 seasons for investigating the efficacy of Chrysoperla carnea (Stephens) larvae release against Cassida vittataVill. and Scrobipalpa ocellatella Boyd.larvae in sugar beet fields, at the same time in conserving arthropod predators (true spiders “Araneae”, C. carnea, Coccinellidae, Anthocoridae and Formicidae), in comparison with conventional insecticides (Tac 48% EC, Diracomel 90% SP and Shalinger-Super 24% SC). The results indicated that the conventional insecticides induced reduction in the mean number of S. ocellatella larval population with 91.00, 86.00 and 89.03%, respectively in 2016/2017 season, and 92.00, 90.00 and 92.13%, respectively in 2017/2018 season. While in case of C. vittata the chemical insecticide treatments induced reduction in the mean number of larval population with 91.00, 93.40 and 94.00%, respectively in 2016/2017 season as well as 92.40, 94.10 and 94.33%, respectively in 2017/2018 season. Also, the mean of reductions in the surveyed and associated arthropod predators as a result of using conventional insecticides against S. ocellatella larvae were 96.71, 96.55, and 96.55%, respectively in 2016/2017 season as well as 95.30, 94.00 and 92.00%, respectively in 2017/2018 season. While in case of using chemical insecticides against C. vittata larvae, the reductions in the mean population of the surveyed and associated arthropod predators in sugar beet fields were 97.40, 96.30 and 95.00%, respectively in 2016/2017 season as well as 96.00, 94.00 and 93.30%, respectively in 2017/2018 season. While in the treatment of release the predatory insect, C. carnea larvae against S. ocellatella larvae induced reduction in the mean number of the larval population by 57.13 and 43.40% in 2016/2017 and 2017/2018 seasons, respectively. While in case of C. vittata larvae, the reduction in the mean number of larval population recorded 49.00 and 45.13% in 2016/2017 and 2017/2018 seasons, respectively. Also, the surveyed and associated arthropod predator populations increased by 25.13 and 70.00% in 2016/2017 and 2017/2018 seasons, respectively. While the increasing in C. carnea populations were 22.00 and 44.13% in 2016/2017 and 2017/2018 seasons, respectively as a result of release the predatory insect, C. carnea for controlling both of S. ocellatella and C. vittata, respectively. Finally, these results show the important role of releasing C. carnea larvae as a biocontrol agent for controlling C. vittata and S. ocellatella larvae, at the same time in enhancing arthropod predator populations in comparison with conventional insecticides.

Ecological and Biological Studies on the Citrus Flower Moth Prays citri (Millière) (Lepidoptera: Hyponomeutidae) in Qalyubia Governorate, Egypt

The investigation was carried out during two years in citrus orchards in Qalyubia Governorate 2015 – 2016, to study ecological and biological aspects of the Citrus Flower Moth Prays citri (Milliere) (Lepidoptera: Hyponomeutidae). Data illustrated from ecological and biological points of view. Ranjpure lime (Citrus auranifolia) was the most preferred variety (highly susceptible) of infested by P. citri. While lemon (Citrus limon) which is considered as “moderately susceptible” exhibit less preferable to P. citri, but not seen any infested flowers in navel orange (Citrus sinensis) was the lowest preferred variety, throughout the investigation 2015 – 2016. One peak of infestation of P. citri in spring under weather conditions of Qalyubia Governorate. Predatory potential of Chrysoperla carnea (Steph) larvae on citrus flower moth P. citri larvae, under laboratory conditions was highly significant in mean consumption rate of 2nd and 3rd instars The total consumption by the third instar of C. carnea was significantly than the second instar . Biological results indicated that Female laid eggs both individually 54.6 eggs in average per female, Incubation period lasted 1.07 days, hatchability was 67.7 % in average, Larval and pupal stage period was 6.37 and 5.33 days respectively, female and male longevity lasted 4.3 and 3.6 days respectively. Life cycle 12.77 days while Generation lasted 13.79 days under 29.4°C and 62.7 % RH.

Potential impact of host pest fed on Bt-modified corn on the development of Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae)

Laboratory experiments were conducted to study the potential impact of genetically modified corn hybrid, transgenic Bacillus thuringiensis (Bt)-expressing (Cry2Ab/1Ac), and the corresponding isogenic untransformed Bt-free hybrid on biological parameters of the green lacewing predator, Chrysoperla carnea (Stephens). The effectiveness of transgenic (Bt)-expressing (Cry2Ab/1Ac) on C. carnea developmental parameters (larval duration, pupal duration, mortality %, pupation %, adult emergence %, and adult duration time) was investigated in the first experiment. In the second experiment, the effect of Bt Cry2Ab and Cry1Ac partially purified toxins on the hatchability of C. carnea eggs compared to cypermethrin was examined. Additionally, the toxicity effect of Angoumois grain moth, Sitotroga cerealella, eggs sprayed with BtCry2Ab/1Ac mixture and cypermethrin on C. carnea was tested. The results showed that the mortality percentage of C. carnea fed on aphids reared on Bt corn (40%) was less than that fed on aphids reared on non-Bt corn (50%). Moreover, the larval mortality %, net pupation, and adults’ emergence percentage of C. carnea larvae fed on aphids reared on Bt corn and non-Bt corn were not significantly different. On the other hand, the hatchability data showed that the chemical insecticide (cypermethrin) severely affected the C. carnea eggs compared to Cry2Ab/1Ac toxins. These findings proved that adopting biopesticide formulation based on Bt toxins or Bt-modified crops will not only affect C. carnea but also enhance its ability as a potential biological pest control agent.

The influence of microsporidian pathogens from commercially available lady beetles on larval development of the green lacewing, Chrysoperla carnea, in the absence of infection.

In North America, more than 70 species of natural enemies are available for pest control, including the aphid predators, Adalia bipunctata L. (two-spotted lady beetle) and Hippodamia convergens Guérin-Méneville (convergent lady beetle), and the generalist predator Chrysoperla carnea Stephens (green lacewing). The two lady beetle species are known to host microsporidian pathogens: Nosema adaliae was originally described from Adalia bipunctata and Tubulinosema hippodamiae from H. convergens. Microsporidia are spore-forming pathogens that typically produce chronic, debilitating disease. Because the spores of both pathogens are transovarially transmitted through beetle eggs, the predation behavior of lacewing larvae provides an opportunity for the transmission of these pathogens when infected lady beetles and lacewings share the same local environment. In this study, uninfected and microsporidia-infected eggs from A. bipunctata and H. convergens were offered to C. carnea larvae. The development of larvae that consumed N. adaliae-infected eggs was not affected, but larval development was prolonged by almost 3 days for those that consumed two or more T. hippodamiae-infected eggs. Prolonged larval development is considered to be costly because larvae remain vulnerable to cannibalization by sibling larvae or other predators. Longevity did not differ significantly between sexes of C. carnea, and the sex ratio of newly eclosed adults did not differ from the previously reported sex ratio of 1♂: 1♀. Upon examination by light microscopy at the end of the trial, two C. carnea larvae were infected with N. adaliae and none were infected with T. hippodamiae, suggesting that T. hippodamiae influenced lacewing larval development without establishing an infection.

Treatments with Metarhizium brunneum BIPESCO5 and EAMa 01/58-Su strains (Ascomycota: Hypocreales) are low risk for the generalist predator Chrysoperla carnea

Metarhizium spp. (Hypocreales: Clavicipitaceae) are used as alternatives to hazardous pesticides. During host infection, they secrete secondary metabolites such as destruxin A. Information on the fate of those secondary metabolites in the food chain and their risk to human and animal health is scarce. In the present work, predator–prey bioassays were performed to evaluate the behavior and survival of green lacewing Chrysoperla carnea (Neuroptera: Chrysopidae) larvae when presented with armyworm Spodoptera littoralis (Lepidoptera: Noctuidae) larvae treated with Metarhizium brunneum BIPESCO5 and EAMa 01/58-Su strains. Moreover, ecotoxicological studies were done using HPLC–MS to monitor the fate of destruxin A in the prey–predator system. HPLC–MS confirmed the presence of destruxin A at low concentrations in S. littoralis larvae infected with BIPESCO5 (approximately 0.014 μg/g) and EAMa 01/58-Su (approx 0.031 μg/g) strains, whereas the metabolite was not detected in C. carnea larvae consuming M. brunneum-treated S. littoralis larvae. Furthermore, C. carnea larvae preferentially fed on healthy prey versus M. brunneum-treated prey as revealed by both the higher predator ratio feeding on S. littoralis control larvae and the higher per capita number of control larvae consumed by the predator compared to M. brunneum-treated larvae. Moreover, this preference was inversely related to the post-inoculation period of S. littoralis larvae treated with M. brunneum. Furthermore, C. carnea larvae fed on healthy prey gained more weight than those fed on treated individuals. Both M. brunneum treatments used against S. littoralis larvae may be considered low risk to C. carnea due to the lack of fungus-related mortality in the predator and the lack of movement of destruxin A from the prey to the predator. However, further studies on other nontargets and with more strains of M. brunneum are needed to evaluate their possible simultaneous use in integrated pest management.

Using of Chrysoperla carnea (Stephens) Larvae as a Biological Control Agent against Phyllocnistis citrella Stainton.

Using of Chrysoperla carnea (Stephens) Larvae as a Biological Control Agent against Phyllocnistis citrella Stainton.

Laboratory Evaluation of the Effect of Insecticides on Non-target Organisms: 1- The Predatory Green Lacewing, Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae)

A study purposed to evaluate the acute residual toxicity of six insecticides (different groups); Dursban and Malathion (OP), Chess (Selective feeding broker), Spintor (bioinsecticide), Biogard: (Bacillus thuringiensis) (bacteria), and Biover: (fungus) on immature stages of the predator, Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) was carried out under laboratory conditions. Lethal and sub-lethal effects of the tested insecticides (4 concentrations each) on the development of the eggs (3 ages) and the 2nd instar larvae of the predator were assayed. The eggs were treated using the dipping method, while the larvae were treated using the residual film contact method. LC50, LC90, LC99 and the sub-lethal concentration (LC20) for each insecticide were estimated. Hatchability values, percentages of the treated eggs as well as percentages of larvae were calculated. Pupation and adult emergence percentages were estimated and compared with those of the untreated check to study the residual effect on the treated larvae, using LC20 of each insecticide. The dose-mortality responses of theeggs were compared in terms of differences in slopes and LC50 values. Data showed that the 3-day old eggs were more tolerant to the tested insecticides than the newly ones. The mean mortality percentages of treated larvae were: 100, 100, 55, 50, and 20% for Dursban, Malathion, Biogard, Chess and Spintor, respectively. According to the classification of (IOBC/WPRS), Dursban and Malathion were classified as harmful insecticides, Biogard and Chess as moderately harmful, and Spintor as harmless insecticde. C. carnea larvae showed a relative tolerance to the insecticides tested as they pupated and developed successfully to the adult stage. The highest larval mortality (24%) was recorded for Dursban, while the lowest one (18%) was for Spintor compared with (10%) for the control. Statistical analysis of accumulated larval mortality indicated that there were insignificant differences among the mortality percentages in any of the studied insecticides and also between the treated larvae with each insecticide and the control. Spintor was the most suitable insecticide recommended to be used in IPM programs as it is safe for different stages of C. carnea.

Feeding Efficiency of Green Lacewing, Chrysoperla carnea (Stephens) against Different Species of Aphid in Laboratory Conditions

Green lacewing, Chrysoperla carnea Stephens (Neuroptera: Chrysopidae) is the most effective polyphagous predator of different species of aphids and is commonly known as “aphid lion” . The experiment on feeding efficiency of green lacewing was studied in the laboratory of Entomology Division, NARC, Khumaltar, Lalitpur, Nepal from 21st , December 2015 to 26th, March 2016. The known number of predatory larva of green lacewings were fed with known number of seven different species of live aphid and frozen Corcyra eggs representing each treatment. The treatments were replicated four times. The predatory efficiency was calculated by counting the number of consumed host per day. The result revealed that the predatory efficiency of C. carnea larvae were increased from first to third instar and third instar were more voracious as compare to first two instars. It consumed significantly the highest rice moth, Corcyra cephalonica followed by Aphis craccivora and others aphid species, respectively. From this experiment, it is evident that the green lacewing is potent bio-agent against different aphid species and hence further research is required simultaneously in the farmer’s field conditions.Int. J. Appl. Sci. Biotechnol. Vol 5(1): 37-41

Metabolite Profiling Reveals a Specific Response in Tomato to Predaceous Chrysoperla carnea Larvae and Herbivore(s)-Predator Interactions with the Generalist Pests Tetranychus urticae and Myzus persicae.

The spider mite Tetranychus urticae Koch and the aphid Myzus persicae (Sulzer) both infest a number of economically significant crops, including tomato (Solanum lycopersicum). Although used for decades to control pests, the impact of green lacewing larvae Chrysoperla carnea (Stephens) on plant biochemistry was not investigated. Here, we used profiling methods and targeted analyses to explore the impact of the predator and herbivore(s)-predator interactions on tomato biochemistry. Each pest and pest-predator combination induced a characteristic metabolite signature in the leaf and the fruit thus, the plant exhibited a systemic response. The treatments had a stronger impact on non-volatile metabolites including abscisic acid and amino acids in the leaves in comparison with the fruits. In contrast, the various biotic factors had a greater impact on the carotenoids in the fruits. We identified volatiles such as myrcene and α-terpinene which were induced by pest-predator interactions but not by single species, and we demonstrated the involvement of the phytohormone abscisic acid in tritrophic interactions for the first time. More importantly, C. carnea larvae alone impacted the plant metabolome, but the predator did not appear to elicit particular defense pathways on its own. Since the presence of both C. carnea larvae and pest individuals elicited volatiles which were shown to contribute to plant defense, C. carnea larvae could therefore contribute to the reduction of pest infestation, not only by its preying activity, but also by priming responses to generalist herbivores such as T. urticae and M. persicae. On the other hand, the use of C. carnea larvae alone did not impact carotenoids thus, was not prejudicial to the fruit quality. The present piece of research highlights the specific impact of predator and tritrophic interactions with green lacewing larvae, spider mites, and aphids on different components of the tomato primary and secondary metabolism for the first time, and provides cues for further in-depth studies aiming to integrate entomological approaches and plant biochemistry.

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.

Exploiting physical defence traits for crop protection: leaf trichomes ofRubus idaeushave deterrent effects on spider mites but not aphids

Plants possess anti-herbivore defences that could be exploited for crop protection. The potential for deploying physical defence traits for more sustainable pest management (i.e. reduced pesticide application) has not been fully realised. Using a perennial crop (red raspberry, Rubus idaeus), we take the novel approach of quantifying within- and between-genotype variation in a resistance trait, leaf trichome density, to determine precisely the effect of trichomes on host plant preference and suitability for two shoot-feeding arthropods, the European large raspberry aphid (Amphorophora idaei) and two-spotted spider mite (Tetranychus urticae). Additionally, we tested whether this trait influenced searching behaviour of a generalist herbivore predator (lacewing larvae, Chrysoperla carnea). Although there was no consistent genotypic variation in R. idaeus suitability for T. urticae, our hypothesis that T. urticae would avoid high leaf trichome density was supported on certain genotypes. The deterrent effect was mainly on egg deposition rather than leaf selection by adults, with up to sixfold differences in leaf preference depending on the genotypes offered. By contrast, there was significant genotypic variation in R. idaeus suitability for A. idaei (10-fold variation in aphid abundance), but, contrary to our prediction, aphid preference and infestation levels were unrelated to leaf trichome density. Instead, A. idaei performed best on vigorous genotypes, indicating that plant tolerance traits contributed to R. idaeus suitability for aphids. Leaf trichomes had little effect on the behaviour of the beneficial control agent C. carnea larvae. We conclude that physical anti-herbivore defences, specifically leaf trichomes, could be deployed to deter particular arthropod pests. However, the mechanistic approach adopted here is necessary to avoid antagonistic effects on other pests or on natural enemies.

Preference and Performance of Hippodamia convergens (Coleoptera: Coccinellidae) and Chrysoperla carnea (Neuroptera: Chrysopidae) on Brevicoryne brassicae, Lipaphis erysimi, and Myzus persicae (Hemiptera: Aphididae) from Winter-Adapted Canola.

In the southern plains of the United States, winter-adapted canola (Brassica napus L.) is a recently introduced annual oilseed crop that has rapidly increased in hectares during the past 10 yr. Winter canola fields are infested annually with populations of Brevicoryne brassicae (L.) and Lipaphis erysimi (Kaltenbach), and these Brassica specialists are known to sequester plant volatiles from host plants, producing a chemical defense system against predators. Myzus persicae (Sulzer) is also common in winter canola fields, but as a generalist herbivore, does not sequester plant compounds. These three aphid species are expected to affect predator survival and development in very different ways. We conducted laboratory studies to 1) determine whether Hippodamia convergens (Guérin-Méneville) and Chrysoperla carnea (Stephens) larvae demonstrate feeding preferences among winter canola aphids and 2) describe the suitability of these prey species. Predators demonstrated no significant preference among prey, and each aphid species was suitable for predator survival to the adult stage. However, prey species significantly affected development times and adult weights of each predator species. Overall, predator development was delayed and surviving adults weighed less when provided with L. erysimi or B. brassicae, which sequestered high levels of indole glucosinolates from their host plants. Our results indicate that although common winter canola aphids were suitable prey for H. convergens and C. carnea, qualitative differences in nutritional suitability exist between Brassica-specialist aphids and the generalist M. persicae. These differences appear to be influenced by levels of sequestered plant compounds that are toxic to aphid predators.

Toxicity of spinosad on common green lacewing Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) larvae via ingestion technique under laboratory conditions

The use of selective insecticides could improve conservation of natural enemies and therefore contribute to the success of integrated pest management programmes. In this study, the toxicity of one selective insecticide, spinosad to common green lacewing Chrysoperla carnea (Stephens) was evaluated. Several stages of C. carnea larvae were exposed to spinosad via ingestion technique under laboratory conditions. The used quantities of spinosad were less than the maximum recommended rate given on the product label. In ingestion bioassay tests, a direct relationship was detected between the concentration of spinosad and mortality rate of first instar larvae. So that, the applied of 250 and 2500 ppm of spinosad caused 35 and 90% mortality, respectively. Mortality rate was recorded 1–3 days of post treatment. An implementation of 250 ppm of spinosad on second and third instar larvae showed negligible mortality rate after 3 days, whereas the first instars larvae suffered 35% mortality. On the basis of collected data we could conclude that spinosad is not merited to be considered to have an environmental safety profile on C. carnea similar to well-established conventional biological insecticides.

Functional Response of Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) to Sugarcane Whitefly Aleurolobus barodensis (Maskell) in Laboratory Conditions

A functional response study of Chrysoperla carnea (Stephens) larvae to different densities of sugar cane whitefly Aleurolobus barodensis (Maskell) was conducted in test tubes at 26 ± 2 °C, 65 ± 5 % RH. Chrysoperla carnea showed two different types of functional response in larval instars. First instar exhibits type II. However, second and third larval instars revealed type III functional response. Based on modified Holling’s disk equation, the highest searching rates (a) of 0.82 ± 0.0247 h−1 was found for first instar larva. For second and third larval instars, the attack coefficient (b) were 0.002 ± 0.030 and 0.0025 ± 0.0424 respectively. The shortest handling time (Th) per prey was observed at third instar stage (1.574 ± 0.0568 h) followed by second and first instar with 1.72 ± 0.0411 h and 1.919 ± 0.0568 h respectively.

The green lacewing, Chrysoperla carnea: preference between lettuce aphids, Nasonovia ribisnigri, and Western flower thrips, Frankliniella occidentalis.

This study investigated the prey preference of 3rd instar green lacewing, Chrysoperla carnea Stephens (Neuroptera: Chrysopidae), between western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), and lettuce aphids, Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae) in laboratory experiments at 25 ± 1° C and 70 ± 5% RH with five prey ratios (10 aphids:80 thrips, 25 aphids:65 thrips, 45 aphids:45 thrips, 65 aphids:25 thrips, and 80 aphids:10 thrips). Third instar C. carnea larvae readily preyed upon both thrips and aphids, with thrips mortality varying between 40 and 90%, and aphid mortality between 52 and 98%. Chrysoperla carnea had a significant preference for N. ribisnigri at two ratios (10 aphids:80 thrips, 65 aphids:25 thrips), but no preference for either prey at the other ratios. There was no significant linear relationship between preference index and prey ratio, but a significant intercept of the linear regression indicated an overall preference of C. carnea for aphids with a value of 0.651 ± 0.054. The possible implications of these findings for control of N. ribisnigri and F. occidentalis by C. carnea are discussed.

Consumption of Immature Stages of Colorado Potato Beetle by Chrysoperla Carnea (Neuroptera: Chrysopidae) Larvae in the Laboratory

The Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), has been an important defoliator of potatoes for 150 years. Although the use of insecticides allowed drastic reductions of CPB populations, resistance development against active substances has been observed. In this context, biological control using predatory larvae of the lacewing may represent a good alternative. CPB egg and larval consumption rates have been evaluated for all Chrysoperla carnea (Stephens) instars for 24 h. While first and second C. carnea instars only consumed eggs (1.3 and 1.8), first (1.5 and 2.4) and second (0.6 and 0.8) CPB instars, third instar of lacewing consumed all CPB immature stages: 6.8 CPB eggs, 8.5 first, 4 s, 0.5 third and 0.1 fourth CPB instars. This third instar killed 4-fold more CPB larvae than other larval stages. Handling time for third instar lacewing has been evaluated at 52 min on first instar CPB, 102 min on second instar and 164 min on third instar. Our laboratory assays highlight a potential for lacewing larvae to control CPB immature stages with a greater efficiency on young CPB larval stages. Fields assays are however needed to confirm efficiency of this CPB natural enemy under field conditions.

Intraguild Predation between Lady Beetles and Lacewings: Outcomes and Consequences Vary with Focal Prey and Arena of Interaction

AbstractWe examined reciprocal intraguild predation (IGP) and cannibalism among various combinations of Coleomegilla maculata DeGeer and Chrysoperla cornea Stephens larvae as they developed feeding on greenbugs, Schizaphis graminum Rondani, on sorghum plants in microcosms. Pairs of C. maculata larvae suppressed aphids better than pairs of C. carnea larvae or heterospecific larval pairs and yielded the highest rate of plant survival. IGP by C. carnea larvae occurred mostly in the first instar, whereas C. maculata larvae were more aggressive in later instars. Although C. carnea was the superior intraguild predator, winning 62.7% of contests in microcosms, this value increased to 88.9% when the experiment was repeated in petri dishes without plant material, regardless of whether greenbugs or eggs of Ephestia kuehniella Zeller were offered as focal prey. Provision in petri dishes of the sessile, higher quality prey (Ephestia) as opposed to greenbugs, improved the survival of solitary larvae and delayed cannibalism and IGP until later developmental stages in both species. Larvae of C. maculata that cannibalized took longer to develop and weighed less at pupation, independent of the arena or prey offered. Although larvae of C. carnea did not pay a cost for cannibalism or IGP in microcosms, there were some negative developmental effects of IGP in petri dishes, particularly on the Ephestia diet. These results illustrate how the plant, as a substrate, can mediate the strength of IGP interactions and how the relative suitability of the focal prey can influence both the timing and consequences of cannibalism and IGP.

POPULATION FLUCTUATION, BIOLOGICAL FEATURES OF DUBAS BUG (Ommatissus lybicus DeBerg (HOMOPTERA :TROPIDUCHIDAE ) ATTACKING DATE PALM TREES (Phoenix dactylifera L.) AND ITS BIOLOGICAL CONTROL BY Chrysoperla carnea (Steph.) LARVAE.

The Palm trees, attacking by many insect pests and among the most important of these insect pests Dubas bug Ommatissus lybicus DeBerg (Homoptera: Tropiduchidae ). The study of the population fluctuation of Dubas bug O. lybicus was carried out in Helwan on date palms in correlation with studying associated natural enemies. Field studies were carried out during two successive seasons (2010/2011 and 2011/2012) by fortnightly visits to examine the fronds of the selected palms. The data showed that there are two generations per every year (spring and autumn generations) on Date palm trees. There was a negative correlation between Dubas numbers and each of temperature and relative humidity. There was no significant differences between the two seasons. The most widely spread predators were Chrysoperla carnea (Steph.), Coccinella undecimpunctata L., Sphodromantis sp. As respect to biological studies on dubas bug, O. lybicus were carried out in 2009. The obtained results showed that the insect pest had two annual generations (spring and autumn generations) and the adult passed through five nymphal instars before maturity. The spring generation lasted 166.5±12.85 days, while autumn generation lasted 145±6.20 days. The nymphal stage lasted 53.5±1.87 days for the spring generation and 51.5±1.87 days for the autumn generation. Adult females lived 63±5.6 days and 91.4±13.6 days in spring and autumn generations, respectively. The respective figures for males were 33.5±6 and 76±9 days. The number of de­posited eggs ranged from 146.5±8.23 eggs/female for the spring generation to 146.5±2.45 eggs/female in autumn generation. The incubation period of the egg stage reached 117.5±1.87 days and 60±3.32days for spring and au­tumn generations, respectively. Statistical analysis showed that there were significant differences between developmental time means of eggs and adults for both generations. Results also showed that there were significant differences between spring and autumn life span periods (235.5±16.30 and 164±9.09 days, respectively). Nymphal stage of dubas bug showed five developmental instars with five moulting, with significant differences recorded among means of developmental periods among nymphal instars (8.5±1.29, 10.5±1.29, 13±1, 11.5±1.29, 14±1 and 8±1, 8.5±1.29, 12±1, 13±1, 13.5±1.29 days) for spring and autumn generations, respectively. The results showed significant differences between male and female longevities for both generations. The biological control of dubas bug by Ch.carnea Larvae, showed that the Ch. carnea larvae has the ability to consume average 16.4±6.9 nymphs of the first nymphal instar of dubas bug during 24 hours.