Carnea Larvae Research Articles

Predation, fecundity and life table parameters of Chrysoperla carnea Stephens, 1836 (Neuroptera: Chrysopidae) on two factitious preys

Chrysoperla carnea is an important pest predator, widely used for controlling insect pests. In the present study, predation and life table parameters of the predator on two factitious foods (namely: Galleria mellonella and Achroia grisella) were studied under laboratory conditions. On G. mellonella (egg stage), the development of predatory females and males was shorter than on A. grisella. In contrast, on larval stage, A. grisella recorded the shorter developmental period of predatory males and females than on G. mellonella. On both stages of A. grisella, C. carnea gave the highest reproduction rates. Life expectancy for female stage was recorded maximum of (68.0 days) on A. grisella eggs. C. carnea larvae consumed more G. mellonella larvae than A. grisella. Net and finite predation rates of C. carnea were higher on A. grisella eggs than on G. mellonella. This study indicated the suitability of both factitious preys for rearing C. carnea.

Biology and predation of the Chrysoperla carnea (Stephens) (Insecta: Neuroptera: Chrysopidae) feeding on two important spider mite pests (Acari: Tetranychidae) under low humidity.

The biology and predation of the generalist predator, Chrysoperla carnea (Stephen) (Neuroptera: Chrysopidae) were studied while feeding on motiles of two economically important spider mite pests: citrus brown mite (CBM), Eutetranychus orientalis (Klein) (Acari: Tetranychidae) and date palm mite (DPM), Oligonychus afrasiaticus (McGregor) (Acari: Tetranychidae) under low relative humidity (RH) (35 ± 5%). Results showed that the predator larvae did not pupate when fed on CBM and DPM motiles at both low and high RH. The shortest total predator larval duration was against motiles (14.65 ± 0.15 days) and eggs (15.42 ± 0.80 days) of CBM at low and high RH, respectively. Adult longevity, however, was higher when C. carnea was fed on the eggs of Ephestia cautella (Walker) (Lepidoptera: Pyralidae) (male: 32.00 ± 1.61 days; female: 36.75 ± 0.25 days) than CBM eggs (male: 13.00 ± 0.00; female: 31.00 ± 2.00). The highest total predation by the predator larvae were found against the eggs of CBM (12671.11 at high RH) followed by motiles of CBM and DPM (4696.53 and 4088.16 at low RH), respectively. Considering the significance of CBM and DPM as a pest in the arid climate of Saudi Arabia, it is essential to understand how C. carnea responds to these pests at low RH. These results depict that the predator larvae voraciously fed on eggs and motiles of mite pest species revealing its potential use as a biological control agent against spider mites at both low and high RH levels. The high predation rate and completion of life cycle on the eggs of CBM could also be considered as satisfactory indication of the potential use of C. carnea larvae for spider mite management. The inability of the predator larvae to complete the life cycle against motiles of CBM and DPM could help to devise a management plan for multiple/repeated releases of the predator larvae.

Lifecycle Completion and Reproductive Improvement of Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae), Following a Prey Shift Routine During Larval Development.

The present study aimed to assess the lifecycle completion and reproductive improvement of green lacewing, Chrysoperla carnea (Stephens), larval instars in a prey shift routine while alternatively feeding on motiles of two-spotted spider mite, Tetranychus urticae Koch (natural prey), and the eggs of almond moth, Ephestia cautella (Walker) (factitious prey). The results showed that C. carnea larvae successfully completed their lifecycle and life span in the treatments where either the 2nd (T2) or 3rd (T3) instar larvae were fed with the eggs of E. cautella while other instars were provided with motiles of T. urticae, i.e., 1st-3rd and 1st-2nd, respectively. The predator larvae failed to transform from pupae to adults when only the 1st instar larvae were fed on the E. cautella eggs (T1). Similar results were found when all predator instars were reared on the motiles of T. urticae (T4). The shortest mean total larval duration and preoviposition period, the highest fecundity and fertility, and balanced sex ratio were recorded when 3rd instar larvae were fed only on E. cautella eggs (T3). The longest adult longevity and oviposition period were recorded when only the 2nd instar larvae were fed on E. cautella eggs (T2). The findings of the present study would be helpful in developing a self-sustained mite biological control strategy using C. carnea and provide a roadmap for future studies to elucidate the larval release efficiency of C. carnea with the supplementary diet for the management of greenhouse mite pests.

Toxicity and fitness evaluation of Chrysoperla carnea resistant strains on cotton mealy bug Phenacoccus solenopsis Tinsely

Toxicity and fitness evaluation of Chrysoperla carnea resistant strains on cotton mealy bug Phenacoccus solenopsis Tinsely

Predation efficacy of Chrysoperla carnea on two economically important stink bugs

Larvae of the green lacewing Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) are generalist predators feeding on a range of pests in agroecosystems. Little is known about the suitability of stink bugs as prey for lacewing larvae. In the present laboratory study, the predatory efficacy of C. carnea on two economically important stink bugs, Halyomorpha halys (Stål) and Nezara viridula (L.) (Hemiptera: Pentatomidae), was evaluated at three constant temperatures (16, 21, and 26 °C) in different arenas (10-cm diameter dishes with bean pod slices or caged small bean plants). We found that second and third instars of C. carnea readily prey on the first instars of both stink bug species. However, only third instars of C. carnea could successfully kill and feed on second instars of either pentatomid. The complexity of the arena, as well as the life stage of the prey and predator influenced the predation efficacy of C. carnea on stink bug nymphs, whereas temperature did not. The observed predation rates on the early instars of both stink bugs suggest that augmentative releases of C. carnea larvae may have some potential in greenhouse crops, particularly against N. viridula infestations, whereas in open field crops their natural populations may also contribute to pest suppression within the broader predator guild.

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.

The Role of Chrysoperla carnea (Steph.) and Beauveria bassina for Controlling Cabbage Aphid, Brevicoryne brassicae L. on Cabbage Plants

Saleh, A.A.A., H. El-Nagar, A.A. Khalifa and M.F.M. Zawrah. 2023. The Role of Chrysoperla carnea (Steph.) and Beauveria bassina for Controlling Cabbage Aphid, Brevicoryne brassicae L. on Cabbage Plants. Arab Journal of Plant Protection, 41(3): 321-326. https://doi.org/10.22268/AJPP-041.3.321326 Field experiments were carried out at Kafr Saqr district, Sharkia governorate during 2019/2020 and 2020/2021 growing seasons to evaluate the predator:prey ratios for the release of C. carnea and evaluation of using Beauveria bassiana suspension against the cabbage aphid, Brevicoryne brassicae. The results obtained showed that the effective control of B. brassicae was achieved ten days after releasing the larvae of the predator C. carnea when the predator:prey ratios were 1:5 and 1:10. Meanwhile, at higher ratios (1:20, 1:25 and 1:50), the cabbage aphid B. brassicae numbers decreased 25 days after predator release. The numbers of B. brassicae decreased by 84.69 and 81.61% at 1:5 and 1:10 predator:prey ratio during the first season, respectively. On the other hand, the aphid numbers were reduced by 81.50 and 70.95% at 5 days after the predator’s release during the second season, for the two predator:prey ratios, respectively. Complete reduction of B. brassicae populations was achieved at 15 days after yhe release of C. carnea larvae with predator ratios of 1:5, 1:10 and 1:15, and numbers of B. brassicae at these ratios depressed completely 20 days after release. The results revealed that the best control of B. brassicae populations under greenhouses conditions was achieved by using the lower predator:prey ratio of 1:5 and 1:10 ten days after releasing larvae of C. carnea. The highest mortality rate in B. brassicae population caused by the fungus B. bassiana was 88.33%, recorded at 7 days after the application of spore concentration 1×107 spores/ml and the LC50 obtained in the field was 1.10×106 spores/ml. It can be concluded from this study that C. Carnea and B. bassiana are effective biocontrol agents in controlling the cabbage aphid B. brassicae in the field. Keywords: B. brassicae, Chrysoperla carnea, Beauveria bassiana, Predator release.

A Roundup herbicide causes high mortality and impairs development of Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae)

Glyphosate has and is being used extensively in herbicide formulations worldwide. Thus, glyphosate-based herbicides (GBH) substantially add to the environmental load of pesticides and warrant a strict risk assessment. Ecotoxicological testing of herbicides focuses on non-target plants and higher animals while direct effects on arthropods are only cursory tested on the premise of contact exposure. However, oral exposure, as we show in our case, can be highly relevant for systemic pesticides, such as GBH. Specifically, in crop systems including genetically modified crops that are tolerant to GBH, these herbicides and their breakdown products are present both internally and externally of the crop plants and, therefore, are ingested by the crop-associated arthropod fauna.We tested the effects of oral uptake of the Roundup formulation WeatherMax on larvae of the lacewing Chrysoperla carnea, a model organism in ecotoxicity testing programs. Long-term oral exposure of C. carnea larvae throughout its juvenile life stages was tested with concentrations ranging from 0.001 to 1 % dilution, thus, lower than the 1.67 % recommended for field applications. Inhibition of metamorphosis was observable at 0.1 % but at a concentration of 0.5 %, GBH significantly impaired cocoon formation and led to massive lethal malformations. At GBH concentration of 1 % half of the individuals remained permanent larvae and no adult hatched alive. The effects observed followed a clear dose-response relationship.The hazard caused by direct insecticidal action of GHB after oral uptake is highly relevant for the environmental safety and reveals a gap in regulatory risk assessments that should urgently be addressed, specifically in light of the on-going insect decline.

Feeding potential and development of <em>Chrysoperla carnea</em> (Neuroptera: Chrysopidae) on <em>Paracoccus marginatus</em> (Hemiptera: Pseudococcidae) under no-choice conditions

Purpose: Considering the predatory effectiveness of Chrysoperla carnea (Neuroptera: Chrysopidae), studies were carried out at National Agricultural Research Centre, Islamabad, Pakistan to determine the feeding potential and developmental period of its larval instars on Paracoccus marginatus (Hemiptera: Pseudococcidae). Research Method: Eggs, 1st, 2nd, and 3rd nymphal instars and adults of P. marginatus was provided to all three larval instars of C. carnea in a Completely Randomized Design experiment, replicated ten times. Findings: Results indicated that all C. carnea larval instars were found to feed on all P. marginatus stages. Overall mean consumption of C. carnea larvae on P. marginatus eggs, 1st, 2nd and 3rd instar nymphs, and adults was 1359.8, 1409.1, 1012.4, 1165.7 and 130.30 individuals, respectively. Third instar C. carnea larvae was more voracious than 2nd and 1st instars. The shortest developmental period (12.40±0.37 days) of C. carnea larvae was recorded on 3rd nymphal instar of P. marginatus. Moreover, C. carnea larvae took 14.90±0.23, 14.00±0.25, 13.10±0.23, and 13.60±0.34 days on eggs, first, second nymphal instars and adults of P. marginatus, respectively to complete their development. Originality/value: Therefore, it is suggested that C. carnea should be included as a key component in the integrated management of P. marginatus, especially its 3rd larval instar

Spodoptera litura (Lepidoptera: Noctuidae) rearing on artificial feed with Chrysoperla carnea predation (Neuroptera: Chrysopidae)

S. litura was reared on artificial meals in a controlled laboratory setting at 26.1°C, 16:8 h L:D, and 65.5% RH at the National Agricultural Research Center (NARC) in Islamabad, Pakistan, to evaluate its premature, mature adult stage characteristics and predation by C. cornea. On the artificial diet, the results for various parameters, including total larval duration (19.1 days, 45 percent), pre-pupal period (3.4 days, 92 percent), pupal period (7.05 days, 83 percent), and total immature duration from eggs to adult stage (33.4 days, 33 percent), as well as percent survival rate, were recorded. On a corn-based artificial diet, data on the pre-oviposition period (2.4 days), oviposition period (5.4 days), post-oviposition period (1.63 days), female fecundity (1366 eggs), and adult longevity (8.66 days) of mature stages of S. litura were collected. When supplied as prey, the predator's biological parameters and predatory capacity, C. carnea, were tested on two stages of S. litura (eggs and 1st instar larvae). The studies indicated that the prey significantly affected the total larval duration, immature duration, and % survival rate. The entire larval period was greatly minimized when C. carnea was offered eggs of S. litura for feeding. Additionally, higher % survival and fecundity were observed feeding with S. litura eggs, followed by 1st instar larvae. C. carnea consumed 443 S. litura eggs and 395 S. litura larvae during its larval development. Daily consumption of C. carnea larvae reached a maximum of 73 eggs and 53 1st instar larvae of S. litura. Comparatively, C. carnea larvae recorded maximum egg predation compared to 1st instar larvae of S. litura and the shorter developmental period when eggs were offered as prey. Moreover, 3rd instar larvae of C. carnea were found more voracious than early instars.

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.

Conspecific neighbors and kinship influence egg cannibalism in the green lacewing, Chrysoperla carnea (Stephens)

BackgroundChrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) is an illustrious predator that performs cannibalism upon facing small and defenseless conspecifics. Eating preference of C. carnea larvae was investigated between conspecific and host (Sitotroga cerealella) eggs. Early instars of C. carnea express significant preference toward conspecific eggs over host eggs. Experiments were carried out to examine the role of conspecific neighbors in execution of cannibalistic decision. These cannibalistic behaviors of larvae were also investigated through locomotion bioassays using the video tracking software ANY-maze®.ResultsLarvae commit low egg cannibalism when alone but express higher cannibalism in the presence of conspecific larvae in the neighborhood. The role of relatedness in egg cannibalism was investigated when larvae were offered a choice between conspecific eggs from related and unrelated parents. Larvae did a discrimination between eggs of their own parents and those of other parents.ConclusionBehavioral bioassays showed attraction toward conspecific eggs and the eggs of unrelated parents. This study emphasizes the significance of informational and descriptive cues that modulate the cannibalistic expression in C. carnea.

Post-Dropping Behavior of Potato Aphids (Macrosiphum euphorbiae)

Dropping behavior is an effective antipredator defense utilized by many insects including aphids, which drop from plants to lower plant parts or underlying substrates to avoid attack from predatory invertebrates. While research commonly focusses on triggers of dropping, less attention is given to what happens to prey individuals following escape drops. In this study, the duration of tonic immobility, recovery rates, and cases of “instant recovery” (re-clinging to lower plant parts) exhibited by potato aphids (Macrosiphum euphorbiae) that dropped from potted seedlings in response to introduced ladybird (Adalia bipunctata) adults, lacewing (Chrysoperla carnea) larvae, and a standardized tactile stimulus were investigated in relation to a range of environmental factors. Air temperature had a negative correlation with the duration of post-dropping tonic immobility; as temperature increased, time spent motionless decreased. Aphids also showed a pattern of increased recovery rate at higher temperatures. Aphids may be selected to move off the substrate quicker to avoid risks of overheating/desiccation at higher temperatures; and/or higher body temperature facilitates locomotion. Stimulus type also influenced recovery rate back to the original seedling, with aphids generally recovering after the standardized stimulus quicker than after dropping triggered by a real predator. Considering cases of instant recovery onto lower-reaches of the host seedling, seedling height influenced the likelihood of re-clinging, with aphids that managed to instantly recover dropping from, on average, taller seedlings than aphids that dropped to the substrate. Plant architecture could mitigate the costs of dropping for aphids, but further studies quantifying understory foliage cover are needed.

Evaluating the Impact of Two Generalist Predators on the Leafhopper Erasmoneura vulnerata Population Density.

Simple SummaryErasmoneura vulnerata, a grapevine leafhopper native to North America, was detected in Europe (North-eastern Italy) in the early 2000s. Although it is considered a minor pest in its native range, outbreaks of this species have been reported in North-eastern Italy. In this study, we investigated the potential of two generalist predators, i.e., Chrysoperla carnea and Orius majusculus, in suppressing E. vulnerata in laboratory and semi-field experiments. Both species significantly reduced nymph numbers in laboratory and semi-field conditions. For this reason, field trials were performed. Predator releases in vineyards reduced E. vulnerata abundance by about 30%. Since naturally occurring E. vulnerata antagonists exert a moderate impact and the effectiveness of natural insecticides is limited, the augmentative release of generalist predators can be considered a complementary tool in controlling E. vulnerata populations in vineyards, particularly in organic farms.Outbreaks of the Nearctic leafhopper Erasmoneura vulnerata represent a threat to vinegrowers in Southern Europe, in particular in North-eastern Italy. The pest outbreaks are frequent in organic vineyards because insecticides labeled for organic viticulture show limited effectiveness towards leafhoppers. On the other hand, the naturally occurring predators and parasitoids of E. vulnerata in vineyards are often not able to keep leafhopper densities at acceptable levels for vine-growers. In this study, we evaluated the potential of two generalist, commercially available predators, Chrysoperla carnea and Orius majusculus, in suppressing E. vulnerata. Laboratory and semi-field experiments were carried out to evaluate both species’ predation capacity on E. vulnerata nymphs. The experiments were conducted on grapevine leaves inside Petri dishes (laboratory) and on potted and caged grapevines (semi-field); in both experiments, the leaves or potted plants were infested with E. vulnerata nymphs prior to predator releases. Both predator species exhibited a remarkable voracity and significantly reduced leafhopper densities in laboratory and semi-field experiments. Therefore, field studies were carried out over two growing seasons in two vineyards. We released 4 O. majusculus adults and 30 C. carnea larvae per m2 of canopy. Predator releases in vineyards reduced leafhopper densities by about 30% compared to the control plots. Results obtained in this study showed that the two predators have a potential to suppress the pest density, but more research is required to define appropriate predator–prey release ratios and release timing. Studies on intraguild interactions and competition with naturally occurring predators are also suggested.

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

Effects of a Salicylic Acid Analog on Aphis gossypii and Its Predator Chrysoperla carnea on Melon Plants

The salicylic acid analog BTH (benzo-(1,2,3)-thiadiazole-7-carbothioic-acid S-methyl ester) induces systemic acquired resistance by promoting plant resistance against numerous plant pathogens and some insect pests. The objective of the research was to evaluate the activation of plant defenses with BTH on melon (Cucumis melo L., Cucurbitaceae) and its effects on the herbivore Aphis gossypii Glover, 1877 (Hemiptera: Aphididae) and on the aphid predator Chrysoperla carnea (Stephens, 1836) (Neuroptera: Chrysopidae). Under laboratory conditions, plants were sprayed with BTH (50 g/ha) zero (B0), four (B4), and seven (B7) days prior exposure to insects. B0 treatment resulted in 100% mortality of aphid nymphs and disrupted adult feeding behavior (recorded by electrical-penetration-graphs technique), by prolonging the time to reach the phloem, requiring more probes to first salivation and reducing ingestion activities. There were no effects on feeding behavior of A. gossypii fed on B4 plants but on its life history because fewer nymphs were born, intrinsic rate of natural growth decreased, and mortality increased. There were no effects on biological parameters of aphids reared on B7 plants. Prey consumption by C. carnea larvae when predated A. gossypii fed on BTH-treated plants was not different among treatments. Therefore, BTH enhances the suppression of A. gossypii in the short term, without negative effects on the predatory larva C. carnea, which makes this plant strengthener a useful tool to be considered in integrated pest management programs.

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.

Functional Response of Chrysoperla carnea (Neuroptera: Chrysopidae) Larvae on Saissetia oleae (Olivier) (Hemiptera: Coccidae): Implications for Biological Control

Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) is a voracious predator of soft-bodied insects such as juveniles of scale insects and the black scale Saissetia oleae (Olivier) (Hemiptera: Coccidae) is an important pest of several crops, such as the olive tree. However, the predatory efficiency of C. carnea on S. oleae has been unstudied yet. The present work aimed to study the functional response of larvae of C. carnea fed on S. oleae nymphs. In a controlled laboratory environment, increasing densities of S. oleae second and third nymph stages were offered to newly emerged specimens of the three larvae instars of C. carnea. After 24 h, the number of killed S. oleae was recorded and the functional response of C. carnea was assessed. The three larval stages of C. carnea displayed a type-II functional response, i.e., killed prey increased with higher S. oleae densities up to a maximum limited by the handling time. The attack rate did not significantly differ among the three instars while the maximum attack rate was significantly higher for the third instar. The handling time of the first larval instar of C. carnea was higher than that of the third instar. Our results demonstrated that S. oleae could act as a food resource for all larval stages of C. carnea. Furthermore, the third larval stage of the predator was the most efficient in reducing S. oleae densities. These results suggest that C. carnea larvae could contribute to S. oleae control in sustainable agriculture.

Biological Characteristics of Chrysoperla carnea Steph. Fed on Two Prey Hosts Under Laboratory Conditions.

Biological characteristics of the predator Chrysoperla carnea, aphid lion were studied in the laboratory at a temperature of. 25±1°C, 70±5% relative humidity, and 16:8 h of daily light / dark periods. two different preys were tested as hosts for C. carnea larvae. The predator larvae were fed on newly emerged larvae of pink bollworm, Pectinophera gossypiella,and adult members of Aphis craccivora, Cowpea aphid (2-3 days old), The results showed that the duration of larval and pupal period of predator was observed differences which recorded 8.46± 0.82 and 6.92± 0.86 days, respectively, when the predator larvae fed on PBW larvae, while recorded 8.25± 0.96 and 6± 0.15 days, respectively, when the predator larvae fed on adult aphids. The larval survival percentage was 88.1% and 90.2% respectively, while the emergence of the adult was 87.4% and 94.7% respectively, Data showed the incubation period of eggs was similar in two treatments, the duration of C. carnea females had higher than the duration of males. The percent of egg hatchability recorded a higher value 95.87% when the predator larvae fed on adult aphids and recorded 91.51% when its fed on PBW larvae.