Chrysopidae Research Articles

Dynamics of Natural Mortality Factors of Immature Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) in Sugarcane Adjacent to Forest Fragments

ABSTRACTPest regulation may be favoured in crop fields adjacent to semi‐natural vegetation such as fragments of the Atlantic Forest in Southeastern Brazil. Therefore, the objective of this study was to analyse the dynamics of mortality factors for eggs and larvae of Diatraea saccharalis (Lepidoptera: Crambidae) in sugarcane adjacent to two types of forest fragments (Plateau and Gallery) at two distances from these fragments during two growing seasons. In each area (seven sugarcane plots), two 50 m long transects were established, parallel and spaced at 5 and 100 m from the field edge, and cohorts of the insect at each stage of development were monitored. The collected data were used to construct an ecological life table and determine the main mortality factors. Natural mortality factors that could not be characterised were grouped as unknown. In both seasons and stages of development observed, there was no difference in mortality between the two types of forest fragments (Plateau and Gallery) or between the two distances from the forest. For the egg stage, the mortality factors were classified as inviable due to infertility, predation, parasitism, desiccation and dislodgement. In both seasons, there was a significant difference in the natural mortality factors of D. saccharalis, with predation distinct from the others. Ants (Hymenoptera: Formicidae) and green lacewings (Neuroptera: Chrysopidae) were the most frequent predatory agents and occurred at both distances and types of forest fragments. For the larval stage, the mortality factors were classified as predation, parasitism, drowning and unknown, with the unknown group differing from the others. Unknown factors might have included predation, larval movement towards other plants and displacement caused by wind after hatching. Overall, predation is a key mortality component of D. saccharalis suppression. Therefore, agricultural practices focused on the conservation of natural enemies such as predators may provide more sustainable management.

Influence of Height on the Abundance and Richness of Green Lacewings (Neuroptera: Chrysopidae) in an Anthropically Modified Habitat.

Investigation of the diversity of lacewings (Neuroptera: Chrysopidae) is crucial in agricultural systems, as these insects are important predators of many pest species. Recent studies have shown that height influences the abundance and richness of insects. Information on these factors is scarce for species of Chrysopidae at different heights in agricultural and forest environments. This study aimed to evaluate the influence of height on the abundance and richness of green lacewings in an anthropically modified environment. Multilure traps baited with putrescine and ammonium acetate were placed in four areas of the "Luiz de Queiroz" Campus (Piracicaba, São Paulo State, Brazil) at two heights (2 and 10m) from April 2019 to March 2020. Species captured in traps hung at 2 and 10m above the ground surface were studied with the faunistic analysis ANAFAU, using ecological parameters and diversity indices. The similarity between the species was measured using the Morisita-Horn coefficient. Thirteen species of Chrysopidae were captured, and more species and specimens of green lacewings were collected with the traps at 2m than at 10m, that is, height influenced the abundance and richness of the lacewing species. Leucochrysa (Nodita) cruentata (Schneider) was predominant in most areas studied. The highest diversity and abundance of green lacewings was observed on Areão farm in trap at 2m height. However, Ceraeochrysa claveri (Navás) and Ce. everes (Banks) showed a more similar ecological pattern. Multilure traps baited with putrescine and ammonium acetate were effective in sampling green lacewings, mainly at 2m height.

Linking landscape structure, floral resource distribution, pollen use and movement distances of a generalist predator

Abstract Understanding the habitat use and movement patterns of natural enemies in agricultural landscapes is essential for enhancing biological pest control. Since many natural enemies rely on floral resources, the distribution of these resources in combination with movement behaviour likely influence biological control in field crops. Nevertheless, few studies have assessed natural enemy movement at the landscape scale. Here we estimated minimal movement distances of the green lacewing Chrysoperla carnea based on consumed pollen and the spatial distribution of the respective plant species in 24 agricultural landscapes (500 m radius). Lacewings were sampled using sticky traps in the centre of each landscape, and the consumed pollen were identified. The location of the most important pollen‐providing plants was mapped in each landscape. Distances to potential sources of pollen consumed by 346 lacewings were used to derive minimal movement distances. Lacewings consumed mostly pollen from insect‐pollinated plants that were present within 500 m from the sampling location. The distance to the nearest source of consumed pollen exceeded 200 m in 31% of lacewing individuals, demonstrating the relevance of the landscape scale to understand their population dynamics. Distances were shorter to insect‐pollinated than to wind‐pollinated plants, and shorter early than late in the season. Mean and median distances to pollen sources were negatively associated to flower availability and edge density in the landscape, but this was not the case for minimal distances. Synthesis and applications. Our findings suggest that the spatial distribution of flowering wild plants can inform movement patterns of lacewings and other flower‐visiting insects in agricultural landscapes. In addition, the location of floral resources in the landscape is important for its capacity to sustain natural enemies. Given the strong reliance of lacewings on pollen from nearby insect pollinated woody plants, the promotion of native shrubs and trees, such as Prunus, Salix and Castanea, should be prioritized for natural enemy enhancement in agricultural landscapes. Doing this in the form of hedgerows or agroforestry systems would lead to only minimal reduction in production areas and provide additional benefits such as biodiversity conservation.

Polygenic, autosomal, and stable spirotetramat resistance in Chrysoperla carnea resulting in increased fitness.

Green lacewing, Chrysoperla carnea (Stephens) is a generalist predator used as a biological control agent in agro ecosystems. In order to use chemical and biological control in an integrated way, it is advantageous to know about natural enemy resistance response to a selected chemical. To determine C. carnea spirotetramat resistance potential, a population collected from the field was selected in the laboratory. Then we determined how spirotetramat resistance was inherited and how much it impacts the fitness of C. carnea. After eighteen selections with spirotetramat, the selected population (Spiro-Sel) of C. carnea had a 47-fold of resistance when compared to an UNSEL population. Inheritance results showed that spirotetramat resistance was inherited as an autosomal, incompletely dominant and polygenic trait. The values of effective dominance decreased from 0.87 (incomplete dominant) to 0.00 (complete recessive) as the concentration of spirotetramat increased from 625 mg/L to 10000 mg/L. The Spiro-Sel strain had no cross resistance to chlorfenapyr (1.10-fold), deltamethrin (1.26-fold) and chlorpyrifos (1.27-fold). After 7 generations without selection pressure resistance to all experimental insecticides in the Spiro-Sel strain was stable. Fitness data of the Spiro-Sel, Cross A, Cross B, UNSEL and susceptible strains of C. carnea showed that spirotetramat resistance increased the fitness of the selected green lacewing population. Life history parameters like fecundity, net reproductive rate, and relative fitness of the Spiro-Sel strain significantly increased when compared to the susceptible or unselected strains of C. carnea. These findings show that C. carnea is a perfect candidate for integrated pest management (IPM) programmes that combine biological control methods with selective pesticide applications to manage a variety of insect pests. Additionally, it would reduce the possibility of pests developing pesticide resistance despite repeated applications. It would be an excellent choice for widespread releases and be effective in most spray programs.

The genome sequence of a green lacewing, Nineta flava (Scopoli, 1763).

We present a genome assembly from an individual Nineta flava (green lacewing; Arthropoda; Insecta; Neuroptera; Chrysopidae). The genome sequence spans 732.30 megabases. Most of the assembly is scaffolded into 7 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 16.16 kilobases in length.

Green Lacewing Chrysoperla externa Is Attracted to Volatile Organic Compounds and Essential Oils Extracted from Eucalyptus urograndis Leaves.

Plant herbivore interactions have long been recognized as a complex interplay influenced by various factors, including plant volatile emissions. Understanding the role of these volatiles in mediating plant predator interactions is crucial for developing sustainable pest management strategies. This study investigated the olfactory preferences of Chrysoperla externa larvae for volatiles emitted by Eucalyptus urograndis leaves, focusing on both seedlings and essential oils (EOs). We used Y-tube olfactometry to compare larval preferences between the clean air and various plant treatments, including undamaged and herbivore-damaged leaves. Chemical analysis of EOs revealed higher concentrations of oxygenated monoterpenes and sesquiterpenes in young and damaged leaves, particularly linalool, which has been implicated in insect attraction. Our results showed a significant preference for volatiles emitted by young damaged leaves over clean air for both seedlings (χ2 = 11.03, p = 0.001) and EOs (χ2 = 9.76, p = 0.002). Chrysoperla externa larvae are significantly attracted to specific volatiles from damaged E. urograndis leaves, suggesting these compounds could serve as cues for natural enemy foraging. Our findings enhance the understanding of plant-predator dynamics and suggest potential applications of eucalyptus plantations to sustain C. externa populations for biocontrol purposes.

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.

Comparative evaluation of biological control programs and chemical pesticides for managing insect and mite pests in cucumber greenhouses: a sustainable approach for enhanced pest control and yield

BackgroundCucumber plants are susceptible to several economically damaging pests, including whiteflies, aphids, thrips and spider mites. This study aimed to evaluate the efficacy of two biological control programs, utilizing different releases of bio-agents, in comparison with chemical control method. The bio-agents used were the aphid parasitoid Aphelinus albipodus Hayat and Fatima (Hymenoptera: Aphelinidae), the green lacewing Chrysoperla carnea (Steph.) (Neuroptera: Chrysopidae) and the predatory mite Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) in two release rates; low and high. Additionally, a chemical pesticides treatment was included for comparison in managing the pests in cucumber greenhouses during the winter seasons of 2022 and 2023, in Egypt. Abundances of whitefly, aphids, thrips and spider mites were recorded weekly throughout the study.ResultsThe aphid population in the greenhouse with high release rate (BIO 2) showed the highest reduction, with percentages of 84.55 and 89.88% in 2022 and 2023, respectively. Both greenhouse with low release rate (BIO 1) and BIO 2 exhibited significant reductions in the whitefly population, with proportions of 71.31 and 72.01% in 2022, and 82.05 and 85.94% in 2023, respectively. The thrips population also experienced notable reductions in both BIO 1 and BIO 2 greenhouses, with percentages of 72.08 and 75.71% in 2022, and 59.93 and 61.38% in 2023, respectively. However, the pesticide treatment demonstrated the lowest reduction in populations of aphids, whitefly and thrips in both seasons. Nevertheless, in all treatments in the two evaluated seasons, the high release rate of the predatory mite, P. persimilis (15 individuals/m2), proved to be highly effective in maintaining the mite populations below the economic threshold level. However, the population density of the two-spotted spider mite, Tetranychus urticae Koch. (Acari: Tetranychidae), increased in the pesticide-treated greenhouse, indicating the development of resistance to pesticides. Although the tested programs resulted in similar yields, the biological control approach offered the advantage of pesticide-free produce and reduced production costs.ConclusionFor pest management in cucumber growing in greenhouses during winter, it is recommended to use biological control agents at a low release rate at the early occurrence of pests. This approach can help minimize pest populations effectively.

New indications for the life habits of long-legged aphidlion-like larvae in about 100-million-year-old amber

AbstractLarvae of lacewings (Neuroptera) are known to be fierce predators today. Most characteristic are their prominent piercing-sucking stylets, which are used for venom injection and sucking out the fluids of the prey. Among lacewing larvae, aphidlions (larvae of the groups Chrysopidae and Hemerobiidae, green and brown lacewings) are today highly specialised to feed on aphids and evolved strategies to not be detected and attacked by, e.g., aphid-protecting ants. Fossil relatives of modern aphidlions seem to have also employed other strategies. For the species Pedanoptera arachnophila from about 100-million-year-old Kachin amber, Myanmar, an interaction of its larvae with spiders has been assumed. We present here new specimens resembling these larvae, including one piece of Cretaceous Kachin amber with a syn-inclusion of an aphidlion-like larva and an immature planthopper, indicating planthoppers as potential prey of the group about 100 million years ago. The morphology of the lacewing larva, with a trapezoid head capsule (in dorsal view), simple, toothless stylets, very elongate legs, and a spindle-shaped trunk, indicates that it is conspecific or at least closely related to P. arachnophila. We reconstruct the possible ontogenetic sequence of Pedanoptera arachnophila and discuss its ecology.

Testosterone maintains male longevity and female reproduction in Chrysopa pallens

Vertebrate testosterone, an androgen present in the testes, is essential for male fertility. Vertebrate-type steroid hormones have been identified in insects, but their function remains unknown. Insect vitellogenin (Vg) is usually a female-specific protein involved in reproductive processes. However, males of some species, such as the green lacewing Chrysopa pallens, have Vg. Here, we demonstrated that the knockdown of C. pallens male Vg by RNAi significantly shortened the lifespan of males, suppressed the reproduction of post-mating females, and strikingly reduced the abundance of several immune-related compounds, including testosterone. LC-MS/MS revealed that C. pallens male testosterone had the same structure and molecular mass as vertebrate testosterone. Topical testosterone application partially restored the lifespan of Vg-deficient males and the reproduction of post-mating females. These results suggest that vertebrate-type testosterone maintains male longevity and female reproduction under the control of the male Vg in C. pallens.

Evaluation of the green lacewing, Mallada signatus as a biological control agent for the invasive tomato potato psyllid, Bactericera cockerelli

Evaluation of the green lacewing, <i>Mallada signatus</i> as a biological control agent for the invasive tomato potato psyllid, <i>Bactericera cockerelli</i>

Testing the Effects of Prey Type on the Life History and Population-Level Parameters of Chrysoperla externa (Neuroptera: Chrysopidae).

Green lacewings are valuable predators, utilized in augmentative biological control against various agricultural pests. However, further studies are required to comprehend the performance of these predators when consuming natural prey. We investigated the capacity of Chrysoperla externa (Hagen) to utilize the following three distinct prey types: the pupae of the coffee leaf miner Leucoptera coffeella (Guérin-Mèneville & Perrottet), the eggs of the sugarcane borer Diatraea saccharalis (F.), and the eggs of the Mediterranean flour moth Ephestia kuehniella (Zeller). The first two of these species are naturally occurring prey found in field crops, while the last serves as a factitious prey species for the mass rearing of natural enemies. We hypothesized that the type of prey would differentially affect the life history and population-level parameters of C. externa. Laboratory experiments were conducted to compare the pre-imaginal survival and developmental times, adult longevity and reproduction, and population growth of C. externa when larvae were provided with each of the three prey items. Results indicated that C. externa utilized the two natural prey items, L. coffeella pupae and D. saccharalis eggs, for its development, reproduction, and population growth. However, larvae developed significantly faster and females exhibited higher reproductive parameters, including fecundity and daily oviposition, when consuming the factitious prey, E. kuehniella eggs. This resulted in a higher intrinsic rate of population increase, as well as shorter times for the population to double in size. Understanding the population dynamics of C. externa when consuming different prey items is crucial for optimizing their utilization in augmentative biological control programs.

Abundance and Seasonal Migration Patterns of Green Lacewings (Neuroptera: Chrysopidae) across the Bohai Strait in Eastern Asia.

Many insects, including green lacewings, migrate seasonally to exploit suitable breeding and winter habitats. Green lacewings are important natural enemies of insect pests worldwide. Here, four dominant green lacewing species, Chrysoperla nipponensis (Okamoto), Chrysopa pallens (Rambur), Chrysoperla furcifera (Okamoto), and Chrysopa formosa Brauer, were investigated for their ability to migrate between northern and northeastern China across the Bohai Strait from late May to late October each year. Furthermore, there were significant interannual and seasonal differences in the number of migratory green lacewings collected. The number of green lacewings in spring was significantly lower than that in summer and autumn, and the highest average number of green lacewings occurred in June. In addition, there were differences in the sex ratio of migrating green lacewings between months, with a greater proportion of females than males. Finally, the seasonal migration trajectories simulated by the HYSPLIT model revealed that the green lacewings captured on Beihuang Island primarily originated from Shandong Province. Accordingly, these findings contribute to our understanding of green lacewing migration in eastern Asia and aid its incorporation within integrated pest management (IPM) packages for several crop pests. Furthermore, long-term tracking of migrant insect populations can reveal ecosystem services and trophic dynamic processes at the macroscale.

Predatory Capacity of the Green Lacewing Chrysoperla zastrowi (Esben-Petersons) on Different Species of Aphids under Laboratory Conditions

Green lacewing, Chrysoperla zastrowi (Esben-Petersons) (Neuroptera: Chrysopidae) is the most effective polyphagous predator of different species of aphids and is commonly known as “aphid lion.” During the study, the green lacewing adults were collected from the flowers of different crop plants in Meerut region. The experiment on feeding potential of green lacewing was studied in the Bio-control Laboratory of Department of Entomology, Sardar Vallabhbhai Patel University of Agriculture &amp; Technology, Meerut from November 2019 to March 2020. The known number of predatory larvae of green lacewings were fed with known number of six different species of live aphids. The total food consumption of a single larva of C. zastrowi were found to be in order of 180.00 ± 1.24 A. craccivora, 171.33 ± 4.42 A. gossypii, 157.67 ± 1.49 B. brassicae, 142.67 ± 2.36 L. erysimi, 131.34 ± 2.19 R. maidis and 119.67 ± 2.94 M. persicae. Results revealed that the third instar were found more voracious than other two instar.

Insecticidal effects of the fast pyrolysis bio-oil against Spodoptera littoralis and Aphis gossypii insect pests

The detrimental effects of agricultural pesticides on human and environmental health necessitate the development of alternatives to conventional pesticides. In the laboratory, the cotton leafworm (Spodoptera littoralis) and aphid (Aphis gossypii) insects were used to evaluate the insecticidal activity of bio-oil derived from olive cake. The application of bio-oil by leaf dipping against S. littoralis demonstrated no mortality at a concentration of 1 % bio-oil. In contrast, the bio-oil showed better results against A. gossypii by slide dip method with LC50 = 1310.40 mg/l and LC90 = 3117.40 mg/l. The combined activity of bio-oil and the biopesticide Beauveria bassiana (bio-oil/B.b) was comparable, with LC50 = 1386.94 mg/L and LC90 = 3142.05 mg/L. The field application (two sprays) of bio-oil, bio-oil/B.b, and a commercial insecticide (alpha super) on aphids revealed a reduction of 52 %, 74.33 %, and 74.67 % in the first spray and 59.67 %, 63.33 %, and73.67 % in the second spray for, bio-oil, bio-oil/B.b, and super alpha respectively. The bio-oil and bio-oil/B.b had significantly less effect on the population densities of two predators (predator mite Amblyseius swirskii and aphid lion Chrysoperla carnea) than the insecticide used. Analyses of bio-oil by gaschromatography–mass spectrometry (GC–MS) identified 30 compounds possibly have pesticidal activity. The most abundant compounds are 9 octadecenoicacid methyl ester, hexadecanoic acid, methyl ester, 6 octadecenoic acid, methyl ester and Phenol, 2methoxy. The pyrolysis byproduct (bio-oil) of olive cake biomass contains bioactive compounds that can be used as biopesticide.

Study on the Population Density of Insect Pests of Broccoli, Brassica Oleracea, in the Jadiriyah Area of Baghdad, Iraq

A field study was conducted in the fields of the College of Agricultural Engineering Sciences at the University of Baghdad in Al-Jadriya during the 2018 agricultural season. The objective was to survey the population densities of pests affecting broccoli (Brassica oleracea). The results revealed that the broccoli plants in the open field were affected by various pests. On September 24, the highest density of two-spotted red mite (Tetranychus urticae) eggs reached 35 eggs per leaf. On November 12, the highest density of mite nymphs was recorded at 28 nymphs per leaf. The leaf miner, Liriomyza sativae, exhibited the highest density of 23 tunnels per leaf on September 17. Additionally, the highest density of whitefly nymphs (Bemisia tabaci) was observed on October 1 and November 17, reaching 29 nymphs per leaf. The results also indicated the presence of the aphid lion, Chrysoperla carnea, as a natural enemy. Furthermore, the parasitoid Diglyphus isaea was found on the leaf miner, while the parasitoid Eretmocerus mundus was identified on the whitefly. Therefore, understanding the species of pests and their density attacking agricultural crops is crucial. This knowledge allows for the release of natural enemies in the field to mitigate pest infestations.

Nanofertilizers and plant metabolites: Investigating their influence on trophic interactions in the cucumber-melon aphid-green lacewing

The role of fertilizers in increasing nutritional content and making host plants more attractive to herbivores has been repeatedly proved. This study investigated the effect of applying three levels of nano-chelated fertilizer (vegetables and summer crops specific fertilizer) (2, 3, and 4 kg/ha) on the levels of malondialdehyde (MDA), and phenylalanine ammonia-lyase (PAL), peroxidase (POD), polyphenol oxidase (PPO), catalase (CAT), ascorbic acid (ASA), flavonoid, and phenolic compounds in cucumber plant (Cucumis sativus L.). Additionally, the research surveyed the influence of fertilization and cucumber metabolite compounds on the life history of Aphis gossypii (Glover) (Hemiptera: Aphididae) and Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) in a tri-trophic context. Host plant content analysis showed that biotic stress resulting from the aphid infestation in cucumber plants increased the POD, PPO, CAT activity, and MDA contents. However, it decreased PAL activity, flavonoid, and phenol contents in the control treatment and 2, 3, and 4 kg/ha of nano-chelated fertilizer levels. Moreover, plant fertilization increased the herbivore population growth rates and decreased the predator population growth rates by affecting the nutritional contents and quality of the host plant. Accordingly, the aphid's intrinsic rate of increase (r) was ranged from 0.319 to 0.365 day−1. While finite rate of increase (λ) was estimated as 1.376 to 1.441 day−1 on control to 2 kg/ha nano-chelated fertilizer treatment. In addition, the intrinsic rate of increase of C. carnea was 0.116 to 0.131 and the finite rate of increase was 1.123 to 1.139 day−1 on 2 kg/ha nano-chelated fertilizer and control treatments, respectively. The maximum and minimum net reproductive rate (R0) values of the aphid were recorded on 3 kg/ha nano-chelated fertilizer and control treatments as 46.34 and 37.18 offsprings, respectively, whilst these values ranged from 145.51 on 2 kg/ha to 196.93 offsprings on 4 kg/ha regimes for the green lacewing. Notably, the utilization of 2, 3, and 4 kg/ha of nano-chelated fertilizer promotes cucumber defensive metabolites compounds such as PAL, POD, CAT, flavonoid, and ASA and induces the plant's resistance to melon aphids directly. It can be concluded that the utilization of nano-chelated fertilizer potentially can enhance cucumber plant resistance to A. gossypii by improving the antioxidant metabolite compounds, and be an effective part of integrated pest management programs.

Population Dynamics of Aphid Pests of Wheat and Their Natural Enemies

Four aphid species (Schizaphis graminum, Sitobion avenae, Rhopalosiphum padi and Diuraphis noxia) were observed when the population dynamics of aphids in four wheat varieties were analysed. Maximum population abundance (104± 1.79 aphids/ plant) was observed during middle of March. Rhopalosiphum padi and D. noxia were predominant throughout (52.86.1± 0.21 and 56.10± 0.24 aphids/ plant, respectively). The variety ANAJ-2017 showed the least incidence (26.28± 0.27 aphids/ plant) being more resistant. Aphid parasitism was also more in ANAJ-2017 with the parasites Aphidius ervi (15.35± 0.13) and Praon volucre (12.45± 0.12). Abundance of predators (ladybird beetle, green lace wing, syrphid fly and spiders) was observed with the highly infested varieties UJALA-2016 and FSD-2008. With incidence of aphids, temperature showed positive correlation while relative humidity (RH) and rainfall did not show any significant effect. The yield varied significantly among the tested varieties and it was found positively correlated with aphid incidence with ANAJ-2017 exhibiting the maximum 1000 grain weight (55 g).

Efficacy of Insecticides Against Major Sucking Insect Pests of Okra and Their Effect on Natural Enemies

Field experiment was conducted at the central research field, during kharif (March to July 2022). The experiment was laidout in RCBD (randomized complete block design). Ten treatments were evaluated against jassid Amrasca biguttula (Ishida) and whitefly Bemisia tabaci (Gennadius). At vegetative stage, lowest number of A. biguttula (0.25/ leaf) and B. tabaci (0.12/ leaf) was observed with emamectin benzoate +abamectin @ 0.50 g/ l and chlorantraniliprole + thiamethoxam @ 0.50 ml/ l. respectively, A. biguttula(1.16/ leaf) and B. tabaci (0.33/ leaf) was recorded as lowest with emamectin benzoate + abamectin @0.75 g/ l at fruiting stage. The lowest fruit infestation (9.56%) was observed with chlorantraniliprole +thiamethoxam @ 0.75 ml/ l. Maximum number of ladybird beetle, Coccinella septempunctata (L) (2.59/plant); spider, Hippasa agelenoides (Simon) (1.20/ plant) and green lacewing, Chrysoperla carnea (Stephens)(2.50/ plant) were observed when no insecticide was used. Both chlorantraniliprole + thiamethoxam @0.75 ml/ l and emamectin benzoate + abamectin @ 0.75 g/ l led to the least number of C. septempunctata(0.33/ plant). Flubendiamide @ 0.50 g/ l led to insignificant number of H. agelenoides (0.33/ plant). Thehighest fruit yield (19.56 t/ ha) was achieved from emamectin benzoate + abamectin @ 0.50 g/ l.

Tithonia diversifolia: beneficial companion plant to control Yellow Aphids on sugarcane fields in Tanzania

To find sustainable ways to protect its sugarcane areas from the key pest Sipha flava (Hemiptera: Aphididae) in north Tanzania, the local company TPC Limited funded a 6 months project in coordination with the French Agricultural Research Centre for International Development (CIRAD) to assess different agroecological practices, such as the use of companion plants around sugarcane fields. In this study, the influence of the flowering species Tithonia diversifolia located at the field edges as a potential banker plant for conservation biological control of the yellow sugarcane aphid was evaluated. Predatory species were identified by direct capture and/or regular observations and the intensity of aphid damage was evaluated through number of colonies. Twenty-four aphid predator species were identified being hosted by T. diversifolia, and the vicinity of this plant reduced by 86% the number of S. flava colonies in the sugarcane edges. These species belonged mostly to family Coccinellidae (ladybugs), Syrphidae (hoverflies), Chrysopidae (green lacewings), Dolichopodidae (long legged flies). This is the first paper evaluating T. diversifolia’s potential as a banker plant in sugarcane crops for pest control.