Major Insect Pests Research Articles

Toxicity of Essential Oil from Plectranthus amboinicus (Lamiales: Lamiaceae) against Sitophilus zeamais (Coleoptera: Curculionidae)

Abstract Maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), is a major insect pest of stored grain products, causing extensive damage to both grain quantity and quality. The application of synthetic insecticides to control this insect has a negative impact on human health and the environment. Essential oils derived from natural plants are recognized as user- and environmentally friendly alternatives. The use of essential oils from Lamiaceae, which exhibit toxic properties through contact, fumigation, and repellency, provides another option for protecting stored products from various insect pests. The aim of this research was to study the chemical constituents and insecticidal activity of essential oil extracted from the leaves of Indian borage, Plectranthus amboinicus (Lour.) (Lamiales: Lamiaceae), against S. zeamais adults.The chemical composition of the essential oil was analyzed using gas chromatography–mass spectrometry, and the insecticidal activity against adult maize weevils was investigated in the laboratory. The experimental plan followed a completely randomized design with five replications of seven treatments or concentrations of the essential oil: 0, 0.5, 1, 1.5, 2, 2.5, and 3 µl/ml air. The results revealed that the essential oil from the leaves of P. amboinicus contained 23 chemical constituents (97.51%). Thymol (49.96%) was identified as the main compound followed by caryophyllene, trans-α-bergamotene, 3-methyl-4-isopropylphenol, γ-terpinene, p-cymene, caryophyllene oxide, humulene, 4-hydroxy-2-methylacetophenone, 2-hydroxy-2-phenylbutyramide, (2-oxazolidinylidene)malononitrile, hexestrol, terpinen-4-ol, 1-octen-3-ol, (1R,7S,E)-7-isopropyl-4,10-dimethylenecyclodec-5-enol, α-bisabolene, isoaromadendrene epoxide, α-farnesene, 4-carene, α-muurolene, 3-hexen-1-ol, ledene oxide-(II), and α-myrcene, respectively. The fumigation toxicity (median lethal concentration) to maize weevil adults at 48 h was 292.53 µl/ml air. The essential oil from the leaves of P. amboinicus, when applied at a concentration of 2 µl/ml air for 144 and 168 h, resulted in adult maize weevil mortality exceeding 90%. The highest concentration tested (3 µl/ml air) led to exceptionally high mortality rates, with 99–100% of the maize weevils succumbing to the treatment. These findings demonstrate that essential oil from P. amboinicus leaves holds promise as a fumigation insecticide for reducing the population of maize weevils, a significant pest in stored products.

Insecticidal evaluation of various plant extracts against the red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae); A major stored grains insect pest

Insecticidal evaluation of various plant extracts against the red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae); A major stored grains insect pest

Influence of weather factors on population dynamics of major insect pests in moringa (Moringa oleifera Lam.) in south Tamil Nadu

Influence of weather factors on population dynamics of major insect pests in moringa (Moringa oleifera Lam.) in south Tamil Nadu

Abundance and Dispersion Indices of Helicoverpa armigera (Lepidoptera: Noctuidae) on Tomato Plant in Nigeria

Helicoverpa armigera is among the major insect pests that pose a threat to tomato production in Nigeria with an insufficient understanding of its population parameters, and available environmentally friendly control materials which are essential for the development of reliable and sustainable management strategies that can minimize the frequent use of synthetic pesticides; which are hazardous to the environment, non-target organism, and humans. The present study was conducted with the objectives of establishing population abundance and dispersion of H. armigera. Surveys were conducted in the savannah agroecological zone of Nigeria through fortnightly field visits to tomato farms from July to September 2019 (rainy season), and month of December 2019 to March 2020 (dry season), making a total of seven (7) and Nine (9) visits respectively. Ten plants were randomly selected and tagged from each farm, for observation of the presence of H. armigera larvae on the upper and lower parts early in the morning (6:00-7:30 am) on all sampling. Numbers found on each plant were counted and recorded with dates. Data obtained were subjected to analysis of variance and the least significant difference (LSD) at 0.05% level of probability was used to separate significant means. Data were further used in calculating the various dispersion indices. The result indicates that H. armigera was higher at 8 weeks after planting and aggregated on the upper part of the plant with a higher population in the dry season. Abundance and dispersion indices of H. armigera on tomato plants reported in this study will provide for appropriate decision-making in designing eco-friendly management of the pest.

Pyramiding aphid resistance genes into the elite cowpea variety, Zaayura, using marker-assisted backcrossing

The cowpea aphid (Aphis cracivora) is a cosmopolitan insect pest that causes economic damage on cowpea. Although the pest persists at all the growth stages of the crop, in West Africa, aphids are the only major insect pests that farmers regularly control at the vegetative stage. Thus, deploying aphid-resistant crop varieties can reduce farmers' expenditure on insecticide. The availability of different biotypes of the pest and reports of resistance breakdown necessitates pyramiding of sources of aphid resistance to develop a more robust genotype for durable resistance. Two aphid-resistance genes, sourced from SARC-1-57-2 and IT97K-556-6, were introgressed through gene pyramiding technique into a farmers’ preferred cowpea variety, Zaayura, using marker-assisted backcrossing. A simple sequence repeat (SSR) marker, CP 171F/172R, and an allele-specific single nucleotide polymorphism (SNP) marker, 1_0912, were used for foreground selection of the SARC-1-57-2 and IT97K-556-6 aphid resistance genes, respectively. A stepwise backcross approach was used to introgress the major aphid resistance QTL (QAc-vu7.1) from IT97K-556-6 into Zaayura using the marker 1_0912 coupled with intermittent screening under artificial aphid infestation. After the fourth backcross generation, three heterozygous BC4F1 of Zaayura/TT97K-556-6 were intercrossed to Zaayura Pali to develop intercross F1 (ICF1). Three true ICF1 hybrids allowed to self to produce ICF2. Five (5) out of 48 ICF2 plants which were genotyped with the two foreground markers had the two aphid resistance genes fixed in the double homozygous dominant state. For background selection, out of 192 allele-specific markers screened, only 47 polymorphic markers were identified and used for the background analysis of the pyramided lines. The recurrent parent genome recovery ranged from 72 to 93.8 %. ICF2_Zaa/556/SARC-P6 had the highest recurrent parent genome and the least heterozygosity among the five improved lines. The five pyramided lines showed superior resistance under artificial aphid infestation as compared to the two donor parents with damage scores ranging from 2.0 to 2.3. On the field, however, there were no significant differences between the pyramided lines and their recurrent parent for all the agronomic traits measured except for grain yield. The pyramided lines do not only stand the chance of being released as new varieties but are also valuable genetic resources for other breeding programs that seek to improve cowpea for aphid resistance.

Seasonal Incidence of Major Insect Pests of Chilli and Their Correlation with Weather Parameters

Study Design: Randomised Block Design (RBD) with three (3) replications. Place and Duration of Study: Biswanath College of Agriculture, Assam Agricultural University, Assam,India. The experiment was conducted during Rabi 2022-23. Methodology: Suryamukhi variety of chilli from packages of practices for Organic crops of Assam was used for this investigation. Three sucking pests viz, Aphis gossypii, Scirtothrips dorsalis, Amrasca biguttula biguttula and one fruit borer Helicoverpa armigera was found infesting the chilli plants. Weather parameters such as maximum temperature, minimum temperature, average relative humidity, rainfall and bright sunshine hours were correlated with the insect populations. Results: Aphids were positively correlated with sunshine hours (r=0.503*), thrips showed negative correlation with average relative humidity (r= -0.620*), jassids had a negative correlation with minimum temperature (r=-0.701*) and fruit borer showed negative correlation with sunshine hours (r= -0625**). Rainfall had no significant effect on incidence of pest population in chilli. Conclusion: Insect pest populations are highly influenced by weather parameters. Through this research we can develop new pest management strategies according to their appearance and peak activity period.

Seasonal incidence of insect pest of banana (Musa paradisiaca) from Gangetic basin of West Bengal, India

Present study was carried out during 2018–23 at Bidhan Chandra Krishi Viswavidyalaya, Nadia, West Bengal with a view to ascertain the seasonal incidence of major insect pests and occurrence of new emerging pests of banana (Musa paradisiaca L.) crop. The study revealed that leaf and fruit scarring beetle Basilepta subcostata (Jacoby) was most dominating insect-pest followed by rugose spiralling whitefly (Aleurodicus rugioperculatus Martin). All the studied weather parameters collectively influenced 90, 87, 87 and 77% of variations in the incidence of B. subcostata (Jacoby), Odioporus longicolis (Olivier), A. rugioperculatus (Martin) and Oligonychus sapienticolus (Gupta), respectively. Barring Oligonychus sapienticolus (Gupta), all other studied insects had significant positive correlation with different weather parameters except sunshine hours that showed positive correlation with the spider mite. Besides, few insects were recorded as emerging problem of banana crop in this state like banana lace wing bug Stephanitis typica (Distant), sucking pest of banana foliage and brown tussock moth Olene mendosa (Hubner) feeding on the unfurled leaf of the seedling suckers and thus causing considerable damage.

Seasonal fluctuation and alternative host plants of vegetable crop-infesting tephritids in non-vegetable growing areas in South Sudanese zone of Burkina Faso.

This study was carried out in 3 types of biotopes where vegetable crops are not grown to highlight their contribution to the dynamics of vegetable-infesting flies. To this end, a trapping system based on a sexual attractant, the Cuelure associated with an insecticide was set up in 18 biotopes (6 natural areas, 6 mango orchards, and 6 agroforestry parks) in the regions of Hauts Bassins and Cascades in the South-West of Burkina Faso. During the trapping monitoring, which was done every 2wk to collect insects captured, fruits present in 3 types of biotopes were sampled and incubated for insect emergence. Ten Dacus (Fabricius) [Diptera: Tephritidae]species and Zeugodacus cucurbitae (Coquillett) [Diptera: Tephritidae] were trapped in the study area. The predominant species captured was Z. cucurbitae (52.93%) followed by Dacus punctatifrons (Karsch) [Diptera: Tephritidae] (29.89%) and Dacus humeralis (Bezzi) (12.71%). Six tephritid species were emerged from 6 wild fruit species belonging to Cucurbitaceae, Apocynaceae, and Passifloraceae families. Fruit flies were more abundant from Jul to Nov with peaks observed in Aug or Oct depending on the species. Citrullus colocynthis L. (Cucurbitaceae), Lagenaria sp. (Cucurbitaceae), Passiflora foetida L. (Passifloraceae), and Passiflora sp. acted as reservoir host plants of Dacus ciliatus (Loew), Dacus bivittatus (Bigot), Dacus vertebratus (Bezzi) [Diptera: Tephritidae], D. punctatifrons, and Z. cucurbitae, the major vegetable insect pests in West Africa. The 3 types of biotopes acted as suitable refuge areas of vegetable crop-infesting fruit flies either for the favorable microclimate or for the alternative host plants.

Comparative study on the repellency and chemical profiles of different chilli peppers formulations against Sitophilus oryzae L. (Coleoptera: Curculionidae) in stored wheat

The weevil Sitophilus oryzae L. (Coleoptera: Curculionidae) is the major insect pest of stored grains, including wheat. This study tested the repellency effectiveness of three formulations, including chilli dry powder (CDP), chilli ethanol extract (CEE), and chilli crude extract (CCE), from different chilli peppers of Capsicum annuum L. and Capsicum chinense Jacquin varieties (Solanaceae), against S. oryzae using a modified cup bioassay arena. Repellency responses varied significantly (P ≤ 0.001) within the three different formulations, where the CEE formulation at the concentration of 5 g (w/w) demonstrated the highest effectiveness, effectively deterring the highest number of insects (mean number of repelled insects ± SE) after 24 h of treatment across tested chilli varieties such as Guntur Sannam chilli (GSC) (15.0 ± 0.6), Kashmiri chilli (KC) (16.0 ± 0.0), and Bhut Jolokia chilli (BJC) (18.0 ± 0.6). CDP formulation closely followed, displaying notable repellency activity against the same varieties. Conversely, the CCE formulation exhibited the least effectiveness in repelling the adult weevils. Thus, the repellency activity observed was time-, concentration-, and formulation-dependent. Further, the percentage repellency (PR) assay conducted by following the area preference method demonstrated that the Bhut Jolokia chilli exhibited the highest repellency percentage (61.2%) at a concentration of 0.251 μg/cm2, by categorizing it as a class IV repellent. Gas chromatography-mass spectrometry (GC-MS) analysis detected the presence of capsaicinoids like capsaicin and dihydrocapsaicin, alongside various non-capsaicinoids such as n-hexadecanoic acid and n-pentadecylacetamide, etc., in the ethanolic fraction of chilli pepper varieties, suggesting that the observed differences in the repellency activity might be attributed to varying chemical compositions, warranting further detailed exploration in this domain. These findings provide valuable primary insights into the prospective application of chilli pepper formulations from different varieties as a repellent against S. oryzae.

To study the population dynamics of major insect pests in black gram (Vigna mungo L. Hepper) in relation to weather parameter

to study the population dynamics of major insect pests in black gram (Vigna mungo L. Hepper) in relation to weather parameter

Optimizing the releasing strategy used for the biological control of the sugarcane borer Diatraea saccharalis by Trichogramma galloi with computer modeling and simulation

One of the challenges in augmentative biological control programs is the definition of releasing strategy for natural enemies, especially when macro-organisms are involved. Important information about the density of insects to be released and frequency of releases usually requires a great number of experiments, which implies time and space that are not always readily available. In order to provide science-based responses for these questions, computational models offer an in silico option to simulate different biocontrol agent releasing scenarios. This allows decision-makers to focus their efforts to more feasible options. The major insect pest in sugarcane crops is the sugarcane borer Diatraea saccharalis, which can be managed using the egg parasitoid Trichogramma galloi. The current strategy consists in releasing 50,000 insects per hectare for each release, in three weekly releases. Here, we present a simulation model to check whether this releasing strategy is optimal against the sugarcane borer. A sensitive analysis revealed that the population of the pest is more affected by the number of releases rather than by the density of parasitoids released. Only the number of releases demonstrated an ability to drive the population curve of the pest towards a negative growth. For example, releasing a total of 600,000 insects per hectare in three releases led to a lower pest control efficacy that releasing only 250,000 insects per hectare in five releases. A higher number of releases covers a wider range of time, increasing the likelihood of releasing parasitoids at the correct time given that the egg stage is short. Based on these results, it is suggested that, if modifications to the releasing strategy are desired, increasing the number of releases from 3 to 5 at weekly intervals is most likely preferable.

Taxonomic Distribution of Major Insect Pest of Rabi Season at Jhansi (U.P.) Using Solar Powered Light Traps

The experiment was conducted at Bundelkhand University, Jhansi (UP) during the period March and April, 2021 to study the taxonomic distribution of insect pest species collected in Solar powered Light Traps model SMV- 8 and SMV- 9 using low energy light source i.e. 7w UV LED. According to taxonomic analysis, 8 insect species were recorded and they belong to four orders and eight families. Based on the number of species collected, the order Lepidoptera had the biggest collection (42 per cent), followed by the order Coleoptera with 3 species (40 per cent). The pyraliidae family has the most insect pests (25 per cent), followed by the Scarabaeidae family (19 per cent).

Strong resistance to β-cyfluthrin in a strain of the beetle Alphitobius diaperinus: a de novo transcriptome analysis.

The lesser mealworm, Alphitobius diaperinus, is an invasive tenebrionid beetle and a vector of pathogens. Due to the emergence of insecticide resistance and consequent outbreaks that generate significant phytosanitary and energy costs for poultry farmers, it has become a major insect pest worldwide. To better understand the molecular mechanisms behind this resistance, we studied a strain of A. diaperinus from a poultry house in Brittany that was found to be highly resistant to the β-cyfluthrin. The strain survived β-cyfluthrin exposures corresponding to more than 100 times the recommended dose. We used a comparative de novo RNA-Seq approach to explore genes expression in resistant versus sensitive strains. Our de novo transcriptomic analyses showed that responses to β-cyfluthrin likely involved a whole set of resistance mechanisms. Genes related to detoxification, metabolic resistance, cuticular hydrocarbon biosynthesis and proteolysis were found to be constitutively overexpressed in the resistant compared to the sensitive strain. Follow-up enzymatic assays confirmed that the resistant strain exhibited high basal activities for detoxification enzymes such as cytochrome P450 monooxygenase and glutathione-S-transferase. The in-depth analysis of differentially expressed genes suggests the involvement of complex regulation of signaling pathways. Detailed knowledge of these resistance mechanisms is essential for the establishment of effective pest control.

From weeds to natural enemies: implications of weed cultivation and biopesticides for organic onion production.

Weed management is challenging for vegetable crops that are highly sensitive to weed competition, such as onions. Thrips (Thysanoptera: Thripidae) are major insect pests of onions, causing damage through feeding, and vectoring bacterial pathogens causing bulb rot. Both thrips and their associated pathogens are known to survive on many weed species in onion growing regions. Combining weeding with biopesticides may synergistically manage thrips and reduce disease prevalence. However, disturbances from weeding may negatively impact natural enemies. We estimated the effects of organic weed management and biopesticides on weed density, thrips and natural enemy activity, disease severity, and yield. The experiment was a randomized complete block design, with 4 replications of each weeding (control, tine-weeded twice, tine-weeded 4 times, and hand-weeded) and biopesticide (control, OxiDate 2.0, Serenade) combination. Arthropods were monitored using yellow sticky cards, and weed counts, marketable yield, and bulb rot prevalence were estimated. Hand-weeding resulted in the lowest weed density and thrips abundance. Additionally, hand-weeding produced a 9× higher yield compared to all other treatments. Significant interactions were observed between tine-weeding and biopesticide treatments on the prevalence of bulb rot. Natural enemy abundance was slightly negatively impacted by weeding, dependent on the year. DNA metabarcoding results showed high parasitoid diversity in this onion system and high numbers of reads for multiple genera containing important known biological control agents. Our study suggests hand-weeding is necessary in the southeast for maximum onion yield. Future research should focus on exploring the impact of management on natural enemy communities in onion systems on a large scale.

Seasonal Incidence of Major Insect Pests in Mungbean; Vigna radiata (L. Wilczek)

The current studies on seasonal incidence of major insect pests were carried out at Students’ Instructional Farm of Acharya Narendra Deva University of Agriculture & Technology, Kumarganj, Ayodhya (UP), India during Kharif 2022 and 2023. The current study revealed that whitefly, B. tabaci was commenced from the second fortnight of July and touched the peak at 32th (9.8 whitefly per cage) and 35th SMW (9.4 whitefly per cage) in both the year, respectively. The populations of B. tabaci had a significant negative correlation with rainfall (r= -0.699) in Kharif 2022. The jassid had the highest population in 34th SMW (4.6 jassid/cage) in Kharif 2022, while in second year, maximum jassid population of 5.1 jassid/cage was recorded during 33rd SMW. Wind speed had a significant and negative effect (r=-0.804) on the population of jassid during Kharif 2023. Seasonal abundance of thrips showed that, in first year, the thrips activity reached maximum at 33rd SMW (1.2 trips/5 flower buds). In next season, peak population of 1.4 thrips per 5 flower buds was in 32nd SMW. The correlation study during both the season revealed that the sunshine hours (r= -0.683) showed significant and negative effect on thrips population in 2023. Peak pod borer damage was observed in 36th SMW (5.3%) and 35th SMW (6.7%) during 2022 and 2023, respectively. Correlation between pod borer damage and weather parameters showed that wind speed had negative and significant (r= -0.707) effect on borer damage in first year.

Pigeon pea crop stage strongly influences plant susceptibility to Helicoverpa armigera (Lepidoptera: Noctuidae).

Helicoverpa armigera Hübner (Lepidoptera: Noctuidae; Hübner) is the major insect pest of pigeon pea [Cajanus cajan; Fabales: Fabaceae; (L.) Millspaugh] worldwide. Research to develop pest management strategies for H. armigera in pigeon pea has focused heavily on developing less susceptible cultivars, with limited practical success. We examined how pigeon pea crop stage influences plant susceptibility to H. armigera using a combination of glasshouse and laboratory experiments. Plant phenology significantly affected oviposition with moths laying more eggs on flowering and podding plants but only a few on vegetative plants. Larval survival was greatest on flowering and vegetative plants, wherein larvae mostly chose to feed inside flowers on flowering plants and on the adaxial surface of expanding leaves on vegetative plants. Larval survival was poor on podding plants despite moths laying many eggs on plants of this stage. When left to feed without restriction on plants for 7 days, larvae feeding on flowering plants were >10 times the weight of larvae feeding on plants of other phenological stages. On whole plants, unrestricted larvae preferred to feed on pigeon pea flowers and on expanding leaves, but in no-choice Petri dish assays H. armigera larvae could feed and survive on all pigeon pea reproductive structures. Our results show that crop stage and the availability of flowers strongly influence pigeon pea susceptibility to H. armigera. An increased understanding of H. armigera-pigeon pea ecology will be useful in guiding the development of resistant varieties and other management tactics.

Bio-Efficacy of Newer Insecticides on Major Insect Pests of Rice (Oryza sativa L.)

Present study was carried out at the Farm of Institute of Agricultural Sciences, Banaras Hindu University, Varanasi during 2022-23. In order to study the bio-efficacy of insecticides; field experiment was laid with six treatments viz., chlorantraniliprole 0.53%G @ 29.81 g a.i/ha,chlorantraniliprole 0.53%G@39.75g a.i/ha, chlorantraniliprole 0.53%G@49.69 g a.i/ha, chlorantraniliprole 0.4G@ 40 g a.i/ha and fipronil 0.3G @75 g a.i/ha including the untreated control. In case of stem borer and leaf folder chlorantraniliprole 0.53%GR @39.75g a.i/haprovided significantly better control followed by chlorantraniliprole 0.53% GR @ 49.69g a.i/ha, Fipronil 0.30% GR@ 75g a.i/hachlorantraniliprole 0.53%G @ 29.81 g a.i/ha and Chlorantraniliprole 0.40% GR@ 49.69g a.i/ha. It was concluded that the Bio-efficacy of insecticidal treatments against major pests of paddy showed that chlorantraniliprole 0.53%G 39.5g a.i/ha was first best insecticidal treatment against both Lepidopteran insect pests of paddy.

Comparative Efficacy of different Funnel Diameters in Light Traps against Major Phototactic Insect Pests of rabi Season

Light traps have been long used to reduce and manage insect populations. Although there are numerous types and designs of insect light traps. Four distinct light traps were employed for the study and positioned within the BSP Unit Adhartal, JNKVV Jabalpur from mid-November 2022 to mid-April 2023 for the study of the efficiency test of different funnel diameters of light traps based on performance. Comparative studies of light trap catches revealed that 50 cm funnel diameter light traps have given higher response in following species for Helicoverpa armigera (13.91%), Agrotis ipsilon (14.36%), Creatonotus gengis (13.97%), Gryllus bamaculatus (22.26%), Gryllotalpa orientalis (45.30%), Nezara viridula (9.82%), Amata cyssea (13.35%), Asota ficus (7.01%), Perina nuda (21.78%), and Thysanoplusia orichalcea (22.75%). There was a statistically significant increase in trap catches in the 50 cm funnel diameter light traps compared to the 40 cm funnel diameter traps. However, there was a statistically non-significant difference between the 40 cm and 50 cm funnel diameter traps for Spodoptera litura and Theretra oldenlandiae species, although the trap catches were numerically higher in the 50 cm funnel diameter traps because 50 cm funnel diameter provide large catchment area for insects.

Insecticidal Activity of Ten Plant Extracts on Cucumber [Cucumis sativus (L.)] Insect Pests in a Rainforest Transition Zone of Nigeria

Cucumber, Cucumis sativus L. an important vegetable crop in southwestern Nigeria, faces significant threats from a diverse array of insect pests, requiring the application of synthetic insecticides for optimal fruit production. The associated drawbacks of insecticide usage, combined with its adverse effects on consumer health, highlight the need for an alternative control strategy. Field trials were carried out during the cropping seasons of 2013 and 2014, and subsequently repeated in the 2019, to assess the effectiveness of ten plant extracts against the insect pests of cucumber. The treatments were leaf extracts from ten plant species: Cymbopogon citratus, Carica papaya, Ocimum gratissimum, Vernonia amygdalina, Chromoleana odorata, Azadirachta indica, Gmelina arborea, Hyptis suaveolens, Alstonia boonei, and Ageratum conyzoides. Additionally, a synthetic insecticide, Lambdacyhalothrin, and water were applied as check and control treatments, respectively. The experiment was laid out in a randomized complete block design with three replicates. Data collected were subjected to analysis of variance at 5% probability. The major insect pests associated with cucumber were leaf pests such as Aulacophora nigripennis, A. hilaris, A. foveicollis, Epilachna chrysomelina, and the fruit borer Bactrocera cucurbitae. The application of leaf extracts resulted in a notable reduction (p < 0.05) in populations of cucumber insect pests. The densities of E. chrysomelina, Aulacophora spp., and B. cucurbitae, along with their associated damage to cucumber leaves and fruits, demonstrated a significant decrease when cucumber was treated with leaf extracts of A. conyzoides and G. arborea. The effectiveness of A. conyzoides and G. arborea leaf extracts in controlling pests was evident, leading to a substantial increase in cucumber fruit yield. Consequently, these could be used as a practical alternative to synthetic insecticides.

Efficacy of Botanical Oils on Adult Mortality, Egg Laying, Hatchability and Adult Emergence of Callosobruchus. Maculatus (F.) (Coleoptera: Chrysomelidae: Bruchidae)

The cowpea weevil Callosobruchus maculatus Fabricius, is the major insect pest that threatens effective legume storage. The laboratory experiment was conducted to assess the efficacy of four different botanical oils (Clove, Eucalyptus, Jojoba and Lemon) against the cowpea weevil, C. maculatus by using residual film technique. All the botanical oils were applied at two different concentration levels (0/50 and 0.75%). The results showed that all used oils significantly increased the mortality and reduced the mean number of eggs laying, hatchability and emergence percentages compared to the untreated control. The treatment of cowpea seeds with oils reduced slightly the germination but swelling percentage was higher in treated seeds than control. The results also indicated variation in the activity of botanical oils regarding the stage of the insect, the plant origin of the oils and concentration level. The present study suggested that botanical oils (Clove, Eucalyptus, Jojoba and Lemon) may be preferred option than conventional pesticides far the protecting stored pulse grains against stored products insect pests’ infestation, especially C. maculatus.