Insect Pests Research Articles

Toxicity of Essential Oil from Artemisia herba-alba (Asso.) against Two Insect Pests of Stored Products

This study aimed to examine the insecticide properties of Artemisia herba-alba essential oil (EO) against two main insect pests of stored products Tribolium castaneum and Sitophilus zeamais. The toxicity of EO was tested using contact and fumigant bioassays. Repellent activity was also studied using the preference zone method on filter paper. Using GC/MS analysis, the major compounds were, respectively, camphor (23.61%), α-thujone (13.67%), chrysanthenone (11.21%), 1,8-cineole (10%) and β-thujone (7.65%). In both insects, the toxicity tests applied showed a significant increase in the percentage of mortality according to the doses tested (p ≤ 0.05). Moreover, the probit analysis exposed lower values of doses and lethal concentrations (LD50, LD90, LC50, and LC90), which justified the toxic effect of EO on the two insects. In addition, EO caused a significant repulsion after 1 h and 2 h of exposure. The results obtained suggest that A. herba-alba EO can be an excellent alternative to chemical insecticides in the conservation of stored products.

Evaluation of Commercial Head Cabbage (<i>Brassica oleracea </i>L.) Varieties in Kellem Wollega Zone

Cabbage <i>(Brassica oleraceae</i> var.capitata) is one of the most important leafy vegetables worldwide and is adapted to cool moist conditions. The experiment was conducted at two sub-sites of Haro Sabu Agricultural Research Center from 2020-2024 at Belam FTC and in 2024 at Gute Anani FTC of Kellem Wollega zone, during main cropping season. Six commercial head cabbage were evaluated with objective the objective of selecting and recommending high yielder, disease and insect pest tolerant head cabbage varieties at for potential areas of Kellem Wollega. Analysis of variance(ANOVA revealed that the main effect of variety showed highly significant effect on days to head initiation and significant on plant height, plant spread, head length, average head weight, marketable yield, total yield and disease reaction. Similarly the main effect of environment showed highly significance on all recorded parameters. The highest (26.4tha<sup>-1</sup>) and the lowest (20tha<sup>-1</sup>) marketable yield were recorded from Bakker and Delta varieties. Hence Bakker and Olter varieties were recommended for the yield increment of head cabbage in the studied areas of Western Oromia.

Physical and chemical characterization of wild tomato Solanum habrochaites accessions for resistance to the sweetpotato whitefly

Sweetpotato whitefly Bemisia tabaci is a significant worldwide insect pest affecting tomato production, causing direct damage during feeding and transmitting multiple plant viruses to this crop. Continuing research to improve integrated pest management (IPM) of sweetpotato whitefly is required to maintain profitable tomato production for growers. This study evaluated the resistance of eight wild tomato accessions of Solanum habrochaites and four commercial tomato cultivars of Solanum lycopersicum to sweetpotato whitefly infestation. Field experiments were conducted at the Wiregrass Research and Extension Center at Auburn University, where whitefly populations were reported in vegetable crops. Accessions and cultivars were evaluated for resistance to whiteflies through the ability to reduce the insect population, analysis of the presence of glandular trichomes, and the profile and quantification of terpenes of each tomato species. Results indicated significant variations in whitefly population dynamics among the wild tomato accessions and commercial tomato cultivars. Wild tomato accessions of S. habrochaites had higher numbers of glandular trichomes and distinct terpene profiles, particularly sesquiterpenes, known for their pest-repellent properties. Multivariate analysis identified three clusters based on terpene profiles and trichome types correlating with whitefly resistance. Accessions of S. habrochaites PI127826, PI134418, and G29258 had prominent results. They significantly reduced whitefly nymph development compared to cultivars of S. lycopersicum. The GC-MS analysis of leaflet extracts revealed that accessions of S. habrochaites had higher levels of sesquiterpenes, including α-zingiberene, β-caryophyllene, and α-humulene, with PI127826 uniquely producing Ar-curcumene and 9-hydroxy-zingiberene. Results highlight the potential of wild tomato accessions of S. habrochaites in breeding programs to enhance whitefly resistance in tomatoes, which can support a sustainable IPM program.

Insecticidal and Repellent Activity of Essential Oils from Seven Different Plant Species against Tribolium castaneum (Coleoptera: Tenebrionidae).

Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) is the most destructive pest of stored grain commodities. To control the attack of this insect pest, it is important to develop non-hazardous alternatives to replace fumigants. This study examined the fumigant toxicity and repellent activity of seven essential oils (Chinopodium ambrosiodes, Pinus roxburghii, Zanthoxylum armatum, Lepidium sativum, Azadirachta indica, Baccharis teindalensis, and Origanum majorana) against adult T. castaneum under controlled laboratory conditions. The fumigant toxicity and repellent activities of essential oils were tested using five different doses (62.5, 125, 250, 500, and 1000 µg) in vapour-phase fumigation and four-arm olfactometer bioassays, respectively. In vapor-phase fumigation bioassays, mortality data were recorded after 24, 48, and 72 h. The results showed that C. ambrosiodes and P. roxburghii essential oils are potential fumigants against adult T. castaneum. In repellency bioassays, a one-week-old adult population of T. castaneum was used to test the repellency potential of the essential oils. The results indicated that C. ambrosiodes and P. roxburghii had significant repellency potential against T. castaneum. Overall, we conclude that these essential oils have strong repellent and fumigant properties and can be used as potential repellent compounds to deter the insects.

Side effects of semi-synthetic insecticide spinetoram on the whitefly parasitoid Encarsia formosa.

Insecticide risk assessment for biological control agents is essential for implementing integrated pest management (IPM) programs. Spinetoram is a naturally derived insecticide used to control a variety of agricultural sap-sucking insect pests, and Encarsia formosa Gahan (Hymenoptera: Aphelinidae) plays a key role in the biocontrol of greenhouse whiteflies. Despite its presumed safe ecotoxicological profile, the side effects of spinetoram on E. formosa are partially unknown, especially at sublethal doses. In the laboratory, we estimated the lethal concentrations (LC) of spinetoram on E. formosa by topical exposure of pupae and 48 h residual contact exposure of emerged adults. Afterwards, we assessed the impact of spinetoram LCs on the life history traits (juvenile development, adult longevity, parasitism, adult emergence) and population growth parameter (the instantaneous rate of increase, ri) of the parasitoid. Probit analysis allowed the estimation of LC10 = 0.10 mg/L, LC50 = 0.56 mg/L, and LC90 = 3.28 mg/L. Spinetoram at LC10 had no impact on the observed parameters of E. formosa. Conversely, spinetoram at LC50 and LC90 significantly reduced adult longevity by 19.2% and 40.6%, total parasitism by 33.4% and 38.7%, and total adult emergence by 29.6% and 39.1%, respectively. Also, the ri of E. formosa was significantly affected by spinetoram LC50 and LC90 with a reduction of 8.17 and 29.83%, respectively. Our results suggested that spinetoram significantly threatens the effectiveness of E. formosa when applied at the field recommended rate. However, further validation of spinetoram under greenhouse conditions is required for a comprehensive risk assessment for E. formosa in IPM programs. © 2024 Society of Chemical Industry.

Spatial Patterns of Adelges tsugae Annand (Hemiptera: Adelgidae) in Eastern Hemlock Stands: Implications for Sampling and Management.

Understanding the spatial patterns of insect pests and their associations with their environments is crucial for developing effective sampling and management plans. This study was conducted to identify optimal sampling units for the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae) and to characterize its spatial distribution patterns in hemlock (Tsuga canadensis (L.) Carrière) stands in West Virginia, USA. To determine the optimal sampling unit, we randomly selected 24 branches from each of 46 A. tsugae-infested hemlock trees. The locations and number of A. tsugae ovisacs on each branch were recorded and the coefficient of variation was used to choose the optimal sampling units. To determine the spatial patterns of A. tsugae, each of the three 1-ha hemlock stands was divided into 100 grids, and ovisac counts were taken from the center of each grid. Semivariograms and spatial analysis by distance indices (SADIE) were used to analyze the spatial patterns of A. tsugae. In addition, various environmental and biological factors were measured to explore their spatial associations with A. tsugae. The results of this study revealed that the A. tsugae ovisacs exhibited spatial aggregation within branches, predominantly at the tips, and a 50 cm branch approximately 3 m above the ground was the optimal sampling unit. The spatial aggregation of A. tsugae in the hemlock stands was evident, and positive spatial associations were found between A. tsugae populations and factors including the aspect, tree diameter at breast height, and tree height. These findings offer valuable insights for the sampling and management of A. tsugae.

The biogeographic patterns of the olive fly and its primary symbiont Candidatus Erwinia dacicola across the distribution area of the olive tree.

The olive fly, Bactrocera oleae (Rossi, 1790), is the major insect pest of olives attacking both cultivated and wild olive. Bactrocera oleae carries a primary and vertically transmitted symbiont, the bacterium Candidatus Erwinia dacicola. As any primary symbiont, it plays an important role in the reproduction and lifespan of the fly. The genetic 16S rRNA diversity of the primary symbiont and the mitochondrial haplotype variation of the insect host were simultaneously examined in 54 olive fly populations. The aim was to unravel the biogeographic patterns of this economically relevant host-bacteria interaction across a wide distribution area. Three symbiont haplotypes were identified. The primary symbiont showed a lower haplotype diversity than that of its host, a characteristic indicative of a long-term interaction. A significant genetic and geographic association between host and primary symbiont was observed, with an East-West genetic differentiation pattern in the Mediterranean basin, coinciding with the historical genetic distribution of the olive tree. The study shows promise, informing and aiding the development of future tools for the control of the olive fly.

Potent and selective ‘genetic zipper’ method for DNA-programmable plant protection: innovative oligonucleotide insecticides against Trioza alacris Flor

Chemical insecticides increased the chemical burden on natural ecosystems posing environmental health risk factor. The urgent need for a more sustainable and ecological approach has produced many innovative ideas, including eco-friendly ‘genetic zipper’ method (or CUAD platform) based on contact oligonucleotide insecticides. Oligonucleotide insecticides have enjoyed success recently on many sternorrhynchans showing highly adaptable structure for distinct insect pest species and selective mode of action. In this article, we describe the efficiency of the oligonucleotide insecticides (briefly, olinscides or DNA insecticides) Alacris-11 and Laura-11, as well as their combined use in mixture (1:1), designed for control of bay sucker (Trioza alacris Flor), an important psyllid pest of noble laurel (Laurus nobilis L.). These olinscides are based on short unmodified antisense DNA oligonucleotides that target ITS2 between 5.8S rRNA and 28S rRNA in pre-rRNA (Laura-11) and 28S rRNA region in mature 28S rRNA and pre-rRNA (Alacris-11). The maximum pest mortality, observed on the 14th day of the experiment, comprised 95.01 ± 4.42% for Alacris-11, 97.16 ± 2.48% for Laura-11, and 98.72 ± 1.14% for their mixture (1:1). The control oligonucleotide CTGA-11 did not cause any significant mortality (9.38 ± 0.57%), emphasizing selectivity in the action of oligonucleotide insecticides. The results show potent and specific nature of oligonucleotide insecticides for pest control and open up new frontiers in control of economically important psyllids in agriculture and forestry, including Asian citrus psyllid (Diaphorina citri Kuwayama) and many others. Scientists can easily adopt ‘genetic zipper’ method for plethora of insect pests because DNA is a programmable molecule and provides game-changing characteristics for plant protection.Graphical

Symbiont community assembly shaped by insecticide exposure and feedback on insecticide resistance of Spodoptera frugiperda

Exploring the mechanism of microbiota assembly and its ecological consequences is crucial for connecting microbiome variation to ecosystem function. However, the influencing factors underlying microbiota assembly in the host-microbe system and their impact on the host phenotype remain unclear. Through investigating the prevalent and worsening ecological phenomenon of insecticide resistance in global agriculture, we found that insecticide exposure significantly changed the gut microbiota assembly patterns of a major agricultural invasive insect pest, Spodoptera frugiperda. The relative importance of various microbiota assembly processes significantly varied with habitat heterogeneity and heterogeneous selection serving as a potential predictor of the host’s insecticide resistance in field populations. Moreover, disturbance of the gut microbiota assembly through antibiotics was revealed to significantly affect the rate and heritability of insecticide resistance evolution, leading to a delay in insecticide resistance evolution in this insect pest. These findings indicate that the gut microbiota assembly process of the insect host is influenced by persistent exposure to habitat conditions, particularly insecticides. This variation in insecticide exposure-related community assembly process subsequently influences the insect host’s insecticide resistance phenotype. This study provides insights into gut microbiota assembly processes from a symbiotic perspective and underscores the significant impact of symbiotic community changes on host phenotypic variation.

Assessment of Piper longum L. (Piperaceae) leaves toxicity on the adults of Tribolium castaneum (Herbst, 1797) (Coleoptera: Tenebrionidae)

BackgroundNumerous insect pests attack stored grains causing both qualitative and quantitative losses. The most damaging pest that infests dry stored produce is the red flour beetle, Tribolium castaneum, a secondary pest of stored goods. This pest, especially in its adult stage, exhibits resistance to chemical insecticides, thereby rendering the traditional pesticides ineffective in controlling it. Phyto-derivatives, which are strong insecticides and also ecologically benign, have gained interest as non-chemical solutions for controlling this pest. Hence, the objective of this study was to investigate the potential of Piper longum leaf extract insecticidal action as an environmentally benign insecticide for the first time against the adults of T. castaneum. In this study, P. longum leaf ethanol extract was tested against the adults of T. castaneum by petri dish bioassay method. Ad hoc studies to verify significant mortality for the initial confirmation of adulticidal activity were conducted for 24 h at different dosages of 62.5, 125, 250, 500 and 1000 mg/L of P. longum leaf ethanol extract. Thereafter, dosages set at 10, 20, 30 and 40 mg/L for the fractions of P. longum leaf ethanol extract were conducted. Prior to this, the leaf extract of this plant was subjected to column chromatography for fractionation. The fractions tested for adulticidal activity were subjected to gas chromatography–mass spectroscopy.ResultsSignificant adulticidal action with 100% adult mortality was observed in ethanol extract of P. longum leaves. Among the fourteen fractions (F0–F13) obtained tested, only fractions, F5, F10 and F13, demonstrated adulticidal activity, and the remaining fractions displayed poor activity. One hundred per cent morality was noted in T. castaneum adults after 96 h at 40 mg/L in F5 and F10, and in F13 at 20 mg/L, and their respective LD50 values were 17.6, 26.6 and 10.0 mg/L. The fractions F5, F10 and F13 contained fatty acids, viz., hexadecanoic acid, dotriacontane and heptacosane in F5; tetradecanoic acid and nonadecanoic acid in F10; and octadecanoic acid, aspartame and tridecanoic acid in F13, revealed through gas chromatography–mass spectroscopy.ConclusionsThe results of the study showed that P. longum ethanol leaf extract revealed significant adulticidal activity and is a promising toxic agent to the adults of T. castaneum. The fatty acids in the ethanolic leaf extract fractions of P. longum could have caused toxicity to the adults of T. castaneum. According to the current literature survey, this is the first research report on the adulticidal activity of P. longum leaf extracts against the adults of T. castaneum.

Understanding Farmers Problem and Training Needs on Apricot Production in Trans Himalayan Ladakh, India

A survey was conducted among 500 apricot growers in Ladakh to identify constraints faced in their production system and their grassroots training needs.Of the growers surveyed, 47.8 % of respondents were having less than 20 apricot trees. Most (53.8 %) grew apricots for drying, 31.2 % for fresh consumption, and 15 % for kernel oil. A significantly high number of respondents(44.8 %) reported 11-30 % fruit wastage, while 31.4 % reported 31-50 % fruit wastage. Lack of marketing opportunities and harvesting tools were cited as the main reasons for fruit wastage. The growers do not follow the standard growing practices, and the knowledge about insect pests and diseases is poor in the region. The most significant constraints in apricot production were lack of appropriate fruit drying technology, followed by high insect pest infestation, lack of marketing opportunities, lack of fencing around the field, insufficient water for irrigation purposes, and non-availability of nursery plants. Growers were open to a wide variety of sources of information on apricot production, with the most commonly selected response being friends/ relatives (53.2 %), followed by television (22.4 %), training and awareness camps (15.8 %), and radio (3.6%). The findings will help researchers, extension personnel, administrators, and policymakers to bring reforms to the apricot industry.

EpOME mediates the immune resolution and its alkoxide analog enhances the virulence of microbial insecticides against the legume pod borer, Maruca vitrata

Excessive and unnecessary immune responses cause serious adverse effects due to self-tissue damage and energy consumption, particularly at the late stage of infection to terminate the induced immunity. Unlike mammals, which use long-chain fatty acid oxylipins, C18 oxygenated polyunsaturated fatty acids are suggested to act as immune resolvins in insects, including two epoxyoctadecamonoenoic acids (9,10-EpOME and 12,13-EpOME). This study investigated the physiological roles of EpOMEs in immune resolution in the lepidopteran insect, Maruca vitrata. The levels of two EpOMEs in the larvae increased during the late infection stage upon immune challenge. At their peak concentrations at 96 h post-infection (pi), both EpOMEs were found at similar levels: 323.18 pg/mg body weight for 9,10-EpOME and 322.07 pg/mg body weight for 12,13-EpOME. Both EpOMEs inhibited cellular and humoral immune responses, with 12,13-EpOME being more potent than 9,10-EpOME. Genes associated with EpOME synthase and degradation, identified as Mv-CYP1 and Mv-sEH, were detected in various developmental stages and tissues of M. vitrata. RNA interference (RNAi) targeting Mv-CYP1 failed to inhibit the immune response, whereas RNAi targeting Mv-sEH enhanced the immunosuppression. In contrast to the acute (< 12 h pi) immune response involving eicosanoid biosynthesis, the expression of these two genes linked to EpOME metabolism increased significantly at the late infection stage (> 12 h pi). Several alkoxide analogs of EpOME, with the epoxide group replaced by an alkoxide group, were synthesized; one such derivative demonstrated substantially greater efficacy than the natural EpOMEs in inhibiting the immune response. Additionally, using EpOME alkoxide significantly increased the effectiveness of microbial insecticides. Moreover, exposing young larvae to sublethal doses of EpOME alkoxide or sEH inhibitor induced severe developmental delays. These results suggest a novel strategy for insect pest control using insect immune resolvin analogs.

Conservation agriculture compared to conventional tillage improves the trade-off between ground-dwelling arthropod trophic groups for natural pest regulation in cotton cropping systems

Conservation agriculture is an innovative approach based on minimal soil disturbance, soil cover with crop residues, and crop rotation, which increases the biodiversity of soil macrofauna thus contributing to nutrient cycling and soil aggregation. In addition, macrofaunal abundance may play a role at regulating insect pest populations. The study aims to predict the effects of soil management practices (conventional tillage and conservation agriculture) on the abundance of soil macrofauna and herbivore predation in cotton (Gossypium hirsutum L.) based cropping systems. We conducted a field experiment with a randomized complete block comprising two treatments, Conventional Tillage (CT) and Conservation Agriculture (CA), and six replications in a cotton-maize rotation system from 2020 to 2023. Soil monoliths and pitfall traps were installed in both treatments to collect ground-dwelling arthropods, to analyse the influence of soil management practices on their abundance, their trophic groups, and the rate of pest predation by generalist predators. Pest predation rates were assessed using artificial caterpillars made from plasticine. The results showed significant positive effects of soil management practices on herbivory rate, herbivore abundance, predator abundance, omnivore-predator abundance and pest predation rate. The average herbivory rate was 9.8 % in the conservation agriculture plots and 11.6 % in the conventional tillage plots. Overall, the predation rate was 58.9 % in the conservation agriculture plots and 21.8 % in the conventional tillage plots. The abundance of predators and of omnivore-predators were significantly higher in conservation agriculture than in conventional tillage. These findings suggest that conservation agriculture practices improve soil macrofauna and pest regulation, with potential benefits on soil quality and sustainability in cotton cropping systems.

Evaluating the Effects of Epichloë Fungal Endophytes of Perennial Ryegrass on the Feeding Behaviour and Life History of Rhopalosiphum padi.

The bird cherry-oat aphid, Rhopalosiphum padi (L.), is an economically significant pest of pasture grasses, the latter being capable of hosting several fungal endophyte-perennial ryegrass symbiota rich in alkaloids and toxic to vertebrates and invertebrates. Measuring aphid feeding behaviour can provide insights into the effectiveness and mode of action of different fungal endophytes. This study investigated the effects of different Epichloë-perennial ryegrass symbiota on the feeding behaviour of R. padi using the electrical penetration graph technique while also assessing the aphid life history. In most cases, endophytes had significant feeding deterrence and paired fecundity and mortality effects. But, in some instances, endophytes with the highest aphid mortality did not significantly deter feeding, suggesting a more complicated scenario of interactions between the relative concentration of metabolites, e.g., host plant defence response metabolites and alkaloids, and/or physical changes to leaf morphology. Overall, this study sheds light on the mode of action of Epichloë endophytes against aphids and highlights the importance of Epichloë-perennial ryegrass symbiota in the management of insect pests such as aphids in pasture-based grazing systems.

Constitutive and inducible tomato defenses contribute to Bacillus thuringiensis lethality against Spodoptera exigua

In nature, insect herbivory exerts continuous selective pressure on plants that, in turn, have developed a wide array of constitutive and inducible defenses to fight against attackers. Since plant defenses may affect higher trophic levels, including entomopathogens, further research is required to understand how plant compounds influence insect-pathogens interactions and their implications for integrated pest management programs. Here, we evaluated the impact of tomato defenses on the lethality produced by the bacterial entomopathogen Bacillus thuringiensis (Bt) against second instar larvae of Spodoptera exigua. We first examined the effect of constitutive defenses from fifteen wild tomato species and forty cultivated varieties (Solanum lycopersicum) on S. exigua larval growth and susceptibility to Bt. The results showed larvae fed on wild tomato species had a reduced larval growth compared to larvae fed on cultivated varieties, whereas susceptibility to Bt was similar between both groups. We then selected six cultivated varieties, including those with high and low impacts on larval growth and Bt-induced mortality, to further explore the effect of inducible defenses. Elicitation of defenses by methyl jasmonate (MeJA) reduced larval growth and increased basal mortality. Additionally, when larvae were infected with Bt, MeJA treatment further increased their susceptibility to the entomopathogen. Metabolomic analysis confirmed a reprogramming of tomato leaf metabolism following MeJA elicitation, with an induced accumulation of bioactive compounds, such as saponins or flavonoids, known for their anti-herbivory properties in most tomato varieties. Overall, these data reveal that both constitutive and inducible tomato defenses not only protect the plant by directly affecting the insect pest but also enhance the efficacy of bacterial entomopathogens

Evaluating sampling techniques for quantifying Asiatic garden beetle (Maladera formosae) (Coleoptera: Scarabaeidae) infestations in commercial mint.

The Asiatic garden beetle, Maladera formosae Brenske (AGB), has become a significant pest of commercial mint fields in northern Indiana. Larval feeding on mint roots can cause stunted growth and plant death when densities are high. Sampling approaches that provide reliable estimates of larval densities in mint have not been established, leaving farmers without the knowledge necessary to implement integrated pest management (IPM) strategies. To address this knowledge gap, we evaluated strategies for estimating AGB larval densities and plant performance in commercial mint systems. We used 2 sampling methods to collect larval density and plant performance data from 3 mint fields and conducted simulations to optimize sampling intensity (accuracy and precision) and sampling scheme (random vs. systematic) using these data. Additionally, we examined the sensitivity and efficiency of each sampling method. Compared to the cup-cutter method, the quadrat method provided the most accurate and precise estimates of larval density and plant performance, with ≤ 7 samples required per 0.2 ha. Quadrat excavation was also more sensitive, increasing the probability of detecting AGB larvae within a 32 m2 plot by 76.7%, and requiring significantly less time to survey an equivalent volume of soil for AGB larvae. When the quadrat method was employed, random sampling schemes provided below-ground biomass estimates that were significantly closer to the true mean of the sampling area. The results of this research will facilitate the development of IPM decision-making tools for farmers and support future research for AGB and other soil insect pests affecting mint production.

A tomato a day keeps the beetle away - the impact of Solanaceae glycoalkaloids on energy management in the mealworm Tenebrio molitor.

Solanine (SOL), chaconine (CHA), and tomatine (TOM) are plant secondary metabolites produced mainly by the species of Solanaceae family, such as tomato Solanum lycopersicum L. These glycoalkaloids (GAs) have a wide range of biological activity, also in insects. However, their mechanisms of action are not precisely understood. The purpose of the study was to investigate how pure GAs and tomato leaf extract (EXT) affect glycolysis, Krebs cycle and β-oxidation of fatty acid pathways in Tenebrio molitor L. beetle. For this purpose, the larvae were injected with SOL, CHA, TOM, and EXT at two concentrations (10-8 and 10-5M). For experiments, fat body, gut, and heamolymph samples were collected 2 and 24h after injection. Then, the changes in the expression level of phosphofructokinase, citrate synthase, and β-hydroxyacyl-CoA dehydrogenase were measured using the RT-qPCR technique. The catalytic activity of these enzymes and the carbohydrate level in insects after GA treatment were determined by spectrophotometric method. Furthermore, the analysis of the amount of amino acids in tissues was performed with a GC-MS technique. The results obtained show that the GAs changed the activity and expression of the genes encoding key enzymes of crucial metabolic pathways. The effect depends on the type of GA compound, the tissue tested, and the incubation time after treatment. Furthermore, TOM and EXT affected trehalose concentration in the insect hemolymph and led to accumulation of amino acids in the fat body. The observed changes may indicate a protein degradation and/or enhanced catabolism reactions for the production of ATP used in detoxification processes. These results suggest that GAs alter energy metabolism in the mealworm T. molitor. The study contributes to our understanding of the mechanisms of action of secondary metabolites of plants in insects. This knowledge may allow the design of new natural biopesticides against insect pests because proper energy metabolism is necessary for the survival of the organism.

UNLOCKING COMMERCIAL POTENTIAL: CPF 249, A MEDIUM-MATURING SUGARCANE VARIETY FOR PUNJAB

The substantial growth of sugar industry and the need to ensure national food security entail the extension of crushing season for sugar mills in Punjab by introducing medium and late maturing sugarcane varieties. The variety CPF 249 is a cross of CP 87-1628 × CP 84-1198, was developed from fuzz imported in 2002 from the Sugarcane Station in Canal Point, USA, and subsequently grown at the Sugarcane Research Institute, Faisalabad. Following successful initial selection, CPF 249 underwent four years of testing in preliminary, semi-final, and final varietal trials from 2008 to 2012. This medium-maturing variety demonstrates high tonnage and superior sugar recovery compared to other medium-maturing varieties such as CPF 247, SPF 245, and HSF 240. Furthermore, CPF 249 exhibits resistance diseases and insect pests, positioning it as an excellent alternative to SPF 245, SPF 234, and HSF 240 throughout Punjab. Economically, it offers a significant advantage, yielding an additional profit of Rs. 223,000 over SPF 245, Rs. 138,000 over HSF 240, and Rs. 54,000 per hectare compared to other local checks.

Assessing the Impact of Weather Parameters on the Population Dynamics of Insect Pests in Cucurbit Vegetables under Mid-Hill Conditions of Himachal Pradesh

A study focusing on population dynamics of sucking and leaf-eating some insect pests along with their correlation with weather parameters in cucurbits was conducted at research field, Department of Entomology, Dr. YSPUHF, Solan, H.P., India from June-October, 2019 and 2020. The results revealed that Amrasca biguttula biguttula (I), Trialeurodes vaporariorum (W), Aulacophora foveicollis (L), Henosepilachna vigintioctopunctata (F), Liriomyza trifolii (B), Aulacophora sp., were recorded as the major insect pests. In bitter gourd, maximum population of jassids recorded was (2.33/leaf) in first week of August while, maximum whitefly population in bottle gourd (2.96/leaf) during last week of August and in ridge gourd during last week of July (3.76/leaf). The maximum red pumpkin beetle population on bitter gourd (2.4 beetles/plant) and bottle gourd (2.6 beetles/plant) was observed during last week of August while, hadda beetle attained peak population during first and third week of August in ridge gourd (1.0/plant) and bitter gourd (1.1 adults/plant), respectively. Maximum leaf miner infestation (2.7 mines/leaf) in bottle gourd and ridge gourd was observed during first and third week of August. All pest attained maximum population between 30 to 32 SMW when weather parameters values were Tmax: 27.50 to 28.90; Tmin: 20.60 to 20.80 oC; RH: 79 to 80 %; Rainfall: 25.80 to 30.20 mm. Relative humidity and rainfall played major role with non-significant positive influence on the population build-up of these pests in cucurbit crops along with temperature. The present findings on weather-driven pest dynamics can inform strategies to boost crop yields and reduce farmers' economic losses in similar environments.

Push-Pull Intercropping Increases the Antiherbivore Benzoxazinoid Glycoside Content in Maize Leaf Tissue.

Push-pull technology refers to a promising mixed cropping practice for sustainable agricultural intensification, which uses properties of intercrop and border crop species to defend a focal crop against pests. Currently, the most widely practiced system uses Desmodium spp. as intercrop and Brachiaria or Napier grass as border crops to protect maize (Zea mays) against both insect pests and parasitic weeds. Several previous studies have demonstrated the efficacy of the push-pull system, but research on the underlying chemical mechanisms has mostly been limited to laboratory and glasshouse experiments that may not fully reproduce the complexity of the system under natural conditions. To address this limitation, we performed a large-scale study in farmer-operated push-pull maize fields in three east African countries. We compared maize leaf extracts from plants grown on push-pull fields with maize from fields employing conventional agricultural practices to assess the influence of push-pull cultivation on the maize metabolome. We identified two benzoxazinoid glycosides, which are known to have antiherbivore properties and were present in greater relative abundance in push-pull-cultivated maize leaves across three countries. Our data thus suggest that maize cultivated under push-pull has an increased resistance to herbivore attack compared to maize grown under conventional local agricultural practices.