F1 Progeny Production Research Articles

Predicted impact, establishment and distribution of Heikertingerella sp. (Coleoptera, Chrysomelidae), recently released for the biological control of Tecoma stans in South Africa

Abstract Biological control practitioners are required to demonstrate that candidate agents are not only safe for release, but will establish widely in their new range with a significant impact on the target weed. We conducted this study in quarantine to provide insight into the impact and distribution of the root‐feeding flea beetle Heikertingerella sp. (Chrysomelidae), released in early 2023 against the invasive tree Tecoma stans (L.) (Bignoniaceae) in South Africa. We studied the effects of low and high beetle densities on plant growth and biomass, and F1 progeny production by the beetle. There were significant reductions in plant growth and biomass accumulation in the beetle‐exposed plants, relative to the controls. P1 adults damaged significantly more leaflets, with significantly higher F1 progeny production, at high beetle densities. The MaxEnt model predictions suggested that most of South Africa is climatically highly suitable for Heikertingerella sp., particularly along the southern and eastern coasts where the weed is most prevalent. Only the inland regions of the Northern Cape Province, depicting the driest and hottest part of the country where the weed does not occur, were predicted to be unsuitable for Heikertingerella sp. The beetle's thermal physiology, as determined by its critical thermal minimum and maximum temperatures and lower and upper lethal temperatures (LT50), suggests tolerance to temperature extremes in at least four of the eight provinces that fall within the range of T. stans in South Africa. Our results further justify the release of Heikertingerella sp. in areas predicted as suitable in South Africa.

Benzyl alcohol, benzyl benzoate and methyl benzoate as bio-insecticides against dried bean beetle Acanthoscelides obtectus (Coleoptera: Tenebrionidae)

Acanthoscelides obtectus is most dangerous pest of preserved beans. The current study used benzyl alcohol (BA), benzyl benzoate (BB), and methyl benzoate (MB) to control A. obtectus. Contact and fumigant toxicity tests were performed to evaluate the efficacy of the used compounds. The contact toxicity assay revealed a significant mortality rate with LC50 reached at low concentrations of 0.57, 0.68, and 0.94 μL/g for BA, BB, and MB, respectively. BA possesses significant fumigant toxicity and outperforms MB and BB, with an LC50 achieved at concentration of 8.91 μL/L. In comparison to the control group, BA, BB, and MB have anti-feedant efficacy against A. obtectus. Furthermore, even at a low concentration of 0.5 μL/g, these compounds induced a significant suppression of A. obtectus F1 progeny production. The BA and BB activities persisted until day 5 after treatment while MB activity sustained for 3 days only. These compounds significantly inhibited acetylcholinesterase, decrease in the level of reduced glutathione (GSH), and elevated malondialdehyde (MDA). In conclusion, BA, BB, and MB are particularly promising choices for controlling the bean beetle A. obtectus because they are low in cost, of natural origin, and the European Food Safety Authority (EFSA) approved their use in animal feed.

Application of nitrogen, phosphorus, potassium + carbon fertilizer improves the growth of Tecoma stans and the performance of its root-feeding biological control agent, Heikertingerella sp.

ABSTRACT The invasive tree Tecoma stans (L.) Juss. ex Kunth var stans (Bignoniaceae) has been targeted for biological control in South Africa since 2003. Plant nutrients contained in fertilizers typically improve host-plant quality, thereby enhancing the fitness of insect herbivores deployed as weed biocontrol agents. We investigated the effect of increasing nutrient levels (fertilizer treatments) on the growth of potted T. stans plants and on the subsequent performance of the root-feeding beetle Heikertingerella sp. (Chrysomelidae). Enhanced performance of Heikertingerella sp. in culture will improve mass-rearing initiatives for releases in South Africa. Ten newly emerged mating pairs of Heikertingerella sp. were exposed under glasshouse conditions to caged plants that were treated with four regimes of nitrogen: phosphorus: potassium 2:3:2 (14%) + carbon (8%) fertilizer, namely zero (control), low (5.6 g/m2), medium (9.4 g/m2) and high (13.2 g/m2). Increasing nutrient levels significantly increased leaf production and above – and below-ground biomass accumulation in T. stans plants. Similarly, the performance of Heikertingerella sp. was improved substantially, with significantly and progressively higher levels of P1 adult feeding and F1 progeny production, and significantly and progressively reduced F1 developmental times, under increasing nutrient levels. While F1 adult size was significantly increased by fertilizer application relative to the controls, there were no significant differences between the three nutrient levels. Although the high fertilizer application rates were the most suitable for the culturing and mass-rearing of Heikertingerella sp. adults, medium fertilizer applications may prove more economical to improve host-plant quality and boost beetle numbers for release.

Bioefficacy of Aguaria salicifolia and Plectranthus kirbii leaf powders to protect bean grains against infestation by Acanthoscelides obtectus (Coleoptera: Chrysomelidae)

The bioefficacy of Plectranthus kirbii and Aguaria salicifolia leaf powders to protect stored bean against infestation of Acanthoscelides obtectus was assessed. The ability of these plants to induce adult mortality, inhibit progeny production, reduce grain damage and insect population growth, as well as to preserve seed viability was tested at different contents. Plectranthus kirbii and A. salicifolia caused significant mortality to adult A. obtectus. The LC50 of P. kirbii and A. salicifolia were 11.67 and 12.67 g/kg respectively after 10 days of contact. The F1 progeny production was significantly inhibited by both powders. The two powders considerably suppressed population of A. obtectus and reduced weight loss of bean after six months of storage. The seeds treated with P. kirbii and A. salicifolia significantly germinated compared to the untreated ones. Considering these results, A. salicifolia and P. kirbii could be used for the protection of stored beans.

Forced Egg Laying Method to Establish F1 Progeny from Field Populations and Laboratory Strains of Anopheles Mosquitoes (Diptera: Culicidae) in Thailand.

Successful monitoring of physiological resistance of malaria vectors requires about 150 female mosquitoes for a single set of tests. In some situations, the sampling effort is insufficient due to the low number of field-caught mosquitoes. To address this challenge, we demonstrate the feasibility of using the forced oviposition method for producing F1 from field-caught Anopheles mosquitoes. A total of 430 and 598 gravid Anopheles females from four laboratory strains and five field populations, respectively, were tested. After blood feeding, gravid mosquitoes were individually introduced into transparent plastic vials, containing moistened cotton balls topped with a 4 cm2 piece of filter paper. The number of eggs, hatching larvae, pupation, and adult emergence were recorded daily. The mean number of eggs per female mosquito ranged from 39.3 for Anopheles cracens to 93.6 for Anopheles dirus in the laboratory strains, and from 36.3 for Anopheles harrisoni to 147.6 for Anopheles barbirostris s.l. in the field populations. A relatively high egg hatching rate was found in An. dirus (95.85%), Anopheles minimus (78.22%), and An. cracens (75.59%). Similarly, a relatively high pupation rate was found for almost all test species ranging from 66% for An. minimus to 98.7% for Anopheles maculatus, and lowest for An. harrisoni (43.9%). Highly successful adult emergence rate was observed among 85-100% of pupae that emerged in all tested mosquito populations. The in-tube forced oviposition method is a promising method for the production of sufficient F1 progeny for molecular identification, vector competence, insecticide resistance, and bioassay studies.

Efficacy of botanicals in controlling F1 progeny production in Tribolium castaneum (Herbst)

Laboratory bioassays (30±2°C temperature, 70±5% r. h. and 12:12, L: D conditions) were performed to evaluate the insecticidal effects of eight different plant extracts against Tribolium castaneum (Herbst). Dichloromethane extracts of Lantana camara, Calotropis procera, Polygonum hydropiper, Jatropha curcas, Datura metel, Annona squamosa, Vitex negundo and Murraya koenigii were applied to whole-wheat flour at different doses of 40, 50, 60 and 75 mg respectively and placed in different jars. Hundred newly emerged adults were introduced into each jar for mating, oviposition and later removed from the corresponding jars. The emerging adults (F1) were counted and weighed. Results were analyzed statistically. It was observed that all the plant extracts significantly reduced the production of F1 individuals (F1 progeny production) with Calotropis procera and Jatropha curcas showing the highest efficacy.

Insecticidal Efficacy and Repellency of Trans-Anethole Against Four Stored-Product Insect Pests

In this study, it was investigated that repellency and insecticidal efficacy of trans-anethole of botanical origin on major stored product on pests species, namely Sitophilus granarius (L.) (Coleoptera: Curculionidae), Sitophilus oryzae (L.) (Coleoptera: Curculionidae), Tribolium confusum Jacquelin du Val (Coleoptera, Tenebrionidae) and Tribolium castaneum (Herbst) (Coleoptera, Tenebrionidae). Repellency effect was evaluated by choice test in petri dishes, while the mortality effect was examined by exposure to wheat treated at different concentrations, such as 1, 2, 3, 4, and 8 μL trans anethole. In efficacy tests, after 72 hours exposure, the highest adult mortality was found on T. castaneum with a 60% mortality, while other test species showed no significant mortality. On the other hand, repellency tests revealed varying degree of repellency depending on the application dose of trans-anethole. It was determined that S. granarius belongs to repellent class III, while all of the other species fall under repellent class IV. F1 progeny decreased as trans-anethole concentration increased, and in this context 8 μL of trans-anethole is proved to be the optimal concentration causing maximum decrease in progeny production. Among the insect species tested, T. confusum was found to be the most sensitive to trans-anethole with 100% decrease in F1 progeny production. Our results indicate that trans-anethole can be used as a potential repellent for the control of major stored grain pests. Additionally, trans-anethole, by its contact efficacy, might be considered as a grain protectant against S. granarius, S. oryzae, T. confusum and T. castaneum.

Anephrogenic phenotype induced by SALL1 gene knockout in pigs

To combat organ shortage in transplantation medicine, a novel strategy has been proposed to generate human organs from exogenous pluripotent stem cells utilizing the developmental mechanisms of pig embryos/foetuses. Genetically modified pigs missing specific organs are key elements in this strategy. In this study, we demonstrate the feasibility of using a genome-editing approach to generate anephrogenic foetuses in a genetically engineered pig model. SALL1 knockout (KO) was successfully induced by injecting genome-editing molecules into the cytoplasm of pig zygotes, which generated the anephrogenic phenotype. Extinguished SALL1 expression and marked dysgenesis of nephron structures were observed in the rudimentary kidney tissue of SALL1-KO foetuses. Biallelic KO mutations of the target gene induced nephrogenic defects; however, biallelic mutations involving small in-frame deletions did not induce the anephrogenic phenotype. Through production of F1 progeny from mutant founder pigs, we identified mutations that could reliably induce the anephrogenic phenotype and hence established a line of fertile SALL1-mutant pigs. Our study lays important technical groundwork for the realization of human kidney regeneration through the use of an empty developmental niche in pig foetuses.

Bioefficacy of Three Selected Plant Species against the Cowpea Bruchid (Callosobruchus maculatus F.): A Green Paradigm for Post-Harvest Pest Management

Callosobruchus maculatus (Coleoptera: Bruchidae) is the most damaging insect pest of storage legumes and pulses. Control of this insect pest infestation primarily relies upon the extensive use of synthetic insecticides. However, the increasing serious problems associated with these chemical compounds have led to the need for more effective biodegradable natural products. In this context, plants appear to play a much greater role as a new class of eco-friendly products for the controlling of populations of this post-harvest insect pest. Therefore, three plants, Pimenta dioica (allspice), Ruta graveolens (garden rue) and Piper betle (betel) were evaluated with the intention of finding the most effective plant species as a desirable alternative to synthetic insecticides in suppressing C. maculatus populations in storage. Potential contact and fumigation repellent properties of leaf powders were assessed using a modified single-choice cup bio assay technique. Twenty laboratory reared one day old adult insects were exposed to 1, 3, 5, 7, and 9 g doses of the three leaf powders separately. All the repelled insects were counted after a three hour exposure period. Observations on both contact and fumigation repellency, for P. dioica leaf powder revealed an exceptionally high effect of 99% whereas P. betle and R. graveolens exhibited only 41% and 42.% repellent effects respectively for the highest dose (9 g). When three doses (1, 5, and 9 g) of P. dioica leaf powder were tested separately to evaluate its effect on F1 progeny production and duration for adult emergence, the highest dose produced extremely high reduction (p<0.05) in F1 adult emergence (6.78±3.25) compared with that of the control (55.60±8.16). Time duration for adult emergence showed that the two higher doses significantly differed with that of the control (21.90±1.24 days) indicating significantly high toxic effect of the powder. With the highest dose, 37.45±3.02 days were required for adult emergence, which was indicative of a growth regulatory effect. Following standard procedures, phytochemical constituents of aqueous, methanol, ethyl acetate and n-hexane extracts of P. dioica leaf powder were determined and the highest number of constituents (Alkaloids, saponins, flavonoids, tannins, and phenols) was obtained with methanolic extract. It can be suggested that one or many of these constituents may be responsible for its very high repellent, toxic and growth regulatory properties. The overall results of the present study clearly indicate that P. dioica leaf powder could be utilized quite successfully to suppress C. maculatus populations with the longstanding objective of developing an eco-friendly green pesticide. Keywords: Callosobruchus maculatus, Pimenta dioica, Ruta graveolance, Piper betle, Repellency

Chemical Composition and Bioactivity of Three Plant Essential Oils against Tribolium castaneum (Herbst) and Sitophilus oryzae (L.)

Three essential oils extracted from German chamomile, Matricaria chamomilla, Anise, Pimpinella anisum and cumin, Cuminum cyminum were assessed against two of the major stored grain insect species, Sitophilus oryzae (L.) and Tribolium castaneum (Herbst). The chemical composition of the essential oils was determined by gas chromatography (GC) and GC/mass spectrometry. The bioactivity of the oils determined was assessed against both species. A concentration of 100000 ppm, essential oils caused 100% mortality of S.oryzae after 96 h. of exposure, whereas, T. castaneum were more tolerant to the oils than S. oryzae. At this concentration, the values of F1 progeny production, progeny reduction (%) and grain weight loss (%) of both insect species were lower than other concentrations. Eventually, all oils exhibited a negative impact on some biological aspects of both insects. These results highlight the potential of these oils as grain protectants and antifeedants, and consequently could be suitable for the management of insect pests in grain stores.

Efficient method for establishing F1 progeny from wild populations of Anopheles mosquitoes

BackgroundThe changing malaria situation in Madagascar requires additional knowledge on the physiology and behaviour of local mosquito vectors. However, the absence of established colonies for several anopheline species present in Madagascar constitutes a limiting factor. To avoid labour intensive work and uncertainty for success of establishing Anopheles colonies from Malagasy species, field collections of blood-fed females and in-tube forced oviposition were combined to reliably produce large numbers of F1 progeny.MethodsBlood-fed females were captured in zebu stables or open zebu parks. Oviposition was induced by enclosing gravid females in eppendorf tubes as initially described for Anopheles funestus. The effect of cold anaesthesia on inducing in-tube forced oviposition and on egg yield was assessed for five Anopheles species, namely Anopheles coustani, An. funestus, Anopheles mascarensis, Anopheles arabiensis and Anopheles squamosus. The production of eggs from in-tube forced oviposition and standard egg laying in cages was compared.ResultsFor the five anopheline species studied, the in-tube forced oviposition method had different efficacy ranging from 35.6 to 71.1% females willing to lay eggs in tubes. Interestingly, prior anaesthesia increased significantly the proportion of ovipositing females for An. mascarensis. Prior anaesthesia has a marginal effect on the number of eggs produced. However, the overall yield in eggs collected using the in-tube forced oviposition method largely exceeds the number of eggs that can be produced by females free to oviposit in cages.ConclusionThe efficiency of the method allowed the production of F1 progeny in numbers sufficiently large for developing detailed analyses of the five species tested, including behavioural studies, insecticide resistance assessment and molecular characterization, as well as vector competence studies. It should be applicable to other anopheline species difficult to colonize.

Larvicidal efficacy of some indigenous plant extracts against epilachna beetle, epilachna vigintioctopunctata (FAB.) (coleoptera: coccinellidae)

The study was carried out to assess the larvicidal efficacies of some indigenous plant seed extracts against epilachna beetle, Epilachna vigintioctopunctata in the laboratory of the Department of Entomology, HSTU, Dinajpur, Bangladesh. Petroleum ether and methanol solvent extracts of ata (Annona squamosa), neem (Azadirachta indica), dhutura (Datura metel) and castor (Ricinus communis) seeds were evaluated for their larvicidal properties against the larval stage of E. vigintioctopunctata. The result revealed that all the tested plant extracts had more or less insecticidal effect against the larvae and their progeny. Among the plant extracts, ata seed extract in methanol solvent performed the highest toxicity (LD50 value 0.031 mg/insect) in larval stage after 72 hours exposure time. The effects of the extracts on fecundity, fertility and F1 adult emergence of the epilachna beetle at doses 4.0, 2.0 and 1.0 ml/l of water including untreated control were also evaluated. The result indicated that, among the extracts, ata seed extract at maximum dose (4.0 ml/l water) showed the highest efficacy with the inhibition of total eggs (74.1%), viable eggs (80.4%) and number of emergent adult progeny (87.3%). The result also revealed that the number of eggs, number of viable eggs and F1 progeny production decreased with the increase of doses. All the treated doses effectively reduced the epilachna beetle as compared to untreated control.Bangladesh J. Agril. Res. 40(3): 451-463, September 2015

Grain Health Protectant Activity of Essential Oils against Infestation and Damage of Haricot Bean by Zabrotes subfasciatus (Boheman)

Experiments were conducted to evaluate the efficacy of essential oils extracted from Chenopodium ambrosioides (L.), Rosmarinus officinalis (L.), Eucalyptus globulus (Labill), Trachyspermum ammi (Sprague) and Cymbopogon citratus (Stapf) against Zabrotes subfasciatus (Boheman) (Coleoptera: Bruchidae) under laboratory condition (27±3°C, 50-70% RH ). The test insects were reared in glass jar and investigated on whole Awash-1 haricot bean variety grains. A standard insecticide, primiphos-methyl 5% dust and untreated control were included for comparison. The experiment was arranged in a completely randomized design in three replications. Essential oils from the above mentioned plants were admixed with the bean grains at the rate of 750 mg/150 g of seeds. The rate of primiphos-methyl was 0.125 g/150 g of seeds. The results showed that there was complete mortality (100%) of Z. subfasciatus adults within 24 hours after treatment due to C. ambrosioides, E. globulus, T. ammi and C. citratus. Application of essential oils to bean grains significantly reduced progeny production of Z. subfasciatus. Over 97% inhibition of F1 progeny production by the pest was recorded for all essential oil treatments at the highest dose of 750 mg. Application of essential oil extracts also significantly reduced the rates of haricot bean Original Research Article Degaga; AJEA, 9(1): 1-7, 2015; Article no.AJEA.16761 2 grain infestation (up to 100%) by Z. subfasciatus. Furthermore, essential oil extracts admixed to the bean grain proved to have no significant effects on the germination capacity of the treated haricot bean grains. From the current experiment it can be concluded that the tested botanicals are as effective as primiphos-methyl which gave 100% control of Z. subfasciatus and can be used for the management of the pest.

Assessment of grain damage and weight loss caused bySitophilus oryzae(L.) feeding on split pulses

An experiment was carried out at the Entomology Laboratory, Horticultural College and Research Institute for Women, TNAU, Trichy in November-December 2013 to estimate the comparative storage losses in split pulses caused by Sitophilus oryzae L. under room and controlled conditions. A completely randomized design (CRD) was used with seven treatments (T1= sorghum, T2 = red gram, T3= chick pea, T4 = black gram, T5 = green gram, T6= fried gram and T7= lentil) each replicated four times. The assessed parameters were per cent weight loss, number of F1 progeny and per cent grain damage. Among the split pulses red gram dhal was found to be the most suitable host of pulse feeding population with 58.25 and 43.00 F1 progeny production, 93.50 and 91.25 per cent grain damage and 28.14 and 37.15 per cent weight loss under room and controlled condition followed by green gram, chick pea, black gram, fried gram and lentil. The assessed parameters were higher in sorghum feeding population on sorghum grains than at pulse feeding population on pulse grains.

Toxic and antifeedant activities of prenylated flavonoids isolated from Tephrosia apollinea L. against three major coleopteran pests of stored grains with reference to their structure–activity relationship

Four prenylated flavonoids, isoglabratephrin, (+)-glabratephrin, tephroapollin-F and lanceolatin-A, were isolated from Tephrosia apollinea L. and tested against three stored grain insects. Using the filter paper bioassay, compounds showed adulticidal activity against Sitophilus oryzae (L), Rhyzopertha dominica (F) and Tribolium castaneum (Herbst) at concentrations of 0.875, 1.75 and 3.5 mg mL− 1. At 3.5 mg mL− 1, tephroapollin-F was the most toxic (78.6%, 64.6% and 60.7% mortality was recorded after 10 days exposure of S. oryzae, R. dominica and T. castaneum, respectively). The F1 progeny production of insects was affected after parental exposure to flavonoids, where S. oryzae was the most susceptible. A nutritional bioassay, employing a flour disc and test concentrations of 0.65, 1.3 and 2.6 mg g− 1, revealed a significant reduction in the relative growth rate, relative consumption rate and efficiency of conversion of ingested food by all insects. The structure–activity relationship among the tested flavonoids was discussed.

Inhibitory effects of plant extracts on growth, development and α-amylase activity in the red flour beetle Tribolium castaneum (Coleoptera: Tenebrionidae)

The bioinsecticidal effects of methanolic extracts of the leaves of castor bean, Ricinus communis, and papaya, Carica papaya, on the red flour beetle, Tribolium castaneum, were studied. More specifically, larval weight, larval mortality, percentage pupation, percentage adult emergence and F1 progeny production were recorded. We also studied the effects of the extracts on α-amylase activity and amylase gene expression in T. castaneum. The extracts of R. communis and C. papaya, which were administered in a diet, increased larval mortality and extended the durations of the larval and pupal periods. Feeding them an extract-treated diet also reduced the percentages of larvae that pupated and of adults that emerged and the number of F1 progeny. α-Amylase activity was inhibited and glucose content reduced in the larvae and adults of these insects. This inhibition of α-amylase activity by the R. communis and C. papaya extracts was concentration dependent in vitro. In addition, amylase gene expression was reduced in insects fed a diet containing C. papaya, but not R. communis extract. These results indicate that the bioinsecticidal effects of the leaf extracts are mediated by inhibiting the gene expression and activity of enzymes involved in sugar metabolism.

Effects of Gamma Radiation on Mature Larvae of Pectinophora gossypiella (Saunders) and their F1 Progeny

The mature larvae of Pectonophora gossypiella (Saunders) obtained from the laboratory culture maintained on casein wheat germ diet were irradiated at 35, 45, 55 and 65 Gy doses at a dose rate of 30.8 Gy/min. in a Cs-137 gamma irradiator. The pupation was delayed as the radiation dose increased. Furthermore, larval survival to pupal and adult stages were also susceptible to gamma radiation doses were increased. Females were more susceptible to gamma radiation than males. The effect of gamma radiation on reproduction in P1 moths following irridation of mature larvae was dose dependent. As the dose of mature larvae increased, average egg production, hatch percentage and adult longevity reduced. Egg production, was reduced more drastically in the crosses Untreated Male x Treated Female (UTM x TF) and Treated male x Treated Female (TM X TF) than the crosses Treated Male x Untreated Female (TM x UTF). Complete sterility was recorded when treated males were paired with treated females at 45 Gy and higher doses of gamma radiation. The results on the egg production, hatch percentage and adult longevity of F1progeny of male parents following irridation of mature larvae showed that egg production was reduced significantly in crosses UTM x F­1 Female at 35 Gy and complete sterility was recorded at higher doses. In crosses F1 Male x F1Female, complete sterility was recorded at all the test doses of gamma radiation. The radiation doses higher than 35 Gy were more lethal either in F1 Male x F1 Female. The adult longevity was unreliable in all the crosses. However, moths were short-lived in both F1 Male x F1 Female and UTM x F1 Female progeny of treated pink bollworm females crossed with untreated males following irradiation of mature larvae indicated similar results as recorded in the case of male treated parents. However, complete sterility was recorded in F1 Male x F1 Female and UTM x F1 Female crosses and a few eggs were laid in F1 Male x F1 Female crosses at 35 Gy dose with 14.76 percent egg hatch.

Insecticidal activity of Poppy (Papaver somniferum L.) seed oil against cowpea weevil (Callosobruchus maculatus F.) in stored cowpea

In this study, the insecticidal effect of Poppy (Papaver somniferum) seed oil was investigated against Callosobruchus maculatus (Bruchidae) in cowpea, at different concentrations and exposure time. The Poppy seed oil at 2, 4, 6, 8 and 10 ml/kg was tested against adults of C. maculatus, and the mortality was counted after 24, 48 and 72 h of exposure. All tests were conducted at 27–30 °C and 65 ± 5% r.h. The experiments were carried out based on the factorial experiment by randomized complete design with four replications. Twenty-five insects with 0–24 h old were used for each replication. The effect of Poppy seed oil on the reduction of emergence of insects in next generation (F1) was also assayed. The results of experiments indicate the significant differences between concentrations and exposure time (p < 0.0001), and the increase of concentrations and exposure time increased mortality. The amount of mortality at high concentrations was remarkable, and highest mortality rate (96.91%) was recorded at 10 ml/kg, after 72 h of exposure. The application of oil significantly reduced F1 progeny production and even at lowest concentration (2 ml/kg), the amount of F1 production was reduced more than 70%, compared with control treatment. Complete (100%) reduction in progeny production was recorded at the rates of 8 and 10 ml/kg. The results of seed germination assay showed no significant differences between control and treated seed, and no harmful effect was observed on the seed germination. These results proved that Poppy seed oil can be used as a controlling agent of storage pests, especially C. maculatus, although more detailed studies are necessary.

Comparative efficacy of NeemAzal and local botanicals derived from Azadirachta indica and Plectranthus glandulosus against Sitophilus zeamais on maize

The efficacy of NeemAzal powder, two local neem (Azadirachta indica) products [neem seed powder (NSP) and neem seed oil (NSO)], as well as a local Lamiaceae, Plectranthus glandulosus leaf powder, applied at four different rates for the control of Sitophilus zeamais was determined. Mortality was recorded 1, 3, 7 and 14 days after S. zeamais infestation, followed by the determination of F1 progeny production. Grain damage, population increase and grain germination were assessed for treated grains that were stored for 4 months. Grains treated with P. glandulosus powder and NSP had relatively low mortality (5.0–22.5%) after 3 days whereas NeemAzal and NSO had higher mortality (55.0–98.8%). Maximum mortality of 99, 100, 96 and 74% were achieved for NeemAzal (12 g/kg after 14 days), NSO (4 ml/kg after 7 days), NSP (40 g/kg after 14 days) and P. glandulosus powder (40 g/kg, after 14 days), respectively. In the same order, 7-day LC50 values were 0.02 g/kg, 1.46 ml/kg, 12.44 g/kg and 28.9 g/kg. The three neem products greatly reduced progeny emergence, while P. glandulosus powder was less effective. NeemAzal protected the grains against S. zeamais damage better than the local neem products, which in turn provided far better grain protection against the weevil damage than P. glandulosus powder. NeemAzal was superior to the local neem products in grain protection against germination loss, with P. glandulosus being the least effective. NeemAzal and NSO had sufficient efficacy to be a component of an integrated management package for S. zeamais.

Insecticidal activities of essential oil of Callistemon viminalis applied as fumigant and powder against two bruchids

AbstractThe fumigant and contact toxicity of essential oil (EO) extracted from the leaves of Callistemon viminalis and its aromatized clay powder (ACP) was evaluated against adults of Acanthoscelides obtectus and Callosobruchus maculatus (Coleoptera: Bruchidae). The results obtained for fumigation assays showed that C. maculatus seems to be more susceptible (LC50 = 0.019 μl/cm3) to the vapours of the essential oil than A. obtectus (LC50 = 0.011 μl/cm3) after 12 h exposure. On the other hand, A. obtectus seems to be more susceptible (LD50 = 0.133 μl/g) to the essential oil applied by contact on grains than C. maculatus (LD50 = 0.170 μl/g) after 2 days exposure. The ACP was also very toxic towards the adults of A. obtectus (LD50 = 0.100 μl/g) and C. maculatus (LD50 = 0.098 μl/g) by contact on grains. At the doses of 0.133 μl/g and 0.266 μl/g, mortalities caused by ACP on grains were higher than those caused by the same dose of EO against the two bruchids. It is also established that both the EO and the ACP caused higher inhibition of F1 progeny production of A. obtectus than that of C. maculatus. The loss of insecticidal activity of the two materials in the course of time has been observed; however, the toxicity of the ACP was more persistent than that of the oil in the course of time when applied on grains. These results suggest that EO from the leaves of C. viminalis can be used as fumigant agent against A. obtectus and C. maculatus. In addition, it could be advisable to use an adsorbent mineral material as carrier of this EO for the prolongation of its insecticidal activity in the course of time.