Repellency and insecticidal activities of Thapsia garganica crude extract against some important pests

Repellency and insecticidal activities of Thapsia garganica leaf methanolic extract were investigated against Tribolium castaneum, Myzus persicae, Phthorimaea operculella, and Spodoptera littoralis. Repellency and toxic activities (by ingestion and topical application) were evaluated on T. castaneum nymphs and adults. Topical application treatment caused total larval growth inhibition at 10%, until mortality after 7 days. The highest mortality was recorded with 94% at the same concentration. Methanolic extracts incorporation into T. castaneum larvae artificial diet at 10% caused 100% mortality after 3 days. The extract at 1% cause high repellent effect on T. castaneum after 60 min of exposure, while M. persicae was less sensitive. P. operculella female’s showed sensitivity by a repellent effect at oviposition. Egg’s number laid on treated tubers at 1% and 2% decreased significantly to 32% and 72%, respectively. In addition, methanolic extracts had a preventive effect on P. operculella larval penetration. In fact, the number of larvae was reduced by 30.46% and 76.12% in the treated tubers at 1% and 2%, respectively. For S. littoralis, a low antifeeding effect was recorded. However, the relative growth rate (RGR), conversion of ingested and digested food to biomass, were decreased. The approximate digestibility increased. Moreover, a delay in larval development was observed. This study suggests that the leaf extract of T. garganica could be applied as bio-insecticide

The Tunisian Artemisia Essential Oil for Reducing Contamination of Stored Cereals by Tribolium castaneum

Esencijalna ulja triju vrsta roda Artemisia (A. absinthium L., A. campestris L. i A. herba-alba (Asso)) ispitana su spregnutom tehnikom plinske kromatografije i masene spektrometrije (GC-MS), te je utvrđen njihov mogući insekticidni i repelentni učinak na skladišnog štetnika žitarica Tribolium castaneum (Herbst). Provedeni su in vitro pokusi ispitivanja fumigacijskog i repelentnog učinka. Kemijska karakterizacija esencijalnih ulja pokazala je da u pelinovom ulju prevladavaju biciklični monoterpeni. Ulje pravog pelina (A. absinthium) sadržavalo je najviše bicikličnih monoterpena, bicikloheptana, naftalena i cikloalkena, a ono vrste A. campestris najviše seskviterpena i acikličnih monoterpena. Bijeli pelin (A. herba-alba) imao je najviše p-mentan tipa monoterpena, tetrahidropirana, kumena, tetrahidrofurana, ketona, benzenoidnih spojeva i monocikličnih monoterpena. Ispitivanje fumigacijskog učinka pokazalo je da su tri zasebno primijenjena ulja prouzročila veliki mortalitet štetnika. Najmanju srednju smrtnu dozu (LC50=142,8 μL/L) imalo je ulje bijelog pelina. Ulje vrste A. absinthium imalo je jači i brži repelentni učinak od ostalih vrsta. Mješavina esencijalnih ulja triju vrsta pelina imala je antagonistički učinak u svim ispitanim kombinacijama. Ovaj rad naglašava važnost moguće primjene esencijalnih ulja pelina, naročito vrsta A. herba-alba (bijelog pelina) i A. absinthium, na suzbijanje štetnika na uskladištenim proizvodima.Essential oils of three species of Artemisia genus (A. absinthium L., A. campestris L. and A. herba-alba (Asso)) were analyzed by gas chromatography–mass spectrometry (GC-MS) and their potential insecticidal and repellent activities against the stored grain insect Tribolium castaneum (Herbst) was investigated. Fumigant and repellent activity bioassays were investigated in vitro. Chemical characterisation of essential oils showed that the bicyclic monoterpenes were predominant in all Artemisia essential oils, A. absinthium essential oil having the highest content of bicyclic monoterpenes, bicycloheptanes, naphthalenes and cycloalkenes. A. campestris had the highest content of sesquiterpenoids and acyclic monoterpenoids. A. herba-alba was characterised by the highest amounts of menthane monoterpenoids, oxanes, cumenes, oxolanes, ketones, benzenoids and monocyclic monoterpenes. Fumigant bioassay demonstrated that the three types of oil applied separately caused significant insect mortality. The lowest median lethal dose, LC50=142.8 μL/L, was observed with A. herba-alba. In repellency test, essential oil of A. absinthium was more potent with more rapid action than all other species. The mixture of Artemisia sp. essential oils showed an antagonistic effect in all the tested combinations. This study highlighted an important potential of Artemisia sp. especially A. herba-alba and A. absinthium in the control of the pests of stored products

Biochemical and molecular identification of a native Bacillus thuringiensis gv. cytolyticus isolate with insecticidal effect against the pod borer larvae (Helicoverpa armigera)

Bouslama, T., Laarif, A., Chattaoui, M., Vial, L., Lavire, C., and Doré, J., and Rhouma, A. 2023. Biochemical and molecular identification of a native Bacillus thuringiensis gv. cytolyticus isolate with insecticidal effect against the pod borer larvae (Helicoverpa armigera). Tunisian Journal of Plant Protection 18 (2): 71-91

Antifeedant and insecticidal properties of Solanum elaeagnifolium extracts on the African Cotton Leafworm

Antifeedant, malformations, and growth inhibition induced by leaves and seeds methanolic extracts of Solanum elaeagnifolium against Spodoptera littoralis were investigated. Seeds and leaves extracts were added to an artificial diet which was found to have an inhibitory effect on the growth of the larvae. The highest growth inhibition was recorded on larvae treated with seeds extract (59.68%) compared to leaves extract (45.17%). The toxicity was demonstrated by a reduction of the weight do to the anti-feeding activity, an elongation of the larval stadiums until development stopping and larval mortality. The seeds extract shows strong antifeedant activity (28.50%) as compared to leaves extract tested (6.64%). The larval mortality was caused by seeds extract (100%) in response to exuviation difficulties. While, the leaves extract caused various degrees of morphogenesis abnormalities in pupae, with mortality rate around 80%. Our results suggest that seeds methanolic extract of S. elaeagnifolium shows an effective insect growth inhibiting and exhibits great promise in suppressing the population of S. littoralis

Fumigant activities of essential oils and their mixtures from cultivated aromatic plants against Spodopteralittoralis (Boisduval, 1833)

The objective of the present study was to investigate the insecticidal activity of essential oils from cultivated aromatic plants and their combinations against larvae of Spodoptera littoralis. Essential oils from Salvia officinalis, Mentha longifolia and Origanum majorana and their mixtures were tested by fumigation. The ability to kill more than 80% was observed in all tested essential oils at 200µL/Lair. In the case of individual essential oils, the LC50 were ranged from the most toxic to the least as fellow: M. longifolia (31.66 μL/L) followed by S. officinalis (42.70 μL/L) and O. majorana (58.28 μL/L). Moreover, the combination of S. officinalis with M. longifolia and with O. majorana might be the two most effectives in controlling the insect than individuals essential oils and the other combinations. The investigation of the efficiency of each essential oil and combination allow us to create potent combinations for the development of powerful eco-friendly control agents

Effects of Melia azedarach leaf extracts on nutritional behavior and growth of Spodoptera littoralis. Akacha, M., Chaieb, I., Laarif, A., Haouala, R., and Boughanmi, N. (Tunisia)

Synthetic chemicals used nowadays as insecticides caused many negative effects (pollution, toxicity…) which led to an increasing interest in botanical insecticides because of their minimal costs and less ecological side effects. In this respect, the activity of Melia azedarach leaf extract against the third stage larvae of armyworm (Spodoptera littoralis) has been assessed in this study. The aqueous and ethanolic extracts exhibited an antifeedant activity against S. littoralis larvae according to the applied doses. Ethanolic extract reduced the food consumption and digestibility inducing growth rate decrease of the armyworm larvae. An increase in the larval stage duration was also observed as well as anomalies. Pupation stage was affected and occurred only for the lowest doses with a significant decrease in pupa weight. Consequently, ethanolic M. azedarach leaf extract may be used in the alternative control strategies against S. littoralis pest

Evaluation of repellent activity and toxicity of three essential oils against Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) using a mixture design

Economic damages caused by pest infestation during storage is a major problem in developed and developing countries. Synthetic pesticides have been mainly used to control stored product pests since 1960. Nowadays, appearance of resistance and human health’s risks underline the alternative research needs. Plants essentials oils are recognized as a safe alternative for insecticide applications. The present study was conducted to investigate the insecticidal activity of a number of essential oils from cultivated aromatic plants and their combinations against Tribolium castaneum. Three essential oils and their mixtures were evaluated by fumigation and repellent effectiveness tests against Tribolium castaneum. Bioassays indicated that M. longifolia EO has the most important insecticidal potential as fumigant and repellent. Our results indicated that fumigant and repellent activities of essential oils mixtures can be improved by synergistic and Additive effect. Whereas, some combination exhibited a low insect mortality and repellency regenerated by the antagonistic effect. In our study we underlined the insecticide potential of the essential oils mixture but other studies should be elaborated for a new pesticide elaboration

Insecticidal Activities of Fruit Peel Extracts of Pomegranate (Punica granatum) against the red flour beetle Tribolium castaneum

Aqueous, ethanol and methanol fruit peel extracts of Punica granatum were tested under laboratory conditions for their insecticidal activities against larvae and adults of the red flour beetle, Tribolium castaneum. The beetles were exposed to the different extracts by topical application and ingestion treatment. Highest mortalities were recorded on larvae treated with ethanol extract with mortalities of 72 and 56% for topical application and ingestion treatment respectively. The three extracts exhibited anti-feeding effects (70% > AFI ≥ 50%) against T. castaneum larvae whereas only methanol extract exhibited a low anti-feeding activity (50% > AFI ≥ 20%) against adults. Additionally, only ethanol extract showed repellent activity. Results suggested the presence of toxic active components in the ethanol fruit peel extract acting by mainly ingestion and topical application. The treatment with this botanical insecticide may be promising in protecting stored grains from coleopteran pest infections