Fumigant activity of (E)-anethole identified in Illicium verum fruit against Blattella germanica

The insecticidal activities of materials derived from the fruit of star anise, Illicium verum, against adults of Blattella germanica were examined by direct contact application and fumigation methods, and compared with those of DDVP, deltamethrin and hydramethylnon. The biologically active constituent of the Illicium fruit was characterized as the phenylpropene, (E)-anethole, by spectroscopic analysis. In a filter paper diffusion test with females, (E)-anethole caused 80.3% mortality at 0.159 mg cm-2 at 1 and 3 days after treatment (DAT), whereas 16.7% mortality at 3 DAT was achieved at 0.079 mg cm-2. DDVP and deltamethrin gave > 90% mortality at 0.019 mg cm-2 at 1 DAT. At 0.009 mg cm-2, DDVP and deltamethrin showed 73.3 and 60% mortality at 1 DAT, respectively, but 93.3 and 76.7% mortality at 3 DAT. Hydramethylnon exhibited 0 and 93.3% mortality at 0.159 mg cm-2 at 1 and 3 DAT, respectively, whereas 6.7% mortality at 3 DAT was observed at 0.079 mg cm-2. In a fumigation test with females, (E)-anethole was much more effective in closed cups than in open ones, indicating that the insecticidal activity of the compound was largely attributable to fumigant action. (E)-Anethole and DDVP caused 100% mortality at 0.398 and 0.051 mg cm-2 4 and 1 h after treatment, respectively. (E)-Anethole showed 46.7% mortality at 0.199 mg cm-2 at 3 DAT, whereas deltamethrin and hydramethylnon at 0.796 mg cm-2 was ineffective for 3-day period. As naturally occurring insect-control agents, the I verum fruit-derived materials described could be useful for managing populations of B germanica.     

Synergistic and antagonistic interactions of terpenes against Meloidogyne incognita and the nematicidal activity of essential oils from seven plants indigenous to Greece

BACKGROUND: Biorational means for phytonematode control were studied within the context of an increasingly ecofriendly pest management global approach. The nematicidal activity and the chemical composition of essential oils (EOs) isolated from seven plants grown in Greece and ten selected compounds extracted from them against second‐stage juveniles (J2) of Meloidogyne incognita (Kof. & White) Chitwood were evaluated using juvenile paralysis experiments. Additionally, synergistic and antagonistic interactions between nematicidal terpenes were studied using an effect addition model, with the comparison made at one concentration level. RESULTS: The 96 h EC₅₀ values of Foeniculum vulgare Mill., Pimpinella anisum L., Eucalyptus meliodora A Cunn ex Schauer and Pistacia terebinthus L. were 231, 269, 807 and 1116 µg mL^?1, respectively, in an immersion bioassay. Benzaldehyde (9 µg mL^?1) was the most toxic compound, followed by γ‐eudesmol (50 µg mL^?1) and estragole (180 µg mL^?1), based on 96 h EC₅₀ values. The most potent terpene pairs between which synergistic actions were found, in decreasing order, were: trans‐anethole/geraniol, trans‐anethole/eugenol, carvacrol/eugenol and geraniol/carvacrol. CONCLUSION: This is the first report on the activity of F. vulgare, P. anisum, E. meliodora and P. terebinthus, and additionally on synergistic/antagonistic nematicidal terpene interactions, against M. incognita, providing alternative methods for nematode control. Copyright © 2010 Society of Chemical Industry     

Bioactivity of essential oils from leaves and bark of Laurelia sempervirens and Drimys winteri against Acyrthosiphon pisum

BACKGROUND: The pea aphid, Acyrthosiphon pisum (Harris), is a cosmopolitan pest that attacks a wide range of legume crops and vectors important plant virus diseases. In this project, essential oils from the leaf (L) and bark (B) of Laurelia sempervirens (Ruiz & Pavón) Tul. (L) and Drimys winteri JR Forster & G Forster (D) were extracted, and their deterrent and insecticidal activities were tested under laboratory conditions. RESULTS: By use of GC‐MS, safrole was found as the main constituent in LL and LB oils, while the main constituents were more diverse in DL and DB oils. In the deterrent bioassays with A. pisum under choice conditions, the four oils were active, with LL being the most active, followed by LB, DB and DL. The respective deterrence indices were 1.0, 0.89, 0.87 and 0.46 when aphids were exposed for 24 h to 4 µL mL^?1. Although there was no aphid mortality when oils were sprayed on faba bean leaves before aphid infestation, there was 58 and 42% mortality when settled aphids were directly sprayed with 4.0 µL mL^?1 of LL and LB respectively; DB and DL oils caused ≤18% mortality. In a third series, the essential oils of LL and LB caused 100% mortality when applied at a dose of 64 µL L^?1 air by fumigation to faba bean plants infested with A. pisum; at the same dose, DB and DL oils caused 68 and 63% mortality respectively. When fumigation was limited to 2 h, the respective LC₅₀ values for LL and LB oils were 10.6–14.3 µL L^?1 air and 9.8–13.2 µL L^?1 air. CONCLUSION: Because of their high deterrent and insecticidal activities, the essential oils from leaf and bark of L. sempervirens may be explored as potential natural aphicides. Copyright © 2010 Society of Chemical Industry     

Composition and biological activity of essential oils from Labiatae against Nezara viridula (Hemiptera: Pentatomidae) soybean pest

BACKGROUND: Plant essential oils have been recognised as an important natural source of insecticide. This study analysed the chemical constituents and bioactivity of essential oils that were isolated via hydrodistillation from Origanum vulgare L. (oregano) and Thymus vulgaris L. (thyme) against eggs, second instar and adults of Nezara viridula (L.). RESULTS: The major component of oregano was p‐cymene, and, for thyme, thymol. The ovicidal activity was tested by topical application; the essential oil from thyme was more effective. The fumigant activity was evaluated in an enclosed chamber; the LC₅₀ values for oregano were 26.8 and 285.6 µg mL^?1 for nymphs and adults respectively; for thyme they were 8.9 µg mL^?1 for nymphs and 219.2 µg mL^?1 for adults. To evaluate contact activity, a glass vial bioassay was used; the LC₅₀ values for oregano were 1.7 and 169.2 µg cm^?2 for nymphs and adults respectively; for thyme they were 3.5 and 48.8 µg cm^?2 respectively. The LT₅₀ analyses for contact and fumigant bioassays indicated that thyme was more toxic for nymphs and adults than oregano. Both oils produced repellency on nymphs and adults. CONCLUSION: These results showed that the essential oils from O. vulgare and T. vulgaris could be applicable to the management of N. viridula. Copyright © 2011 Society of Chemical Industry     

Insecticidal compounds from the essential oil of Chinese medicinal herb Atractylodes chinensis

BACKGROUND: In a screening programme for new agrochemicals from Chinese medicinal herbs, the essential oil of Atractylodes chinensis (DC.) Koidz was found to possess strong insecticidal activity against the common vinegar fly, Drosophila melanogaster L. The essential oil was extracted via hydrodistillation, and its constituents were determined by GC‐MS analysis. RESULTS: The main components of A. chinensis essential oil were β‐eudesmol (21.05%), β‐selinene (11.75%), γ‐elemene (7.16%) and isopetasam (5.36%). Bioactivity‐directed chromatographic separation on repeated silica gel columns led to the isolation of five compounds, namely atractylon, α‐elemol, β‐eudesmol, hinesol and β‐selinene. β‐Selinene, α‐elemol and hinesol showed pronounced contact toxicity against D. melanogaster adults, with LD₅₀ values of 0.55, 0.65 and 0.71 µg adult^?1 respectively. Atractylon and β‐eudesmol were also toxic to the fruit flies (LD₅₀ = 1.63 and 2.65 µg adult^?1 respectively), while the crude oil had an LD₅₀ value of 2.44 µg adult^?1. CONCLUSION: The findings suggested that the essential oil of Atractylodes chinensis and its active constituents may be explored as natural potential insecticides. Copyright © 2011 Society of Chemical Industry     

Extraction of allyl isothiocyanate from horseradish (Armoracia rusticana) and its fumigant insecticidal activity on four stored‐product pests of paddy

BACKGROUND: Isothiocyanates (ITCs) extracted from Armoracia rusticana Gaertn., May & Scherb. have been shown previously to have insecticidal activity. Allyl isothiocyanate (AITC), a major component of ITCs with high volatility, was therefore extracted using different methods and tested as a fumigant against four major pest species of stored products, maize weevil Sitophilus zeamais (Motsch.), lesser grain borer Rhizopertha dominica (F.), Tribolium ferrugineum (F.) and book louse Liposcelis entomophila (Enderlein). RESULTS: Whereas there was no significant difference between hydrodistillation and supercritical carbon dioxide fluid extraction in extraction rate for AITC from A. rusticana, both methods resulted in higher extraction efficiency than water extraction. AITC fumigation showed strong toxicity to the four species of stored‐product pests. Adult mortality of 100% of all four pest species, recorded after 72 h exposure to AITC fumes at an atmospheric concentration of 3 µg mL^?1, showed no significant difference from that of insects exposed to phosphine at 5 µg mL^?1, the recommended dose for phosphine. CONCLUSIONS: The results suggest good insecticidal efficacy of AITC against the four stored‐product pests, with non‐gaseous residuals on stored products. AITC obtained from A. rusticana may be an alternative to phosphine and methyl bromide against the four pest species. Copyright © 2009 Society of Chemical Industry     

A new aqueous suspension concentrate formulation of cis‐permethrin and its insecticidal activity

Isomers of pyrethroids usually have different insecticidal activities. Permethrin, a non‐cyano pyrethroid, is not an exception and cis‐permethrin is much more active than the trans‐isomer against Triatoma infestans, vector of Chagas' Disease in Argentina. The large‐scale separation of cis‐ and trans‐permethrin was performed by successive recrystallizations from ethanol‐water mixtures. An aqueous suspension concentrate (flowable) formulation of pure crystalline cis‐permethrin was prepared and assayed for its insecticidal activity on wood and ceramic surfaces against nymph V of T infestans. This formulation was at least three times more effective than deltamethrin, with LC₅₀ values on ceramic of 0.11 µg cm⁻² and 0.33 µg cm⁻² respectively. On wood surfaces, the LC₅₀ value was 0.57 µg cm⁻² compared with 3.20 µg cm⁻² for deltamethrin. Against other insect species such as Periplaneta americana, Aedes aegypti and Culex quinquefasciatus, the suspension concentrate formulation of cis‐permethrin was, however, less effective than similar formulations of deltamethrin or β‐cypermethrin. © 2000 Society of Chemical Industry     

溴甲烷、环氧乙烷真空熏蒸杀虫灭菌技术研究

真空情况下,利用溴甲烷、环氧乙烷杀虫、灭菌是一种安全、快速、有效的技术措施。为了使此技术广泛应用到农林种子、苗木、卫生防疫以及文史资料诸方面杀虫灭菌,试制成功一台容积工立方米的PCV-1000程序控制真空熏蒸机,并进一步进行溴甲烷、环氧乙烷杀虫灭菌效果及其熏蒸后残余毒气处理方法的研究。溴甲烷75—90克/立方米处理2小时,环氧乙烷90—120克/立方米处理3小时,可杀死各种形式的包装内的谷斑皮蠹和花斑皮蠹幼虫,赤拟谷盗和锈扁谷盗成虫以及玉米象和绿豆象各虫态等害虫。环氧乙烷灭菌能力较强,对动物炭疽菌、4001芽孢杆菌500克/立方米处理5小时或300克/立方米处理12小时,灭菌效果100%。溴甲烷和环氧乙烷混合使用对棉花枯萎病菌效果良好,对棉籽发芽率影响不大。熏蒸后残余毒气处理,用5%氢氧化钠酒精液吸收溴甲烷,破坏率可达96%以上。环氧乙烷用自来水淋洗法,水合分解率可达98%以上。     

Studies on diets and population dynamics of the cigarette beetle Lasioderma serricorne F. (Col., Anobiidae)

Aromatic spice crops such as coriander, Coriandrum sativum L., and fennel, Foeniculum vulgare L., are among the major seeds exported to the international market. Observations on the stores of these crops revealed differences in their susceptibility to the cigarette beetle, Lasioderma serricorne (F.) (Col., Anobiidae). Coriander seeds proved to be the most appropriate diet for the beetle. The population dynamics of L. serricorne (F.) was determined, showing 3 generations during the period from May to October.     

Studies on diets and population dynamics of the cigarette beetle Lasioderma serricorne F. (Col., Anobiidae)

Aromatic spice crops such as coriander, Coriandrum sativum L., and fennel, Foeniculum vulgare L., are among the major seeds exported to the international market. Observations on the stores of these crops revealed differences in their susceptibility to the cigarette beetle, Lasioderma serricorne (F.) (Col., Anobiidae). Coriander seeds proved to be the most appropriate diet for the beetle. The population dynamics of L. serricorne (F.) was determined, showing 3 generations during the period from May to October.     

Evaluation of semiochemical toxicity to houseflies and stable flies (Diptera: Muscidae)

BACKGROUND: The housefly, Musca domestica L., and stable fly, Stomoxys calcitrans (L.) are cosmopolitan pests of both farm and home environments. Houseflies have been shown to be resistant to a variety of insecticides, and new chemistries are slow to emerge on the market. Toxicities of selected semiochemicals with molecular structures indicative of insecticidal activity were determined against adults from an insecticide‐susceptible laboratory strain of houseflies. The three most active semiochemicals were also evaluated against recently colonized housefly and stable fly strains. RESULTS: Nineteen semiochemicals classified as aliphatic alcohols, terpenoids, ketones and carboxylic esters showed toxicity to houseflies and stable flies. Rosalva (LC₅₀ = 25.98 µg cm^?2) followed by geranyl acetone and citronellol (LC₅₀ = 49.97 and 50.02 µg cm^?2) were identified as the most toxic compounds to houseflies. Permethrin was up to 144‐fold more toxic than rosalva on the susceptible strain. However, it was only 35‐fold more toxic to the insecticide‐tolerant field strain. The compounds generated high toxicity to stable flies, with LC₅₀ values ranging from 16.30 to 40.41 µg cm^?2. CONCLUSION: Quantification of LC₅₀ values of rosalva, citronellol and geranyl acetone against susceptible housefly and field‐collected housefly and stable fly strains showed that semiochemicals could serve as potent insecticides for fly control programs. Copyright © 2010 Society of Chemical Industry     

Aerosol delivery of trail pheromone disrupts the foraging of the red imported fire ant,Solenopsis invicta

BACKGROUND: The fire ant, Solenopsis invicta, is one of the most aggressive and invasive species in the world. The trail pheromone Z,E‐α‐farnesene (91% purity) was prepared, and disruption of worker trail orientation was tested using an ethanol‐based aerosol formulation presenting a single puff of this compound by airbrush and compressed air. Trail‐following behaviour was recorded by overhead webcam and ants digitised before and after presentation of the aerosol treatment at four rates (1.6, 16, 160 and 1600 ng cm^?2). RESULTS: Ants preferred 110 ng cm^?1 over 11, 1.1 and 0.11 ng cm^?1 for trail following. Within seconds of presentation of 1600 ng cm^?2, the highest dose tested, trail disruption was observed. Disruption was evident as reduced arrival success and reduction in the trail integrity statistic (r²), as well as increased deviation from the trail (deg). The distribution of walking track angles was also flattened. CONCLUSIONS: The feasibility of using aerosol for delivery of trail pheromone was demonstrated, but the need for high purity combined with the difficulty of commercial supply makes this technique impractical. However, the commercial production of Z,E‐α‐farnesene of high purity by industrial biotechnology or from (E)‐nerolidol may be possible in future, which would facilitate further development of trail pheromone disruption of S. invicta. Copyright © 2012 Society of Chemical Industry     

Evaluation of semiochemical toxicity to Aedes aegypti,Ae. albopictus and Anopheles quadrimaculatus (Diptera: Culicidae)

BACKGROUND: Mosquitoes are the most important vectors of human pathogens. Wide‐scale use of pesticides has led to the development of resistance to most common insecticide groups. The need to develop novel products that have a low impact on human health and the environment is well established. The toxicity of selected semiochemicals with molecular structures indicative of insecticidal activity was determined against adult Aedes aegypti (L.) and Anopheles quadrimaculatus (Say). The two most active insecticides against Ae. aegypti were also evaluated against Ae. albopictus (Skuse). RESULTS: Fifteen semiochemicals classified as terpenoid alcohols, ketones or carboxylic esters showed toxicity to both mosquito species. Geranyl acetone (LC₅₀ = 38.51 µg cm^?2) followed by citronellol (LC₅₀ = 48.55 µg cm^?2) were the most toxic compounds to Ae. aegypti, while geraniol and lavonax, with LC₅₀ values of 31.88 and 43.40 µg cm^?2, showed the highest toxicity to An. quadrimaculatus. Both geranyl acetone and citronellol were highly toxic to Ae. albopioctus. No semiochemical showed fumigation activity against either species. All semiochemicals persisted for less than 24 h when tested on filter paper. CONCLUSION: Quantification of LC₅₀ values of several semiochemicals against Ae. Aegypti, An. quadrimaculatus and Ae. albopioctus showed that semiochemicals not only modify insect behaviors but also hold potential as potent insecticides for mosquito control programs. Copyright © 2010 Society of Chemical Industry     

Evaluation of the suppression ability of rice (Oryza sativa) on Monochoria vaginalis by measuring photosynthetic photon flux density below rice canopy

Field experiments involving eight cultivars were conducted in 1998 and 16 cultivars in 1999 to study the ability of rice (Oryza sativa L.) to suppress Monochoria vaginalis (Burm. f ) Kunth through light competition. Dry weights of M. vaginalis shoots in early season culture exceeded those in normal season culture of any rice cultivars. The relative photosynthetic photon flux density (R‐PPFD), which was calculated as the ratio of the photosynthetic photon flux density (PPFD) below the rice canopy to that measured above the rice canopy, varied according to rice cultivar. A strong linear correlation was observed between the mean R‐PPFD at 29–35 days after transplanting (DAT) (r² = 0.80; p < 0.01 in 1998; r² = 0.63, p < 0.001; and r² = 0.93, p < 0.001 in 1999), or 36–42 DAT (r² = 0.66, p < 0.05 in 1998; r² = 0.72, p < 0.001; and r² = 0.97, p < 0.001 in 1999), and the dry weight of M. vaginalis shoots at approximately 60 DAT. Data from the three experiments could be pooled into one regression line because intercepts and regression coefficients were not significantly different. The r² values of the combined regression were highest when R‐PPFD was expressed as the mean of measurements taken during 14 days (from 29 to 42 DAT; r² = 0.81, p < 0.001). The shortest period for measuring mean R‐PPFD in order to obtain a meaningful relationship with M. vaginalis shoot dry weight was 7 days (from 29 to 35 DAT; r² = 0.78, p < 0.001). For that same period, relationships between M. vaginalis shoot dry weight at 60 DAT and rice tiller number or leaf area index (LAI) at ground level were weak. However, there were negative relationships between M. vaginalis shoot dry weights at 60 DAT and rice LAI measured 20 cm above the ground, plant heights or rice shoot dry weight, but these coefficients of determination were smaller than those calculated by R‐PPFD for the same period. Thus, the ability of rice to suppress M. vaginalis can be evaluated more accurately by measuring mean R‐PPFD below the rice canopy for 7 days (from 29 to 35 DAT) than by measuring rice LAI, plant height and shoot dry weight.     

Effect of pre‐storage seed treatments on adult mortality,oviposition and development of Callosobruchus chinensis L. (Bruchidae: Coleoptera), and the viability of mungbean (Vigna radiata (L.) Wilczek) in India

Abstract

The adult mortality of Callosobruchus chinensis L. was 100% within 24 h after artificially infesting seeds pretreated with inert clay and stored for 12 months under ambient conditions. Pre‐treatment with thiram and delsan‐30 (TCMTB) were also effective in controlling the adults by impairing oviposition. The seeds maintained over 80% germination up to 12 months of storage under all the treatments.     

Bioactivity of compounds from Acmella oleracea against Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) and selectivity to two non-target species

BACKGROUND: Tropical plants are recognised sources of bioactive compounds that can be used for pest control. The objective of this study was to evaluate the biological activity of compounds present in Acmella oleracea (Asteracea) against Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), which is the main pest of tomato crops in Latin America. The selectivity of these compounds to the predator Solenopsis saevissima (Smith) (Hymenoptera: Formicidae) and to the pollinator Tetragonisca angustula (Latr.) (Hymenoptera: Apidae: Meliponinae) was also of interest. RESULTS: A bioassay screening with hexane and ethanol extracts from 23 plants was performed. The hexane extract of A. oleraceae was the most active of the extracts and was selected for further study. The following three alkamides were isolated from a hexane extract of the aerial parts of A. oleracea : spilanthol, (E)‐N‐isobutylundeca‐2‐en‐8,10‐diynamide and (R, E)‐N‐(2‐methylbutyl)undeca‐2‐en‐8,10‐diynamide. All of the isolated compounds showed insecticidal activity, with spilanthol being the most active (LD₅₀ = 0.13 µg mg^?1) against T. absoluta . The alkamides were selective to both beneficial species studied. CONCLUSION: The crude hexane extract of A. oleraceae showed high insecticidal activity and can be used to control T. absoluta in organic or conventional crops. Quantification of LD₅₀ values of isolated compounds against T. absoluta showed that alkamides could serve as potent insecticides for T. absoluta control programmes. Spilanthol was the main alkamide active isolated. This alkamide is the most promising as it has the highest insecticidal activity and is selective to non‐target organisms. Copyright © 2011 Society of Chemical Industry     

Anoplophora species in Europe: infestations and management processes1

By the end of summer 2005, four sites of infestation by Anoplophora glabripennis (Coleoptera, Cerambycidae) had been detected in three European countries: Austria in 2001, at Braunau am Inn; France in 2003, at Gien, and in 2004, at Sainte‐Anne‐sur‐Brivet; and Germany in 2004, at Neukirchen am Inn. Two sites of infestation by Anoplophora chinensis have been detected in two European countries: Italy in 2000, at Parabiago, and France in 2003, at Soyons. The history of the A. glabripennis and A. chinensis discoveries is presented, as well as the respective management responses (monitoring and destruction of the infested trees). By the end of summer 2005, the eradication was not yet fully achieved in any of the four A. glabripennis‐infested sites. In contrast, no new A. chinensis‐infested trees had been found at Soyons, France, since 2003. At Parabiago, Italy, monitoring is taking place: the A. chinensis infestation affects 16 municipalities over more than 60 km². By summer 2005, destruction on a large scale of the infested trees had not yet taken place, but tree‐cutting of more than 1000 trees had been planned for winter 2005‐06. Given the current substantial extent of the A. chinensis infestation near Milan, and the density of the established A. chinensis populations, there is a high probability that the status of the pest in Italy will soon be raised from ‘introduced’ to ‘invasive’.     

Insecticidal activity of surfactants and oils against silverleaf whitefly (Bemisia argentifolii) nymphs (Homoptera: Aleyrodidae) on collards and tomato

The insecticidal activities of four surfactants (Cide‐kick, Silwet L‐77, M‐Pede and APSA‐80), a dishwashing detergent (New Day), a mineral oil (Sunspray oil), a cotton seed oil and a vegetable oil, alone or in combination, were tested against nymphs of Bemisia argentifolii Bellows & Perring on collards and tomato. Silwet L‐77 was more effective (>95% mortality) than Cide‐Kick or APSA‐80 at rates from 0.25–1.00 g AI litre⁻¹ but caused severe phytotoxicity to tender tomato leaves at all but the lowest rate. New Day dish detergent at 2.0 ml litre⁻¹ caused mortality (95%) comparable to M‐Pede insecticide soap at 10‐fold greater concentration. A New Day ingredient, cocamide DEA, was considerably more active than the other ingredients or the commercial mixture. Additional surfactants added to Sunspray oil increased efficacy in some treatments, but not others. Toxic responses of 2nd‐ and 3rd‐ instar whiteflies to vegetable oil and cotton seed oil at 5.0 and 10.0 ml litre⁻¹ plus 0.4 g AI litre⁻¹ APSA‐80 ranged from 22.1 to 79.9% and 66.3–88.7% mortality, respectively. Whitefly mortality was greater on tomato than on collard in six of seven instances when differences between host plants were significant. Our results indicate that the these surfactants and oils have good potential for controlling B argentifolii. © 2000 Society of Chemical Industry     

Effects of cultural conditions on fungal biomass,blastospore yields and toxicity of fungal secreted proteins in batch cultures of Metarhizium anisopliae (Ascomycota: Hypocreales)

BACKGROUND: Recently, two fungal proteins with apparent molecular masses of 11 and 15 kDa and insecticidal activity against Ceratitis capitata (Wied.) have been purified from the crude soluble protein extract (CSPE) secreted by the entomopathogenic fungus Metarhizium anisopliae (Metsch.) Sorokin (strain EAMa 01/58‐Su) in Adamek's liquid medium. The feasibility of culturing this strain in fermentation facilities in order to harvest and formulate the insecticidal proteins for C. capitata control is mainly dependent on the ability to produce high concentrations of the active proteins at a reasonable cost. RESULTS: These studies report that, in batch cultures of EAMa 01/58‐Su strain, the carbon (C) and nitrogen (N) ratios and sources are important considerations with respect to fungal biomass production, blastospore yield and secretion of insecticidal proteins against C. capitata adults. The data indicate that the type and concentration of N source in the medium influence the production of insecticidal protein and thus the toxicity of the CSPEs. The electrophoretic analysis suggests that the monomer of 11 kDa plays an important role in the insecticidal effect described. Concerning biomass production, no clear differences were found between media with different C and N sources and C:N ratios in total biomass production at day 7. Conversely, important differences were found among the media in terms of blastospore yields. CONCLUSIONS: By optimising the culture media, the insecticidal effect of the CSPE against C. capitata can be improved. In the CSPE from G₄₀:P₂₀ (40 g L^?1 glucose and 20 g L^?1 peptone in dH₂O), the LC₅₀ and the LT₅₀ were 7 and 4.5 times lower than in the CSPE obtained from Adamek. Copyright © 2010 Society of Chemical Industry     

Contact and fumigant toxicity of Armoracia rusticana essential oil, allyl isothiocyanate and related compounds to Dermatophagoides farinae

BACKGROUND: The toxicity to adult Dermatophagoides farinae of allyl isothiocyanate identified in horseradish, Armoracia rusticana, oil and another 27 organic isothiocyanates was evaluated using contact + fumigant and vapour‐phase mortality bioassays. Results were compared with those of two conventional acaricides, benzyl benzoate and dibutyl phthalate. RESULTS: Horseradish oil (24 h LC₅₀, 1.54 µg cm^?2) and allyl isothiocyanate (2.52 µg cm^?2) were highly toxic. Benzyl isothiocyanate (LC₅₀, 0.62 µg cm^?2) was the most toxic compound, followed by 4‐chlorophenyl, 3‐bromophenyl, 3,5‐bis(trifluoromethyl)phenyl, cyclohexyl, 2‐chlorophenyl, 4‐bromophenyl and 2‐bromophenyl isothiocyanates (0.93–1.41 µg cm^?2). All were more effective than either benzyl benzoate (LC₅₀, 4.58 µg cm^?2) or dibutyl phthalate (24.49 µg cm^?2). The structure‐activity relationship indicates that types of functional group and chemical structure appear to play a role in determining the isothiocyanate toxicities to adult D. farinae. In the vapour‐phase mortality bioassay, these isothiocyanates were consistently more toxic in closed versus open containers, indicating that their mode of delivery was, in part, a result of vapour action. CONCLUSION: In the light of global efforts to reduce the level of highly toxic synthetic acaricides in indoor environments, the horseradish oil‐derived compounds and the isothiocyanates described herein merit further study as potential acaricides for the control of house dust mite populations as fumigants with contact action. Copyright © 2011 Society of Chemical Industry