No-choice Feeding Tests Research Articles

Evaluation of thermally-treated wood of beech (Fagus sylvatica L.) and ash (Fraxinus excelsior L.) against Mediterranean termites (Reticulitermes spp.)

Termite resistance of thermally-treated ash (Fraxinus excelsior L) and European beech (Fagus sylvatica L) against subterranean termites (Reticulitermes banyulensis) was evaluated. A laboratory no-choice feeding test following the standard EN 177 was performed to assess the efficacy of this thermo-modification against subterranean termites in the Mediterranean area. After 8 weeks period of exposure, results showed that durability against termites was slightly improved for thermally-treated beech wood, which was classified as moderately durable. However, in case of thermally-treated ash wood, samples were highly biodegraded by termites, revealing no increase in their durability and being classified as non durable.

Potential predation of non-webbuilding spider assemblage on cotton pests Helicoverpa armigera and Spodoptera littoralis (Lepidoptera: Noctuidae)

The relative feeding rates and preferences of a hunting-spider assemblage inhabiting southern Spanish cotton fields for two major cotton pests, Helicoverpa armigera (Hübner) and Spodoptera littoralis (Boisdubal) (Lepidoptera: Noctuidae), were analyzed under laboratory conditions. First, a no-choice feeding test was used to determine relative feeding rates for hunting-spider families and species, offering a fixed number of 10 neonate larvae of H. armigera or S. littoralis and observing predation after 2 h, 4 h, 8 h, and 24 h. In a second test, Drosophila melanogaster, a very palatable alternative prey, was used to determine the degree of preference for cotton pest larvae. The mean number of first-instar lepidoptera larvae consumed by hunting spiders after 24 h was 8.57±0.25. As expected, spiders showed no preference for either of the two cotton pest species H. armigera and S. littoralis over the other. Results also showed that cursorial spiders of the families Miturigidae (represented here by Cheiracanthium pelasgicum) and Philodromidae consumed significantly higher percentages of larvae than crab spiders belonging to the Thomisidae family after 2 h and 24 h, respectively. In the prey choice test, Cheiracantium pelasgicum displayed a strong preference for cotton pest larvae while Thomisidae and Oxyopidae showed no significant preference. In addition, as the attack sequence progressed, Ch. pelasgicum showed a clear tendency towards the alternation of prey while Thomisidae, and more irregularly Oxyopidae, maintained their preference for D. melanogaster. These findings confirmed both the considerable potential value of some cursorial spiders (e.g. Ch. pelasgicum) in the biological control of lepidopteran cotton pests and the relatively low impact of other hunting spiders, e.g. Thomisidae, on pests of this kind.

Erratum to: Effective Control of Slug Damage through Tobacco Extract and Caffeine Solution in Combination with Alcohol

Slug (Lehmannia valentiana) is known as a particularly troublesome pest in greenhouse, and commonly controlled by chemical bait molluscicides containing either metaldehyde or carbamate. These chemicals often caused undesirable side effects such as significant toxicity in non-target organisms or contamination in food and environment. We conducted several laboratory trials with natural products such as caffeine and tobacco extract or their mixtures combined with ethyl alcohol to assess their molluscicidal efficiency on slug. Slug mortality was evaluated after the three chemicals were sprayed in various concentrations on the slugs in pots. Ethyl alcohol of 10% provided above 90% mortality rate, whereas 3–7% resulted in below 30% mortality rate. Ethyl alcohol (5–7%) mixed with 0.5% caffeine or tobacco extract increased the slug mortality from 50% to 80%. In no-choice feeding test to investigate the behavioral response of the slug to the food, Chinese cabbage leaves were dipped in a mixture of caffeine (0.5%) and alcohol (5 or 7%). The caffeine mixture appeared to act as a repellent compared with the untreated, but tobacco extract/alcohol mixture (0.5/7%) provided a pattern attracting slugs. When two mixtures of caffeine/ethyl alcohol (0.5/5%) and tobacco extract/ethyl alcohol (0.5/7%) were sprayed on marigold seedlings, slug damage decreased by more than 65% compared with the control. Phytotoxic effect such as leaf burn on marigold seedlings was shown by caffeine/alcohol mixture but not by tobacco extract/alcohol mixture. In conclusion, the mixture of 0.5% tobacco extract and 7% ethyl alcohol could be a proper control method for slug in green house without causing any negative impact to environment or plants.

Physical properties and termite durability of maritime pine Pinus pinaster Ait., heat-treated under vacuum pressure

An original heat treatment performed under vacuum pressure was investigated. Maritime pine samples were treated at six different temperatures: 140, 160, 180, 200, 230 and 260°C. The physical and mechanical consequences, i.e. bending strength (MOR), modulus of elasticity (MOE), hygroscopic behaviour, equilibrium moisture contents and anti-swelling efficiency (ASE) were studied. A no-choice feeding test according to the NF EN 117 standard was achieved. Temperatures up to 200°C had no significant effect on wood properties. However, at 230 and 260°C, the decrease in MOR was severe, reaching 42.5 and 62.5%, respectively. Whatever the treatment conditions, wood samples were still highly degraded by termites, revealing no increase in their durability.

Host range of Secusio extensa (Lepidoptera: Arctiidae), and potential for biological control of Senecio madagascariensis (Asteraceae)

Secusio extensa (Lepidoptera: Arctiidae) was evaluated as a potential biological control agent for Madagascar fireweed, Senecio madagascariensis (Asteraceae), which has invaded over 400 000 acres of rangeland in the Hawaiian Islands and is toxic to cattle and horses. The moth was introduced from southeastern Madagascar into containment facilities in Hawaii, and host specificity tests were conducted on 71 endemic and naturalized species (52 genera) in 12 tribes of Asteraceae and 17 species of non-Asteraceae including six native shrubs and trees considered key components of Hawaiian ecosystems. No-choice feeding tests indicated that plant species of the tribe Senecioneae were suitable hosts with first instars completing development to adult stage on S. madagascariensis (78.3%), Delairea odorata (66.1%), Senecio vulgaris (57.1%), Crassocephalum crepidioides (41.2%), and at significantly lower rates on Emilia fosbergii (1.8%) and Erechtites hieracifolia (1.3%). A low rate of complete larval development also was observed on sunflower, Helianthus annuus (11.6%), in the tribe Heliantheae. However, sunflower was rejected as a potential host in larval-feeding and adult oviposition choice tests involving the primary host S. madagascariensis as control. Although larvae died as first instars on most test species, incomplete development and low levels of feeding were observed on nine species in the tribes Heliantheae, Cardueae and Lactuceae. Larvae did not feed on any non-Asteraceae tested, including species with similar pyrrolizidene alkaloid chemistry, crops, and six ecologically prominent native species. Because all species of Senecioneae are non-native and weedy in Hawaii, these results indicate that S. extensa is sufficiently host-specific for introduction for biological control. High levels of feeding damage observed on potted plants indicate that S. extensa can severely impact the target fireweed as well as D. odorata, a noxious weed in native Hawaiian forests.

Cordeauxia edulis and Rhododendron tomentosum extracts disturb orientation and feeding behavior of Hylobius abietis and Phyllodecta laticollis

The use of plant-based compounds to control insect pests is an alternative to the use of synthetic pesticides. We evaluated the repellent and antifeedant effects of Cordeauxia edulis Hemsley (Fabaceae) and Rhododendron tomentosum Harmaja (Ericaceae) extracts against Hylobius abietis L. (Coleoptera: Curculionidae) and Phyllodecta laticollis Suffrian (Coleoptera: Chrysomelidae). Repellent properties were evaluated by monitoring responses of adult insects toward the odor from extracts or extraction solvents (controls) in a Y-tube olfactometer, and choice or no-choice feeding tests were conducted by applying extracts or extraction solvents on stems of Scots pine [Pinus sylvestris L. (Pinaceae)] and European aspen [Populus tremula L. (Salicaceae)], host plants of H. abietis and P. laticollis, respectively. Extracts of R. tomentosum repelled adults of both insect species effectively. However, extracts of C. edulis did not repel H. abietis although its ethyl acetate extract showed repellence against the adults of P. laticollis. Feeding by H. abietis was significantly reduced by a methanol extract of C. edulis, and methanol and hexane extracts of R. tomentosum. Feeding by the adults and larvae of P. laticollis was significantly reduced by extracts from both plant species. Concomitant with less feeding, larval growth was retarded by ethyl acetate extracts of both plant species. Gas chromatography-mass spectrometry analyses of the volatile components of the extracts showed that extracts from both plant species were mixtures of various terpene and non-terpene compounds, which showed quantitative and/or qualitative variations between plant species and extraction solvents. This experiment showed that extracts from both plant species effectively manipulated the orientation and/or feeding behavior of the two beetle species. Hence, they may be considered as potential alternatives to synthetic chemical pesticides.

Pleiotropic physiological consequences of feedback-insensitive phenylalanine biosynthesis in Arabidopsis thaliana

A large proportion of plant carbon flow passes through the shikimate pathway to phenylalanine, which serves as a precursor for numerous secondary metabolites. To identify new regulatory mechanisms affecting phenylalanine metabolism, we isolated Arabidopsis thaliana mutants that are resistant to the phytotoxic amino acid m-tyrosine, a structural analog of phenylalanine. Map-based cloning identified adt2-1D, a dominant point mutation causing a predicted serine to alanine change in the regulatory domain of ADT2 (arogenate dehydratase 2). Relaxed feedback inhibition and increased expression of the mutant enzyme caused up to 160-fold higher accumulation of free phenylalanine in rosette leaves, as well as altered accumulation of several other primary and secondary metabolites. In particular, abundance of 2-phenylethylglucosinolate, which is normally almost undetectable in leaves of the A. thaliana Columbia-0 accession, is increased more than 30-fold. Other observed phenotypes of the adt2-1D mutant include abnormal leaf development, resistance to 5-methyltryptophan, reduced growth of the generalist lepidopteran herbivore Trichoplusia ni (cabbage looper) and increased salt tolerance.

Inhibitory effect of an endophytic fungus, Neotyphodium lolii, on the feeding and survival of Ostrinia furnacalis (Guenee) (Lepidoptera: Pyralidae) and Sesamia inferens (Walker) (Lepidoptera: Noctuidae) on infected Lolium perenne

To examine the feasibility of using endophytic fungi (/endophyte) as biological control agents against insect pests of host plants, the effect of Neotyphodium lolii, an endophyte living in perennial ryegrass, Lolium perenne L., was studied using two species of caterpillars: the Oriental corn borer, Ostrinia furnacalis (Guenee) (Lepidoptera: Pyralidae) and the pink borer, Sesamia inferens (Walker) (Lepidoptera: Noctuidae). Choice and no-choice feeding tests using endophyte-infected and endophyte-free clonal L. perenne indicate that endophyte-infected L. perenne have excellent resistance to O. furnacalis and S. inferens. Larvae of O. furnacalis significantly preferred endophyte-free to endophyte-infected grass. The ratio of surviving insects rapidly declined on infected grass and the survival curve on infected grass was similar to that of larvae of the no-food control. A similar trend occurred with S. inferens. These results indicate that N. lolii-infected L. perenne contains strong deterrent or toxic effects that affect O. furnacalis and S. inferens feeding and survival.

Potential and Realized Feeding Niches of Neotropical Hispine Beetles (Chrysomelidae: Cassidinae, Cephaloleiini)

Accurate descriptions of feeding habits are essential to understanding the evolution of dietary preferences and the high levels of diversification within the Chrysomelidae. Both primary observations and summaries suggest that the cassidine beetle tribe, Cephaloleiini, is a species-rich group of feeding specialists on monocot hosts. However, accurate host ranges are poorly defined for most hispine beetle species. To better document occurrence and feeding, we censused the Cephaloleiini associated with rolled leaves of five species of Marantaceae and six species of Heliconiaceae (Zingiberales) in lowland Central Panama. Additionally, we conducted choice and no-choice feeding tests on a subset of both the plants and beetles encountered in the censuses. Both types of data suggest that most species of Cephaloleiini feed on a greater variety of related plant species than has previously been reported.

Lethal dose and horizontal transfer of bistrifluron, a benzoylphenylurea, in workers of the Formosan subterranean termite (Isoptera: Rhinotermitidae)

The lethal dose and horizontal transmission of bistrifluron were examined in workers of the Formosan subterranean termite Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae) in laboratory no-choice feeding tests. The concentration of bistrifluron in baits was 5,000 ppm (wt/wt) in a series of tests. When termites were exposed to bistrifluron bait for 1 week, toxicity appeared slowly with an LT50 (50% lethal time) of 6.2 weeks. Much faster efficacy was observed after 2-week exposure. The amount of bistrifluron recovered from moribund termites indicated that approximately 400 ng/termite or more bistrifluron should accumulate in a single worker for insecticidal efficacy. The bistrifluron amount analyzed from various body parts of the termite body was not significanly different between immediately after 1-week exposure to bistrifluron bait and after the subsequent 2-week exposure to untreated bait. The rate of bistrifluron transferred from 20 donors to 20 recipients in 1 week was 6% of the amount of bistrifluron taken by the donors during the 1-week exposure to bistrifluron bait, and much smaller amounts of bistrifluron were transferred from donors to recipients for the subsequent 2 weeks. The bistrifluron that was originally ingested by C. formosanus workers appeared to partly remain in the termite body.

Feeding responses of the western dry-wood termite Incisitermes minor (Hagen) (Isoptera: Kalotermitidae) against ten commercial timbers

Five Japanese timbers, four timbers from the USA, and one Malaysian timber were evaluated for their resistance to the invasive dry-wood termite Incisitermes minor (Hagen) using laboratory choice and no-choice feeding tests with holed specimens. The highest survival rates of I. minor in both the heartwood and sapwood no-choice feeding tests were more than 70% after 3 months. When offered sapwood and heartwood choice feeding tests and the combined choice feeding tests, the highest survival rates of I. minor were more than 75% after 3 months. With regards to the percentage of wood mass losses in the no-choice and choice feeding tests, karamatsu (Larix leptolepsis), buna (Fagus crenata), and Douglas fir (Pseudotsuga menziesii) were classified as “resistant” species among the ten sapwood specimens. In the heartwood no-choice and choice feeding tests, the resistant species were buna, karamatsu, Douglas fir, sugi (Cryptomeria japonica), akamatsu (Pinus densiflora), and western red cedar (Thuja plicata). The ranking of the resistance of the ten commercial timbers against I. minor was buna > karamatsu > sugi > western red cedar > Douglas fir > rubber > western hemlock > hinoki > spruce.

Laboratory Evaluation of Bistrifluron, a Benzoylphenylurea Compound, as a Bait Toxicant Against <I>Coptotermes formosanus</I> (Isoptera: Rhinotermitidae)

Bistrifluron, a benzoylphenylurea compound, was evaluated with regard to its efficacy against workers of Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae) by using three laboratory tests. In the no-choice feeding test, the mortality of bistrifluron-treated worker termites was significantly higher than that of termites exposed to the same concentrations of hexaflumuron (e.g., 6 wk at 500 ppm, 4 wk at 5,000 ppm, and 2 wk at 50,000 ppm) and untreated controls. Bistrifluron showed higher dose dependence and a faster speed of action than hexaflumuron. Both bistrifluron and hexaflumuron had feeding-deterrent effects at 5,000 ppm in the two-choice feeding test, although the mortality of worker termites exposed to bistrifluron or hexaflumuron at 5,000 ppm was not significantly different from untreated controls. In the allogrooming inhibition test, to examine effects of bistrifluron on allogrooming behavior of termites, termite movement was affected at 1 wk before termites died when exposed to 5,000 ppm bistrifluron. These results indicate bistrifluron is effective as a bait toxicant at 5,000 ppm; however, bistrifluron may cause some feeding repellency at > or = 5,000 ppm.

Effects of heartwood extractive fractions of Thuja plicata and Chamaecyparis nootkatensis on wood degradation by termites or fungi

The effect of selective removal of extractives on termite or decay resistance was assessed with matched samples of Thuja plicata Donn ex D. Don and Chamaecyparis nootkatensis (D.Don) Spach heartwood. Samples were extracted using a variety of solvents and then exposed to the subterranean termite Coptotermes formosanus Shiraki in a no-choice feeding test or to the brown-rot fungus Postia placenta (Fr.) M. Larsen & Lombard in a soil bottle test. At the same time, the effect of naturally occurring variations in heartwood extractives on termite or decay resistance was evaluated by testing samples from the inner and outer heartwood of five trees of each species against C. formosanus and P. placenta and analyzing matched wood samples for their extractive content. The results suggest that the methanol-soluble extractives in T. plicata and C. nootkatensis play an important role in heartwood resistance to attack by C. formosanus and P. placenta. Total methanol-soluble extractive content of the heartwood was positively correlated with both termite and decay resistance; however, there was much unexplained variation and levels of individual extractive components were only weakly correlated with one another. Further studies are under way to develop a better understanding of the relationships between individual extractive levels and performance.

Investigating Antitermitic Compounds from Australian White Cypress Heartwood (Callitris glaucophylla Thompson et Johnson) Against Coptotermes formosanus Shiraki

Antitermitic activities of extracts obtained from the heartwood of Australian white cypress (Callitris glaucophylla Thompson et Johnson) were investigated in an attempt to detect and identify the presence of biologically active compounds against Coptotermes formosanus Shiraki. Extraction of compounds was achieved by successive extraction using dichloromethane and methanol. Three sesquiterpene alcohols, guaiol, α-eudesmol and β-eudesmol and two monoterpene acids, (−)-citronellic acid and geranic acid, were found in the C. glaucophylla heartwood extracts based on high performance liquid chromatography (HPLC) and gas chromatography/mass spectrometry (GC/MS) analysis. Antitermitic activity of each fraction obtained from methanol extracts was demonstrated by repellent and no-choice feeding tests. One of the strong termiticidal active compounds identified was columellarin and another sesquiterpene lactone fraction showed repellent activity.

Discrimination of Sodium Tetraborate by Anastrepha suspensa Loew (Diptera: Tephritidae)

Newly-emerged adults (4 h old) and 10-d-old Anastrepha suspensa Loew were exposed to 0 to 5% concentrations of sodium tetraborate for 7 d in choice and no-choice feeding tests. With an increase in sodium tetraborate concentration, mortality increased and occurred more quickly; egg production and egg hatch were reduced in both choice and no-choice tests. Fly mortality, egg production, and egg hatch indicated that flies fed about equally on control and sodium tetraborate-containing food when offered a choice. Egg production appeared to be more sensitive to sodium tetraborate than egg hatch. All flies died and no eggs were produced with 1, 3, and 5% sodium tetraborate even when flies were offered the choice of food without sodium tetraborate.

Allomonal and hepatotoxic effects following methyl eugenol consumption in Bactrocera papayae male against Gekko monarchus.

Methyl eugenol (ME), is converted into two major phenylpropanoids, 2-allyl-4,5-dimethoxyphenol and trans-coniferyl alcohol, following consumption by the male fruit fly Bactrocera papayae. Chemical analysis of wild male B. papayae rectal glands, where the compounds are sequestered, revealed the presence of ME metabolites in varying quantities. These phenylpropanoids are shown to be involved in the fruit fly defense both in no-choice and choice feeding tests against the Malayan spiny gecko, Gekko monarchus. After being acclimatized to feeding on fruit flies, geckos consumed significantly fewer ME-fed male flies than controls that consumed all the ME-deprived male flies offered throughout a two-week period. Diagnosis of dissected livers from geckos that consumed ME-fed male flies revealed various abnormalities. These included discoloration and hardening of liver tissue, whitening of the gallbladder, or presence of tumor-like growths in all geckos that consumed ME-fed male flies. Control geckos fed on ME-deprived male flies had healthy livers. When given an alternative prey, geckos preferred to eat untreated house flies, Musca domestica to avoid preying on ME-fed fruit flies.

Effects of a kaolin-based particle film on obliquebanded leafroller (Lepidoptera: Tortricidae).

Studies were conducted in 1997 to evaluate the effects of the kaolin-based particle film formulation M96-018 on adults, eggs, and larvae of the obliquebanded leafroller, Choristoneura rosaceana (Harris). Particle film treatments significantly reduced female longevity, mating success, and number of egg masses oviposited compared with moths on untreated apple leaves in sleeve-cage and screen-cage tests. No differences in mating success or oviposition were caused by the application rates and coverage density of M96-018 on foliage. Females avoided ovipositing on particle film-treated leaves in choice tests. Larval hatch was not affected by topical application or residual exposure to M96-018. Larval weight gain and pupal weight were significantly reduced and larval mortality increased in no-choice feeding tests with M96-018. In choice tests, larvae preferred to feed on untreated leaf surfaces. The negative effects on larval development and survivorship on M96-018-treated foliage did not differ across a fourfold difference in spray application rate. A significant reduction in the number of infested shoots was found in orchard trials when M96-018 was applied before bud break in late March compared with untreated trees. No reductions in larval densities were found compared with an untreated control following prebloom and postbloom applications.

Host Specificity Testing of Galerucella calmariensis L. (Coleoptera: Chrysomelidae) on Wild and Ornamental Plant Species

Abstract Galerucella calmariensis has been widely distributed in North America for biological control of purple loosestrife, Lythrum salicaria. We tested the host specificity of G. calmariensis against 40 nontarget species in 14 previously untested families, determining the ability of G. calmariensis adults to survive, feed, produce eggs, and oviposit on these plants in no-choice tests. When adult feeding occurred, we then tested the potential for adult and larval impacts in a series of choice and no-choice tests. For nontarget plants that may co-occur with L. salicaria, we also tested the propensity for larval and adult attack under conditions of high G. calmariensis density. In no-choice adult feeding tests, G. calmariensis did not feed or survive on most of the species tested. Minor damage was observed on Vernonia fasiculata (Asteraceae) and five members of the Rosaceae, subfamily Rosoideae, Fragaria x. ananassa, Filipendula rubra, Rosa setigera, Alchemilla mollis, and Rubus idaeus. In subsequent choice tests, oviposition never occurred on nontargets and no-choice larval establishment tests showed that neonates could not establish on any of these species. For F. rubra, which may potentially co-occur with L. salicaria, no-choice larval transfer trials showed that third instar G. calmariensis larvae did not feed on F. rubra and pupated at significantly reduced weights. In a large-cage choice study with larvae and adults, no feeding or oviposition on F. rubra occurred. These data support preintroduction host specificity results indicating that normal feeding, oviposition, and development of G. calmariensis is confined to L. salicaria. However, recent field observations confirm the greenhouse studies indicating that transient feeding by teneral adults may occur on some nontargets under no-choice conditions.

Biology and Host Preference of Nephopteryx divisella (Lepidoptera: Pyralidae): Candidate Agent for Biological Control of Leafy Spurge Complex in North America

Euphorbia esula L. (Euphorbiaceae) is a complex of species that has become major weeds in rangelands and pastures in North America. The biology and host specificity of Nephopterix divisella Duponchel (Lepidoptera: Pyralidae) was studied to evaluate its potential as a new biological control agent. This oligophagous, multivoltine stem borer is common on spurges such as E. characias in western and southwestern Europe. The results of no-choice feeding test with 1st instars, showed that the host range is restricted to plant species in the genus Euphorbia. Among them, feeding on E. milii Desmoulins and E. trigona Haworth, both ornamental plants, seems to bar chances for N. divisella to be selected as a leafy spurge biological control agent.

Biologie, distribution et gamme d’hôtes deLophyrotoma zonalis (Hym. : Pergidae), agent potentiel de lutte biologique contreMelaleuca quinquenervia

Since its introduction into southern Florida at the beginning of this century, the Australian paperbark tree,Melaleuca quinquenervia (Cav.) S. T. Blake, has become a major economic and environmental pest. A project to develop biological control agents for this tree in Australia began in 1986. Among a number of potential agents, a defoliating sawfly,Lophyrotoma zonalis (Rohwer) (Hymenoptera: Pergidae), was selected for further study. The larvae of this sawfly are conspicuous defoliators ofMelaleuca trees in northern Queensland. We collected these sawflies from Cairns to Mackay in northern Queensland, and they are also known from the Northern Territory and New Guinea. The life-cycle from egg to adult takes about 12 weeks. The egg, larval and pupal stages are parasitized by dipteran and hymenopteran parasites. We conducted 2234 larval no-choice feeding tests on 46 plant species from 20 families. Although feeding occurred on 35 of these plant species,M. quinquenervia and its close relative,M. leucadendra (L.) L., were preferred. In oviposition tests, larvae only emerged from egg cases laid onM. quinquenervia andM. leucadendra. Our extensive field surveys of nearly 70 tree species foundL. zonalis eggs and larvae only on several closely relatedMelaleuca species. The potential effectiveness of this sawfly as a biocontrol agent is discussed and estimated using the Goeden-Harris scoring system. Quarantine studies of this insect began in Florida in early 1994.