Noubar J. Bostanian

ACARICIDAL PROPERTIES OF ARTEMISIA ABSINTHIUM AND TANACETUM VULGARE (ASTERACEAE) ESSENTIAL OILS OBTAINED BY THREE METHODS OF EXTRACTION

Abstract Essential oils of Artemisia absinthium L. and Tanacetum vulgare L. were extracted by three methods, a microwave assisted process (MAP), distillation in water (DW) and direct steam distillation (DSD), and tested for their relative toxicity as contact acaricides to the twospotted spider mite, Tetranychus urticae Koch. All three extracts of A. absinthium and of T. vulgare were lethal to the spider mite but to variable degrees. The LC50 obtained from the DSD oil of A. absinthium was significantly lower (0.04 mg/cm2) than that of the MAP (0.13 mg/cm2) and DW (0.13 mg/cm2) oil of this plant species. DSD and DW extracts of T. vulgare were more toxic (75.6 and 60.4% mite mortality, respectively, at 4% concentration) to the spider mite than the MAP extract (16.7% mite mortality at 4% concentration). Chromatographic analysis indicated differences in composition between the more toxic DSD oil of A. absinthium and the other two extracts of this plant, indicating that a sesquiterpene (C15H24) compound present in the DSD oil and absent in the other two may enhance the toxicity of the DSD oil. Chemical analysis of the T. vulgare extracts indicated that β-thujone is by far the major compound of the oil (>87.6%) and probably contributes significantly to the acaricidal activity of the oil.

Towards Insecticide Free Apple Orchards: Flowering Plants to Attract Beneficial Arthropods

Tanacetum vulgare, Chrysanthemum maximum, Aster tongolensis and Achillea millefolium were planted to attract and retain predacious and parasitoid arthropods in a Quebec apple orchard. The plants covered one-third of the surface of the experimental block and provided nectar, pollen and refuge for beneficial arthropods. The parasitoid fauna increased several-fold during the study. The most important index of pest management in this study was the quality of the fruit at harvest and it attained 90.8% (clean fruit) in the fifth year of the study. The technique cannot be readily adopted into an orchard that is in full production because it would require several years to build up the beneficial arthropod fauna to an effective bio-control force. During that period, pesticides would not be applied and losses in yield would be commercially unacceptable. Habitat management should be used as a template for biological control of orchard pests over which other bio-control techniques can be superimposed to further increase the quality of the yield at harvest.

Effect of seven new orchard pesticides on Galendromus occidentalis in laboratory studies.

BACKGROUND Biological control of phytophagous mites in orchards requires that pesticides used to manage other arthropod pests or diseases are harmless to predacious mites, as these are essential to keep phytophagous mites at non-injurious population levels. This study evaluates the possible toxic attributes of acetamiprid, imidacloprid, thiacloprid, thiamethoxam, spirodiclofen, spinosad and methoxyfenoxide currently used in western Canadian orchards. RESULTS None of these pesticides has any ovicidal properties against Galendromus occidentalis (Nesbitt). Imidacloprid and acetamiprid were highly toxic to the adults and reduced fecundity significantly. Thiamethoxam and spirodiclofen were non-toxic to adults, but they slightly reduced fecundity. Thiacloprid, spinosad and methoxyfenoxide were harmless to adults and had no effect on fecundity. All compounds showed some repellence at 24 h intervals for 72 h. CONCLUSIONS Imidacloprid and acetamiprid are incompatible with IPM programs because they are toxic to adults and negatively affect fecundity. Thiamethoxam and spirodiclofen need further field evaluation to determine if they are compatible with IPM programs because they slightly reduced fecundity. Thiacloprid, spinosad and methoxyfenoxide are harmless to adults, but they are slightly repellent. Therefore, with the exception of imidacloprid and acetamiprid, all these compounds should be field tested for compatibility in an IPM program.

Effects of five fungicides used in Quebec apple orchards on Amblyseius fallacis (Garman) (Phytoseiidae: Acari)

SummaryThe toxicity of the fungicides captan, dodine, mancozeb, metiram and myclobutanil to adults, nymphs and 0–24 h eggs of Amblyseius fallacis was evaluated in the laboratory. Dodine and mancozeb reduced egg hatch significantly in comparison with water controls and dodine was the most toxic to the nymphs. Captan and metiram had no effect and the remaining fungicides were of intermediate toxicity. None of the fungicides affected the longevity and the fecundity of young females.

Effects of six selected orchard insecticides on Neoseiulus fallacis (Acari: Phytoseiidae) in the laboratory.

BACKGROUND Neoseiulus fallacis (Garman) is a key predator of tetranychid mites in integrated pest management (IPM) programs across Canada. This study identified compounds that would be recommended for tier-II field evaluations in an IPM program. RESULTS The overall egg mortality caused by the six insecticides was negligible as it extended from 0 to 12.1%. Imidacloprid was classified as toxic to adults. The label rate was 7.73-fold the LC(50). Thiamethoxam was classified as moderately toxic to adults, and its label rate was 2.87-fold the LC(50). Acetamiprid and spinosad were classified as marginally toxic, and their label rates were respectively 0.99- and 0.45-fold the LC(50) for adults. Thiacloprid and methoxyfenozide were virtually innocuous to adults. CONCLUSION Methoxyfenozide was totally harmless to all stages of N. fallacis, and it would be included in IPM programs immediately. Acetamiprid, spinosad and thiacloprid had varying degrees of mild toxicity to at least one growth stage of the predator. Therefore, they were recommended for tier-II field testing according to their label claims. Imidacloprid and thiamethoxam were toxic to moderately toxic to adults and had significant adverse effects on fecundity. Therefore, they would be field evaluated only if alternatives were unavailable.

Impact of Lambda-cyhalothrin on Intraguild Predation Among Three Mite Predators

Abstract The impact of a sublethal dose of lambda-cyhalothrin on intraguild predation between three mite predators, Hyaliodes vitripennis (Say), Harmonia axyridis Pallas, and Amblyseius fallacis (Garman) was evaluated in laboratory. The symmetry and level of intraguild predation in selected predator combinations were recorded in the absence and presence of lambda-cyhalothrin. The mobility of the different predatory stages was also recorded in the absence and presence of insecticide. The results showed that lambda-cyhalothrin did not significantly modify intraguild predation but it affected the mobility. A knockdown effect was observed in H. axyridis larvae and in H. vitripennis nymphs, whereas A. fallacis showed an increased mobility. Exposure to a sublethal dose of lambda-cyhalothrin modified predator behavior and must be considered in the implementation of a mite control program in apple orchards.

Laboratory-Based Toxicological Assessments of New Insecticides on Mortality and Fecundity of Neoseiulus fallacis (Acari: Phytoseiidae)

ABSTRACT Neoseiulus fallacis (Garman) is one of the most abundant predatory phytoseid in deciduous fruit orchards under an integrated pest management (IPM) regimen in eastern North America. Laboratory studies using N. fallacis, and the ‘modified excised leaf disc method’ identified four insecticides out of six, that would require second-tier field studies before inclusion in an IPM program for deciduous orchards. The overall egg mortality caused by flubendiamide, chlorantraniliprole, chlothianidin, novaluron, Spinetoram, and spirotetramat ranked from 0 to 37.6%. Larval mortality caused by spirotetramat, spinetoram, novaluron, and chlothianidin ranged from 100 to 78.3%, respectively. Chlorantraniliprole and flubendiamide were virtually nontoxic to larvae. Spinetoram, chlothianidin, and spirotetramat caused 100, 61.4, and 40.2% mortality of adult N. fallacis, respectively. Spirotetramat and chlothianidin significantly reduced fecundity, whereas novaluron, flubendiamide, and chlorantraniliprole had no such adverse effect for the duration of the study (168 h). Chlorantraniliprole and flubendiamide do not require further second tier field studies and may be included in deciduous orchard IPM programs. Spirotetramat is toxic to several growth stages but it has a very short residual activity, and along with novaluron, which is toxic only to larvae, should be evaluated in second-tier field studies. Clothianidin and spinetoram should be evaluated in second-tier field studies only if alternatives are unavailable.

Ground-Dwelling Spider Fauna (Araneae) of Two Vineyards in Southern Quebec

Abstract The spider fauna of vineyards in northern parts of North America are completely unknown, even though spiders represent important natural enemies to phytophagous insects occurring in vineyards. Weekly pitfall trapping in 1998 and 1999 in two vineyards in southern Quebec yielded over 4,600 spiders belonging to 97 species and 16 families. Spider assemblages (diversity and community composition) were similar between the two vineyards independent of environmental differences. However, some species-specific patterns were noted when the two vineyards were compared. High landscape diversity, including fallow fields and adjacent apple orchards, is hypothesized to account for a higher abundance of certain agrobiont species in one of the vineyards. Phenological data shows the most abundant linyphiid species, Tennesseellum formicum (Emerton), exhibits high phenotypic variation, and its multivoltine life cycles may be of adaptive importance for vineyards that are frequently disturbed. We also note several other species exhibiting period of peak activity in the spring [e.g., the wolf spiders Pardosa moesta Banks and Trochosa ruricola (De Geer)] or autumn [e.g., the funnel-web spider Agelenopsis potteri (Blackwall)]. Species turnover was high between sample dates, and data on activity and species richness of two guilds (web-building spiders and hunting spiders) indicate that many species that differ in foraging mode are active during all months of the growing season. The diverse ground-dwelling spider fauna in vineyards is therefore well positioned to prey on phyotophagous pests, and their populations should be conserved in these agroecosystems.

Weevil (Coleoptera: Curculionoidea) Diversity and Abundance in Two Quebec Vineyards

Abstract The wine-making region of southern Quebec in Canada experiences growing conditions that are unique in northeastern North America. After an outbreak of insect pests in 1996, a study of insect groups that may include potential pests or beneficial species was initiated. This article reports on the weevil diversity and abundance during three consecutive years of sampling (1997–1999) in two vineyards. All weevils were collected using pitfall and flight intercept traps. In total, 3,176 specimens were collected, representing 73 species in three families of Curculionoidea. The family Curculionidae was the most species rich, especially the subfamilies Ceutorhynchinae, Curculioninae, and Entiminae. Four of the species recorded are known to feed on the genus Vitis (Vitaceae) in North America: Madarellus undulatus (Say), Barypeithes pellucidus (Boheman), Otiorhynchus ovatus (L.), and Otiorhynchus sulcatus (F.). Of these, O. sulcatus is thought to represent the greatest potential threat based on adult abundance at one of the sites and the negative impact of this species in other wine-making regions in North America. Four species [Ceutorhynchus oregonensis Dietz, Pelenomus waltoni (Boheman), Rhinoncus perpendicularis (Reiche), and Sphenophorus minimus Hart] are recorded in Quebec for the first time. A significant number of weevils collected during this study are adventive species associated with agroecosystems of northeastern North America.

Peripheral‐zone treatments for plum curculio management: validation in commercial apple orchards

Peripheral applications of organophosphate insecticides were evaluated as an alternative strategy for controlling adult plum curculio, Conotrachelus nenuphar Herbst (Coleoptera: Curculionidae) in four commercial orchards in Quebec, Canada. Each orchard was partitioned into a reference and an experimental plot to compare the classical full plot treatment with a peripheral treatment alternative. The experimental plots were divided into five zones, i.e. central, North, South, West and East. Peripheral zones were defined as the first five rows of apple trees (or 20 m wide). Plum curculio adults were monitored weekly by limb tapping. Fresh oviposition scars were evaluated by examining 20 fruitlets per tree on each outermost tree in the peripheral zone and 20 fruit on 25 trees in the central zone. Azinphosmethyl treatments were carried out in the zones where more than 1% fruitlets bore fresh ovipositional scars. Fruit damage was mostly (92%) found in the peripheral zones. Plum curculio damage at harvest varied from 0.0 to 0.7% and from 0.0 to 0.8% in the experimental and reference plots respectively. Total insect damage on fruit at harvest varied from 1.3 to 3.8% in the experimental plots, and from 0.4 to 5.0% in the reference plots. In 1991, there were no significant differences between population indices of the spotted tentiform leafminer, the apple aphid, leafroller species and cicadellids in the peripheral versus central zones. In the experimental plots, populations of woolly apple aphid, two‐spotted spider mite and apple rust mite were significantly higher in peripheral zones than in the central zones. In 1992, there were no significant differences between population indices of peripheral versus central zones for both experimental and reference plots. All localities and years pooled, peripheral zones of experimental plots received 1.22 insecticide treatments, against 1.29 for reference plots. However, central zones of experimental plots received 0.38 insecticide treatments, against 1.13 for reference plots. Assuming a 20 m peripheral zone and a 10 ha square orchard, the percent reduction in insecticides would be ca. 75%.