Predacious fungi that capture and kill nematodes live, amongst other places, in the soil where it is assumed that they participate in the natural control of nematodes, including the plant parasitic species that cause tremendous losses to farmers. There are predacious fungi in the soil which prey on amoebae, rotifers, rhizopods and other small animals but they were not dealt with in this study. [...]

Rove beetles (Staphylinidae) in Ontario soybean-hedgerow agroecosystems were surveyed in 2009-2010 to identify common, widespread species and assess their potential biological control of Soybean Aphid and Bean Leaf Beetle. The spatiotemporal distributions, habitat use, and co-occurrence of staphylinids with soybean pests were studied to provide a framework for future agroecological studies of biocontrol services in soybean. A taxonomic review of the Staphylinina (Staphylinidae: Staphylininae) (‘large rove beetles’) for the geographic area of study was conducted and identification keys were created to assist in future staphylinid research. Common soybean staphylinids were generally exotic, penetrated field interiors, utilized hedgerow habitat outside the growing season and co-occurred with pest populations during vulnerable life stages. Several species exhibited nocturnal activity in soybean foliage. Biocontrol of overwintering Soybean Aphid and Bean Leaf Beetle populations in hedgerows by staphylinids may occur in buckthorn canopies and leaf litter, respectively.

The distribution, biology and host preferences of Cryptorhynchus melastomae Champion (Coleoptera: Curculionidae) were studied in Costa Rica from May to July 2005 and January to May 2006 to determine its suitability as a biocontrol agent for Miconia calvescens DC (Melastomataceae) in Hawaii. Specimen records compiled from various collections indicate a distribution from Mexico to Ecuador. In its native Costa Rica all life stages of C. melastomae are associated with M. calvescens and adults and larvae can severely damage or kill small seedlings. Adults are nocturnal and apparently prefer to feed and oviposit on M. calvescens seedlings. Comparisons between its environmental conditions in Costa Rica and Miconia-infested areas in Hawaii suggest the insect should thrive if released. Initial host range tests indicate that C. melastomae is host-specific to the Melastomataceae. This does not rule it out as a biocontrol agent because all Melastomataceae in Hawaii are invasive weeds; there are no native species on the islands.

Colletotrichum coccodes (Wallr.) Hughes, a foliar pathogen of velvetleaf, is being developed as a bioherbicide. Formulation of living organisms for use as pest control products presents unique problems. This research has achieved the development of an adequate formulation of the pathogen by using kaolin clay or talcum powder (1:2.79 wt/wt) as the fillers to dry conidia. Formulated C. coccodes conidia stored at 4, 30C, or at room temperature in bags permeable to oxygen remained viable and able to infect velvetleaf plants at least six months in storage. Various reported germination stimulants increased germination of formulated conidia, although not significantly, whereas increasing concentrations of cutin resulted in subsequent decreases in germination and appressoria formation of fresh as well as formulated conidia. In controlled environment experiments, 14 day-old velvetleaf seedlings were severely diseased when stearic or oleic acids were added to conidia formulated in kaolin clay or talcum powder, respectively. Combinations of germination stimulants, cutinase and/or pectinase inducers did not significantly increase germination and appressoria formation of C. coccodes conidia. Germination of fresh and formulated conidia increased, although not significantly, with the addition of 1% sucrose.

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Resistance responses of Abutilon theophrasti were investigated to determine defense mechanisms of the weed against Colletotrichum coccodes and to verify if some chemical suppression of the resistance mechanism could be exploited to enhance the virulence. Induced resistance in A. theophrasti has been confirmed in treatments with C. coccodes, benzothiadiazole, bentazon, and acifluorfen. Induction of peroxidase and phenylalanine ammonia lyase (PAL) activities in the leaves that did not contact with the inducing agents was observed after the localized stresses to the first leaf or the root of the plant with those agents. alpha-Amino-oxy acetic acid (AOA), 2-deoxy-D-glucose (DDG), mannose, oxalic acid, and analogues of oxalic acid and mannose were tested to enhance C. coccodes virulence. However, the compounds did not enhance C. coccodes virulence or affect A. theophrasti growth. Strong antifungal effects, poor inhibitory effects on plant defense mechanisms, or minor dependence of A. theophrasti on the defense mechanisms that the chemicals affected could be reasons. The efficacy of C. coccodes increased in the presence of 0.25 kg a.i. ha-1 bentazon more than when C. coccodes was applied alone, while the effect of glyphosate was minimal. Peroxidase activity was strongly induced by the treatment of C. coccodes and increased over time. PAL and activation of peroxidase was inhibited in the presence of bentazon, suggesting the synergy effect by bentazon is probably due to the suppression on the two defense-related enzymes. In conclusion, A. theophrasti exploits various biochemical and morphological types of defense mechanisms against C. coccodes infection. However, the activation of the defense responses can be suppressed or by-passed in an integrated weed management system.

Study of the Entomophthorales infection in selected black fly populations from two outlets of a lake was conducted at the Reserve Faunique du Saint-Maurice (Quebec). Entomophaga near limoniae infected Simulium verecundum/rostratum, whereas Erynia curvispora predominantly parasitized Simulium decorum, and Erynia conica infected Simulium venustum and the Simulium verecundum/rostratum and Simulium vittatum complexes. This is the first report of the presence of Erynia conica and Entomophaga near limoniae in North America and Erynia curvispora in Canada. Entomophaga near limoniae in black flies represents a new association. / A successful method for rearing Simulium rostratum, and the in vitro production of fungal conidiospores, produced a sufficient supply of material to study the cuticular invasion process of Erynia conica in the laboratory. Both Erynia species exhibited a diurnal periodicity in the formation of secondary conidiospores in darkness in vitro. This mode of development was influenced by the pH of the medium. The cyclic pattern in secondary conidia formation by Erynia conica disappeared with exposure to light, which suggests that photoperiod may be a factor contributing to host infection. Only secondary type 2 conidia of Erynia conica produced germ tubes that invaded the cuticle of the proper host, Simulium rostratum as opposed to the primary conidia. The infective unit exhibited delayed germination and formed neither appressoria nor invaded the cuticle of the non-host, Simulium decorum, which may explain the host specificity observed in the field study. Cuticular lipids triggered appressoria formation and penetration pegs on the host black fly and did not seem to inhibit fungal invasion on the non-host. / The effects of selected physical factors on the development of the infective unit of Erynia conica were determined. Germination and sporulation in vitro were influenced by medium pH, environmental temperature and charge of the substrate, but both processes were independent of substrate hydrophobicity. Germination and sporulation occurred throughout the pH and temperature ranges tested, with both achieving maximum at pH 7.5-8.0 and 10-20$ sp circ$C. Temperature range of the germination of the conidiospores in situ was similar that in vitro, which corresponded to the temperature variation in the field. Production of invasive structures was noted for in situ experiments only and was more temperature sensitive than was germination.

Field and growth bench experiments were performed to assess the effect of a selective fungal pathogen of Abutilon theophrasti (velvetleaf) on various aspects of intra- and interspecific competition between this vigorous agricultural weed and soybean (Glycine max). In the absence of the foliar pathogen, Colletotrichum coccodes, A. theophrasti and soybean responded differently to the presence of conspecies or to individuals of the other species. In pure stand, the deleterious effects of intraspecific competition on reproductive output were substantially greater for A. theophrasti than for soybean, especially at lower monoculture densities. In mixtures, however, A. theophrasti reproductive performance was markedly higher than at equivalent monoculture densities, particularly at the lower mixture densities. Soybean reproduction at these lower mixture densities (10 to 20 plants m$ sp{-2}$) was severely curtailed compared with reproductive output at equivalent pure stand densities. A. theophrasti reproductive output was limited more by the presence of conspecies than by the presence of soybean, whereas the opposite trend was observed for soybean. In pure stand, application of C. coccodes had limited impact on either A. theophrasti or soybean yield. However, application of the fungal pathogen in A. theophrasti monocultures caused significant (30-44%) aboveground biomass reductions within five weeks of inoculation, in two of the three years in one field study. Eight weeks following C. coccodes inoculation, A. theophrasti biomass within inoculated monoculture plots did not differ significantly from biomass within uninoculated control plots, although height hierarchies were significantly more developed. In mixtures, C. coccodes applications caused reductions in A. theophrasti growth and reproduction when provided with an adequate dew period. Alternatively, soybean yield losses within inoculated mixture plots were generally lower than for uninoculated control plots, althoug

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