Lupines (Lupinus albus L.) can provide high levels of good quality protein for human and animal nutrition. Unlike soybeans, lupine seeds do not need to be processed before consumption. Being a member of the legume family, lupines improve soil structure and fertility. Lupines also have the advantage of being able to grow in cooler climates and in fields of lower fertility than soybean. Lupine production is relatively new in Eastern Canada and new diseases limit production in this region. In 1990, a Phoma sp. was isolated from diseased lupine in Quebec and Nova Scotia. This research was undertaken to acquire further knowledge about this lupine pathogen. The morphological characteristics of this fungus do not exactly fit the description of any other Phoma sp., but it is very close to P. pinodella. This Phoma sp. on lupines may be a new variety of P. pinodella affecting lupine in particular. In vitro, mycelium grew over a wide range of temperatures (5°--35°C), the optimal temperature being 25°C. Spore germination occurred under different conditions of temperature, from 10°C to 35°C, the optimum being 25°C. Spores germinated at relative humidities from 94% to 100%, (-7.027 to 0 MPa) the optimum being between 98% and 100% (-2.768 to 0 MPa). In controlled environment, disease symptoms appeared over a wide range of leaf wetness durations (8 h--36 h) and temperature regimes (15°C--30°C). The most extensive disease symptoms occurred following 36 hours of leaf wetness duration at 30°C. This Phoma sp. survived over winter in infected stubble of lupines of the previous year crop. The infected crop residue may be another source of inoculum of this seedborne pathogen.

No description available.

Common ragweed (Ambrosia artemisiifolia L., Asteraceae) is an annual herbacious weed that is a troublesome pest in carrot fields of Southwestern Quebec. Over the past decade, ragweed has shown resistance to linuron, the only herbicide that is registered for post-emergence control of this weed in carrots. In this research, the degree of resistance to linuron was investigated for a ragweed biotype collected from a carrot field in Sherrington, Quebec, where a decreased performance of linuron had been noted. This biotype showed a linuron resistance ratio (I50) of 9.09, when compared with ragweed plants collected from a field never sprayed with this herbicide. The fungal pathogen Phoma sp., which had been initially isolated from diseased ragweed leaves in 1993, was considered as a potentially effective biological agent for the control of common ragweed. The pathogenicity of Phoma sp. was re-evaluated during the current research. This fungus was found not to have any appreciable virulence towards common ragweed; it is likely that virulence was lost during storage. Hence, twenty other fungal species were isolated from diseased common ragweed plants and assayed to determine their potential as biological agents against this noxious weed. Varying dew periods, temperatures, spore concentrations, host growth stages, and different types of carrier were evaluated. Only isolates ATT#9, INNA4a, INNA4b, ATT#10, ISO#65, and ISO#68 were able to induce lesions on ragweed foliage at spore concentrations of 106 to 107 spores ml-1, but only after an extended dew period of 48 hrs. No interaction effects on the degree of ragweed control were found when combining five fungal isolates and the insect, Ophraella communa LeSage. However, a possible interactive effect was detected when the fungal isolate ISO#65 and linuron were used in combination.

No description available.