Efficacy of commercially available entomopathogenic nematodes against insect pests of canola in Alberta, Canada.

Certain entomopathogenic nematodes (EPNs) in the families Steinernematidae and Heterorhabditidae are among the most studied biocontrol tools, some of which are commercially available against pest insects. Their use against foliar and subterranean insect pests is largely unexplored in the Canadian Prairies. We conducted a laboratory-based study to produce baseline information on the biocontrol potential of a few commercial EPN species. Percent mortality of flea beetles, diamondback moths (DBMs), lygus, cabbage root maggots, and black cutworms (BCWs) was assessed after 72 hours exposure to Steinernema carpocapsae, S. kraussei, S. feltiae, and Heterorhabditis bacteriophora at varying concentrations (25, 50, 100, and 200 infective juveniles (IJs) per larvae, pupae, or cm2 of soil surface). Irrespective of concentration level, S. carpocapsae and S. kraussei caused significant mortality in DBM and BCW larvae compared with H. bacteriophora.S. kraussei, and S. feltiae were more efficient than S. carpocapsae in controlling root maggot larvae. H. bacteriophora caused zero mortality to root maggots at any concentration. Root maggot pupae were resistant to entry to EPN species tested, likely due to hard outer covering. Compared with root maggot pupae, a moderate level of mortality was observed in DBM pupae, suggesting differential ability of the tested EPNs in killing different life stages of certain pests. All nematode species tested caused low mortality (≤10%) in flea beetle adults. The findings of this investigation form fundamental data essential for carrying out field-based studies on canola and other related crops aimed at control and management of these pest species.

Odour emission rates from manure treatment/storage systems.

The effects of agitation, liquid-only manure, depth and time on odour emission rates were investigated. Manure storage tanks were filled to incremental depths every two weeks. At each depth odour samples were collected twice. The second sample was collected seven days after the first. Odour concentration was measured with an olfactometer. Three different pig-manure treatments were investigated. In one treatment, slurry manure in a storage tank was agitated before and during odour sampling. In a second treatment, the settlable solids in manure were removed gravimetrically over 24 hours and liquid manure was pumped to a storage tank. In the third treatment (control), odour samples were collected from unseparated and undisturbed slurry manure. Overall, the odour emission rates in the agitated manure treatment ranged between 0.39 and 1.02 ou s(-1) m(-2), increased with depth and decreased with time, i.e. after seven days at each depth. In the liquid-only manure treatment, the emission rates ranged between 0.09 and 0.69 ou s(-1) m(-2), increased with depth but the effect of time was not evident. In the control treatment, the emission rates ranged between 0.20 and 0.66 ou s(-1) m(-2) and increased with depth on the first odour sampling day but decreased with depth on the second sampling day.