Project Code: BPR12-080
Project Lead
Silvia Todorova - Anatis Bioprotection Incorporated, Quebec
Michael Brownbridge- Vineland Research and Innovation Centre, Ontario
Leo J Blydorp - Agronomy and Crop Protection Consulting, Ontario
Objective
To develop efficacy and crop tolerance data in support of a regulatory submission for Grandevo® (MBI-203) (Chromobacterium subtsugae) for the management of hairy chinch bug (Blissus leucopterus) in turf
Summary of Results
Background
The hairy chinch bug (Blissus leucopterus) is a destructive lawn pest in many provinces in Canada. With its piercing-sucking mouthparts it feeds on the sap from the crown and stems of the plant and injects toxins into the plant. This disrupts the vascular system of the plant, causing it to wilt, turn yellow, then brown and die. All common turfgrass species in Canada are susceptible to the insect feeding. An alternative solution to chemical control is needed for this insect, particularly due to the increased concerns regarding chemical pesticide use in the urban environment.
The biopesticide Grandevo® (MBI-203) (Chromobacterium subtsugae), developed by Marrone Bio Innovations, was selected as a priority solution by growers at the 2011 Biopesticides Priority Setting Workshop for the management of hairy chinch bugs in turf grass in Canada. Grandevo® has a broad spectrum of control against sucking and chewing insects. The mode of action of Chromobacterium subtsugae on hairy chinch bug is unclear; however some studies have indicated that the bacterium inhibits feeding and reduces weight in some insects.
Approaches
Five trials were conducted in Ontario and Quebec on residential lawns planted with Kentucky blue grass, fescue or raygrass in 2012 and 2013. Trials were carried out against natural hairy chinch bug infestations, targeting mixed-age populations (nymphs and adults). Grandevo was applied twice in 2012 trials, a week apart, by foliar spray at the rates of 100 and 300 grams per 100 meters squared (g/100m2). In 2013 two treatments were applied at the rates of 50 and 100 g/100 m2. Each treatment contained 4 replications and the application volume was 200 millilitres /100 m2. Water alone was applied as the untreated control and Decis (deltametrin) or Millenium (Steinernema carpocapsae) as a commercial standard. Average number of chinch bugs (adults and nymphs) per 0.1 m2 was determined in plots to evaluate efficacy of treatments. Turf grass tolerance was determined by a visual estimate of phytotoxicity to the target turf grass at each sampling date when efficacy was evaluated.
Results
Of the 5 trials, the 2 trials conducted in Ontario in 2012 were inconclusive due to extremely dry weather, while the trial conducted in Ontario in 2013 showed a modest reduction in insect numbers of 10-20%, most likely as a result of dry weather conditions which reduced pest pressure.
More promising data were obtained from two trials from Quebec in 2012 and 2013. In 2012, the results from Quebec indicated that Grandevo applied at the rates of 100 and 300 g/100 m2 provided a reduction of hairy chinch bug populations (adults and nymphs) of 66-89.5% during the first 9 days after treatment. In general, no efficacy differences were observed between rates 100 and 300 g/100 m2. In 2013, trials were conducted at rates of 50 and 100 g/100 m2 to validate the efficacy obtained in 2012. In contrast with 2012, analysis of data in the 2013 trial showed that Grandevo applied at the two rates provided significant reduction in hairy chinch bug numbers (adults and nymphs) by between 70-90% in most assessment periods following the two treatments. Both Grandevo treatment rates controlled the chinch bug density below the economic threshold level (less than 15-20 insects per 0.1m2) by the end of trial. No phytotoxicity was observed regardless of product concentrations over the two years of trials. Results also indicated that Grandevo provided comparable or better effectiveness than the commercial standards.
Discussion
The trials in Ontario were inconclusive in both 2012 and 2013 due to a dry weather; however, promising data were obtained from the Quebec trials in both 2012 and 2013. Although rates 50, 100 and 300 g/100 m2 all significantly suppressed the pest, there was no statistical difference between 100 and 300 g/100 m2. Data generated through these field trials will support a regulatory submission for registration of Grandevo® for use in turf in Canada.