Evaluation of Naturalis-L for the management of tarnished plant bug in strawberries

Project Code BPR12-020

Project Lead

Markus Clodius Agriculture and Agri-Food Canada

Debra Moreau Agriculture and Agri-Food Canada

Objective

To develop efficacy and crop tolerance data in support of a regulatory submission for Naturalis L (Beauveria bassiana strain ATCC 74040) for the management of tarnished plant bug (Lygus lineolaris) in strawberry 

Summary of Results

In Canada approximately 24,521 metric tonnes of strawberry are produced annually with a farm gate value of $53 million. During the 2011 Biopesticides Priority Setting workshop Naturalis L was selected as the priority biopesticide solution for the management of tarnished plant bug (TPB) (Lygus lineolaris) in strawberry, which is a major concern for strawberry growers across Canada. The adult and nymph stages of the insect feed on all parts of the plant, resulting in unmarketable fruit and significant yield losses.

A potential biopesticide solution to this issue is Naturalis-L, an entomopathogenic biopesticide that has been developed by Troy Corporation. This product works through a pathogenic mode of action, where the germinating conidia of B. bassiana infect and kill the targeted insect. Three field trials were conducted in Kentville, Nova Scotia, and Agassiz, British Columbia to determine the value of this product for management of TPB damage.

The Pesticide Risk Reduction Program is currently providing regulatory support to the registrant to facilitate the submission of a quality data package for the first time registration of Naturalis L in Canada, and data from this project will be included in the initial Canadian submission.

Approaches

Three efficacy trials were conducted on strawberries in British Columbia and Nova Scotia in 2012. The trials were laid out in a randomized complete block (RCB) design, with 4 replicates of each treatment and a plot size of 36 m2 (6 rows).

To estimate TPB populations, monitoring first began when plants were in bloom, and treatments began before economic thresholds were reached. Treatments were repeated every 3-5 days depending on the trial, for a total of 2-3 treatments. A commercial standard, Ripcord 400 EC was also tested for comparison. Evaluation of treatment effect was assessed using tapping and/or sweep net methods and counting the number of TPB nymphs and adults. Visual assessment of the sampling area, within each plot, was also done to note any impact of sprays on non-target organisms (e.g. beneficials and pollinators). Crop tolerance was assessed by visually inspecting plants at each pest assessment. At the time of the final harvest, marketable fruit was randomly collected from individual plots, weighed, and fruit yield recorded. Individual fruits were visually assessed for evidence of injury associated with TPB feeding.

Results

Results showed that despite there being no statistically significant difference between Naturalis-L and the controls, TPB numbers were often lower in Naturalis-L plots in comparison to those observed within plots sprayed with water. Surmising that plot size and sampling area may have been too small to accurately assess representative pest pressure specific to a given treatment, results from this trial support Naturalis-L as a potential control agent against TPB nymphs on strawberries.

The data generated in this project is complemented by other data sources and a value package has been developed for inclusion in the registration submission for this product. The Pesticide Risk Reduction program currently is working through its regulatory support team with the registrant toward finalizing the first time registration of this promising product in Canada.

 

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