Elliott: Reduced Pesticide Inputs for Flea Beetle Control in Canola and Mustard

Date: March 2000
Term: 3 years
Status: Completed
Researcher(s): Dr. Robert H. Elliott, Dr. M. Robinson, Dr. L. W. Manna and Dr. G. F. W. Rakow, Agriculture and Agri-Food Canada (AAFC), Saskatoon
SaskCanola Investment: n/a
Total Project Cost: n/a
Funding Partners: ACPC, Federal Matching Investment Initiative

Project Summary

A three-year study was conducted to evaluate the resistance and tolerance of mustard, rapeseed and canola lines to the crucifer flea beetle, Phyllotreta cruciferae, and identify lines with superior agronomic attributes including seedling establishment, plant growth and seed yield. The results indicated that lines of Sinapis alba and Brassica carinata had the highest resistance to flea beetles, whereas lines of B. juncea and B. rapa had the lowest resistance. The lines of S. alba were also the most tolerant to flea beetle damage, whereas lines of B. juncea and B. rapa were the least tolerant to damage.

The crucifer flea beetle, Phyllotreta cruciferae, is a serious pest of canola and mustard in western Canada. After overwintering in non-crop areas, adults migrate into commercial fields and feed on the cotyledons, true leaves and stems of young seedlings. Feeding damage results in seedling mortality, reduced seedling growth, delayed crop development, uneven maturity and lower seed yields or grade.

Crop rotation and biological agents provide limited regulation of flea beetle populations so most producers are dependent on several methods of chemical control, which are costly economically and may pose hazards to applicators or non-target species. Host plant resistance has been proposed as an alternative to chemical control of flea beetles. Previous studies have shown that lines of mustard, rapeseed and canola differ in their attractiveness or palatability to flea beetles, tolerance to flea beetle damage and growth attributes.

Researchers conducted a three-year laboratory and field study in 1995, 1996 and 1997 at the AAFC Research Farm at Saskatoon on nearly 40 lines of Sinapis alba (yellow mustard), Brassica carinata (Ethiopian mustard). B. juncea (oriental and brown mustard), B. rapa (Polish canola) and B. napus (Argentine canola). The objectives of this study were to evaluate the resistance and tolerance of mustard, rapeseed and canola lines to the crucifer flea beetle, and identify lines with superior agronomic attributes including seedling establishment, growth rates and seed yield. Entries were selected on the bases of breeding type, morphological traits, resistance to blackleg and glucosinolate content of the seed.

Flea beetle damage and agronomic attributes of each species varied significantly from year to year. Flea beetle damage was, on average, 10-30% lower in 1995 than in 1996 or 1997. Dry conditions during May and early June limited seedling establishment in 1995, whereas moderate to very high flea beetle damage reduced seedling growth in 1996 and 1997.

Seedling survival, which as been used to evaluate the susceptibility and tolerance of seedlings to flea beetle damage, varied significantly among species. The study results indicated that lines of S. alba and B. carinata had the highest resistance to flea beetles, whereas lines of B. juncea and B. rapa had the lowest resistance to flea beetles. Lines of

S. alba were also the most tolerant to flea beetle damage, whereas lines of B. juncea and

B. rapa were the least tolerant to damage. However, seed yields were similar in S. alba,

B. juncea and B. napus. Yields indicated that B. juncea and B. napus were able to compensate for damage later in development. B. carinata had the highest seed yield indicating that plants were also able to compensate for flea beetle damage during reproductive growth. In each species, lines with superior seedling establishment, growth rate and tolerance to flea beetles usually had the highest seed yield.

Scientific Publications

Elliott, B. (2002). Antixenosis and tolerance of Brassica cultivars to flea beetles – an historical perspective. Invited presentation and abstract for symposium on Crops as New Habitats for Insects: Canola as a Case Study. Proceedings of the Joint Annual Meeting of the Entomological Society of Canada and Manitoba. Winnipeg. October 2002.

Full Report PDF: Reduced Pesticide Inputs for Flea Beetle Control in Canola and Mustard