SUSCEPTIBILITY OF LOW- AND HIGH-GLUCOSINOLATE OILSEED RAPES TO DAMAGE BY FLEA BEETLES, PHYLLOTRETA SPP. (COLEOPTERA: CHRYSOMELIDAE)

1988 ◽  
Vol 120 (2) ◽  
pp. 195-196 ◽  
Author(s):  
R. J. Lamb

The oilseed rape crop, Brassica napus L. and B. campestris L., has undergone a significant chemical transformation during the last 15 years. Plant breeders produced cultivars with only trace levels of erucic acid in the oil compared with 40-50% in early cultivars, and with 18 μmol/g of glucosinolates or less in the oil-free meal compared with 62-1 15 μmol/g (Daun 1983). The new “Canola” cultivars were developed because erucic acid was a suspected health hazard for humans and glucosinolates caused the meal to be unpalatable or toxic to farm animals.

1997 ◽  
Vol 150 (4) ◽  
pp. 414-419 ◽  
Author(s):  
Jeroen A. Wilmer ◽  
Johannes P.F.G. Helsper ◽  
Linus H.W. van der Plas

1998 ◽  
Vol 17 (1) ◽  
pp. 19-23 ◽  
Author(s):  
J. A. Wilmer ◽  
S. R. Abrams ◽  
J. P. F. G. Helsper ◽  
L. H. W. van der Plas

2019 ◽  
Vol 113 (2) ◽  
pp. 808-813 ◽  
Author(s):  
Ola Lundin

Abstract Flea beetles (Phyllotreta spp.) are major insect pests in spring oilseed rape (SOSR; Brassica napus L.). Prohibited use of three neonicotinoid insecticides in the European Union means that there are currently no insecticide seed treatment options available. Insecticide spraying remains as a control option, but there is a need to estimate the economic threshold for crop injury. As a first step to this end, economic injury levels were determined for flea beetles in SOSR. Data from 16 field experiments were used to quantify the relationship between flea beetle crop injury and SOSR yield, and additional data from paired sprayed and unsprayed plots in 12 commercial SOSR fields were used to determine the reduction in crop injury from a pyrethroid spray. There was a strong linear negative effect of flea beetle injury with 19 kg/ha yield loss per percent crop injury to seedlings and a pyrethroid spray reduced crop injury by 39%. These results gave an economic injury level of 11% defoliation of SOSR seedlings under average oilseed rape prices and insecticide use costs in 2017. This is considerably lower than previously used nominal thresholds of 25–30% injury to cotyledons. Increased yields and increasingly cheaper pyrethroids might be the reason for the lower levels of crop injury that warrant chemical control. The economic injury levels presented here can be used to construct economic thresholds that preferably should also take into account crop growth stage, crop growth rate, and anticipated flea beetle activity.


1990 ◽  
Vol 115 (3) ◽  
pp. 363-368 ◽  
Author(s):  
R. J. Darby ◽  
M. V. Hewitt

SUMMARYAn earlier report of leaf scorch and diminished yield when using large amounts of urea on winter oilseed rape (Brassica napus) was investigated by applying 200 kg N/ha as calcium ammonium nitrate (‘Nitro-chalk’) or urea as a single dressing or divided in six ways. The ‘single-low’ variety Mikado (low in erucic acid) was grown in 1986 and was compared with the ‘double-low’ variety Ariana (low in erucic acid and glucosinolates) in 1987 and 1988. No scorch was seen in these experiments. Yield from rape fertilized with prilled urea was, on average, 98% of that from rape fertilized with ammonium nitrate. The timing and distribution of the fertilizer also had little effect on yield, though yield slightly decreased when part of the dressing was withheld during March. The earlier-maturing variety Mikado always outyielded Ariana except when harvest was delayed by bad weather.When plots were fertilized with urea, the oil content of the seed was a little larger than when fertilized with Nitro-chalk, which compensated for the smaller seed yield, resulting in almost equal oil yield from both forms of N fertilizer. Crude protein content was lower after a large single dose of urea fertilizer but parity with ammonium nitrate was restored by smaller amounts applied on a number of occasions. Neither form nor timing of N fertilizer had any consistent effect on the total glucosinolate content.The incidence of disease was significantly greater in rape given either form of N fertilizer than where none was given, but when downy mildew (Peronospora parasitica) was prevalent on pods there was significantly less infection in plots fertilized with urea than with ammonium nitrate.


2020 ◽  
Vol 21 (22) ◽  
pp. 8740
Author(s):  
Daria Chlebek ◽  
Artur Pinski ◽  
Joanna Żur ◽  
Justyna Michalska ◽  
Katarzyna Hupert-Kocurek

Endophytic bacteria hold tremendous potential for use as biocontrol agents. Our study aimed to investigate the biocontrol activity of Pseudomonas fluorescens BRZ63, a new endophyte of oilseed rape (Brassica napus L.) against Rhizoctonia solani W70, Colletotrichum dematium K, Sclerotinia sclerotiorum K2291, and Fusarium avenaceum. In addition, features crucial for biocontrol, plant growth promotion, and colonization were assessed and linked with the genome sequences. The in vitro tests showed that BRZ63 significantly inhibited the mycelium growth of all tested pathogens and stimulated germination and growth of oilseed rape seedlings treated with fungal pathogens. The BRZ63 strain can benefit plants by producing biosurfactants, siderophores, indole-3-acetic acid (IAA), 1-aminocyclopropane-1-carboxylate (ACC) deaminase, and ammonia as well as phosphate solubilization. The abilities of exopolysaccharide production, autoaggregation, and biofilm formation additionally underline its potential to plant colonization and hence biocontrol. The effective colonization properties of the BRZ63 strain were confirmed by microscopy observations of EGFP-expressing cells colonizing the root surface and epidermal cells of Arabidopsis thaliana Col-0. Genome mining identified many genes related to the biocontrol process, such as transporters, siderophores, and other secondary metabolites. All analyses revealed that the BRZ63 strain is an excellent endophytic candidate for biocontrol of various plant pathogens and plant growth promotion.


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