scholarly journals Economic Injury Levels for Flea Beetles (Phyllotreta spp.; Coleoptera: Chrysomelidae) in Spring Oilseed Rape (Brassica napus; Brassicales: Brassicaceae)

2019 ◽  
Vol 113 (2) ◽  
pp. 808-813 ◽  
Author(s):  
Ola Lundin
Keyword(s):  
Brassica Napus ◽  
Oilseed Rape ◽  
Field Experiments ◽  
Flea Beetle ◽  
Crop Growth ◽  
The European Union ◽  
Economic Injury Level ◽  
Flea Beetles ◽  
Crop Injury ◽  
Economic Injury

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.

When is fall feeding by flea beetles (Phyllotreta spp., Coleoptera: Chrysomelidae) on canola (Brassica napus L.) a problem?

2012 ◽  
Vol 92 (1) ◽  
pp. 97-107
Author(s):  
Juliana J. Soroka ◽  
Larry F. Grenkow
Keyword(s):  
Brassica Napus ◽  
Field Experiments ◽  
Flea Beetle ◽  
Brassica Napus L ◽  
Late Season ◽  
The Third ◽  
Flea Beetles ◽  
Seeding Date ◽  
Seed Yields

Soroka, J. J. and L. F. Grenkow. 2012. When is fall feeding by flea beetles ( Phyllotreta spp., Coleoptera: Chrysomelidae) on canola ( Brassica napus L.) a problem? Can. J. Plant Sci. 92: 97–107. Two cultivars of Brassica napus canola were seeded in mid-May and early June in three field experiments in each of 3 yr near Saskatoon, Saskatchewan, to determine the effects of late-season flea beetle feeding on seed yields. In the first experiment, canola was sprayed with insecticide late in the summer to eliminate naturally-infesting flea beetles. In the second, 1×1×1.5 m screen cages were placed over early- and late-seeded canola at flowering and infested with flea beetles as canola matured. In the third investigation, sleeve cages were placed over individual plants and infested with 100 flea beetles. Flea beetles had no detrimental effects on early-seeded canola in any experiment, but did affect seed yields of late-seeded plots in some trials. Over two cultivars in 1 year, late-seeded plants in cube cages infested with about 350 flea beetles per plant when lower pods were turning from translucent to green in colour reduced yield by 241 kg ha−1 over control yields. Seed weights in these late-seeded plots were decreased from 2.68 g per 1000 seeds in uninfested cages to 2.44 g per 1000 seeds in infested cages. Populations of 100 flea beetles per plant in sleeve cages had no effect on harvest parameters in any seeding date or year.

The long-term persistence of seeds of oilseed rape (Brassica napus) in arable fields

2003 ◽  
Vol 141 (2) ◽  
pp. 231-240 ◽  
Author(s):  
P. J. W. LUTMAN ◽  
S. E. FREEMAN ◽  
C. PEKRUN
Keyword(s):  
Brassica Napus ◽  
Oilseed Rape ◽  
Field Experiments ◽  
Petri Dish ◽  
Initial Field ◽  
Seed Loss ◽  
Exponential Decline ◽  
Arable Fields ◽  
Decline Curves

The present paper reports on three sets of experiments exploring the persistence of seeds of oilseed rape (Brassica napus). The first, where known numbers of seeds were buried in September 1991 in two field experiments, demonstrated substantial initial losses of seeds, such that only 0·2 and 3·8% of seeds were still present after 4 months. In these experiments, which were not disturbed by mechanical cultivation, there was little evidence of further decline over the following 13 months. In the second of the two experiments, seeds were then left undisturbed for a further 136 months. A mean of 1·8% of seeds were still present after this period, providing further confirmation of the lack of decline in seed numbers in these undisturbed conditions. In the second pair of experiments, known numbers of seeds of three rape cultivars were broadcast onto plots and then either ploughed into the soil immediately after the start of the experiments, or were exposed to weekly shallow tine cultivation followed by ploughing after 4 weeks. The former created a larger seedbank than the latter. The experiments were then ploughed, annually (Expt 1) or at less frequent intervals (Expt 2); appreciable numbers of seeds survived for 65 months in both. Calculations based on exponential decline curves indicated that 95% seed loss would take 15–39 months, depending on the site, cultivar and initial post-harvest stubble treatment. The third part of the paper is based on more detailed studies of persistence of seeds of six cultivars in Petri dishes and buried in 25 cm pots. This work confirmed that cultivars differed in their persistence, as Apex was confirmed as highly persistent, whereas Rebel was short-lived. There were inconsistencies in the response of cultivar Synergy between the Petri-dish and pot experiment, which need further study. This experiment also reinforced the conclusion of the initial field experiments that little seed loss occurs in the absence of cultivations. Appreciable numbers of rape seeds will persist up to 4 years, in normal cropping conditions and in the absence of cultivation one experiment has confirmed persistence for over 11 years.

scholarly journals Response of Aryloxyphenoxypropionate-Resistant Grain Sorghum to Quizalofop at Various Rates and Application Timings

2012 ◽  
Vol 26 (1) ◽  
pp. 14-18 ◽  
Author(s):  
M. Joy M. Abit ◽  
Kassim Al-Khatib ◽  
Phillip W. Stahlman ◽  
Patrick W. Geier
Keyword(s):  
Growth Stage ◽  
Field Experiments ◽  
Grain Sorghum ◽  
Crop Growth ◽  
Grain Yields ◽  
Crop Injury ◽  
Crop Growth Stage

Conventional grain sorghum is highly susceptible to POST grass control herbicides. Development of aryloxyphenoxypropionate-resistant grain sorghum could provide additional opportunities for POST herbicide grass control in grain sorghum. Field experiments were conducted at Hays and Manhattan, KS, to determine the effect of quizalofop rate and crop growth stage on injury and yield of aryloxyphenoxypropionate-resistant grain sorghum. Quizalofop was applied at 62, 124, 186, and 248 g ai ha−1at sorghum heights of 8 to 10, 15 to 25, and 30 to 38 cm, which corresponded to early POST (EPOST), mid-POST (MPOST), and late POST (LPOST) application timings, respectively. Grain sorghum injury ranged from 0 to 68% at 1 wk after treatment (WAT); by 4 WAT, plants generally recovered from injury. The EPOST and MPOST applications caused 9 to 68% and 2 to 48% injury, respectively, whereas injury from LPOST was 0 to 16%, depending on rate. Crop injury from quizalofop was more prominent at rates higher than the proposed use rate in grain sorghum of 62 g ha−1. Grain yields were similar in treated and nontreated plots; applications of quizalofop at different timings did not reduce yield except when applied MPOST at the Manhattan site.

OBSERVATIONS ON DISTRIBUTION, SEASONAL LIFE HISTORY, AND ABUNDANCE OF FLEA BEETLES (COLEOPTERA: CHRYSOMELIDAE) THAT INFEST RAPE CROPS IN MANITOBA

1979 ◽  
Vol 111 (12) ◽  
pp. 1345-1353 ◽  
Author(s):  
H. G. Wylie
Keyword(s):  
Life History ◽  
Brassica Napus ◽  
Relative Abundance ◽  
Flea Beetle ◽  
Phyllotreta Cruciferae ◽  
Main Species ◽  
Phyllotreta Striolata ◽  
Flea Beetles ◽  
History Of

AbstractPhyllotreta cruciferae (Goeze) was usually the most abundant flea beetle on crops of Argentine rape, Brassica napus L., in Manitoba, followed in order by Phyllotreta striolata (F.) and Psylliodes punctulata Melsh. These three species and small numbers of Phyllotreta bipustulata (F.) were present on volunteer rape in the spring. A few specimens of a fifth rape-eating species, Phyllotreta robusta Lee, were trapped in April after hibernating. The three main species were recorded in all 16 localities in which samples of flea beetles on rape crops and/or volunteer rape were collected. Details of seasonal life history of each species are presented, as well as data on the abundance of the three main species throughout the year on rape crops, in overwintering habitats and on volunteer rape in spring. The relative abundance of P. cruciferae, P. striolata, and Ps. punctulata in different rape-growing areas of Manitoba is discussed.

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
Keyword(s):  
Brassica Napus ◽  
Erucic Acid ◽  
Chemical Transformation ◽  
Oilseed Rape ◽  
Health Hazard ◽  
Farm Animals ◽  
Flea Beetles ◽  
Significant Chemical

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.

Segregation of Triazine-Resistant Chloroplasts after Introduction into Winter Type Oilseed Rape (Brassica napus L.) by Protoplast Fusion

1990 ◽  
Vol 45 (5) ◽  
pp. 478-481
Author(s):  
R. Hain ◽  
J. E. Thomzik
Keyword(s):  
Brassica Napus ◽  
Plant Growth ◽  
Protoplast Fusion ◽  
Oilseed Rape ◽  
Field Experiments ◽  
Rflp Analysis ◽  
Winter Oilseed Rape ◽  
Brassica Napus L ◽  
X Irradiation ◽  
Spring Type

Abstract Triazine-resistant chloroplasts of the Canadian spring oilseed rape variety OAC Triton were transferred into four German winter oilseed rape lines and two cultivars of double-low quality by means of protoplast fusion. X-irradiation has been used to reduce the amount of nuclear D N A of the spring type cultivar and to promote cybrid formation. RFLP-analysis showed that some regenerants and their progeny carried both types of chloroplasts. In some instances regenerants and progeny containing mixtures of both chloroplasts not kept under selective conditions lost their triazine-resistant chloroplasts completely during further plant growth. Preliminary results of greenhouse and field experiments indicate that volunteer plants can be eliminated by application of 150-300 g/ha metribuzin (SencorR, Bayer AG) in a stand of triazine-resistant oilseed rape of double-low quality.

Influence of seed size in canola, Brassica napus L. and mustard, Sinapis alba L., on seedling resistance against flea beetles, Phyllotreta cruciferae (Goeze)

1991 ◽  
Vol 71 (2) ◽  
pp. 397-404 ◽  
Author(s):  
R. P. Bodnaryk ◽  
R. J. Lamb
Keyword(s):  
Brassica Napus ◽  
Seed Size ◽  
Seedling Survival ◽  
Flea Beetle ◽  
Sinapis Alba ◽  
Brassica Napus L ◽  
Seedling Resistance ◽  
Phyllotreta Cruciferae ◽  
Flea Beetles ◽  
Sinapis Alba L

Seedlings of Brassica napus L. 'Westar' or Sinapis alba L. 'Ochre' grown from seeds of various size were offered to flea beetles, Phyllotreta cruciferae (Goeze) in feeding tests for damage assessment. The proportion of cotyledon area damaged in both species was highest for seedlings grown from small seeds in choice and no-choice feeding tests. The proportion of seedlings killed by flea beetle feeding was also highest in seedlings from small seeds, an effect that was especially pronounced at high beetle densities (10/seedling) where 100% of seedlings from small seeds of B. napus were killed compared to 28.3% of seedlings from big seeds. For S. alba, at 20 beetles/seedling, 45.4% of seedlings from small seeds were killed compared to only 9.1% of seedlings from big seeds. Seedlings grown from big seeds of S. alba tolerated low levels of damage caused by flea beetle feeding or by scissors. No evidence for tolerance was obtained for seedlings from small seeds of S. alba or for seedlings from big or small seeds of B. napus. "Big seeds" appears to be a desirable trait that enhances crucifer seedling resistance to flea beetle attack and results in increased seedling survival. Key words: Brassica napus 'Westar', Sinapis alba 'Ochre', Phyllotreta cruciferae, flea beetle, seed size, resistance

Sign in / Sign up

Export Citation Format

Share Document